Naval Architect & his Profession

The Future of Shipping Industry - Nuclear Ship Propulsion

2012-01-21T04:59:00.000-08:00

Marine industry, like other fuel dependent enterprises, faces a danger of fuel shortage. At present fossil fuels feature at top on list of fuels used in this industry. Of these, diesel is the one used most frequently under various names such as gas oil, marine gas oil (DMX, DMB), intermediate fuel oil (IFO), residual fuel oil (RMA, RML) etc.

But they are under immediate danger of exhaustion. In this scenario, marine nuclear propulsion steps in as the savior. However, how much can the shipping industry rely on this new technology?

What is nuclear marine propulsion?

For those who don’t know much about it, nuclear marine propulsion refers to use of nuclear energy for purpose of propulsion of ships. It makes use of a nuclear reactor where a nuclear reaction can be carried out under controlled conditions. Such reaction produces immense energy which can be tapped and used to power anything from small vessels to a cruise ship.

The nuclear reaction carried out is a fission reaction wherein a heavier molecule splits into smaller ones producing energy along with the products. This energy produced is mainly used to heat water that can be further used to produce steam for the purpose of nuclear ship propulsion.

Status of nuclear marine propulsion

Use of nuclear ships is increasing gradually though this idea has been present for long. Nuclear reactions have been used to produce energy for other commercial purposes mainly electricity production for some time now. But idea of marine propulsion using this energy was proposed somewhere in 1940s when the first design for a nuclear marine propulsion engine was made. Since then, nuclear ships have become designed and used. Right now, the marine propulsion dependent on nuclear energy is found mainly in armed forces and navy but soon commercial and domestic nuclear ships will also become just as common.

Mostly merchant cargo ships like American NS Savannah (1962-1972) and German NA Otto Hahn (1968- 1972) or nuclear powered ice breakers have been in use for brief periods. At present, only few ships based on nuclear marine propulsion are in use on experimental basis.

Why is nuclear marine propulsion a good idea?

Amongst all the speculations and standing doubts about use of marine propulsion system based on nuclear energy, there are some key factors that make this a good idea, whatever way you look at it.

In the current scenario of extreme fuel shortage, nuclear ships are the answer that everyone has been looking for. Energy produced from nuclear reactions is immense which can be used easily.

Since amount of energy produced in every reaction is quite large, a single time energy production can be used for a propulsion ship for a long time. Nuclear ships offer a refilling solution of as less as once a month. This could make shipping a speedy and hassle free process.

A nuclear reactor is designed to produce energy under controlled conditions. It is compact and can be moved around easily. So apprehensions about practicality of a nuclear reactor on ships, boats and vessels can be put to a rest.

Nuclear military ships like submarines can survive for months underwater without feeling the need to resurface for refueling. This can make combative forces much more efficient.

Fuel efficiency of nuclear propulsion engines is more than most of the fuels currently in use. This means that amount of energy derived from nuclear reactions per unit weight is more than any other fuel.

The better power to weight ratio means that nuclear ships can have better weight carrying capacity than other ships, offering quicker traveling over longer distances with greater load.

Nuclear ships tackle problem of air pollution too as there is no production of undesirable smoke or particular pollutants that have become a menace all over the world.

Why can’t we trust this technology much right now?

The picture of a nuclear energy powered propulsion ship seems very rosy. However, there is a downside with this whole scenario. Some of the points not so good with this technology are:

Nuclear reactions produce immense energy, which if not controlled can lead to disastrous results. As such, even a minor fault can lead to accidents with massive implications all over the world.

Most apprehensions lie with use of something as dynamic as nuclear energy on ships which can be occupied by thousands of people at sometimes.

In case of accidents of nuclear ships, there is a huge chance of contamination of water bodies with nuclear fuels that can damage marine life and human population both. During the brief usage of such ships, the number of accidents due to minor technical faults has been proportionately large.

Due to the need for ships to travel across the world, there is a need for nuclear reactors to be able to bear that sort of wear and tear. The nuclear reactor should be secured to prevent its undesirable movement on the ship.

The major problem faced by every nuclear ship would be of disposal of nuclear waste. With increasing use of nuclear fuel all over the world, there is an increasing stack of nuclear waste that humans are still struggling to dispose of. In absence of a practical solution to dispose of excessive amount of nuclear wastes that will be produced due to such ships, there could be more problems in long run.

At last, one major apprehension with this energy is its political and moral implications. There will always be fear of this energy being misused which remains one of the major political reasons to be cautious about this energy.

There is a future in nuclear energy for marine propulsion but still there is a long way to go before we can see a fully fledged ship running on nuclear marine propulsion system.

Submarine Escape Technology

2011-11-07T09:00:00.000-08:00

With the loss of all hands aboard the S-4 in 1927 came an interest in the possibility of escaping from a sunken submarine. Lieutenant Swede Momsen together with several others designed an oblong, rubber bag that recycled exhaled air. It had a container or soda lime, which removed carbon dioxide from exhaust air and a charge of fresh air from the 225 pound system common to submarines of the time. The "lung" was strapped around the neck and chest and the escaping submariner breathed normally as he made a slow ascent up a line to a buoy on the surface.

Training on the device was wide-spread with hundred foot ascent towers in New London and Pearl Harbor. The short-coming of the device was its shallow depth limit. The Lung was good down to about one hundred feet, but a test depths of submarines at the time was over four hundred feet.

The Momsen Lung was designed as a vehicle for a one-way trip to the surface of the ocean. This singular quality would be replicated in subsequent devices through the next thirty years.

Momsen also pioneered the use of an escape bell which could be mated to the forward torpedo room hatch of a fleet type submarine. The bell was used in the rescue of submariners from the USS Squalus which had gone down from a main induction mishap off the coast of New Hampshire.

During the 1960's the British worked on a series of escape mechanisms. They simultaneously investigated compartment escapes and lock-out systems.

The former roughly equated to an escape from the after torpedo room of an American fleet type boat where a sleeve in the deck hatch was reversed and bolted in place. By partially flooding, then pressurizing the compartment with the 225 pound air system crew members could duck under the lip of the sleeve and get to the surface. The latter was equivalent to the escape trunk in the forward torpedo room of a fleet type boat where the same procedure could be replicated in successive four man escapes.

The British air lock system combined with a method of quick ascent called blow-and-go was successful down to depths of two hundred sixty feet. It should be noted that Germans had made many successful escapes using blow-and-go by riding a bubble or bubble mass to the surface. The British developed a Built-In-Breathing-System hood which was tested down to four hundred fifty feet in laboratory conditions. The rate of ascent was six feet per second with fifty second stops at five intervals.

Attempts to reproduce the laboratory ascents found that the system was good to only two hundred sixty feet, the same as the Blow-and-Go. The BIBS was improved to include an immersion suit which significantly increased the viability of free ascents down to about three hundred feet. They have concluded that ascents from depths below about three hundred fifty feet are too dangerous to attempt by marginally trained crew members.

During the 1960s the United States developed the Stienke Hood (Variously misspelled Steinke and Stenke). The free ascent device consisted of a plastic hood which, when partially charged with treated air, provided four hundred fifty one pounds of buoyancy. As the ascent progressed the crew member breathed the expanding air and excess air was discharged from the hood automatically. Once again the limit of this device was less than many test depths of submarines during the same period.

As test depths increased down to 2000 feet and as operational depths of modern nuclear powered boats out-distanced free ascent methodology the Navy adopted Submersible Emergency Inflation Suits or SEIS. These replicated the British technology and are currently carried aboard modern submarines. However, the gap between operational depths and recoverable depths meant that greater reliance had to be placed in a rescue vehicle that could dive to the stricken submarine, be attached to deck hatches and carry crew members to the surface. Successive dives can be made using this system and the depths at which rescues can be made equal that of the submarine's test depth.

The most significant problem facing the rescue vehicle approach is the tricky job of aligning the vehicle to the hull hatch. Angles-of-lie aggravate the problem and it is here that a new hard suit is of value. The Hardsuit 2000, an Atmospheric Diving System built by a Vancouver, Canada firm allows descents by divers down to 2000 feet. The system can be either umbilicaled to a surface ship or carried as a back pack for free descents. The ADS allows hoses for air, power and fluids to be run to a stricken submarine at hitherto impossible depths. Additionally, the ADS assists in the coupling of ROVS to deck hatches.

Not only does hardware continue to be developed for rescue of crew members at great depths, international submarine rescue seminars have become a bi-annual event with nearly every submarine possessing nation participating.

Submarine Hull Strength

2011-11-07T08:55:00.000-08:00

The following excerpt is from the hull strength introductory chapter of "Steep Angles and Deep Dives". It provides some basic information on submarine hull strength including the definition of test depth and high yield:

Test depth is a theoretical number corresponding to the amount of area pressure that can be applied to a hull before it is violated by either distortion, warping, buckling or cracking. The pressure hull acts to prevent an equalization of pressure on both sides of the hull surface. When pressure is equal on both sides of a hull, such as is the case in a submarine's external ballast tanks, there is no need to attend to the problem of potential collapse.

Test depth can be thought of as an engineering estimate of what pressure will be required on one side of a hull to breach the hull, taking into account such factors of hull strength as hull diameter, hull thickness, framing, and intrusions. Naval engineers tend to be conservative in their estimates and the varied factors tend to render an estimate as just that, an estimate. The engineers back into the problem by first estimating the crush depth of a hull, then creating the theoretical test depth by a applying a decimal factor to the crush depth. Different national navies apply varying factors. The United States Navy has used a factor of 1.5, but this has changed many times. Of course, computers are able to make such estimates much more trust-worthy, however, the accounts described "Steep Angles and Deep Dives" are, for the most part, in hulls designed before the advent of the computer.

In the American Navy, hull designers depend on the experience of submarines to verify their estimates. Buships requires a submarine captain to immediately notify both Buships and the Chief of Naval Operations in writing when a boat under his command exceeds test depth. The captain's professional career may be jeopardized by a zealous attention to recording a dive that went wrong. Only in wartime can a captain reasonably explain the need to exceed test depth. For this reason submarines exceeding test depth sometimes fail to make note of the dive in their deck logs.

The simplest application of determining hull strength is the hull thickness. The thicker the hull metal the stronger the hull and the deeper the test depth, assuming all other factors are constant. Prior to the Balao class U.S. submarine, hulls were built of mild steel (MS) which had a maximum tensile strength of 60,000 pounds per square inch and a yield strength of 45,000 psi with 23 percent elongation. The thickness of hull plating until about 1943 was specified in terms of the weight of a square foot of plate rather than the actual thickness, and this was gradually increased from 20 pound plate (approximately one half inch) to twenty seven and a half pounds per square inch in the Salmon (SS-182).

Another change in the Balao class was the change in material used for hulls. High tensile steel was a chromium-vanadium alloy with a maximum tensile strength of 50,000 psi with 20 percent elongation. When the composition was changed to titanium-manganese alloy, because of wartime shortages, the strength dropped to 45,000 psi. The Salmon's hull was about seven eighths of an inch thick giving her a test depth of 250 feet. Conning tower shells were thicker as protection against surface guns.

The thick-skinned boats came along in 1942 with a test depth of 412 feet. These boats had the same seven eighths inch thick hull as Salmon, but the quality of hull steel ie., high tensile strength steel had significantly improved. The crush depth of these boats was estimated to be around 450 feet. Fleet type submarines built during the Second World War were to last through much of the cold war. These boats have careers that have lasted over fifty years with many still being used by foreign navies.

After the war the Navy built several fast attack submarines. These had hulls about an inch and a half thick. They had a test depth of 700 feet. The same hull thickness and quality of steel was used on the early nuclear submarines.

A modern nuclear powered submarine normally has a test depth of over 2000 feet. This huge increase in operational depth came about from increasing the thickness of a hull, from strides in improving the quality of steel, from improvements in the manufacturing process and in hull framing.

Steel is an alloy made up of several metals other than iron. These may include chromium, nickel, manganese, titanium and a host of others. Metallurgy is the science of combining these elements to produce an iron metal that meets a specific need, in this case a hull which is resistant to sea pressure. During the Second World War Krupp of Germany and others used advanced techniques to produce hull plating of unusually high quality. America inherited some of the formulae and steel mills benefited by the German experience.

The key to producing metal hulls suitable to deep diving submarines is the quality of yield strength in combination with compression strength. Accurately controlled element content and relatively high percentages of alloy additives produces strength. The compression strength curve is relatively flat until it reaches a point where the molecules can no longer bind, then the metal fails by cracking and splitting. On the other hand it is possible to produce a metal hull that has the quality of bending rather than rupturing. It yields under pressure where its elasticity, (elongation) gradually succumbs to increasing pressure. The trick for the metallurgist is to strike a compromise and to use the correct ratio of alloy elements to gain a hull plate that resists pressure to the maximum through high compression strength, but yields enough to forestall the rupturing of the metal.

Steel strength is often measured by tensile strength. In this test the metal is pulled on both ends until it parts. Tensile strength is related to compression strength even though the tests are opposite, one pulling and the other pushing. For this reason submarine steel strength is often measured in tensile strength, not withstanding the nature of sea pressure as a compression force.

American submarines such as the Seawolf and Virginia use HY (high yield) 100 metals. These designators attend to the elements used in the submarine hull's alloy where essentially the higher the number the more resilient and resistant the metal is to pressure.

The combination of elements to produce an alloy with great strength is only half the story of producing submarine hulls. The second factor in the manufacturing process is the tempering of the steel and shaping of the plates into a final form. Once again, the basic concept is that a slow-cooling steel tends to be resilient and a quick cooling steel tends to be brittle. Metallurgists in the middle ages learned this early on and after shaping a red hot sword on an anvil plunged it into water. This gave the sword a fine cutting edge resistant to chipping and dulling. The down side was that when struck by another sword it tended to shatter rather than yield. Thus, a submarine's hull plating is cooled at a specific rate designed to produce the best combination of stress and yield factors.

The shaping of the plate in the factory is accomplished with huge hydraulic rollers. The shaping process is also a compromise. Some alloys are cold rolled. This is the optimum in terms of preserving the alloy's strength in the shaping process, however, as the thickness of the plate increases the effect of the rolling becomes less and less. The modern mill now uses computers to cold roll submarine hull plates. Each pass through the rollers bends the steel a small amount until after many ( in some cases hundreds) of such passes through the rollers the plate conforms to the correct hull curvature.

In determining the diameter of the pressure hull the engineer takes into account the metal thickness that will be required to meet a given strength level. The less the diameter the thinner the metal can be. The size of machinery largely determines the diameters of submarines. As the design of the submarine progresses the diameter of the hull inevitably increases. (Modern Trident missile submarines have a forty three foot diameter pressure hull) This necessitates a thicker hull where the alloys used and the shaping process are constant. Once again, the hull design process is one of compromise where interplaying factors are balanced against one another until a final design with an estimate of test depth is reached.

The curved plates of metal to make up the submarine's hull are further strengthened by frames. Lateral framing was known to the Vikings, although they started with a hull shape and only after the strakes had been laid did they imbed the frames into the preformed hull. Submarine hull strength is in large part a function of frame strength and spacing. Cross sections of frames are normally "T" shaped and can be within the pressure hull, on the exterior of the pressure hull, or both. The externally braced hull was the standard in submarine design, because piping and conduit cannot penetrate frames without compromising strength. With modern welding techniques it has been possible to grip the hull plate to the frame with such force that external framing is successful.

The distance between frames is crucial to determining test depth since this distance is where a compressed hull will yield or fail. The distance is a design function taking into account the factors described in this section.

The cylinder is the optimal shape for a submarine hull. A sphere is better still, however, the shape of a sphere does not accommodate a moving vessel through water. Only in experimental and exploration vehicles is the spherical hull shape used. A submarine is in essence, a long cylinder, made up of many sections welded together.

The tapered ends of the fleet type submarine (forward torpedo room and after torpedo room) called for innovation since the cylindrical form had to be compromised. These compartments were flattened for hydrodynamic reasons. Fleet type boats had exterior framing, however, in these end compartments the frames were interior as well as exterior. The deviation from circularity although small, produced a bending moment putting the shell plating under compression and the face plate of the frame under tension. Thus, the mass-produced fleet type boats had framing partly on the inside and partly on the outside of the pressure hull.

Three dimensional curvature for modern hemispherical bows require conical shaping, and tapered hull plating that in turn requires extensive welding.

The welding of the many plates and commensurate framing necessitates the greatest care. The weld seam must have the same strength as the abutting hull plates. This means that if welding is accomplished by hand the welder must be of the highest technical competence. Although a submarine may be similar to others in its class each is essentially hand built. Automation is limited, but computerization is extensive.

Hull butting is exact. Each cylindrical hull section must precisely match the adjoining section. Each cylindrical section has its edges ground to an approximate forty five degree knife edge. When two sections are mated the two edges form a trough. Actually, there are two troughs, one on the inside of the cylinder and the other on the outside. The welder (or machine) places the first bead at the deepest point of the trough. The next weld layer is placed on top of the deeper layer. As the process continues and the wedge shaped trough widens, more and more beads are placed side by side to fill the trough. Many hundreds of beads are required to bring the level of beading to the surface of the abutting hull sections. It is a long and tedious job and quality inspections are constant.

Unfortunately, a perfect cylindrical hull with precise welding and engineered frame spacing must be punctured to allow various pipes, coaxial cables and rotating shafts access to the exterior of the hull. Wherever such a hull opening occurs the hull must be reinforced by building up the thickness of the surrounding area. The larger the opening (such as for hatches) the stronger must be the build-up. Even when every effort is made to compensate for the loss of strength from a hull opening the point of violation will be the point of failure when the hull exceeds test depth.

Time destroys the hull from several directions. The metal itself fatigues over time. Additionally, the sea takes its toll with corrosion eating at the metal. Hull modifications requiring welding, heat the hull and thereby reduce the effectiveness of the initial tempering. Nicks, gouges and scrapes collectively take their toll.

The Fleet Type boat designed and built during the Second World War were subsequently equipped with snorkels and modified into Guppies. These were often given to other nations under various alliances. Many of these boats are still operating as naval units in foreign navies. They are only now being replaced by more recently built boats.

Marine Engineering Courses in India - MARINE ENGINEERING & RESEARCH INSTITUTE (MERI) - KOLKATA

2011-10-16T04:24:00.000-07:00

MARINE ENGINEERING & RESEARCH INSTITUTE (Marine Engineering & Research Institute) Marine Engineering & Research Institute erstwhile Directorate of Marine Engineering Training (DMET), with its Headquarters at Kolkata and branch at Mumbai was established in the year 1949 to impart training to the Marine Engineering Cadets. The headquarters of the Institute is headed by the Director and the branch by the Dy. Director. The Marine Engineering & Research Institute Kolkata conducts 4 year Marine Engineering Course equivalent to Degree course in Marine Engineering. The intake capacity of the above course is 120 per year. Both institutes are fully equipped to impart effective training in all the branches of Marine Engineering. The cadets for admission to Marine Engineering & Research Institute, Kolkata, are selected through a combined all India entrance examination conducted by IITS, all over the country

The Marine Engineering Training in India had its formal beginning in 1927 on board the Training Ship 'T.S. Dufferin" which provided facilities for training both of nautical and engineering merchant navy personnel. The main consideration, when this Training Ship was inaugurated, was mainly to inculcate sea-sense in cadets.

With the country obtaining Independence in 1947, it was realized that the newly independent vast country was in need of a large Merchant Navy. At the same time vast technological changes brought in by the gigantic war efforts of the developed countries during World War II, also showed inadequacy of the training systems. As a result, on the recommendation of

Merchant Navy Officers Training Committee', constituted in 1947, by Govt. of India, immediately after independence, the function of pre-sea training of Marine Engineers was transferred to 'Directorate of Marine Engineering Training' from the year 1949 with its headquarters in Kolkata and a branch at Mumbai.

Marine Engg. Training at MERI, Kolkata has undergone several changes in 70 - decade.
In 1977 / 78, an expert committee nominated by Govt. of India, headed by Prof. Shankarlal recommended certain reorientation in

Course curriculum
Class contact hours
Practical Training / Pattern.

(MHRD accorded approval to graduation certificate issued by the Institution as equivalent to First degree in Marine Engg. with effect from 1982-entry for the purpose of recruitment to the Senior posts and services under Central Govt.)

(The Graduation certificate issued by the Institution also got recognition of The Institution of Engineers (India) as an exempting qualification from their A & B examinations from 1982 onwards.
*Further the course has also got the approval of AICTE.

*In order to meet the IMO requirements for Marine Engineers working on board the ship the training curriculum in this Institute has also been oriented to cover the STCW 95 convention.

*For Quality accreditation the 'System Manual' and the 'Procedure Manual' have already been prepared and the Institute is in the process of getting ISO-9000 certification.

INFRASTRUCTURE :
LAND AREA
33 acres (approx.) at P-19, Taratala Road, Kolkata 700 088.

CLASS ROOMS
4 Nos. which can accommodate 120 cadets & 10 Nos. which can accommodate 40 cadets.

LABORATORY
State of the art laboratories _ Mechanical Lab., Hydraulic Lab., Heat Lab., Electronic Lab., Electrical Lab., Control Lab., Boiler Lab., Computer Lab., Marpol Lab., Fire Fighting Lab., Simulation Lab., Seamanship Lab.

LIBRARY
Facility of full fledged technical library comparable to the very best in the country is available to the candidates in the training center and services available in terms of books, journals, videos and periodicals etc.

WORKSHOP
Fully equipped in-house workshop having Test Rig and working models of ship's machinery and component parts.

HOSTEL
Residence in the hostel is compulsory. Final year cadets are given single seated rooms while junior cadets share accommodation in the hostels. All cadets are required to be members of the joint mess run by the cadets which is subsidised by Grant-in-Aid from the Govt. A cooperative store is run by the cadets for their benefits. All cadets are required to be members of the cooperative store.

UNIFORM
Cadets must wear uniform throughout their period of training. At the commencement of training, articles of uniform as per printed "list of uniform" of this Directorate are to be purchased by the cadet.

DISCIPLINE
High standard of paramilitary type of discipline is maintained in this Institution. All cadets must carefully read and understand the standing orders, rules and regulations etc. and abide by them at all times. The Director reserves the right to impose on a cadet punishment including fine, suspension and dismissal from the training in the event of any breach of discipline.

SCHOLARSHIP
A number of scholarships both on merit and financial conditions of the parents are available to the cadets of MERI.

DEPOSIT
Personal accounts are opened in the name of each cadet at the time of joining the course and are operated throughout his period of training of four years. Yearly statements will be
given to the cadets.

FEES & OTHER EXPENSES
FOR INDIAN CADETS :
Quarterly hostel rent, tuition fees, mess estt. charges etc.
(@Rs. 700/- per month for general cadets and @Rs. 600/- per month
for SC/ST cadets ).

For General cadets - Rs. 2100/- (quarterly).

For SC/ST cadets - Rs. 1800/- (quarterly).
Mess charges (Rs. 1000/- p.m.) for all cadets Rs. 3000/- (quarterly).
Caution money ( one time ) for all cadets Rs. 500/-
Medical & Sports charge ( Rs. 100/- per month) for all cadets
Rs. 300/- (quarterly).
Computer / Internet System charges (Rs. 150/- p.m.) for all cadets
Rs. 450/- (quarterly).
Upkeepment of hostel / hygiene (Rs. 30/- p.m.) for all cadets
Rs. 90/- (quarterly).

FOR FOREIGN CADETS :
Mess estt. and tuition fees etc. U.S. $4000 per annum.
Medical, Sports Charge, Caution U.S. $300 per annum.
money etc.
Mess charges (variable) Same as applicable to Indian cadets.

ENTRY STANDARDS
1. The maximum at entry level :
(I) For general category candidates not to exceed 20 years.
(II) For SC/ST category candidates not to exceed 25 years.

2.The educational standards for entry to this course is a pass in 10+2 school level with Physics, Chemistry and Mathematics and qualify through Joint Entrance Examination conducted by Indian Institute of Technology all over India followed by counseling.

3.Qualified candidates are required to produce a detailed medical report of self from a qualified body during counseling. An appropriate medical board also checks the eye sight in particular and all other aspects in general at the same time. Only successful candidates through both these tests are eligible for admission.

DURATION OF COURSE :

The training curriculum is conducted in eight semesters spread over four years and makes adequate coverage as per International Marine Organizations requirements / regulations.

The course also includes in-depth coverage of various allied engineering topics e.g. Mechanics of Machines, Mechanics of Materials, Advanced Mathematics, Advanced Computer Science, Electronics, Fluid Mechanics etc. so that a passed candidate has adequate reserve to pursue the development and research work in his chosen area, if he so desires.

Extensive further training is given in Physical Exercise, Parade, Housekeeping, Swimming and Outdoor games, under daily routine in order to ensure that every trainee acquires the mental, moral and physical attributes essential for development as Marine Engineer. Every trainee will be issued a Training and Assessment Record Book (TAR) and he is responsible for upkeep and security of the book.

On successful completion of this training program, assessment and examination by the administration, trainees should be competent to carry out safely the watch keeping duties of an engineer officer on board a ship and be fully conversant with the maintenance and operation of machinery and equipment fitted on board a ship.

Campus interview is held every year by different Shipping Companies and all the cadets are absorbed in different Indian and foreign shipping companies. Successful Marine Engineers from this Institute have been manning the ships holding the life line of economy not only of India, but also of many foreign countries.

Contact Person

Shri S.Mukhopadhya, Director
Marine Engineering and Research Institute,
P-19, New Taratalla Road,
Kolkatta - 700 088
Tel No: 033-4014794/76
Fax No:033-4014333
E-Mail:director@merical.ac.in

Web Site : www.merical.ac.in

INDIAN SHIPPING INDUSTRY - SOME FACTS

2011-10-16T04:20:00.001-07:00

Shipping plays an important role in the transport sector of India's economy. Approximately, 90 per cent of the country's trade by volume (70 per cent in terms of value) is moved by sea. India has the largest merchant shipping fleet among the developing countries and ranks 20th amongest the countries with the largest cargo carrying fleet with 8.83 million GT as on 01.06.2008 and the average of the fleet being 18 years. Indian maritime sector facilities not only transportation of national and international cargo but also provides a variety of other services such as cargo handling services, shipbuilding and ship repairing, freight forwarding, lighthouse facilities and training of marine personnel, etc.

Coastal Shipping

Coastal Shipping is an energy-efficient, environment-friendly and economical mode of transport in the Indian transport network and a crucial component for the development of domestic industry and trade. India, with her 7,517 km long costline studded with 13 major ports and 200 non-major ports provides congenial and favourable conditions for the development of this alternate mode of transport.

Aids to Navigation

Since Independence, India has made rapied growth in aids to Marine Navigation. From 17 Lighthouses prior to Independence, the present strength of aids to Navigation consists of 171 Lighthouses, one Lightship, one Loran-C Chain Stations, 59 Racons, 21 Deep Sea Lighted Buoys 01 wreck making and 22 installations under Differential Global Positioning System (DGPS). To cater the needs of light stations in the islands and for maintaining the buoys, the Directorate General of Lighthouses and Lighships is maintaining three launches, one mechanised boad and two large ocean going vessels, M.V. Sagardeep-II ad M.V. Pardeep.

Maritime Training

The Director General of Shipping is responsible for creation of the trained manpower required for the merchant navy fleet of the country. This national obligation is being met through the Government training institutes and a number of other approved training institutes in the private sector. The importance of organised training was recognised in the year 1927 when the Training Ship "Dufferin" was established. Since then many highly skilled Indian seafarers have been trained in India who have earned commendable reputation at home and abroad.

The four training institutes, which were established by the Government are:-

Trainingn Ship 'Chanakya' which conducts
1. Three years B.Sc degree course in Nautical Sciences under the University of Mumbai
2. Pre-Sea training course for Deck Cadets.
Marine Engineering and Research Institute (MERI), Kolkata which conducts four years degree course in Marine Engineering under Jadavpur University.
Marine Engineering & Research Institute (MERI), Mumbai conduct
1. one year Training Marine Engineering Course for graduate Mechnical Engineerings and
2. Three-year B.Sc. degree course in Martime Sciences (polyvalent degree) under the University of Mumbai
LBS College of Advance Maritime Studies & Research, Mumbai, conducts alomst 46 post-sea training courses for serving Marine Officers.

In addition to the above, there are about 124 training institutes in the private sector approved by the Director General of Shipping, imparting pre-sea and post-sea training in various disciplines.

Shipping Corporation of India Limited

The Shipping Corporation of India Ltd (SCI) was formed on 2nd October 1961. The present authorised capital of the Company is Rs. 450 crore and paid up capital is Rs 282.30 crore. The status of SCI has been changed from a private limited company to Public limited from 18 September 1992. The SCI was conferred 'Mini Ratna' status by the Government of India on 24 Feburary 2000. At present, the Government is holding 80.12 per cent of share capital and the balance is held by financial institutions, public and others (NRIs, Corporate Bodies, etc.). SCI signed Memorandum of Understanding with the Ministry of Shipping, Road Transport & Highways, Government of India on 27 March 2008.

On 8th March, 2007, SCI was awarded MOU Excellence Certificate for the year 2004-05 and 2005-06 by the Government of India, Ministry of Heavy Industry and Public Enterprises, Department of Public Enterprises. SCI was the winner of the best international solution award and the third annual HBSC global payments and cash management partnership award, which was posted in Bangaluru on 5th November 2007. The SCI won the "Shipowner/operator of the year 2007" at the seatrade middle east and Indian sub-continental award 2007, held in Dubai in November, 2007 SCI also won the "Shipowner of the year 2007" at Lloyds list Middle east and Indian Sub-continental award, held in Mumbai in November 2007

Cochin Shipyard Limited

Situated in the Western coast of India in the city Cochin, State of Kerla, Cochin Shipyard is the largest shipyard in the country. Incorporated in the year 1972, Cochin Shipyard can build ships upto 1,10,000 DWT and repair ships upto 1,25,000 DWT. The year has built varied types of ships including tankers, bulk carriers, ports crafts, offshore vessels and passenger vessels. The orders executed by CSL in recent past include carriers for M/s Clipper Group, Bahamas, firefighting tugs for M/s ATCO, Saudi Arabia and Platform Supply Vessels for M/s Deep Sea Supplies, Norway.
The yard is also a leading ship-repairer of the country and has repaired more than 1200 ships of all types. These include upgradation of vessels belonging to ONGC, periodical lay up repairs and life extension of ships of Navy and Coast Guard. The yard had been consistently achieving profits for the last several years.

Garden Reach Shipbuilders & Engineers LTD. KOLKATA

The Garden Reach Shipbuilders & Engineers Limited was incorporated as a joint stock company in 1934, under the name M/s Garden Reach Worskhop Limited (GRW). The Government of India acquired the company in 1960. It was renamed as "Garden Reach Shipbuilders & Engineers Limited (GRSE)" on 01 January 1977.
The company builds and repairs warships and auxillary vessels for the Navy and Cost Guard. Its present product range includes corvettes, frigates, fleet tankers, patrol-vessels, fast attack craft, high technology ship brone equipment, portable bailey type steel bridges, turbine pumps for the agricultural sector, Marine Sewage Treatment Plants, Diesel Engines etc. "Mini-Ratna Status Category-I" was conferred on GRSE on 5 September 2006.

Hindustan Shipyard Limited, VISAKHAPATNAM

Hindustan Shipyard Limited (HSL), Visakhapatnam as set up in 1941 in the private sector and was taken over by the Government in 1952. In 1962, the shipyard became a central public sector enterprise. The shipbuilding capacity of the yard is 3.5 pioneer class vessels of 21,500 DWT each. The maximum size of vessel that could be built is 50,000 DWT.
HSL is the first shipbuilding yard in the country which was awarded ISO:9001 certification by Lloyds Register of Quality Assurance, London for international standard of quality assurance. For ship repairs, the yard has facilities such as modern dry dock, wet basin, repair shops, etc., and it can undertake repairs of submarine, tankers adn ships up to 70,000 DWT. HSL has an exclusive offshore platform construction yard capable of constructing two platforms per annum.

Hooghly Dock and Port Engineers Limited, KOLKATA

Hooghly Dock and Port Engineers Limited (HDPEL), Kolkata became a Central Publi Sector Undertaking in 1984. The company has two working units in Howrah District of West Bengal, one at Salkia and another at Nazirgunge. The installed capacity in shipbuilding is 1,100 tonnes per annum and in ship repairs 125 ships per annum. Apart from a dry dock and a jetty, it has six shipways. The yard is capable of constructing various types of ships (including passenger ships) and other vessels such as dredgers, tugs, floating dry docks, fishing trawlers, supply-cum-support vessels, multi-purpose harbour vessels, lighhouse tender vessels, barges, mooring launches, etc., and undertaking repairs of different types of vessels.

Marine Propellers- Pitch and How to Measure it?

2011-10-16T04:00:00.000-07:00

A propeller can be defined as follows: A mechanical device formed by two or more blades that spin around a shaft and produces a propelling force in ships/boats.

There are various technical terms to define the propeller's characteristics such as: diameter, pitch, disc area relation, hub, bore etc. All these characteristics are calculated to design the optimal propeller accordingly to specific needs of the ship owner and ship characteristics.

In this blog entry, we are going to define what is the propeller pitch and the importance at the time to select it.

Pitch: Is the displacement a propeller makes in a complete spin of 360° degrees. This means that if we have a propeller of 150” pitch it will advance 150 inches for every complete spin as long as this is made in a solid surface; in a liquid enviroment, the propeller will obviously slide with less displacement.

The pitch concept is not exclusive for propellers, other mechanical devices like screws also use it. For instance, a screw with 5 mm of pitch will advance 5 mm for every complete turn when hit by the screwdriver. In fact, the "screw propeller" concept is literally making reference to that the propeller works exactly like a screw.

It is very important that both, pitch and diameter, are properly calculated. If for any given HP the pitch is too big, the propeller becomes heavy and demands more power than the engine can reach and vice-versa, if the pitch is too small then we have a light propeller that wouldn't absorb the engine's full power.

So, what would be the appropriate pitch? Certain parameters need to be checked like power, rpms, gear reduction, size of vessel, vessel application (i.e. a trawler or a tugboat needs power while a yacht requires velocity).

How do you measure propeller pitch

The procedure underlined below will give an approximate method to measure the pitch of a propeller of a boat.

Necessary equipment to perform it:

Protractor (angle measurement)
Level
Plumb Line (not necessary on small props)
Square Set or Squadron (mm, in or ft)
Compass

Procedure :

Equipment

On a leveled surface, make a layout of: a center point, a circle with a diameter equal to the larger propeller hub diameter, and a circle with an approximate diameter that pass through the widest part of the blade to be measured.

Put the propeller with the pitch side up, and center it with the larger diameter previously layout.

Leveled surface

Necessary Layouts

From the diameter that pass through the widest part of the blade, measure the perpendicular heights from the surface to the points located on both sides of the blade on the pitch side, that will serve to find the height differences between these two points.

In this procedure, layout on the surface and over the layout diameter , the two points that will help us to define the projected angle over the surface, which will be measured with the protractor as shown in the picture.

Measuning heights from the layout diameter,
and marking the proyected points

Measured Angle

Finally, with the obtained data, the pitch will be determined with the following formula:

Marine Propellers- Optimum Number of Blades

2011-10-16T03:51:00.000-07:00

The choice of the number of blades is one of the first decisions to be made in the design of a screw propeller.

Marine screw propellers usually have 3, 4 or 5 blades, of which four blades are the most common.

Two-bladed propellers are used on sailing ships with auxiliary power, as they offer the lower resistance when in the sailing condition.

The problem with two-bladed propellers for most vessels is that such propellers require very large diameters to get the blade area required for effective thrust.

Three-bladed propellers have generally proven to be the best compromise between blade area and efficiency.

Four or five-bladed propellers and even more blades are useful for two reasons. First, their extra blades create more total blade area with the same or less diameter. 4 blades propellers, however, would seldom be as efficient as the three-bladed because the closer blades create additional turbulence, literally scrambling up each other's water flow.

Another reason to use more than three blades is to reduce vibration. If a propeller is in the habit of producing annoying, rhythmic thumping and humming, a propeller with more blades will often solve the problem. Every time the blades of the propeller pass under the hull or by the strut, they cause a change in pressure that causes a push. If the push is strong enough, it generates a bang. Lots of rapid bangs equal vibration.

Conclusion: the less number of blades the more efficiency, the higher number of blades the smoothest and uniform performance. This must be always taken in consideration when selecting the proper Diameter, Pitch, Blade Area and Shape.

Marine Propellers- Manufacturing Tolerances

2011-10-16T03:47:00.000-07:00

In the area of the propulsion many applications exist, that they go from crafts of fishing, of pleasure, of load and of speed between many other's.

It's for that reason that a classification of propeller's exists that determine the tolerances that it should have a propeller, according to the necessities of a craft.

The ISO 484/ 2-1981 Norm establishes the tolerances for the production of propeller's in all their geometric dimension. And divide them in the following classes

This norm contemplates all the dimensions of the propeller's like they are: Pitch, Diameter, Chord Length, Rake, Thickness and separation between blades

The norm requests that they are revised the dimensions of certain radios, this according to the type of propeller that is manufactured.

Class	Ratio
S & I	Close to the hub 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.95
II	Close to the hub 0.5, 0.7, 0.9
III	Close to the hub 0.5, 0.7, 0.9

The tolerances in pitch vary between the several classes how it show the following chart.

PITCH	S	I	II	III
Local pitch	± 1.5%	± 2%	± 3%	---
Prom. pitch for ratio	± 1%	± 1.5%	± 2%	± 5%
Prom. pitch for blade	± 0.75%	± 1%	± 1.5%	± 4%
Prom. pitch for propeller	± 0.5%	± 0.75%	± 1%	± 3%

The tolerances for the angular deviation between two serial blades are given according to the following chart.

Class	Angular Tol.
S y I	± 1º
II y III	± 2º

TOLERANCES ON TICKNESS

Clase

III

Max. Tol. with a minimum of

+2%

2mm

+ 2.5%

2.5mm

+4%

4mm

+6%

6mm

Min. Tol. with a minimum of

-1%

-1mm

-1.5%

-1.5mm

-2%

-2mm

-4%

-4mm

TOLERANCES ON RAKE

Class	S	I	II	III
Tolerance	± 0.5%	± 1%	± 1.5%	± 3%

NOTE: Rake is expressed like a percentage of the diameter of the propeller.

TOLERANCES ON THE LENGTH OF THE BLADE SECTIONS

Class

III

Tolerance with a minimum of

± 1.5%

7mm

± 2%

10mm

± 3%

13mm

± 5%

15mm

TOLERANCES IN DIAMETER

Class	S	I	II	III
Tolerance	± 0.2%	± 0.3%	± 0.4%	±0.5%

All the previous tolerances define the geometry of a propeller in accordance with the ISO 484/ 2-1981 Norm.

The same as this norm for the geometry of the propeller exists, the norm is also used SAE-J755 like reference in order to scheme the hub of a propeller.

This contains specified the dimensions of the most common standard bores, the same as the dimensions of the keyway.

These tolerances are those that they are considered in the production of any RICE propeller.

Marine Propellers - What is the best material

2011-10-16T03:45:00.000-07:00

Properties of Bronze for Marine Propellers

COMPARATIVE SERVICE DATA. The superiority of nickel aluminum bronze has been convincingly demonstrated by an in-service test.

One propeller of each material was installed on a 6,000 ton twin screw carrier, which subjects its wheels to unusually severe service by operating on the Orinoco River in Venezuela.

The sand bars and sand in suspension in this river are responsible for damage to the ship’s propellers, needing frequent reconditioning or replacement.

The nickel aluminum bronze (starboard) propeller has suffered little mechanical damage or erosion, while the manganese bronze (port) propeller was rather severely damaged and required frequent repair.

The U.S. Navy is using nickel aluminum bronze material for propellers for ice-breaking service, and after a full season of operation excellent results were noted.

Propeller efficiency. Less obvious perhaps than the data presented in Table 1, but more important from a service standpoint, is propeller efficiency. The design engineers are most impressed by the ability of nickel aluminum bronze to retain its original smooth machined surface over a long period of time, thereby retaining its high efficiency factor. Numerically the improvement in efficiency would lie in the order of 1.5-3.0 per cent, with resultant fuel savings. The exact efficiency increase would depend upon the propeller size, design factors and length of service.

Design Benefit. As nickel aluminum bronze is in itself approximately 10 per cent lighter in weight than manganese bronze, and can be designed to thinner sections because of its higher strength, other advantages become apparent. For example, loading stresses on the tailshaft and bearings are reduce, thus permitting smaller shafts.

Resistance to Notch Sensitivity. The ability of nickel aluminum bronze to resist failure under impact when notched, contributes greatly to its value as a propeller material.

Maintenance. Maintenance of nickel aluminum bronze propellers is greatly reduced compared to that of manganese bze it has superior resistance to bending, breaking and wearing, including cavitation are directly associated with the material properties.

Reparability. Nickel aluminum bronze is readily reparable with the inert gas process, or by direct electric rod welding. Little or no pre-heat is required, and unlike to copper-zinc brasses, it is not subject to stress corrosion cracking and therefore does not necessarily require a stress relief treatment.

Propeller cost. Reduced weight of nickel aluminum bronze in conjunction with increased strength of the material allows designing the propeller approximately 15 % less in weight than a comparable manganese bze propeller. Although the former is more costly by the price per pound, the long term cost reduction is appreciable.

TABLE 1 - TEST RESULTS OF NICKEL ALUMINUM AND MANGANESE BRONZE

Item

Nickel Aluminum Bronze

Manganese Bronze

Chemical composition %

Copper	78 - 81	55 – 60
Zinc	In “all others”	Reminder
Nickel	4.5 - 5.5	-
Iron	3.5 –5.5	0.9 – 2.0
Manganese	0.5 – 1.0	0.3 – 0.9
Aluminum	9.0 – 10.3	0.7 – 1.0
Lead	0.01 max	0.4 max
Tin	In “all others”	1.5 max
All Others	0.5 max	-

Mechanical Properties (Normal Range)

Yield	35 – 43,000 psi	27 – 33,000 psi
Tensile	80 - 95,000 psi	60 - 72,000 psi
% Elong in 2 in	15 – 30	20 – 35
Proof stress	28,000 psi	14 – 16,000 psi
Brinell hardness	152 – 190	112 – 130
Fatigue – air	21 – 25,000 psi	9 – 14,000 psi
Fatigue – salt water	18 – 22,000 psi	9 – 12,500 psi
Density – lb/cu in	0.273	0.297

Spin Test

Weight loss – grams	2.48	9.21
Loss – Mg/in²/day Mg/dm²/day	6.5 99.0	24.0 376.0
In penetration/yr	0.019	0.063
At tip – in	0.005	0.012

Propellers of nickel aluminum bronze

Propellers of manganese bronze

Construction of Marine and Offshore Structures, Third Edition

2011-03-12T22:52:00.000-08:00

Construction of Marine and Offshore Structures, Third Edition
By Jr, Ben C. Gerwick

Publisher: CRC
Number Of Pages: 813
Publication Date: 2007-03-05
ISBN-10 / ASIN: 0849330521
ISBN-13 / EAN: 9780849330520
Binding: Hardcover

Book Description:

For two decades, Ben Gerwick's ability to capture the current state of practice and present it in a straightforward, easily digestible manner has made Construction of Marine and Offshore Structures the reference of choice for modern civil and maritime construction engineers. The third edition of this perennial bestseller continues to be the most modern and authoritative guide in the field. Based on the author's lifetime of experience, the book also incorporates relevant published information from many sources. Updated and expanded to reflect new technologies, methods, and materials, the book includes new information on topics such as liquefaction of loose sediments, scour and erosion, archaeological concerns, high-performance steel, ultra-high-performance concrete, steel H piles, and damage from sabotage and terrorism. It features coverage of LNG terminals and offshore wind and wave energy structures. Clearly, concisely, and accessibly, this book steers you away from the pitfalls and toward the successful implementation of principles that can bring your marine and offshore projects to life.

Summary: The only marine and offshore construction book you need
Rating: 5

This book is FULL of information, interesting, readable, and explanatory. This book takes a long time to get through though, which I suppose is great value. The following are the chapters:

1. Physical Environmental Aspects
2. Geotechnical Aspects (Seafloor)
3. Ecological and Societal Impacts
4. Materials and Fabrication (Structures)
5. Construction Equipment (Vessels)
6. Marine Operations
7. Seafloor Modifications and Improvements
8. Installation of Piles
9. Harbor, River, and Estuary Structures
10. Coastal Structures
11. Steel Jackets
12. Concrete Gravity-Base Structures
13. Other Applications of Offshore Construction Technology
14. Moored Floating Structures
15. Pipeline Installation
16. Plastic and Composite Pipelines, Cables
17. Topside Installation
18. Underwater Repairs
19. Strengthening Existing Structures
20. Removal and Salvage
21. Constructability
22. Deep Sea Construction
23. Arctic Structures

The first three chapters provide excellent background information. Chapters 4-6 are more specific but still general enough to be required reading. The remaining chapters are for you to choose which are most applicable to your company's operations. I don't think any one company actually does all the types of work this book covers, but it's still good to have the introductory knowledge. (Note topside fabrication, which albeit is accomplished on a quayside, is not discussed.) The chapter on constructability is a more recent and important topic.

A competitive advantage is technical knowledge (or at least awareness) of the many different methodologies to achieve satisfactory execution, and this book describes many of them in marine and offshore construction. It is a must read for operations and project engineers, construction supervision, planners/schedulers, and even project managers.

Designing Cathodic Protection Systems for Marine Structures and Vehicles

2011-03-12T22:50:00.001-08:00

Designing Cathodic Protection Systems for Marine Structures and Vehicles (Astm Special Technical Publication// Stp)
By Harvey P. Hack

Publisher: ASTM
Number Of Pages: 111
Publication Date: 1999-11
ISBN-10 / ASIN: 0803126239
ISBN-13 / EAN: 9780803126237

This significant new ASTM publication is specifically aimed at cathodic protection in seawater. It summarizes the latest criteria and philosophies for designing both sacrificial and impressed cathodic protection systems for structures vehicles in seawater.

Seven peer-reviewed papers cover:

• A new approach that allows for the formation of calcareous deposits in a more accurate fashion than older, traditional methods

• Physical scale modeling of ICCP systems used by the U.S. Navy and how the results are translated into actual ship design

• Formulation and performance of aluminum anodes in various environments

• A protection design example for a geometrically complex warf structure

• Practical experiences involving deep water structures, such as offshore oil platforms

• Boundary Element computer modeling--latest technology for predicting cathodic protection current distribution and magnitude

• Preventing corrosion of space shuttle solid rocket boosters during ocean recovery

This volume is a valuable technical reference tool for designers of marine cathodic protection systems and evaluators of designs performed by others.

Table of Contents

Overview

The Slope Parameter Approach to Marine Cathodic Protection Design and its Application to Impressed Current Systems
Hartt W.

Design of Impressed Current Cathodic Protection (ICCP) Systems for U.S. Navy Hulls
Lucas K., Thomas E., Kaznoff A., Hogan E.

Relationship of Chemical Components and Impurities of Aluminum Galvanic Anodes Upon the Cathodic Protection of Marine Structures
Schrieber C.

Cathodic Protection System Design for Steel Pilings of a Wharf Structure
Nikolakakos S.

Cathodic Protection Requirements for Deepwater Systems
Menendez C., Hanson H., Kane R., Farquhar G.

Computational Design of ICCP Systems: Lessons Learned and Future Directions
DeGiorgi V., Lucas K.

Cathodic Protection Deployment on Space Shuttle Solid Rocket Boosters
Zook L.

Analysis and Design of Marine Structures by: Carlos Guedes Soares, P.K. Das

2011-03-12T22:47:00.000-08:00

Analysis and Design of Marine Structures
By Carlos Guedes Soares, P.K. Das

Publisher: CRC
Number Of Pages: 564
Publication Date: 2009-03-02
ISBN-10 / ASIN: 0415549345
ISBN-13 / EAN: 9780415549349

Product Description

'Analysis and Design of Marine Structures' explores recent developments in methods and modelling procedures for structural assessment of marine structures, and is a valuable reference source for academics, engineers and professionals involved in marine structures and design of ship and offshore structures.

From the Back Cover

The MARSTRUCT series of conferences started in Glasgow, UK in 2007, and has the aim of becoming a bi-annual specialised conference dealing with Ship and Offshore Structures. The initial impetus and support for this series was given by the Network of Excellence on Marine Structures (MARSTRUCT), which brings together 33 European research groups and is now in its 6th year of funding by the European Union.

'Analysis and Design of Marine Structures' explores recent developments in methods and modelling procedures for structural assessment of marine structures:

- Methods and tools for establishing loads and load effects;

- Methods and tools for strength assessment;

- Materials and fabrication of structures;

- Methods and tools for structural design and optimisation;

- Structural reliability, safety and environment protection.

The book is a valuable reference source for academics, engineers and professionals involved in marine structures and design of ship and offshore structures.

Coastal Engineering: Process, Theory and Design Practice By A. Chadwick

2011-03-12T22:46:00.000-08:00

Coastal Engineering: Process, Theory and Design Practice
By A. Chadwick

Publisher: Taylor & Francis
Number Of Pages: 416
Publication Date: 2004-11-03
ISBN-10 / ASIN: 0415268419
ISBN-13 / EAN: 9780415268417

Product Description:

The United Nations estimate that by 2004, in excess of 75% of the world's population will live within the coastal zone. These regions are therefore of critical importance to a majority of the world's citizens. The coastal zone provides important economic, transport, residential and recreational functions, all of which depend upon its physical characteristics, appealing landscape, cultural heritage, natural resources and rich marine and terrestrial biodiversity. This resource is thus the foundation for the well being and economic viability of present and future generations of coastal zone residents The pressure on coastal environments is also being exacerbated by rapid changes in global climate. The value of the coastal zone to humanity, and the enormous pressure on it, provide strong incentives for a greater scientific understanding which can ensure effective coastal engineering practice and efficient and sustainable management.

Coastal Engineering: Processes, Theory and Design Practice is the only book providing a thorough introduction to all aspects of coastal processes, morphology and design of coastal defences. The use of detailed and state-of-the art modelling techniques are an important theme of this book, and there are numerous case studies showing actual examples where mathematical modelling has been applied through engineering judgement.

With thorough coverage of the theory, and practical demonstration of the applications, Coastal Engineering: Processes, Theory and Design Practice is a must have for all students and engineers working in coastal management and engineering.

Handbook of Composites, 2nd Edition

2011-03-12T22:42:00.000-08:00

Handbook of Composites
Ed. by S. T. Peters

Publisher: Chapman & Hall
Number Of Pages: 1120
Publication Date: 1998
ISBN-10 / ASIN: 0412540207
ISBN-13 / EAN: 9780412540202

Product Description:

This new edition of the Handbook of Composites follows the first edition in providing up-to-date information on materials, processes, and applications of composite materials. In addition to describing current developments in the industry, it provides readily accessible information on test methodology and design analysis techniques. Coverage has been expanded to include the new material forms of metal-matrix, carbon-carbon and ceramic composites as well as polymeric-based composites. This second edition covers technologies for all new materials as well as modeling, characterization and testing techniques. All resin systems in current use are covered as well as speciality resins such as BMIs and cyanates, newer high-temperature resins and thermoplastics. The fibers section has been updated and a new section on particulate reinforcements has also been added. All traditional processing methods involving autoclaves, filament winding, pultrusion, table rolling and textile preforming are included along with the newer processes of resin transfer molding, fiber placement, and thermoplastic processing. An extensive discussion of composite surface treatment, mechanical fastening and adhesive bonding has been added. The design and analysis section has been expanded with chapters dealing with laminate and composite structure design, analysis methods and the new important subject of design allowables substantiation. There are new chapters on damage tolerance, repair, safety and reuse of composites as well as applications of composites to medical, construction and sporting goods. With contribution from an international team of experts, the Handbook of Composites will continue to be the primary reference in the composites field.

CONTENTS
Contributors
Preface
About the editor
Foreword
Acknowledgements
Introduction, composite basics and road map
1 Overview of composite materials

PART ONE: BASIC MATERIALS
Polymeric matrix systems
2 Polyester and vinyl ester resin
3 Epoxyresins
4 High temperature resins
5 Speciality matrix resins
6 Thermoplastic resins
Reinforcements and composites
7 Fiberglass reinforcement
8 Boron, high silica, quartz and ceramic fibers
9 Carbon fibers
10 Organic fibers
11 Particulate fillers
12 Sandwich construction
13 Metal matrix composites
14 Ceramic composites
15 Carbon-carbon composites

PART TWO: PROCESSING METHODS
General composites and reinforced plastics
16 Hand lay-up and bag molding
17 Matched metal compression molding of polymer composites
18 Textile preforming
19 Table rolling of composite tubes
20 Resin transfer molding
21 Filament winding
22 Fiber placement
23 Pultrusion
24 Processing thermoplastic composites
Advanced composites
25 Tooling for composites
26 Consolidation techniques and cure control
27 Composite machining
28 Mechanical fastening and adhesive bonding
29 Surface preparations for ensuring that the glue will stick in bonded composite structures

PART THREE: DESIGN AND ANALYSIS
30 Laminate design
31 Design of structure with composites
32 Analysis methods
33 Design allowables substantiation
34 Mechanical tests

PART FOUR. ENVIRONMENTAL EFFECTS
35 Durability and damage tolerance of fibrous composite systems
36 Environmental effects on composites
37 Safety and health issues
38 Nondestructive evaluation methods for composites
39 Repair aspects of composite and adhesively bonded aircraft structures
40 Reuse and disposal

PART FIVE APPLICATIONS
Land transportation applications
Marine applications
Commercial and industrial applications of composites
Composite biomaterials
Scientific applications of composites
Construction
Aerospace equipment and instrument structure
Aircraft applications
Composites in the sporting goods industry

APPENDICES
Appendix A
Typical properties for advanced composites
Specifications and standards for polymer composites
Appendix B
Index

Ultimate Limit State Design of Steel Plated Structures

2011-03-12T22:06:00.000-08:00

Ultimate Limit State Design of Steel Plated Structures
Authored by J.K. Paik (jeompaik@pnu.edu) and A.K. Thayamballi
John Wiley & Sons Ltd. (http://www.wiley.com), London, August 2002

Steel plated structures are important in a variety of marine and land based applications, including ships, offshore platforms, box girder bridges and box girder cranes. During their life time, the structures constructed using these members are subjected to various types of loading which is for the most part operational, but may in some cases be extreme or even accidental. It has been well recognized that the limit state design approach is better than the traditional allowable stress design approach since the former makes possible a more rigorously designed, yet more economical structure considering the various relevant modes of failure possible.

This book reviews and describes both fundamentals and practical design procedures for the ultimate limit states of steel plated structures. The computer programs, which automate the more advanced and sophisticated design methodologies presented in this book, are provided. While the book consists of 14 chapters and appendices, it is designed as a textbook so that the derivation of the basic mathematical expressions is presented together with a thorough discussion of the assumptions and the validity of the underlying expressions and solution methods.

Chapter 1 presents design principles based on limit states, which can be classified into four types, namely serviceability limit state, ultimate limit state, fatigue limit state and accidental limit state. Corrosion damage model for aging steel structures is also presented in Chapter 1.

Chapter 2 describes buckling and ultimate strength formulations of stiffeners together with attached plating.

Chapter 3 presents elastic and inelastic buckling strength formulations of steel plates under complex circumstances which include load combination, elastically restrained edges (as well as simply supported or fixed conditions), residual stresses and perforations.

Chapter 4 presents post-buckling and ultimate strength formulations of steel plates which takes into account the effects of fabrication related initial imperfections, perforations and corrosion damage.

Chapter 5 presents elastic and inelastic buckling strength of stiffened panels and grillages under combined loads as well as under single types of loads.

Chapter 6 presents post-buckling and ultimate strength formulations of stiffened panels and grillages under combined loads, which take into account the influence of fabrication related initial imperfections.

Chapter 7 presents ultimate strength formulations of plate assemblies such as plate girders, box columns, box girders and corrugated panels.

Chapter 8 presents ultimate strength formulations of ship hulls.

Chapter 9 deals with structural impact mechanics and structural design formulations for accidents such as collision and grounding.

Chapter 10 presents fracture mechanics and residual strength assessment of steel plated structures with existing crack damages and under monotonic extreme loads.

Chapter 11 presents a semi-analytical method for analysis of elastic-plastic large deflection behavior of steel or aluminum plates under combined loads taking into account the influence of fabrication related initial imperfections.

Chapter 12 presents the theory of the nonlinear finite element method simplified on the basis of the plastic node method.

Chapter 13 presents the idealized structural unit method (ISUM) which has now been widely recognized by researchers as an efficient and accurate methodology to perform nonlinear analysis of large plated structures such as ships, offshore platforms, box girder bridges or other steel structures.

Chapter 14 presents some practice problems for each chapter and solutions to selected problems. Finally, Appendices present how to download the computer programs introduced in this book.

The present book is primarily based on the two authors' own insights and developments obtained over more than a total of 50 years of professional experience, as well as existing information and findings by numerous other researchers and limit state practitioners. The intention behind writing this book is to develop a textbook and handy source to the principles of limit state design of steel plated structures. This book has been designed to be well suited to the university students who would be approaching the limit state design technology of steel plated structures perhaps for the first time. In terms of more advanced and sophisticated design methodologies being presented, the book should also meet the needs of structural designers or researchers who are involved in the field of naval architecture, offshore, civil, architectural and mechanical engineering. Hence, apart from its value as a ready reference and an aid to continuing education for the established practitioners, this book can be used as a textbook in teaching courses on limit state design of steel structures at the university level. The reader should be able to obtain an insight into a wider spectrum of limit state design considerations in both an academic and a practical sense.

To order this book please contact: John Wiley & Sons Ltd., Mr. Graham Woodward gwoodwar@wiley.co.uk

MGPS - Marine Growth Preventive System. A Revolution in the making

2011-01-26T00:52:00.000-08:00

Ships while sailing use seawater for several purposes. The seawater is used in the ship’s system and discharged after the use. However, seawater contains several marine organisms which enter the ship along with the seawater and deposit and flourish on the parts of the ship’s system. If preventive measures are not taken, the marine growth can cause damage to the particular part in the long run. In this article we will learn about the causes and effects of marine growth in a ship’s system along with the measures to fight it.

What Causes Marine Growth?

Sea water contains both macro and micro marine organisms such as sea worm, molluscs, barnacles, algae, hard shells like acorn barnades etc. These organisms stick to the surface of the ship and flourish over there, resulting in marine growth.

Marine fouling can form huge clusters of marine growth inside the piping system of the ship. This is mainly caused because of the entering of the seawater into the seawater system. The organisms find the perfect spot inside the system wherein the environmental conditions and other relevant factors such as temperature, ph, nutrients etc are appropriate for them to breed and disseminate.

Effects of Marine Growth

As the marine organisms flourish they block and narrow the passage of cooling water in the ship’s system resulting in the following factors:

- Impairing the heat transfer system.

- Overheating of several water-cooled machineries.

- Increase in the rate of corrosion and thinning of pipes.

- Reduced efficiency which can lead to loss of vessel speed and loss of time.

Fighting Marine Growth

To avoid formation of marine growth MGPS or marine growth preventive system is used onboard ship. Description and working of MGPS is as follows.

Basic principle on which MGPS runs is electrolysis. The process involves usage of copper, aluminum and ferrous anodes. The anodes are normally fixed in pairs in the main sea chest or in such place where they are in the direction of the flow of water.

The system consists of a control unit which supplies impressed current to anodes and monitors the same. While in operation, the copper anode produces ions, which are carried away by water into the piping and machinery system. Concentration of copper in the solution is less then 2 parts per billion but enough to prevent marine life from settling.

Due to the impressed current, the aluminum/ferrous anode produces ions, which spread over the system and produce a anti corrosive film over the pipes, heat exchanger, valves, refrigeration and ac unit etc, internally.

MGPS anodes are fitted with specially designed safety cap which helps in removing the anode for replacement on board ship. Normally MGPS have a design life which coincides with the dry dock of the vessel.

The Job of a Maritime Consultant ! Can Naval Architects shine in this field?

2011-01-26T00:36:00.000-08:00

Maritime consultants are professionals who have the technical expertise to advice and suggest better trade routes and address other necessary shipping concerns to individuals and corporations engaged in the maritime sector to help them boost, advance and further their business positively.

Another important reason that maritime consultants play a very vital role in channelizing today’s shipping industry concerns is because of the various detrimental issues that have cropped up in the field of marine commercialization and marine ecosystem. Maritime consultants can, once again address these concerns by taking matters into their hands and advice the business sector about the dos and don’ts that need to be monitored and taken care of.

In today’s times, the profession of a maritime consultant has become majorly asking. Since the job entails providing expertise, it involves detailed studying and analysis of the concerned issue from the perspective of not only the concerned party but also from the perspective of the environment and any other factors which could cause a debilitating turn to the concerned issue.

Academic Requirements

In terms of educational qualifications, while there are no specific qualifications required to be a maritime consultant, there are quite a few other requirements that good and effective maritime consultants should possess. The main thing that is required is experience, because more the experience maritime consultants have the quality of their services as highly instrumental professionals will be more. Additionally, in terms of experience it would be better if a maritime consultant possesses experience not just pertaining to his native country or region but also of many nations across the world. This feature is important in the profession of maritime consultants because wider is the knowledge background of a maritime consultant, the more reliable his services will be perceived to be. Moreover, since shipping is such a business activity which encompasses oceans and seas which are spread across the globe, it is but natural that the shipping business tends to be a multinational event. And as such, it will be in the interest of maritime consultants if they have experience to deal with not just one country, but innumerable ones.

Also, when it comes to experience about many countries, it becomes equally important for maritime consultants to be fluent in multiple languages apart from English. It is a known fact that, while English is the universal denominator when it comes to languages, there are many nations and people who are not comfortable with speaking English. Therefore, it would be beneficial for maritime consultants if they are able to converse well in such regional languages and reduce the discomfort of the people, thereby garnering more appreciation for their services and expertise – not just in terms of their work and profession, but also in terms of their ease and comfort with many languages.

Conclusion

The profession of maritime consultants is unique because it caters extensively to the shipping industry with no other fields overlapping its scope and ambit. A maritime consultant needs to have the necessary patience and steadfastness to execute his job in a manner befitting the title allotted to his profession. Because, if maritime consultants falter or make a mistake, it could be that the error could be a minor one or it could be that the error is a major one. In the case of the former, rectification is possible but in the case of the latter, the aspect of rectification will be far too late. Therefore, it’s the responsibility of maritime consultants to provide the best possible advices and solutions so as to preserve not just the survival of the shipping industry but also of the ecosystem on which the industry solely depends on. The Naval Architect because of his technical expertise in the designing of ships for various market conditions, can hopefully give a go for this. However, he should not restrict his field to Naval Architecture alone, but alongside broaden his horizons to look into all aspects of the shipping sector. A professional qualification in management is an added benefit.

Naval Architecture & Marine Engineering PHD Program Overviews

2010-12-04T09:11:00.000-08:00

A Doctor of Philosophy, or Ph.D., in Naval Engineering allows students to gain an advanced education in the design and construction of boat systems and structures. A Ph.D. in the field often involves years of intensive, individualized research into a particular aspect of naval architecture.

Doctor of Philosophy in Naval Architecture and Marine Engineering

Ph.D. programs in naval architecture and marine engineering are designed for students who are proficient in engineering and applied mechanics, and who are interested in studying the design of boating structures. Most doctoral programs available in the field of naval architecture allow students to design their own coursework and programs of study. Students can choose a concentration from such areas as naval hydrodynamics, marine systems design, coastal processes, marine design, marine structures, offshore engineering or marine systems management.

Before students embark upon research in a particular area of the naval architecture field, they must run their proposed course of study by a university committee and have it approved. They then spend a designated minimum number of credit hours researching and writing a Ph.D. dissertation that explores or advances theories in a particular subject of marine science study. Some Ph.D. programs also require that students pass an examination on more broad concepts in the field, such as general mechanics or engineering.

Educational Prerequisites

A Ph.D. is the most advanced degree level available in the field of naval architecture and marine engineering. Before a student can enroll in a Ph.D. course of study, he or she must complete a bachelor's and a master's degree program in mechanical engineering, physics, mathematics, civil engineering or aerospace. Many prospective doctoral students must also complete qualifying examinations before enrolling.

Program Coursework

There are no set series of courses in a Ph.D. program in naval architecture and marine engineering. Students are allowed to select their own course of study and research based upon their interests and aspirations in the field. Some areas of study or individualized courses might include the following:

Hydrostatic stability
Vessel arrangements
Hull geometry
Boating structures and design
Marine power systems
Structural mechanics
Marine dynamics
Ship production

Employment Outlook and Salary Info

A naval architect or marine engineer is responsible for researching, conceiving and designing new and advanced boating systems and production platforms. Graduates of a Ph.D. program in the field focus heavily on the research aspects of the industry, and they often receive research positions in academic or naval associations. According to the U.S. Bureau of Labor Statistics, the median annual wage for a naval architect or marine engineer was about $74,330 in 2009 (www.bls.gov).

Colleges offering Naval Architecture & Marine Engineering Courses

2010-12-04T08:53:00.000-08:00

Institute of Shipbuilding Technology,Goa

Institute of Shipbuilding Technology, Goa (ISBT) was established by Society for Industrial & Technical Education of Goa (SITEG) (formerly know as Shipbuilding Industry Society of Goa (SIG)) in the year 1981. Perhaps ISBT is the only institute in India to be established and managed by a group of Industries. Requirement of highly specialized trained manpower by the Shipbuilding / Barge building, repair and allied industries forced the industries in this business to come together under the banner of “Shipbuilding Industry Society of Goa” and established the Institute. Main objective of SITEG is to provide industry with well trained technical manpower to suit their requirements, and conduct retraining programmes for existing workforce.

INSTITUTE OF SHIPBULDING TECHNOLOGY,GOA ( ISBT)

ISBT is a government aided institute receiving grants from Government of Goa, under the Grant-in-aid pattern. Establishment of ISBT is approved by All India Council for Technical Education, New Delhi.

First course to be introduced at ISBT, was Diploma programme in Shipbuilding Engineering in August 1981. This course till today is considered as a unique course to be offered only by ISBT. It is a sandwich type of course with compulsory industrial training of one year at shipyards located in Goa and in neighbouring states. This course is now accepted as entry qualification for Engineer Officers by Directorate General of Shipping, Govt. of India.

Having achieved reasonable success in offering need based Diploma programmes, ISBT introduced Diploma in Mechanical Engineering with specialization in Material Handling Technology/Heat Power Engineering (now as Diploma in Mechanical Engineering) from the academic year 1990-91 and Diploma programme in Electronics Engineering with specialisation in Marine Electronics from the year 1995-96 (now renamed as Diploma in Electronics & Communication).

After the meaningful implementation of World Bank Project, under which this Institute was covered, Institute has well equipped laboratories for all its three departments, a centralized Computer Centre, an air-conditioned Self Learning Centre with attached Audio-Visual Room and other state of art facility for facilitating the teaching-learning process. An investment of around Rs.6.50 crores has gone into development of infrastructure at ISBT under the World Bank Assisted Project.

ISBT, being managed by Industries, enjoys certain advantage as compared to other institutes managed by Govt. or other Societies. To name a few:

1. Easy access to industries for staff and students.

2. Experienced Industrial personnel as Visiting faculty/Guest faculty.

3. Participation of Industry in development of curriculum, infrastructure development, students

assessment, etc..

4. Industry like approaches in all the functional areas of the institute.

5. Efficient utilization of all infrastructure of ISBT.

6. Business like approach in its management.

Academics - Programmes at ISBT

Presently ISBT offers following Diploma Programmes:

Sr.No.	Title	Intake	Duration
01	Diploma in Shipbuilding Engineering (sandwich type course incorporating Industrial Training)	40	4 Yrs.
02	Diploma in Mechanical Engineering	40	3 Yrs.
03	Diploma in Electronics and Communication Engineering	30	3 Yrs.

Admission - Entry to ISBT

Selection of candidates for admission is done centrally by the office of the Directorate of Technical Education, Govt, of Goa. Application Form and Prospectus are issued by them during the month of May.

Eligibility

Eligibility conditions prescribed for admissions:

Candidate should be citizen of India.

Passed SSCE or its equivalent with Science, Mathematics and English in one and same sitting.

Passed from the schools of Goa only. *

Secured minimum 50% marks in aggregate of Science and Mathematics at SSCE (40% marks for SC/ST/OBC).

Resident of State of Goa continuously for minimum 10 years immediately preceding the month of receipt of Application with Admission Rule relaxed for certain categories.

Candidates coming with higher qualification are eligible for exemption in few courses as per the rules of Board of Technical Examinations.

* Apart from the above , certain number of seats are reserved for special category as per the norms laid down in the prospectus.

Special Features

Some of the special features of ISBT are:

ISBT being established and run by Shipbuilding Industry Society of Goa, has a good liason with Industries in Goa and hence provides students easy access to industries for Project Work, Short Term/Long Term Training, etc.

ISBT provides a very dynamic Teaching Learning environment.

Easy access to laboratories, computer center, etc. beyond normal practical hours for additional

knowledge and skill development.

Project Work carried out by students is rated very high.

ISBT has young, dynamic, energetic, well-qualified and trained staff.

Self Learning Center works beyond normal working hours of institute and on Saturday to facilitate students Self Learning.

At ISBT all activities are student centered.

ISBT believes in Personality Development through knowledge and values.

Softwares for Naval Architect - Paramarine

2010-12-04T04:46:00.000-08:00

Paramarine is an integrated ship design system, which provides the full range of naval architecture calculations for operation and through-life ship management. The companion product, Seagoing, is used to manage the current ship condition and provide guidance when the ship is damaged. Seagoing is installed on most major RN ships.

Paramarine integrates practical naval architectural design and engineering alongside military specific calculations. A unique design concept design framework facilitates the flexible review of capability and configuration for both ships and submarines. Balanced designs can be reviewed by the software to identify sources of cost and ease of production.

FUNCTIONALITY

Paramarine provides the following functionality:

Surface and Solid Modelling
Advanced Hullform Generation
Stability (V-Lines, Carpet Plots, Red-Risk, Damage Templates)
Submarine Stability (including Trim and Inclining)
Launching
Docking (Dock block loading)
Seakeeping (PAT or Proteus)
Powering
Endurance
Manoeuvring (Ship, Trimaran and Submarine)
Mercantile, Warship and Submarine Criteria
Structural Design
NS94D Ultimate Strength analysis
Bulkhead Collapse
Crack Propagation
Design for Production
Submarine Pressure Hull analysis
Early Stage Design
Radar Cross Section.

QinetiQ GRC are the developers of the Paramarine^TM suite of software products. This product suite includes:

• Paramarine
• Paramarine SeaWeigh
• Seagoing Paramarine for Ships and Submarines

Paramarine is the worlds only fully integrated Naval Architecture Design and Analysis product that can handle the complexities of ship and submarine design. Its advanced design capabilities are built upon the Siemens PLM Parasolid^TM solid modelling capability, which provides much of the geometric detail required to enable the accurate analytical capabilities – as well as providing excellent geometric exchange with other CAD and CAE systems.

Paramarine SeaWeigh and Seagoing Paramarine, the on-board loading computer variants of Paramarine. These products use the same ship or submarine model and analysis techniques ensuring total compatibility between the systems.

The Paramarine product suite therefore enables rapid concept design and development, eliminating costly data transfer between numerous analysis products. The analytical capabilities provided within Paramarine are fully validated by independent third parties.

You will save time, money and understand your technical risks early in the design process through your use of Paramarine.

Various Modules

Stability and Hydrostatics
The stability and hydrostatics analysis modules are used in the intact and damaged conditions to assess the stability of designs against UK, US and Australian Military as well as UK and International Mercantile Standards. This module has been validated by the UK MoD Naval Authority for Ship Stability and is a core analysis capability within Paramarine and its on-board variants, Seagoing Paramarine and Paramarine SeaWeigh. The sophisticated 3D solid modelling techniques utilised by Paramarine provide the high accuracy required for assessing submarine stability, where complex geometries are often involved.

Powering and Endurance
The Powering and Endurance modules utilise a number of in-built powering series to provide highly accurate powering predictions for a given design. When combined with a mission profile, propulsion system components and energy provision, the endurance for a given design can be determined. This allows the design team to optimise their concepts to maximise endurance, minimise fuel consumption and emissions or trade off different propulsion system options.

Structural Analysis
The extensively validated structural analysis modules utilise capability developed by QinetiQ's Maritime Practice. This capability allows the assessment of the structural capability of ships and submarines in both the intact and damaged conditions. Naval Architects and Design Authorities can assess and optimise longitudinal strength, critical sections, bulkhead collapse, crack growth and residual strength as the design evolves against UK Standards. The allied structural desktop toolkit provides a rapid approach for the definition of plate and scantlings using UK and other classification society rules.

Early Stage Design
The Early Stage Design module is based upon the Functional Building Block Approach developed by UCL.

This module allows the designer to build the concept based upon the various functional requirements placed upon the ship or submarine. The designer is able to specify requirements for weight, volume, power, manning, payload and so on to assess the supply provided within their design. The automatic auditing capability provides the designer with the ability to continually assess the balance of the design and to perform trade-off's for different configurations.

Above Water Vulnerability
This module provides the designer with the ability to assess the vulnerability of a given concept to attack. The user can assess, for a given configuration and threat, the effects of a blast on the integrity of its various systems.

Radar Cross Section Analysis
This module allows a non-expert designer to rapidly identify and correct any design features that result in undesirable radar cross section signature. This is achieved through the provision of polar plots as well as a visual representation via bitmaps or movies which highlight areas of high return for any elevation or polar position.

Advanced Hull Form Generation
Our advanced hull form generation capability utilises state-of-the-art XT Technology, where high quality surfaces can be created from a minimum of bounding and internal curves. A number of sophisticated mathematical techniques are available to provide the basis for the user to create industry standard NURBS surfaces. These are used to develop hull forms, superstructure and appendages. Paramarine provides a wide range of curvature analysis and diagnostic tools to allow the design team to refine their hull forms to their required standards.

Design for Production
This module allows the development of a cost of production for the design based upon the engineering work necessary to build the design, by combining the cost of labour and materials involved in the construction. It allows the design team to assess the merits of different production strategies, as well as trading off different system options. This unique capability provides an alternative to established weight based costing techniques which are dependent on historical data that may not be applicable to today's innovative design and construction techniques.

Manoeuvring
Paramarine provides manoeuvring analysis for ships and submarines. The surface ship module can assess monohull and trimaran manoeuvring for standard and user defined manoeuvres and can also include autopilot inputs. The submarine module is a coefficient based approach for the analysis of underwater manoeuvres.

The FORAN interface
This provides a two-way data transfer capability between Paramarine and Sener’s ship production system, FORAN. The advanced transfer involves Paramarine providing the vessel’s external envelope and internal spatial arrangement (through the subdivided hull) to Sener's FORAN system for production detailing.

Energy efficiency design formula agreed

2010-11-25T11:02:00.000-08:00

A technical benchmarking formula being developed to assess the theoretical energy efficiency of individual ship designs has been finalised.

However, final agreement on the thorny issue of defining ro-ro vessels still needs to be resolved.

The ability to calculate how efficient a ship is by defining its power capabilities, and therefore its CO2 emissions, in relation to its cargo capacity, is seen by regulators as one of the key tools in reducing the shipping industryâ€™s contribution to global warming.

The energy efficiency design index is one of three proposals that have gained some ground in the political debates at the International Maritime Organization over global warming. However, it became bogged down as the proposed formula was seen as being too simplistic to be applicable to may ship types, particularly ro-ro vessels.

Participants at the expert group meeting told Lloydâ€™s List that they made headway in developing correction factors to the formula to allow unique scenarios such as shuttle tankers and ice class vessels be accounted for rather than be unfairly judged.

The objective is that the EEDI is calculated for a proposed ship design and is then matched against a reference line, which it should be under. A series of reference lines, for the major ship types has now been agreed.The IMO has yet to decide how this is to be used to create incentives for efficiency improvements.

The finalised formula will now be presented at the autumn meeting of the IMOâ€™s marine environmental protection committee for final adoption. This MEPC meeting is crucial as it falls just before the next UN climate change meeting Mexico later in the year, the follow up to the lack-lustre Copenhagen talks in December 2009.

Having failed to make headway on the sensitive topic of market based instruments suitable to force shipping to reduce its CO2 footprint, the IMO hopes to able to formally agree the EEDI, the voluntary energy efficiency operational indicator and the ship energy efficiency management plan.

These three are likely to be written into an existing regulation, such as Marine pollution convention, to enable them to become law quickly .

Ro-ro vessels remain a sticking point. There are now four different definitions of ro-ros to ensure vessel designs are not unfairly penalised. As well as car carrying deepsea ro-ro vessels and passenger ferries that have ro-ro capabilities, ro-ros are also defined as weight carriers, or volume carriers to enable their operational profile be better reflected in the design formula and comparable benchmark. How the EEDI applies to ro-ro vessels will now be dealt with in October.

Source: Lloyds' List

Global shipbuilding: An overview

2010-11-25T10:53:00.000-08:00

The global shipbuilding industry has been on an upswing over the past few years. In the period between 2000 and 2005, the world shipbuilding output has grown at a compounded annual rate of 8.3% based on gross tonnage (GT), as opposed to a growth of 4.8% achieved in the past 20 years (1985 to 2005). Strong demand and capacity constraints has led to the world’s shipping order book to sales ratio increase to 3.5 times in 2005, higher than the historical average of 2.1 (between 1982-02).

Shipyards remain fully booked in the medium-term with the delivery period, for the first time since the seventies, extending beyond three years. Since it is the waiting period, which new building prices closely follow as compared to freight rates, the strong new building prices are expected to be maintained over the medium-term. Also, the ships that have been currently booked at higher prices will have full impact on the shipbuilder’s profitability in the next two to three years.

The global shipbuilding industry is primarily dominated by conventional vessels like tankers, bulk-carriers and container vessels. As can be seen from the chart below, conventional vessels accounted for 69% of the world shipping order book at the end of 2005, followed by LNG carriers at 9%. In addition, there exist specialised categories like cruise ships that fall under ‘Passenger Vessels’ category and Offshore Supply Vessels (OSVs) that come under ‘Other Non-cargo Vessels’ category.

Demand drivers: Being a global industry, the fortunes of the shipbuilding industry are closely tied to the growth in world trade. The demand for ships can be classified into incremental demand and replacement demand. In case of incremental demand, growth in world trade increases the demand for vessels, which in turn leads to higher freight rates. The resultant higher freight rates trigger the demand for new vessels from the shipping companies. In case of replacement demand, the demand for vessels is dependent upon the age profile of the existing fleet as well as steel prices. Every ship has a useful life (25 to 30 years) after which it becomes uneconomical to operate them. Replacement demand is triggered when ships approach the end of their useful life. Higher steel prices also decide the extent of replacement demand as they lead to an increase in value of ships to be scrapped.

Major players in the shipbuilding countries: Global market environment in the shipping industry has undergone fundamental changes over the last two decades. For nearly three decades in the post World War II era, shipbuilding industry was dominated by Europe and the US. Shipbuilding being a labour intensive industry, the cost of labour plays an important determinant in a country’s competitiveness position vis-à-vis others. With rising labour cost, shipbuilding activities have slowly moved away from ‘high wage’ Europe and US to low-wage Asia. Over the past 25 years, we have observed the decline of shipbuilding capacity in Europe coinciding with the growth of Japanese shipbuilding. As can be seen in the chart, the share of European Union has declined from 28% in 1983 to 7% in 2005. With the rising labour cost in the late 1980s, Japan was forced to scale down its shipbuilding activities and Korea emerged aggressively. In the past few years, China is taking away an increasingly larger market share of the new building contracts.

The shipbuilding industry is currently dominated by the Japanese and Korean shipyards. In 2005, they together accounted for 73% of the total world output (in number terms), followed by China at 13.5% and European Union (EU) at 7%. The largest shipbuilding companies in terms of capacity are Hyundai Heavy Industries, Daewoo Shipbuilding and Marine Engineering and Samsung Heavy Industries (all Korean).

The conventional large vessel segment like tankers, bulk carriers and container vessels is dominated by Korea, Japan and China. China’s ambitions to become the world’s largest shipbuilder for conventional vessels has resulted in Korea taking a back-seat in this segment and instead focus on new ship development areas like super-large LNG carriers. Japan has been struggling to maintain its market share due to dwindling workforce and higher labour cost. It is currently investing in technology to construct conventional vessels in a short period and thereby compete with China in this segment. Realising its inability to compete with Asian countries in the conventional segment, the EU shipyards have been focusing on ‘Passenger Vessels’ and ‘Offshore Vessels’ segment.

ANSYS and its use in Shipbuilding & Naval Architecture

2010-11-06T11:36:00.000-07:00

Uses of Finite Element Software in Shipbuilding

ANSYS is a general purpose software used for different type of structural analyses and also for
various Engineering fields. Presently different types of analyses are trying to highlight which are
commonly used for Shipbuilding and Offshore structures such as Bulk Carrier, Tanker, Jack Up,
Floating Dock, Naval Vessel etc.
The new Bulk Carrier and Tanker common Rules under the guidance of IACS has specially
emphasized on detail structural calculation by using Finite Element Method. The new
guidelines have come for the Direct Strength Analysis (DSA) procedure in which 35 Load cases
have to be simulated due to wave load as well as Cargo load variation for 3-Hold computer
model. By using ANSYS Macro DSA can be done for Bulk Carrier and Tanker structure. With
ANSYS software the entire DSA time has been reduced drastically.
The ultimate strength of the ship hull girder beyond which the hull will collapse can be analyzed
by using ANSYS. Hull girder failure is caused by buckling, ultimate strength and yielding of
plating and attached stiffeners, which participate in the longitudinal strength. A methodology for
computing the ultimate moment carrying capacity of ship hull girder when subjected to
longitudinal bending moment (vertical hogging or sagging moment); horizontal at any section
are developed. So, the FEM nonlinear analysis has carried out by using ANYS 11, to investigate
the failure.
The Free vibration analysis has been performed for a Passenger vessel to estimate the natural
frequencies and mode shapes by using ANSYS. The hull girder frequencies were compared
with the engine, shaft, propeller frequencies etc, to check for any possible resonance. The
analysis was done for three loading conditions. 1. Light Ship Condition. 2. Fully loaded
departure from port. 3. Fully loaded arrival to port, which cover the major variation of loading
during voyage. Engine room has been separately modeled and analyzed to capture the local
vibration mode in addition with the full ship analyses.
A Non-linear Transint dynamic analysis has been done to determine the damage for the
collisions between two ships. A supply vessel with a specified velocity hits the corner of an
offshore barge. The implicit solver of ANSYS has been utilised for the reqiured analysis. The
geometric, material and contact non-linear properties are being considered.
Wave slamming is an important parameter for designing the forward part of the Ship structure.
The slamming loads are highly dynamic in nature, characterized by very short duration of the
load, usually 10-20 milli-seconds. Transient dynamic analysis carried out for nearly 2000 cases
and proposes a simple method based on this study, for design of structures subjected to
slamming loads. The method also provides for accounting any acceptable value of permanent
deformation criteria for plate thickness and presence of in-plane stresses.
Ships and Submarines structures in their fighting role are susceptible to Underwater shock
generated due to explosion of torpedoes, mines, depth charges etc. The damage inflicted by
Non-Contact Underwater explosion consists of direct shock wave damage of hull, whipping
damage of keel, mechanical damage to onboard equipment and associated systems. The use
of ANSYS and its capability, backed up with the in-house developed software, for Underwater
Explosion analysis of structures.
ANSYS is used for docking study, Crane foundation analysis, bollard analysis, Mast analysis,
local structure stress analysis etc. In a nutshell, ANSYS can help the Ship and Offshore
Structure Designer to design the structure safely with minimum design time utilisation. The
scantlings can be optimized and the new innovative design can be achevied with the help of
ANSYS.

Primer on Naval Architecture- Parametric Roll

2010-11-06T11:16:00.000-07:00

Large containerships are particularly susceptible to the physical phenomenon of parametric rolling due to their hull design featuring a wide, flat stern, pronounced bow flare, fine under-water body and relatively light loaded displacement.
Parametric rolling can lead to loss of or damage to cargo containers and possible damage to the ship. Relying on fundamental physics theory to simulate the build up of energy that takes place during a rolling motion, ABS researchers conducted numerical modeling and sequence simulations to illustrate the gravity force effects on ships as they roll, pitch and heave in a seaway. A ship is particularly susceptible to parametric rolling when encountering either head or following seas.

TECHNICAL DISCUSSION
To transport goods efficiently, modern containerships are being designed for high service speeds necessitating a fine underwater body and relatively low block coefficient. To maximize carrying capacity on such a fine body, the deck is extended as far forward and aft as possible, resulting in a somewhat exaggerated bow flare and pronounced stern overhang.
These characteristics are most prominent in large and ultra-large containerships, making these vessels the most susceptible to parametric rolling. Parametric rolling is not a frequent phenomenon because a finely balanced set of circumstances must exist for this physical event to take place. The ship’s geometry must have certain characteristics. The ship’s length must be comparable to the wavelength of the sea conditions through which it is passing. The ship’s speed must bear a certain relationship to both the wavelength and the vessel’s natural rolling frequency.
As a consequence, instead of a balanced pendulum-like rolling momentum occurring, the ship accumulates energy. As the vessel passes through the waves, it encounters a series of wave peaks and troughs. If the ship length is close to the wavelength, it will rapidly change from hogging to sagging configurations. Because of the fine body, pronounced flare and stern
overhang, the ship effectively changes its beam from slim when hogged with the midships
supported, to wide when the midships is in a trough but the bow and stern are supported by wave peaks.
Since stability varies with beam, as the vessel drives through the series of wave fronts its stability changes significantly as the midship moves from crest (maximum) to trough (minimum).
When this pattern occurs together with a wave encounter frequency that is close to twice the ship’s natural roll frequency, the ship enters a condition of cyclically recurring minimum stability.

Naval Architecture for a Novice

2010-11-04T21:44:00.000-07:00

Are you looking for more information on Naval Architecture ??? What exactly is it about??
Is it any different from other Architecture Courses you have heard about.
Here Mr Ramalingam will answer your queries on Shipping, Shipping jobs, Naval architecture, etc.

What is Naval Architecture?

This article intents to give a brief idea of what naval architecture is all about. What are the various aspects that should be taken into consideration while constructing and designing a ship? Also, Why is the discipline so demanding and what are the factors that drives these demands.

Role of Naval Architecture throughout the ages

Ships are one of the oldest forms of transport. Their structure, functions and equipments have been subject to constant evolution. These constant evolutions are propelled by the ever changing patterns of world trade, by the necessity of the economic alterations and by the incessant advances in technology. Technology has been a vital factor in providing opportunities to build larger, faster and safer ships.

Naval architecture has been an intrinsic part of the evolution of ships. It has been captivating and equally demanding at the same time. It’s a discipline that requires highest degree of discipline too. It is demanding because there is large amount of capital investment that goes in the making of the ship and also because lives of people is on stake.

Diversity demands

Only a busy port will depict the diversity in the structures of floating vessels. It is this diversity in the structures and functions of ships that there arises the need in the application of different ways in construction of a modern ship. The conditions and the functions of a particular ship also play a vital role in the making of the ship.

For example, there are fishing vessels, ranging from small fishing boats that operate daily to the deep ocean explorers that demands facilities to deep freeze their catches. Similarly there are small coastal cargo carriers to extremely large cargo carriers (VLCCs). Also there are drill ships for the explorations of gas, oil and minerals. There are small as well as giant supertankers that carry oil, gases and chemicals. There are huge bulks that carry grains, coal, ore and raw materials.

There are tugs for towing and dredgers and pilot boats for the proper functioning of the ports. There are warships from huge aircraft carriers to frigates. And last but not the least there are ferries as well as massive cruise liners that carry passengers to different corners of the world on long voyages. As you can see the variety of functions demands the variety in the ways and designs of constructions. Naval architecture suffices these demands.

What Drives Demands?

As the structure and size of the ship vary the demands vary. How?

Let’s take an example of a large cruise liner. A large cruise liner is a whole township or a small city in itself. This means, it has several thousands of people onboard. As a result it will need electricity, air conditions, galleys, restaurants, recreation auditoriums etc. To accommodate all the necessities under one roof the general layout must me so strong and impeccable that the ship can carry out its intended tasks effectively and economically. But that is not the end of the factors that needs to be taken for there is a crucial aspect needs to be considered is safety. If there are several thousands of people on board then it is absolutely important that the ship is safe from all aspects.

Additional aspects to be taken into consideration

The kind of propulsion system used on the ship is also a factor that plays a role in the design and construction of the ship. In past the ships had sails which used wind for the propulsion of the ship but nowadays all ships are driven by a mechanical propulsion system. The driving power can be generated by diesel engine, steam turbine, gas turbine or some form of fuel cell. Including the propulsions there are many other systems on board and for the efficient working of the ship it is of utmost importance that the layout conciliates with the various systems.

One more thing that is taken into consideration is that not all the ports have the facility to accommodate all types and sizes of ships. This means that the geography and the depth of water at the port might abstain it from allowing large ships from entering inside. Also, not all ports have the facilities for loading and discharging all types of cargo. For example, not all ports have the facility of gantry cranes for the loading and unloading of containers. Thus this means that a container ship will never be sent to a port where there are no facilities of gantry cranes. This ensures that ships spend far less time in loading and unloading, cargoes remain more secure and most importantly port fees are reduced.

Thus a naval architect masterminds the whole process of designing and construction of ship keeping various aspects in mind. He creates the best possible ship to meet the operator’s needs. He makes a design that is flexible, safe and one which is able to adjust considerable level of risk. A naval architect knows that there is no such thing as a foolproof design and thus he takes all the possibilities into consideration to reduce the consequences of an unavoidable accident and keep the risk factor as low as possible.

One more thing he needs to keep in mind the effects of dangerous and toxic cargoes incase there is an accidental spillage due to collision or human error. There are already stringent rules made pertaining to the adverse effects of toxic cargoes on environment that cannot be compromised and thus it’s absolutely necessary to abide by them and take them into consideration while designing and constructing a ship.

It is hoped that the previous paragraphs will provide the readers with a general overview of naval architecture as a discipline. And as we gradually move forward we will discuss the various topics in details.

Career Scope for Ocean Engineers and Naval Architects

2010-11-01T09:02:00.000-07:00

Ocean Engineers have a wide range of employment opportunities world - wide. Because of the wide variety of work they are involved in and the difficulty to categorise the field comprehensively, the Ocean Engineers are mainly related to engineering field as designers and construction supervisors, they also have scope in areas like Consultancy, Marketing and Sales, Operations, Regulation, Surveying and Overseeing, Research and Development, Education and Training, etc.

Each type of work has its own distinctive character and offers opportunities for initiative and imagination in a wide variety of technical and managerial posts.

The work place may be a large company, a small group, a consultancy or a government department, but their scopes are wide.

As a Coastal Engineer, they are dealing with the dynamic interaction of ocean and its shore by developing shore protection systems like breakwaters, jetties, etc., and designing harbours, ports, etc., and also dealing with civil engineering issues in the coastal environment.

As Offshore Engineers, they design structures like steel jacket structures, concrete gravity platforms, tension - leg platforms, etc., which are capable of withstanding the severe ocean environment.

As an Environmental Engineer, they have to protect the oceans from the harmful effects of mankind's activities. They are involved in harvesting and / or utilizing the oceanic resources such as minerals, wave energy, thermal energy and tidal power.

Depending mainly on the type of Qualifications held and personal inclination, Ocean Engineers may become specialists in one field or develop broad experience in others.

Eventually they may find themselves in senior executive positions using their knowledge and experience of general management as well as their professional skills in engineering and project leadership.

Indeed, aided by the breadth of their education, training and experience, the professional Naval Architects and Ocean Engineers are even successful in top management positions in government, industry and commerce quite outside the offshore field.

Main Areas of Scope :

There are lots of opportunities For Ocean Engineers and Naval Architects in the private, educational, corporate, and governmental sectors.

Some career areas to consider are : Offshore Oil Recovery, Marine metals and corrosion, Environmental Protection, Global Climate Monitoring, Renewable Energy, Underwater Vehicles, Remote Sensing, Marine Transportation, or Naval Architecture and Defence. Therefore, some main areas of scope are as follows :

Design Office :

Ocean Engineers are by necessity innovative and creative personalities. They must have an understanding of the many facets of offshore structure design such as its function, appearance and especially importance at sea safety.

They must be team leaders, able to integrate the inputs of many others to achieve a balanced and coherent whole. As a Naval Architect, apart from the architectural aspects of ship form and layout, they must be able to use complex mathematical and physical models to ensure that the design is satisfactory technically and that it meets the safety rules and standards laid down by Classification Societies and Government Agencies.

Since, the design process demands the extensive employment of computer based information and communication systems. Ocean Engineers should also be well versed in computer software knowledge.

As a design office employee, they are employed by ship and boat builders, offshore constructors, design consultants, and for the ships and submarines of the Navy and the Ministry of Defence.

Major equipment manufacturers also employ teams of engineers, including Naval Architects and Ocean Engineers on the design of such products as propulsion systems, auxiliary systems sub sea production systems and control systems.

Field Engineer :

The task of the ship and boat builders and offshore constructor is to convert drawings and detailed specifications into real structures. A Naval Architect and Ocean Engineers specialising,, in. construction usually holds a management post, taking responsibility for the management of the whole yard / site or for sections of it such as planning, production or the complex operation of fitting out.

There should continuously strive to make construction work efficient through the adoption of new processes and practices and by better training for the work force. The Ocean Engineers must also organise the supply of materials and components, inspection and testing as well as the vital resources of manpower.

Repair work has much in common with construction. Ocean Engineers and Naval Architects in this field can become professional managers in future, who like the builders need to master modern management and associated techniques.

Emergency repair work often offers opportunities for ingenuity and on - the - spot improvisation, and in the offshore engineering world in particular repair frequently involves underwater technology.

Therefore, as a site engineer, they are employed in construction and repair include both large and small shipbuilders and repairers, and those involved in the maintenance and repair of naval ships, submarines, harbours, ports and other offshore structures.

Consultant :

As consultants, Ocean Engineers and Naval Architects provide clients with engineering solutions, technical and commercial guidance and project management for concept design studies, new offshore structure developments, new vessel constructions, refits and conversions.

Therefore, they are employed to give professional advice and technical support to customers of the offshore industry.

Ship Surveyor :

Naval Architects and Ocean Engineers employed by Classification Societies as Ship Surveyors are engaged world - wide in evaluating the safety of ships and marine structures using the Society's Rules and those of intergovernmental organisations such as the International Maritime Organisation.

Plans of ships to be built and eventually classed with the Society are scrutinised, and aspects of design such as strength, stability, and lifesaving approved before construction.

Also during construction, Ship Surveyors carry out inspections to ensure that the quality of the workmanship and materials used is in accordance with the rules and regulations.

Once the vessel or structure is in service, Ship Surveyors will continue to carry out inspections to ensure that any serious defects arising from operation are made good and that a safe and seaworthy structure is maintained.

Government departments employ Naval architects who deal mainly with the framing of safety regulations and the surveying of ships and equipment from the safety point of view.

Research and Development :

Offshore research, in general, enjoys a high reputation world - wide. The Naval Architects and Ocean Engineers, many with post - graduate qualifications, are engaged in research in universities and industry throughout the world.

Classification Societies also devote resources to research and development employing Naval Architects in this field.

This variety of work provides a rewarding challenge to the Ocean Engineers and Naval Architects, not only as engineers but also as managers, consultants, surveyors, scientists, etc.

Institutes offering the Naval Architecture and Ocean Engineering Courses :

The various institutes in India providing Bachelor and Master degree in Ocean Engineering and Naval Architecture are as follows :

S. No.	Institutes	Offered Courses
1	Indian Institute of Technology Madras, Chennai - 600 036.	Ocean Engineering and Naval Architecture
2	Indian Institute of Technology Kharagpur, Kharagpur - 721 302.	B.Tech - Ocean Engineering and Naval Architecture M.Tech - Ocean Engineering and Naval Architecture
3	National Institute of Technology Surathkal, Mangalore - 575025.	M. Tech in Marine Structures
4	National Institute of Technology Calicut, Calicut - 673 601.	M. Tech in Offshore Structures
5	Cochin University of Science and Technology, Cochin.	M.Tech in Ocean Technology
6	Chennai School of Ship Management, Mambakkam, Chennai - 600 048.	Diploma Program in Marine Engineering
7	College of Engineering (Autonomous), Andhra University, Visakhapatnam - 530 003.	B.E. Naval Architecture, M.E. Hydraulic, Coastal & Harbour Engineering
8	Institute of Shipbuilding Technology, Vasco da Gama, Goa - 403 802.	4 Year diploma Program in Shipbuilding Engineering

It is a new field and is making tremendous advancements. It is our only frontier - we know less about the oceans than we do about the moon - so it is new and extremely rewarding. There is so much we have yet to learn about our oceans. Therefore, it is for sure that the career opportunities in this field will absolutely increase further.

There are not enough ocean scientists or engineers to meet all the demands of the day. Also, tomorrow's greatest discoveries in science, medicine and life knowledge will come from the oceans.

Skills for a Naval Architect

2010-11-01T08:51:00.000-07:00

The Job and What's Involved

Naval architects are responsible for the design, construction and repair of ships, boats, other marine vessels and offshore structures, including:

Merchant ships, e.g. oil/gas tankers, cargo ships and cruise liners.
Passenger and vehicle ferries.
Warships, eg frigates, destroyers and aircraft carriers.
Amphibious ships, e.g. submarines, semi-submersibles and underwater vehicles.
Offshore drilling platforms.
High-speed craft, e.g. hovercraft, multi-hull ships and hydrofoil craft.
Workboats, e.g. fishing vessels, tugs, pilot vessels and rescue craft.
Yachts, power boats and other recreational craft.

Some of the craft they work on are very large and complex, and all craft have to be safe and seaworthy. Although engineering on this scale involves whole teams of professional engineers in their respective fields, it is the naval architect who is responsible for co-ordinating the whole project.

Actual work activities vary depending on the type of company, project and role of the architect. They might specialise in one area such as:

- Design
- Construction and repair
- Consultancy
- Research and development
- Regulation, surveying and overseeing

Their work may include:

Preparing design plans of the architecture of the vessel and its layout, using computer software.
Working with complex computer and 3D models to check specifications.
Ensuring that the design meets safety standards and is seaworthy.
Sourcing materials and equipment.
Co-ordinating the construction or repair work.
Evaluating the safety of ships and marine structures.

Naval architects tend to work normal office hours, but may need to work additional hours to meet deadlines. They may be required to travel to shipyards or docks and this could involve spending some time away from home, possibly overseas.

Shipyards, docks and marinas can be noisy and dirty, and work onboard a craft may involve time in the engine room or other areas where there can be fumes, heat and noise. It may be necessary to work outside during bad weather and rough seas.

Office-based design work can involve sitting at a computer for long periods, while work onboard a vessel can mean a lot of walking, bending and climbing.

When visiting construction or repair sites, it may be necessary to wear protective clothing.

Naval architects can be self-employed or work on a contract basis - especially in the small or high-speed craft sectors.

Starting salaries range from around £20,000 to £24,000 a year. The pay for self-employed architects varies depending on their experience, the particular projects they are involved in, and the amount of time they work.

Getting Started with this Career Choice

With the decline in shipbuilding in the UK over the past 20 years, there are fewer shipyards (only four large commercial shipyards are currently in operation), and so fewer openings for naval architects working specifically on new vessels. However, the remaining shipyards are now busy building specialist vessels, particularly for the offshore industry and the Royal Navy.

There are also many opportunities in the design and construction of small craft and yachts. This is an expanding area as a result of the long UK coastline, navigable rivers and canals. Most jobs are based in coastal cities or towns.

Some naval architects work as ship surveyors for the classification societies or the Maritime and Coastguard Agency (MCA), assessing the safety of marine structures and ships. There are now almost 50 classification societies around the world. The main companies have offices in the UK and overseas, so there are opportunities to work in a variety of locations. Many naval architects work abroad, often on large-scale projects outside of Europe.

In all areas, competition for jobs is fierce.

Posts may be advertised in journals such as The Naval Architect and Offshore Marine Technology. There are also recruitment and skills-matching agencies that specialise in marine and engineering posts.

Education and Training

A degree in an engineering subject is usually essential. Relevant degree courses include naval architecture, marine technology or other disciplines of engineering closely related to naval architecture.

Entry to degree courses is with at least five GCSE's/S grades (A-C/1-3) and two A levels/three H grades, including maths and physics, or equivalent qualifications.

The Ministry of Defence (MOD) operates the Defence Engineering & Science Group (DESG) graduate scheme. The scheme gives science and engineering graduates training and work placements within a range of MOD departments.

School leavers may be able to train in marine engineering with the Royal Navy or Merchant Navy. Some organisations, including The Royal Institution of Naval Architects (RINA), offer scholarships to provide financial help during periods of study.

A Few More Exams You Might Need

A diploma or degree in naval architecture or a related subject is normally followed by four years training in design, engineering practice and management, before naval architects can become professionally qualified.

A Diploma will help you make a more informed choice about the type of learning that best suits you and about what kind of work or further study you may want to do afterwards.

Training is normally on the job. New recruits are usually given an individual training programme to meet their particular needs, and a senior engineer is often appointed to act as their mentor. Some companies run RINA and The Institute of Marine Engineering, Science and Technology (IMarEST) accredited training programmes. A full list is available on the RINA and IMarEST websites.

With a sufficient period of training and enough experience, a naval architect can become a member of RINA and register with the Engineering Council UK (ECUK) as a chartered or incorporated engineer.

Case Studies on Ship Structural Failures

2010-11-01T08:35:00.000-07:00

Chronic Cracking in an Aluminum SWATH Research Vessel

Vessel Particulars

LOA: 117’-3 5/8”

Breadth: 53’-0”

Depth: 25’-0”

Draft: 12’-0”

Gross Tonnage: 499

Displacement: 419 LT

Complement: 26 (10 crew, 16 science)

Maximum Speed: 14.5 knots

Endurance: 4000 NM at 8 knots

Builder: SWATH Ocean Systems

Year Built: 1996

ID No.: 1038571

Class: None, COI and Load Line

Flag: US

Owner/ Operator: Monterey Bay Aquarium Research Institute, Moss Landing, CA

Vessel Type: SWATH (Small Waterplane Area Twin Hull), Diesel Electric Propulsion

Hull Material: Aluminum

Figure 1. Profile of R/V WESTERN FLYER

Summary of Structural Failure

R/V Western Flyer has experienced localized cracking to its aluminum structure during typical operations during virtually all of its twelve year life span. Various modifications have been implemented in an attempt to solve this problem.

Background

Design

R/V Western Flyer was designed and built by SWATH Ocean Systems in 1996 for Monterey Bay Aquarium Research Institute (MBARI). The design was based on successful SWATH Ocean Systems designs for smaller vessels. Although USCG was involved in the review of the design, extensive detailed structural analysis was not completed in the design phase.

R/V Western Flyer’s mission is to provide a stable platform for ROV operations for MBARI’s Tiburon in water up to 4000m. Because of the extreme water depth and the rapid changes in weather encountered in the Monterey Basin area, it is necessary for the R/V Western Flyer to be able to operate up to Sea State 5. In order to facilitate ROV deployment and retrieval, especially in higher sea states, an internal moon pool is utilized.

Figure 2 shows a typical transverse web frame. All structure is 5086 aluminum, except for isolated bulkhead and deckhouse framing that is 6061. Web frames are spaced every three feet, with transverse bulkheads every 15 feet.

Figure 2. Transverse Web Frame

Events leading to failure

During one of R/V Western Flyer’s early voyages, the bilge alarm in the steering flat was activated. The crew discovered water seeping through cracks in the transom. Further investigation located cracking in several other locations throughout the vessel. Weather conditions had been moderate (Sea State 3-4) from the starboard beam.

Detailed Description of Structural Failure

While the cracking in the transom was the result of coincident plate seams, butts and corners, the majority of the cracking was in transverse frames and watertight bulkheads in way of the haunch girder notch. Cracking in the transverse frames was primarily in locations without adequate bracketing in way of the notch. Some side shell cracking was seen in way of the transverse bulkheads. See Figure 3.

Figure 3. Haunch Girder Notch

Initial Analysis and Repair

In order to continue operating while extensive structural analysis was performed, the strategy of repair and monitoring was adopted. All cracks were repaired and brackets were installed on those frames without them previously. In order to assess the efficacy of the repair, operation was to proceed in worsening sea conditions with the possibility of altering course to minimize loading on the structure.

In the first two months of limited operation and vessel monitoring, over 100 new cracks developed. All of these cracks were at the ends of welds in the haunch area. A stress monitoring program was installed on the vessel to provide a visual and audible alarm on the bridge to alert the crew of a need to change course.

Two-dimensional finite element analysis was completed on a typical bulkhead and web frame. Loading on the models was determined based on beam seas in Sea States 3-5. The loading on the hull for a regular incident wave over a range of frequencies was calculated using MIT’s wave analysis program (WAMIT). The response in regular waves was applied to a Bretschneider spectrum to determine the extreme loads for each mode (roll, heave, pitch, etc.). Because the extreme forces do not occur together, combinations were created maximizing one mode at a time. The results of this initial FEA showed that even with brackets in place the stress in the haunch girder notch was over 40,000psi in Sea State 5. See Figure 4.

Figure 4. Stress in Transverse Bulkhead, Beam Sea, Sea State 5

Detailed Analysis

In order to understand more fully the response of the structure of the R/V Western Flyer, a global three dimensional finite element model of the entire hull and deckhouse was constructed. See Figure 5.

Figure 5. Global 3-D Finite Element Model

A pressure distribution over the wetted surface of the hull was developed using an equivalent irregular wave. The resulting loading is a squeezing/prying moment acting on the pontoons. This analysis was repeated for the vessel with the proposed modifications to assess their effectiveness. The design load for the modified vessel is higher than the existing due to changes in the pontoons to counteract weight addition.

Figure 6. Deflection Plot, Prying Condition

Results of the global FEA confirmed failures experienced in several areas of the vessel. High stresses were shown in the haunch girder notch areas and at the corners of the deckhouse bulkhead and deck intersections. Panel buckling was calculated (and had occurred) in the transverse structure aft of the moonpool and in areas of the deckhouse.

Modification

The following modifications were accomplished at Bay Ship and Yacht in Alameda, CA between 1998 and 1999.

Faired the notch between the strut and haunch.
Added half frames in way of the haunch.
Deepened existing haunch frames.
Added half frames aft of the moonpool.
Increased stiffening in the deckhouse.
Replaced aft bulkhead of house with thicker plate of stronger aluminum.
Increased diameter of pontoons over a portion of their length to compensate for additional weight.

Figure 7 shows the effect of the modification to the haunch girder notch on the stress distribution.

Figure 7. Haunch/Strut Stress with/without Fairing

End Result

Unfortunately, the 1998 modifications were not sufficient to completely solve the cracking problem on R/V Western Flyer. She continued to experience cracking at the junction of the deckhouse and main deck. Because the deckhouse is stepped away from the side, the prying moment causes the deck to bend up around the house. In 2005, after various other attempts, a strut was added aft at Frame 28 to connect the hulls to resist prying. See Figures 8 and 9. Frame 28 was chosen because it coincides with transverse bulkheads above and below deck, specifically the aft house bulkhead. Because ROV operations are conducted through a moon pool, strut installation any further forward would interfere.

The crew reports no adverse effects on performance due to either the aft strut or the increase in pontoon diameter. Continued crack monitoring shows no additional cracking in way of the haunch or pontoon joints.

Figure 8. Global Model with Strut Installed

Figure 9. Pontoon Strut

Design Observation

In retrospect, there are certain features of the design of R/V Western Flyer that could have been improved in earlier phases. The first is the concave bracketing in way of the haunch joint. In theory this was done to reduce spray. The second is to have the deckhouse side inset from the hull side, especially without, adequate structural members below to help distribute the load where the house side crosses the below deck bulkhead.

While earlier incorporation of the pontoon strut might have obviated some structural modifications, it was ruled out in the initial design due to the interference with ROV operations through the moon pool. It is not likely that the strut alone would have eliminated all cracking problems, particularly in way of the haunch.

Acknowledgements

References:

[1] Dockter, M.E. and K. Schmidt, “SWATH Research Vessel: The Building of RV Western Flyer,” Marine Technology, July 1996.

[2] Van Slyke, Morgan, Leach and Etchemendy, “R/V Western Flyer – Hull Strength Upgrade,” SNAME Pacific Northwest Section, 17 April 1999.

Ballast Water Management

2010-10-24T09:58:00.000-07:00

1. The introduction of invasive marine species into new environments by ships’ ballast water, attached to ships’ hulls and via other vectors has been identified as one of the four greatest threats to the world’s oceans. The other three are land-based sources of marine pollution, overexploitation of living marine resources and physical alteration/destruction of marine habitat.

2. Shipping moves over 80% of the world’s commodities and transfers approximately 3 to 5 billion tonnes of ballast water internationally each year. A similar volume may also be transferred domestically within countries and regions each year. Ballast water is absolutely essential to the safe and efficient operation of modern shipping, providing balance and stability to un-laden ships. However, it may also pose a serious ecological, economic and health threat.

3. Studies carried out in several countries have shown that many species of bacteria, plants and animals can survive in a potent form in the ballast water and sediment carried in ships, even after journeys of several months' duration. Subsequent discharge of ballast water or sediment into the waters of another port may result in the establishment of harmful aquatic organisms and pathogens which may pose threats to indigenous human, animal and plant life, and the marine environment. Although other media have been identified as being responsible for transferring organisms between geographically separated water bodies, ballast water discharge from ships appears to have been among the most prominent. .

CATASTROPHE IN THE WAITING

4. There are thousands of marine species that may be carried in ships’ ballast water; basically anything that is small enough to pass through a ships’ ballast water intake ports and pumps. These include bacteria and other microbes, small invertebrates and the eggs, cysts and larvae of various species. The problem is compounded by the fact that virtually all marine species have life cycles that include a planktonic stage or stages.

5. It is estimated that at least 7,000 different species are being carried in ships’ ballast tanks around the world. The vast majority of marine species carried in ballast water do not survive the journey, as the ballasting and deballasting cycle and the environment inside ballast tanks can be quite hostile to organism survival. Even for those that do survive a voyage and are discharged, the chances of surviving in the new environmental conditions, including predation by and/or competition from native species, are further reduced. However, when all factors are favourable, an introduced species by survive to establish a reproductive population in the host environment, it may even become invasive, out-competing native species and multiplying into pest proportions.

6. As a result, whole ecosystems are being changed. In the USA, the European Zebra Mussel Dreissena polymorpha has infested over 40% of internal waterways and may have required between US$750 million and US$1 billion in expenditure on control measures between 1989 and 2000. In southern Australia, the Asian kelp Undaria pinnatifida is invading new areas rapidly, displacing the native seabed communities. In the Black Sea, the filter-feeding North American jellyfish Mnemiopsis leidyi has on occasion reached densities of 1kg of biomass per m2. It has depleted native plankton stocks to such an extent that it has contributed to the collapse of entire Black Sea commercial fisheries. In several countries, introduced, microscopic, ‘red-tide’ algae (toxic dinoflagellates) have been absorbed by filter-feeding shellfish, such as oysters. When eaten by humans, these contaminated shellfish can cause paralysis and even death. The list goes on, hundreds of examples of major ecological, economic and human health impacts across the globe. It is even feared that diseases such as cholera might be able to be transported in ballast water.

7. India has more than 7500 kms long coast line with12 major ports. Average 5000 ships call in Mumbai port alone and receive 1.8 m tonnes of ballast water each year. Indian coasts are falling prey to the malicious Marine Bio invasion through ballast water. Through port baseline survey and research work, it is established that Mytilopsis sallei, a native of Sub-tropical Atlantic, is found in Mumbai and Vishakhapatnam ports in India.

8. Mytilopsis sallei is a mussel which has invaded Indian sea. This species accumulates in large quantity (10-12 kgs/m ) and creates several maintenance problems with regard to marine structures, equipment and machinery. This species is strong enough to survive in difficult marine climatic conditions and also in polluted and Oxygen deficient water.

TREATMENT TECHNOLOGY

9. Re-ballasting at sea, as recommended by the IMO guidelines, currently provides the best-available measure to reduce the risk of transfer of harmful aquatic organisms, but is subject to serious ship-safety limits. Even when it can be fully implemented, this technique is less than 100% effective in removing organisms from ballast water. Some parties even suggest that re-ballasting at sea may itself contribute to the wider dispersal of harmful species, and that island states located ‘down-stream’ of mid-ocean re-ballasting areas may be at particular risk from this practice. It is therefore extremely important that alternative, effective ballast water management and/or treatment methods are developed as soon as possible, to replace re-ballasting at sea. Significant research and development (R&D) efforts are underway by a number of scientific and engineering research establishments around the world, aimed at developing a more complete solution to this problem.

10. Options being considered include:-

(a) Mechanical treatment methods such as filtration and separation.

(b) Physical treatment methods such as sterilisation by ozone, ultra-violet light, electric currents and heat treatment.

(d) Various combinations of the above.

11. All of these possibilities currently require significant further research effort. Major barriers still exist in scaling these various technologies up to deal effectively with the huge quantities of ballast water carried by large ships (e.g. about 60,000 tonnes of ballast water on a 200,000 DWT bulk carrier). Treatment options must not interfere unduly with the safe and economical operation of the ship and must consider ship design limitations. Any control measure that is developed must meet a number of criteria, including:

(a) It must be safe and reliable

(b) It must be environmentally acceptable

12. One of the problems currently faced by the global R&D community is that apart from the general criteria above, there are currently no internationally agreed and approved performance standards or evaluation system for the formal acceptance of any new techniques that are developed. In addition, many groups are working in isolation from each other, and there are no formal mechanisms in place to ensure effective lines of communication between the R&D community, governments and ship designers, builders and owners. These are vital if the R&D effort is to succeed.

Want to be a Naval Architect?

2010-06-12T06:55:00.000-07:00

An interesting article (By Rahat Bano) from Indian Newspaper 'Hindustan Times'

A conversation between a woman Indian naval officer and an ‘outsider’?
Outsider: So are you working or studying?
Officer: I’m working.
Outsider: Where?
Officer: I’m in the Navy?
Outsider: You mean like a civilian?
Officer: No, I’m an officer.
Outsider: Oh…but like a civilian?
Officer: No, I’m a commissioned officer in the Navy.
Outsider: Oh! So, you wear uniform?
Officer: Yes, I do.
Outsider: So, what do you do in the Navy?
Officer: I’m a naval architect.
Outsider: Oh…it’s a good choice, women have good decorative skills.
Decorative skills? The naval officer wondered “what to say” to that because she’s in one of the most demanding of professions, which involves designing and developing warships, submarines, hovercraft, hydrofoils and merchant ships. She’s a naval architect — a community that’s celebrating a big recent achievement as they’ve just rolled out India’s first indigenously-designed and manufactured stealth warship, INS Shivalik, from the public sector, 200-(odd)-year-old, Mazagon Docks Ltd in Mumbai.

These professionals are a few from among the countless who get to put sails to their childhood pastime of making and floating paper boats in rainwater puddles.
They design, develop and repair a range of watercraft, including merchant ships (tankers, cargo ships, bulk carriers, etc), warships, submarines, passenger ferries, cruise liners, hovercraft, boats, yachts, icebreakers, and other structures such as hydrofoils and oil drilling platforms. They essentially make small floating cities.

Says a faculty member at IIT Delhi, which runs a diploma programme in naval construction for the Indian Navy, “It’s a profession known to mankind by intuition as across the globe, civilisations have grown and prospered around water bodies. The negative side is only individual thinking, based on self-drawn constraints. In a particular location, growth remains limited like most other engineering jobs.”

Apart from the Indian Navy and government and private shipyards, naval architects have opportunity in self-employment. “The career of a naval architect has massive growth potential in entrepreneurship — ship repairs, boatbuilding, shipbuilding, harbours and docks, ship lifts, equipment for the ships, the list goes on,” says the faculty member. The recession in 2008 affected India’s shipbuilding industry, too, but the pall of gloom is lifting, he says.

However, India lacks graduate naval architects. Many drift towards greener pastures — either an MS abroad or an MBA. They get into management positions or fly to better-paying companies in China, Korea and Singapore, says Harish C Narula, chairman, Fibroplast Marine, Noida, which designs and manufactures commercial and defence boats for clients such as the Coast Guard, CRPF, and the Uttar Pradesh Police. “For the last two years, there has been no (graduate) naval architect (taking up a naval architecture job) in India.” So, Narula says he ends up hiring mechanical engineers and training them. The Indian Navy, too, takes in engineers from different branches, including civil, metallurgical, and mechatronics, who are then trained in naval construction.

Narula says the government should open more institutes giving diplomas in naval architecture/shipbuilding as well as BTech in this discipline, to meet market requirements.

The industry is revving up, with the public sector companies in the lead. India requires more vessels, especially for coastal security in view of increased terrorist threats.

What's it about?
Naval architects design, develop and repair watercraft, and other structures such as hydrofoils and oil drilling platforms. They design basic structure (hull geometry), make the final design and do stability calculations, among other activities. Their employers include four Ministry of Defence shipyards i.e. Mazagon Dock Ltd, GSL, GRSE and HSL and Ministry of Surface Transport’s CSL, Kochi, and many private shipyards, shipping companies and boat builders

Clock Work
In a drawing office, shipbuilding yard or ship repair yard:
8.30 am: Check reports from sites, identify bottlenecks, prepare the information matrix for the day and compare with the bigger picture of the job
9.30 am: Meet respective people to remove the difficulties relating to man, material, machinery or any other aspect like access to relevant part of the working space
11.30 am: In the drawing office or at production floor, check drawings, calculations carried out by subordinates; check the progress
1 pm: Lunch
2 pm: Check all the follow-ups
3 pm: Review the progress covering daily weekly and monthly status
4 pm: Assess achievements of the day reschedule the priorities based on the planned milestones
5.30 pm: Reports, briefs and plans of next day
At shipbuilding or ship repair yards: Status of urgent work, deputing workers on next shift as required, assessing safety and health issues
6.30 pm: Back home (Normal office routine)
During sea trials or harbour trials of vessels, round-the-clock work is required, for which deployment schedules are made on the basis of type of trials

The Payoff
. Rs 15,000 onwards a month for a diploma holder. Rs 25,000 onwards a month for a fresh engineer (four-year degree)
. Sky is the limit for an entrepreneur with training in the field

Skills
. Scientific temperament
. Creative and analytical aptitude
. Decision-making skills
. Leadership qualities — ability to manage manpower and material
. Ability to set priorities (to meet deadlines)

How do i get there?
Take up science (physics, chemistry and maths) at the plus-two level. Pursue a BTech degree in naval architecture and ocean engineering, offered at a few institutes in India, for which you need to clear a written entrance test. The Indian Navy takes in graduates in select branches of engineering, who are given post-graduate training at the Indian Institute of Technology Delhi. After the officers earn their diplomas in naval construction from IIT Delhi, the Navy sends them to the naval dockyards in Mumbai, Visakhapatnam, Cochin or Port Blair

Institutes & urls
. IIT Madras and Kharagpur
BTech in naval architecture and ocean engineering as well as a five-year dual BTech/MTech (naval architecture engineering and MTech in applied mechanics in
any of the listed specialisations)
http://jee.iitd.ac.in/availability.htm
. Cochin University of Science and Technology, BTech in naval architecture and shipbuilding
www.cusat.ac.in
. IIT Delhi (Diploma in naval construction, for Indian Navy officers)
www.iitd.ac.in
. Indian Maritime University, Chennai, diploma leading to BSc in shipbuilding and repair
www.imu.tn.nic.in

Pros & Cons
. Constructive work — the fruit of your labour is tangible
. Niche job
. You can design and build small boats (5 metres long) to ultra large crude carriers (400 metres) or floating cities
. Shipbuilding is a cyclic industry, which sees booms and dips by rotation
. Job options limited to some locations
. Opportunities to sail in different types of vessels, from luxury liners to cramped submarines Shipbuilding activity has taken a lead

Security threats and disaster mitigation create the need for more vessels, says a boat manufacturer

What’s the scope in this industry in India? What’s the manpower requirement?
In India, naval architects have been scarce. There were only two colleges teaching naval architecture — IIT Kharagpur and Madras. For the last two years, there has been no (graduate) naval architect (taking up a naval architecture job) in India. So, the real problem is, many good naval architects get into management positions or work in China, Korea and Singapore (because of higher salaries).That’s the supply side.

Government shipbuilding activity has taken a lead. After the terrorist attacks in Mumbai, there is a coastal security requirement. The government wants more ships and boats — for the navy, coast guard, and coastal police to patrol the country’s coastline.

Also, after the September 11 attacks on the US, a UN convention requires every country to patrol and protect sea lanes where ships are moving in its territorial waters. So, more fleets are required.

But due to the shortage of (graduate) naval architects, the Navy and the Indian Register of Shipping are being forced to take other graduates — civil engineers, chemical engineers and train them but they can’t have in-depth design capability.

The government needs to have more institutes of three-year diploma courses. At the same time, it needs to plan and increase seats in four- and five-year degree programmes in naval architecture.

I would like to add that all naval architecture institutes teach shipbuilding and ship design, not boats. Now boats are required in thousands for disaster mitigation, rescue operations during floods, fishing, patrolling.

So, where do you hire people from?
We take fresh graduates and train them on the job.

Harish C Narula, chairman, Fibroplast Marine Interviewed by Rahat Bano

Naval Architecture & Marine Engineering Courses at University of Strathclyde

2010-03-06T09:10:00.000-08:00

Naval Architecture is the engineering speciality which deals with the design, construction, repair and operation of all types of ships and boats.

The Department of Naval Architecture & Marine Engineering offers the following degree courses:

MEng Naval Architecture

BEng (Honours)/MEng Naval Architecture & Marine Engineering

BEng (Honours)/MEng Naval Architecture with Ocean Engineering

BEng (Honours)/MEng Naval Architecture with Small Craft Engineering

The degrees are accredited by the Royal Institution of Naval Architects (RINA) and the Institute of Marine Engineering, Science & Technology (IMarEST) on behalf of the Engineering Council.

Overview of Courses

The degree programmes are stimulating and challenging and provide a broadly-based engineering education. They are taught by the Department of Naval Architecture and Marine Engineering (NA-ME).

The balance of emphasis of the course material evolves as you progress through your degree, from fundamental engineering science and core Naval Architecture and Marine Engineering subjects, to increasing concentration on topics specific to your chosen course.

The flexible programme structure allows transfer between Naval Architecture degree programmes. Transfer is possible between the Naval Architecture with Small Craft Engineering, Naval Architecture with Ocean Engineering, and Naval Architecture degrees up until the end of Year 2. Transfer to and from the Naval Architecture and Marine Engineering course can take place up until the end of Year 1 (and sometimes later). Suitably qualified students may transfer between the BEng and MEng courses.

A range of realistic design projects is made possible though our strong links with the ship and offshore industries. Transferable skills developed through project work and presentations will give you a wide choice of exciting and rewarding careers.

The Courses

Naval Architecture & Marine Engineering

This degree programme is designed to develop engineers who are able to deal with engineering challenges on a wide range of marine vehicles, with additional skills and understanding in the impact and importance of Marine Engineering on their successful design, construction, repair and maintenance. Marine Engineering is the engineering speciality which addresses the design and operation of machinery and propulsion systems for ships and marine structures.

Naval Architecture with Ocean Engineering

This degree deals with other fixed and floating marine structures and systems including offshore oil and gas, renewable energy and ocean resources. The programme is designed to develop engineers who can address the engineering challenges on marine vehicles from giant cruise liners and fast ferries to tidal current turbines and oil platforms.

Naval Architecture with Small Craft Engineering

This course creates designers with all the core skills of ship design, construction, operation and maintenance, along with a particular specialism in the creative design and engineering of small leisure and commercial vessels, including sailing and power yachts, fast ferries, hydrofoils, hovercraft and fishing boats. Small Craft have developed dramatically in recent years. Lighter, faster, stronger and safer vessels are being designed and built using advanced materials and technology combined with creative design engineering.

Course Structure

The degree courses offered by the Department have a flexible credit-based structure. Some of these credits will be elective which you can choose from a wide range of subjects, not only within the Department but also from other Departments and Faculties across the University.

Year 1

You will build the foundations for your specialised skills by studying fundamental engineering science, mathematics, and computing along with introductory classes in naval architecture, marine engineering and marine transportation. You take part in a group project (typically four to five students) to design, build and test a simple container carrying ship model.

Year 2

Focus changes to the study of specialized Naval Architecture and Marine Engineering subjects, such as flotation, stability and safety of ships and marine vehicles, strength of marine structures, properties of materials used in marine structures, manufacturing techniques, and basics of marine machinery and systems. There is a group project in which you apply your engineering knowledge to design, build and test a radio-controlled sailing yacht.

Year 3

You continue to study core Naval Architecture and Marine Engineering subjects, including the resistance (drag) and propulsion of ships, properties of ocean waves, design of marine vehicles, and control of machinery, along with marine business and management. You will also study the first of the specialised modules specific to your chosen degree course. You also carry out an individual project to produce a preliminary design of a ship, using a traditional approach based on the application of established design rules. A focused series of laboratory experiments illustrate important phenomena which will help you understand laboratory techniques used in the marine industries.

Year 4

One or two modules cover core Naval Architecture subjects, with the main emphasis of the other classes being on your chosen specialism:

Marine Engineering includes marine engineering design, marine transmission & propulsion systems, marine electrical systems, and protection of the marine environment.

Ocean Engineering brings in subjects such as analysis of dynamics of structures subject to wind and wave loading, computer prediction of fluid flow around structures (often known as CFD) and technology and performance of renewable energy systems.
Small Craft Engineering includes subjects such as the prediction of the performanceof sailing yachts and powerboats, design of lightweight structures, and the behaviour of high-speed craft.

You can also take part in a team to develop a preliminary design of a sailing yacht or luxury power yacht to a brief supplied by a group of clients. The remaining 30 credits are devoted to an individual project on a related subject of your choice.

Year 5 (MEng only)

MEng students can choose from an extensive list of technical and business modules. There is also a substantial and challenging group design project on a subject chosen by agreement between students and staff. Subjects chosen recently include designs of high-speed cargo ships, tidal current energy devices and Americas Cup yachts

Role of Classification Societies in Shipbuilding : A Primer for Naval Architects & Marine Insurers

2010-02-13T00:00:00.000-08:00

1. A brief history

1.1 The first classification society was formed in 1760 in Lloyd’s Coffee House, London. Lloyd’s Coffee House was a centre for the marine business interests of the day and the Register Society was formed by the customers of the coffee house. The society, later to become Lloyd's Register, was started in order to grade the condition of ships to assist charterers, insurers and other interested parties to assess the risk associated with any particular vessel.

1.2 In the early years classification was simply an assessment of the standard of construction and continuing soundness of ships as determined by the surveyors. In later years the experience and knowledge gained from such assessments led to the creation of rules for the construction and maintenance of ships. Classification rules have been under continuous review and development since that time and now address ship structures and essential shipboard engineering systems.

1.3 Subsequent to the introduction of “open flag registers”, such as Liberia and Panama, and the formation of the United Nations body IMCO (now IMO) to develop regulations concerning technical standards in shipping, Classification Societies have provided statutory certification services on behalf of Flag States.

1.4 Today there are over fifty classification societies in the world. However, 90% of the world merchant fleet (by gross tonnage) is classed by the ten members and two associates of the International Association of Classification Societies (IACS) – an industry trade association that facilitates co-operation between societies.

2. Classification Today

2.1 IACS defines classification as follows:
“Ship Classification, as a minimum, is to be regarded as the development and worldwide implementation of published Rules and/or Regulation which will provide for:
1. the structural strength of (and where necessary the watertight integrity of) all essential parts of the hull and its appendages,
2. the safety and reliability of the propulsion and steering systems, and those other features and auxiliary systems which have been built into the ship in order to establish and maintain basic conditions on board,thereby enabling the ship to operate in its intended service.

3. Perceptions

3.1 Although the IACS definition is clear the perceptions of different actors in the industry do vary. Many view classification societies as the industry regulators. In the IACS paper Ship Safety and Pollution Prevention: The Regulatory Regime,4 Mr Smith implies classification is a regulator when he says
“The regulatory regime concerning ship safety and marine pollution prevention is comprised of classification rules made by classification societies and the regulations contained in the international conventions made collectively by Member States at IMO.” (emphasis added)
This perception is reinforced as a result of the statutory work that the societies carry out on behalf of Flag States. However, classification societies are not regulators.

3.2 AMRIE believes that this blurring of definition and perception hinders the debate on the technical aspects of shipping. In order to place the AMRIE position on classification societies in context the AMRIE view on the regulatory regime, and the role of classification, is outlined below.

4. The Regulatory Regime

4.1 In terms of the international shipping industry the authority and principal jurisdiction a vessel falls under is that of its Flag State (subject to any Port State or Coastal State jurisdiction). This is reflected in customary international law as codified in the Untied Nations Convention on the Law of the Sea (UNCLOS).

4.2 Under Article 94 of UNCLOS the Flag State has certain duties including:
“effectively exercis[ing] its jurisdiction and control in administrative, technical and social matters over ships flying its flag”
taking “such measures for ships flying its flag as are necessary to ensure safety at sea with regard, inter alia, to:
a) the construction, equipment and seaworthiness of ships;
b) the manning of ships, labour conditions and the training of crews, taking into account the applicable international instruments;
c) the use of signals, the maintenance of communications and the prevention of collisions”
“In taking the measures called for…[above]…each State is required to conform to generally accepted international regulations, procedures and practices and to take any steps which may be necessary to secure their observance.”

4.3 In terms of technical matters “accepted international regulations” is generally accepted as meaning those produced by the International Maritime Organisation (IMO). The most important of these in the context of this paper is the Convention on the Safety of Life at Sea (SOLAS) – the only convention that specifies classification as a statutory requirement.

4.4 The SOLAS convention lays down provisions concerning maritime safety. It is the most comprehensive and widely ratified text of its kind and lays down requirements for the construction of ships, fire protection and extinction, life-saving appliances, radio communication and requirements for the carriage of grain and dangerous goods.
SOLAS Part A-1, Regulation 3-1 states:
“In addition to the requirements contained elsewhere in the present regulations, ships shall be designed, constructed and maintained in compliance with the structural, mechanical and electrical requirements of a classification society which is recognised by the Administration in accordance with the provisions of regulation XI/1, or with applicable national standards of the Administration which provide an equivalent level of safety.”

4.5 In is worth noting that although classification is laid down as a requirement it is not mandatory. An administration may use its own national standard if it wishes, although no such standard currently exists.

4.6 In summary, Flag States are the regulators of technical standards working within the framework as codified by UNCLOS and standards defined by international conventions developed under the auspices of the IMO. In terms of structural, mechanical and electrical requirements they can choose which standards they accept and apply, although in practice, they use those of a classification society.

5. Classification

5.1 The primary sources of independent technical expertise in shipbuilding lie with the Classification Societies. Their role is well defined by IACS above – they develop technical standards, i.e. rules, for the construction of ships. They will approve designs against their standard, conduct surveys during the construction of a vessel and issue a certificate to say that the vessel meets the requirements of their standard on delivery. They prescribe regulations requiring periodical surveys and upon satisfactory completion of such surveys endorse the vessel’s classification certificate to indicate that the vessel still meets the required standard. For all these services, fees are charged based on the size and complexity of the vessel.

5.2 Regulators, port states and other interested parties can then accept the certificate as evidence of the standard of the vessel if they so choose.

5.3 In general, shipyards and shipowners pay for the work of Classification Societies. At the new construction stage the owner specifies which Classification Society is to be used, but the contract for the services provided is usually with the shipyard. Upon delivery the owner then has a contract with the Society for the provision of services, including classification related and statutory surveys (see below). The fees charged for these services represent a very small proportion of the costs involved in such projects.

5.4 Most Classification Societies are not for (distributed) profit organisations that exist for the benefit of the industry they serve. Committees that represent the industry, consisting of representatives from ship owners and operators, builders, insurers, charterers and other relevant parties govern such societies. A small number of societies, however, are limited companies with shareholders.

5.5 It is useful to highlight what the societies are not. As discussed above they are not regulators, neither are they enforcement agencies - they have no authority. There are no punitive measures they can take against a ship owner. If the vessel does not meet the required standard as laid out in the rules, and the owner will not carry out remedial work, the classification certificates will be withdrawn - nothing else. Also, they are not responsible for the maintenance of ships - the certificates issued, or in the case of a periodical survey endorsed, indicate that at the time of survey the vessel met the prescribed standard.

6. Statutory role

6.1 In addition to the technical matters addressed by classification, vessels must comply with the technical requirements laid out in the adopted IMO conventions. As outlined above, ensuring such compliance is the responsibility of the Flag States and some do carry out this function, approving plans and conducting surveys themselves. However, many Flag States do not have an administration with sufficient capability or resource to do so and delegate this task to a recognised organisation, usually a Classification Society. The large Societies have authorisations, to varying degrees, from more than 100 Flag States to carry out plan approval, surveys and certification in accordance with international conventions and codes on their behalf. The only non-technical authorisation delegated to Classification Societies is for the ISM code.

6.2 Some argue that, in these circumstances, the responsibility for ensuring compliance is transferred to the Classification Society. However, it should be noted that authorisation agreements do include clauses with regard to Flag State supervision and audit of recognised organisations - acknowledgement of retained responsibility. The AMRIE position in this regard is that the responsibility for safety at sea with regard to the construction, equipment and seaworthiness of ships remains with the Flag State as defined under UNCLOS Article 94. However, this does not absolve the Classification Society of the responsibility to carry out their work in a professional and diligent manner, ensuring that when a certificate is issued - stating that a vessel complies with a pertinent regulation - the vessel does indeed comply. (Nor in a more general sense does it obviate the practical need for Port State control)

6.3 As discussed in the previous section the societies are not enforcement agencies or responsible for maintenance. This position is further demonstrated by the fact that they do not have the authority to withdraw statutory certificates they have issued – this can only be done with the specific authority of the Flag State.

Naval Architecture Colleges- Cochin University of Science & Technology

2010-02-12T23:31:00.000-08:00

Department of Ship Technology, Cochin University

Pride of CUSAT

The Cochin University of Science and Technology's B.Tech. Naval Architecture and Ship Building course is in great demand among students as job is virtually assured on the successful completion of the course.

The Department of Ship Technology has a pride of place at the Cochin University of Science and Technology (Cusat). It has the distinction of offering one of the most-sought after courses in the engineering stream in the country.

The B.Tech. in Naval Architecture and Ship Building course offered by the department has, for the last three decades, attracted thousands of students from across the country.

With the department maintaining 100 per cent placement every year, the demand for the course continues to be on the rise among students. Only three other institutions - IIT Kharagpur, IIT Madras and Andhra University - offer the course in the country.

The curriculum

The B.Tech. course was started in 1975 with a view to creating a new generation of naval architects to meet the requirements of the Indian shipbuilding industry, ship classification societies, research and development organisations and the Indian Navy.

The curriculum of the eight-semester course has been designed to provide students with an in-depth knowledge of the various facets of Naval Architecture along with training in basic Science and Engineering courses.

The major areas of study in the curriculum include ship designing, ship building technology, marine engineering, computer-aided designing (CAD) and computer-aided manufacturing (CAM), offshore structure designing, designing fishing vessels and refrigeration and air-conditioning at sea.

"The course also lays special emphasis on providing technical training to the students. Every year, students are sent to various shipyards, ship repair firms, ports and research and development organisations for training for six to eight weeks," says K.P. Narayanan, head of the department.

Students are also trained in computer programming and computer applications in Naval Architecture and Ocean Engineering.

The sanctioned intake for the B.Tech. course was 39 in 2003. Of the total seats, 12 were reserved for candidates sponsored by the Indian Navy.

Eligibility

Candidates applying for the course should have passed Plus Two/pre-degree examination conducted in Kerala in first class or the examination of any other university/board accepted by the Syndicate of the university with Mathematics, Physics and Chemistry as subjects of study.

The candidate should have secured a minimum of 50 per cent marks in Mathematics and in Mathematics, Physics and Chemistry put together.

The minimum eligibility for economically-backward communities is 45 per cent marks in Mathematics and in Mathematics, Physics and Chemistry put together.

Job prospects

According to Dr. Narayanan, around 30 per cent of the students who had passed out from the department over the years had found jobs abroad.

Several former students of the department had landed lucrative jobs in the United States, Europe, Middle East, Australia, Asian and African countries.

Some of the prominent ship classification societies offering job opportunities include Lloyd's Register of Shipping, Indian Register of Shipping, American Bureau of Shipping and Det Norske Veritas.

M.Tech. programme

The department also offers an M.Tech. programme in Computer-Aided Structural Analysis and Design. The four-semester programme consists of lectures covering subjects like CAD, structural analysis, ocean waves and effects, dynamics of structures and finite element analysis.

The third and fourth semesters are fully devoted to a project carried out within the department or in other approved organisations like Naval Physical and Oceanographic Laboratory (NPOL), Indian Space Research Organisation (ISRO), Structural Engineering Research Centre (SERC) and Defence Research Development Organisation (DRDO). The programme has an intake of 15 seats (five sponsored).

Besides the B.Tech. and M.Tech. programmes, the department offers doctoral programmes in Naval Architecture, Ocean Engineering and related fields.

The department had recently signed a memorandum of understanding (MoU) with Chosun University, South Korea for academic collaboration and exchange of teachers and students.

Recognition

The department is a recognised centre of excellence by the Indian Navy for training Naval officers.

The Union Ministry of Transport has approved the department for the selection of marine engineers. The Royal Institute of Naval Architecture (RINA), London has also given its accreditation to the department.

Propeller Shafting - A primer for Naval Architects & Marine Engineers : Part 3

2010-01-17T04:14:00.000-08:00

The previous blogs have looked at how propellers work and the causes and effects of vibration. This blog is the third part of a trilogy, showing how this information can be used to select the appropriate shaft , gearing and machinery arrangements for a specific warship. Once a suitable hull form has been arrived at and the shaft horsepower needed to drive that hull at the specified speed calculated, the question becomes one of transforming that power into thrust with the maximum efficiency.

The first consideration is weight economy. The propeller, shaft and gearing all represent dead weight that is duplicated with multi-shaft arrangements. In addition, the curve of engine output power as compared to size and weight is not linear; two smaller engines together weigh substantially more than a single larger unit of the same output. It may, therefore, seem that an ideal arrangement will involve keeping such duplication, that is the number of shafts, down to a bare minimum. Provided the total power in question is below the maximum that can be absorbed by a single propeller, then a single shaft arrangement would seem to be the most efficient. If the installed power is greater than the maximum that can be absorbed by a propeller, then the most efficient arrangement would be that involving the fewest number of shafts; in most cases two. Another way of saying this is that the most efficient design for shafting is to load the propellers as highly (that is, to put as much power through) as possible.

For merchant ships this is indeed the case. Merchant ships are designed for economy of construction and use, not for the most efficient use of high power settings. In their case, the economic advantages of a single shaft outweigh any disadvantages from the layout. What this really proves is that merchant ship practice does not carry over into warship design. It is not possible to make arguments for a given configuration for a warship by quoting merchant ship practice. The demands of the two are so different that a comparison between, for example, a liner and a battleship are essentially meaningless.

A single centerline shaft turns out to be a very poor choice for a heavy warship. One problem that's immediately obvious is the dangers of damage or mechanical failure. If that shaft is damaged by, for example, mine or torpedo strikes, bearing failure or any of the other hazards of being a combatant warship, the ship is helpless until the damage is repaired. Experience has shown that accidents and mechanical failure are more of a problem than combat damage but the principle holds; a single shaft exposes the ship to appreciable risk. The same applies to machinery; if a ship is powered by a single engine, then she is held hostage to the reliability of that engine.

There are, however, more serious problems with a single shaft. One is that a ship so equipped cannot use her engines for steering. Below about 10 knots, a ship's rudders become ineffective. In this environment, a single shaft ship is uncontrollable and needs to have tug assistance for docking or other maneuvering requirements. This can be partially cured by using twin rudders that flank the single screw and direct the race from that screw. This reduces the minimum effective speed for rudder control but does not cure the problem completely. Multi-shaft ships can use differential power from their engines to bring about steering control, intrinsically a much safer and more satisfactory situation.

Another mechanical problem with single shaft layouts is the fact that the shaft has to be along the centerline of the ship, for most of its length above the keel. The problem here is that the keel is also the foundation for and primary support of the heavy gun turrets. This point became critical in the era just before WW1 when the weight of gun turrets increased rapidly as gun caliber moved inexorably upwards. One effect of this was to make wing turrets (which obviously could not use the keel as their primary support) less viable. Unless an all-forward armament solution is adopted, we have an immediate design conflict that is extremely difficult to resolve. The only way heavy gun turrets and a centerline shaft can be accommodated is to provide heavy carry-through structures that distribute the weight of the turrets (similar structures were used for wing turrets). These structures are heavy enough to completely eliminate any weight efficiency gains resulting from the use of a single shaft. To make matters worse, they act as a transfer medium by which shock and explosion damage can be carried through from the sides of the ship to the centerline, offsetting the added protection apparently afforded by burying a shaft deep in the hull structure (reports in Dubious and Ghastly of the damage suffered to the center shaft of Scharnhorst illustrate this).

Another serious problem with centerline shafts is vibration. The torsional vibration within the shaft itself cannot be cancelled and will be a constant factor afflicting the ship. The screw itself is operating in the turbulent wake of the hull structure, causing pulses of vibration as the blades hit the turbulence. To make matters worse, this screw is directly under the ship's keel so the vibration pulses strike the centerline of the hull and are immediately transmitted through keel and distributed throughout the ship's structure. Other vibration pulses, travelling down the centerline shaft pass through all the structural nodes of the ship, spreading them throughout the hull structure. The heavy carry-though members provide excellent vibration transmission paths and add to the problems. In merchant ships, these problems are not that serious; merchant ships do not usually use the power settings and use profiles that make vibration a serious concern although the single shaft on most merchant ships does give a characteristic and unpleasant thumping in the aft sections.

For warships, these vibration problems are of grave concern. Yet, they are not the prime problem for single shaft layouts. The main killer for these designs is that centerline propellers are grossly inefficient under the conditions prevailing in warships. For true efficiency, propellers have to act in smooth water yet a centerline prop is, by definition, surrounded by the turbulent wake from a ship's hull. The effect on the propeller's efficiency is devastating. Investigations quoted in the earlier posts have shown that between 15 and 45 percent of the energy supplied to a centerline propeller at high power loadings is lost in inducing vibration within that propeller and its surroundings. In contrast, the equivalent figures for wing propellers are between one and four percent. Related to this is a more fundamental point. As we have already seen, propellers work best when turning slowly, that is when lightly loaded. Their efficiency drops rapidly as loading increases. Therefore, two slow-turning, lightly loaded propellers use power more efficiently than a single faster-turning propeller of equal size.

The next question is, given the propulsive advantages of adopting twin screws over single shaft layouts for surface ships, does the configuration bring any specific disadvantages with it? The first is that a twin-shaft solution requires additional space in the rear end of the ship in order to ensure that there is enough space between the screws to prevent unfavorable interactions. The layout also means that the screws will be closer to the sides of the ship, a feature that will give problems in designing the torpedo protection system in this area. The vulnerability of the shafts is enhanced by the fact that the hulls lines aft mean that those shafts run outside the hull for a substantial proportion of their length. Although this is beneficial in that it reduces the level of vibration transmitted to the hull, it does add to vulnerability compared with a centerline shaft buried within the hull structure.

A factor related to damage control is the engine room design itself. A twin-screw ship will usually require a larger engine room (to accommodate the two engines required for its shafts) than that needed for a single shaft ship. If breached and subject to flooding, this larger volume represents a greater proportional danger to the ship. However, this point is often overstated. The most immediate danger resulting from damage to an engine room is not flooding but loss of power from the generators invariably co-located with the main engines. The time taken to switch from this power to emergency back-up generators can be critical. In this context the dimensions of the engine room are of little consequence. It could be argued that a twin-shaft layout actually has some advantages since it allows the installation of a centerline bulkhead that could restrict damage to one engine room and preserve the other, and its generators, from flooding. Centerline bulkheads are very controversial since they can also cause asymmetric flooding and foster capsizing. Japanese designers liked them; US designers abhorred them. The point is that the choice of shaft arrangements does not compel a decision one way or the other and this is a matter best left to the Instructions to Designers.

On balance, these considerations add up to a conclusion that the gains from using a twin-shaft layout greatly outweigh the weight inefficiency of doubling up on shaft, propeller and gearing. The only time when a single shaft is acceptable is where we have a mobilization design and the primary requirement is to keep the number of engineering bottleneck components to a minimum, the recent US FF and FFG classes being good examples. Here, the driving requirement was to keep the gear cutting to a minimum since this has historically been one of the main bottlenecks in ship production. Another case is where the ship's lines aft are so fine that doubling up on shafting is not practical. In this context, modern submarines, almost invariably single shaft designs, are a very special case due to their highly specialized hull lines.

The next question is; since using twin shafts as opposed to a single centerline shaft shows such great advantages; what happens if we double again and go to a four-shaft solution? Do we see further gains or does the law of diminishing returns apply?

The weight economy arguments against going from twin to a quadruple shaft layout are effectively a repeat of those against going from single to twins. The gearing, shaft and propeller are effectively deadweight while four small turbines weigh more than two larger ones of the same aggregate output. Much of the pro-argument follows along the same lines as well; assuming the screws are the same size, they can be much less heavily loaded and, therefore, operate more efficiently.

The big negative on quadruple screws is that they require a broad aft section; four shafts simply cannot be fitted into a finely tapered stern section without serious design problems. The screws have to be spaced out to prevent unfavorable interactions. In reality this means that the choice is often not between two and four screws of the same size but between two large and four smaller screws and the question now becomes one of the relative propulsive efficiencies for that particular design. However, there is one factor here that is interesting; with proper design, it is possible to arrange quadruple screws so that there is a small but appreciable benefit in propulsive efficiency from the races of the screws and their interaction with each other and the hull lines. This benefit is usually between two and four percent on propulsive efficiency; not a great amount but one worth having.

A major plus for quadruple screws is that the arrangement allows for effective active cancellation of torsional vibration in the shafts. In effect, the shafts on each side can be designed to cancel their torsional vibration and then the pairs on the opposed sides balanced to smooth out what's left.

A big advantage of quadruple screws is damage control. Engine steering in the event of rudder or stern damage is greatly eased. Internally, having four engines opens many possibilities with regard to dividing up the engine rooms and makes plausible the idea of controlling lists from engine room damage by counterflooding opposing areas while maintaining the watertight integrity of others. The important thing is that quadruple screw layouts do not, of themselves, force the designers to any particular solution for compartmentation of the engine room spaces; whether to install a centerline bulkhead remains an option of the designer as determined by the appropriate ItD. Put another way, the use of four smaller engines opens up options not available with different configurations.

So, if four screws is a desirable (but space consuming ) solution, can we gain anything by going a step further and installing six screws? Here, the evidence seems to be that we've hit a point of declining return and that the combination of a very wide hull forced by this arrangement, the dead weight of all the additional shafting etc and possible interactions between the screws means that the penalties outweigh the benefits. Or seem to; the only example I can find of a ship with six screws is the old Russian Popovka class river defense ships. These failed quite badly.

Heading the other way, if, on a given power output, four screws is efficient but space and weight consuming and two screws uses weight more effectively but shows less propulsive efficiency, would a triple screw layout offer a good compromise? A preliminary examination of the figures suggests that it might; a comparison of machinery weight per SHP output between ships using triple and quadruple shaft layouts does show an appreciable advantage to the former. However, as we have seen, this is not the whole story.

Firstly, we are comparing numbers between two ships from two different countries. This is always dangerous since no two countries measure such statistics the same way. There is a strong probability that one set of figures contains components that the others do not. Even if this is not the case, weight economy is only one part of the equation. Propulsive efficiency and vibration are of greater significance as is the effect of the arrangement on the ship as a whole.

Here, triple shafts combine all the worst problems of a single-shaft layout and a twin shaft system. About the only advantage of the triple shaft layout is that it eliminates the vulnerability of the single shaft layout to mechanical damage or accident. The design hydrodynamics is such that the effects of the centerline screw actual degrade the efficiency of the wing propellers. In his memoirs, Admiral Scheer made the following comments on his (triple shaft) battleships.

"The advantage of having three engines, as had each of these ships, was proved by the fact that two engines alone were able to keep up steam almost at full speed; at the same time, very faulty construction in the position of the engines was apparent, which unfortunately could not be rectified owing to limited space' Thus it happened that when a condenser went wrong it was impossible to conduct the steam from the engine with which it was connected to one of the other two condensers, and thus keep the engine itself working. It was an uncomfortable feeling to know that this weakness existed in the strongest unit at the disposal of the Fleet, and how easily a bad accident might result in leakages in two different condensers and thus incapacitate one vessel in the group."

This excerpt has two valuable insights. One is the confirmation that the German ships could maintain speed using their wing shafts only; an indication of the inefficiency and redundancy of the center shaft. The other is the suggestion that the center shaft itself was seen as being a reserve against mechanical failure and/or battle damage. The comments about condenser problems are also interesting but by no means unique. "Condenseritis" was a well-known and pervasive problem with all ships in WW1 and its prevalence in the German fleet should not be seen as unusual.

Triple shafts come into their own where there is a requirement for high output power in a hull with extremely fine lines aft. This was the motivation behind the use of the configuration on the Ark Royal and Illustrious class carriers (the combination of treaty limits restricting the length of the armored box, the need for beam and high installed power all conspired to give the designers heart failure). When the treaty limits were lifted, the British redesigned their carriers (Indefatigable and Implacable) with a conventional four shaft layout.

The final question is, would a five-shaft layout show any particular advantages or limitations? On purely theoretical grounds, it’s difficult to see why this would be adopted; it would simply share the problems of four-shaft and single shaft layouts. I don't think a five-shaft design has ever been seriously considered - if someone does know of such a design, could they please point me to it???

Summary

Single shaft: Advantages; good weight economy in power train components, shaft buried in hull for protection, economy in war-critical production bottleneck items. Disadvantages. Inefficient power utilization, high noise and vibration levels, no redundancy against mechanical or combat damage. No engine steering capability. Severe design problems with regard to other parts of ship

Double shaft: Advantages, relatively efficient with reduced noise and vibration, allows engine steering, and provides redundancy against damage. Disadvantages. Requires wider section aft. Preferred design for smaller warships - say up to light cruiser size.

Triple shaft: Advantages, allows increased power through narrow stern section. Disadvantages. Inefficient power utilization, high noise and vibration levels. Severe design problems with regard to interaction of power train configuration with other parts of ship.

Quadruple shaft: Advantages, very efficient due to favorable prop interactions with reduced noise and vibration, allows engine steering, and provides redundancy against damage. Also, allows flexible subdivision of machinery spaces. Disadvantages. Requires wider section aft. Preferred design for larger warships - from heavy cruiser to battleship size.

Ship Vibrations - A Primer for Naval Architects & Marine Engineers : Part 2

2010-01-10T02:34:00.000-08:00

Vibration has been a matter of concern to ship designers since the end of the 19th century although its presence in ship characteristics was known long before that time and its importance has become much emphasized over the last half century. Some sailing warships, particularly the lightly-built frigates, suffered from serious vibration aft when driven hard, probably as a result of flow interaction while there are accounts of mast/sail combinations causing such severe vibration that crewmen were thrown from their feet or, worse, from their mast-top positions. However, for most of the history of the ship, the problem was not regarded as being of any great importance. The situation began to change with the introduction of steam propulsion. A French naval design book (Theorie de Navir) published in 1894, contains a discussion of ship vibration, written from the premise that the phenomenon was the result of the propeller. The slow-rotating props used at that time had relatively few blades per shaft, a combination that generated a long wave-length (low frequency) vibration that felt like the hull flexing in a heavy sea. This was not regarded as being anything out of the ordinary and probably explains why ship’s trials reports of the era contain so few mentions of vibration unless the situation was really unusual. There were, however, enough really unusual cases to start people thinking.

Vibration is defined as a relatively small amplitude oscillation around a rest position. It can be transverse (at right angles to the rest line), longitudinal (orientated along the rest line) or torsional (twisting around the rest line). Transverse vibration is the most commonly encountered, torsional is frequently present but its effects are subversive, longitudinal vibration is comparatively rare but can cause truly hellish problems. All hull components have “natural frequencies”; these are the frequencies at which the component will vibrate when struck. Another vital term is resonance. This is a state that occurs when the natural frequency of hull components matches that of an imposed vibration. The components act as amplifiers, the effect only being limited by system damping.

Looking at the sources of vibration in a ship, it is easiest to start from the front of the power train and work backwards. Its important to remember that vibration doesn’t really pass through air, it travels along things and the routes that it follows are as important as the vibrations themselves. The boilers of course generate their own series of vibrations but these are largely isolated from the power train proper (the steam lines absorb and damp vibration). The real problems start with the ship’s engines.

Reciprocating and diesel engines are universally bad news. They are not continuous action; they operate in a series of jerks, each of which adds a kick to the vibration patterns. I won’t bother with reciprocating engines since they were dying out by 1914 but diesels are very much of contemporary interest. The problem with diesels is that, for a given size, there is a fixed amount of power generated per cylinder. The only way to add power is to add cylinders (this assumes that engine room dimensions etc prevent the sheer size of the diesel increasing further but I understand there are nasty problems in designing big diesels. Trouble is, if cylinders are added, they lengthen the crankshaft. After a very limited number of additions, the lengthened crankshaft begins to flex and vibrate all on its own. This is torsional vibration at its most elemental and is, by the way, why big automobile engines with a straight line configuration (the so-called straight-8s and so on) got abandoned. On a ship, its a killer.

Steam and gas turbines, when new and/or in good repair, do not, by themselves generate excessive vibration. It’s possible to stand a dime on its edge on the casing of an LM-2500 running flat out (I’ve done it) and watch it stand for several seconds. That happy state will remain as long as the turbine blades continue to be perfect and rotate in a smooth gas flow. Eventually, though, this ceases to be the case. Microscopic defects in the metal of the steam/gas intake and blades eventually fail, causing small pits to appear in the surface of the intake and the blades. These set up eddies in the gas flow that have two bad effects. One is that a turbulent gas flow is much more erosive than a smooth flow so the progressive deterioration of the blade will accelerate. The hotter and higher pressure the intake, the more erosive the gas and the higher the standards of metallurgy required to resist those conditions. If the steam (temperature and pressure) conditions adopted exceed the ability of the metals use din the intake area and blades to resist their erosive effects, then the result will be a short-lived, very unreliable powerplant. With gas turbines, this is less of a problem since they are maintained by pulling the entire engine and replacing it. With steam turbines, deteriorated blades can be replaced but the trend in engine performance is ever-downwards until it reaches a point where performance loss and vibration reach unacceptable levels and the plant is worn out.

The other is that the blades themselves are no longer rotating in a smooth environment and start to shake. This sets up vibration which gets transmitted down the turbine shaft to the gears. Now, there is an interesting effect on a gearbox if it is placed directly between the compressive loads generated by drive shaft from the turbine and the compressive loads traveling up the shafts from the screws. The gearbox explodes. This is not good.

Gearing was impossible with the first generation of turbine driven ships (the direct-drive ships). Since screws work more effectively at slow speeds than at high and turbines work more effectively at high speed than low, there was a dichotomy that could not be resolved. Either the screws ran so fast they cavitated, shaking the ship the way a terrier shakes a rat or the turbines ran so slowly they guzzled fuel. This is when (a) people began to realize there was much more to this vibration business than they had thought and (b) screw design suddenly took several large leaps forward. The solution was a thing called a thrust block that took the compression loadings in the shafts and prevented them being transmitted to the gearbox. This meant geared turbines could be designed and the world got easier. Then somebody had a BLIFFO [Ed - BLInding Flash of the F***ing Obvious]. Mass damps (absorbs) vibration. Mass keeps gears nicely in line and prevents flexing. In ship’s gearing, mass is good. Lets have LOTS of it guys!!! As a result, the thrust blocks and main reduction gearing in a ship are about as over-engineered as it is possible to get. There is a price paid; all that metal takes some design accommodation and there are mechanical penalties in getting the bits moving but they’re nothing compared with the benefits.

The main reduction gearing generates vibration of its own (particularly if a resentful sailor tosses a wrench into it - usually good for a one-year to 18 month refit and repair). But, by and large, it is a vibration sump rather than a generator. What it tends to do is isolate the mechanical vibration forward from the hydrodynamic vibration aft to the great benefit of all. Well - mostly. The massive reduction gears cannot absorb torsional vibration from diesels which is why trying to gear diesels to a common shaft is an unhappy experience. It can be done but the designer usually does so while trying to work out what he did to deserve the punishment.
Coming out of the back end of the main reduction gearing are the shafts. These are important from two points of view. Firstly, they run the a substantial proportion of the length of the ship and carry vibration along that length, transmitting it to any vulnerable component. The shafts are the primary means by which vibration is transmitted into the ship which is why their design and layout is so essential to the success of the design. Secondly, they are important generators of vibration in their own right.

This vibration is both torsional and transverse. The shaft is a long steed rod being twisted at one end. At the other end is the resistance provided by the water against the effort to turn the screw in it. This means that the engine end of the shaft will turn before the screw end, setting up torsional stress in the shaft. When the screw starts to turn, this energy is released in making the screw turn a bit faster. It overruns the engine end so now there is torsional stress in the opposite direction - this is released by slowing the screw down. This happens in a series of cycles and quickly settles down into series of pulses - torsional vibration. There is a trick here. Every so often the gods look down on naval engineers struggling with slide rules in their tiny offices with green steam coming out of their ears and give us a break. The frequency of that torsional vibration is pretty fixed and is proportional to the length of the shaft. If one shaft is half that frequency longer than another, the torsional vibrations from them will cancel out, often almost completely. This is why twin-screw cruisers (for example) usually have asymmetric shaft lengths. With quad-screwed ships, the designer gets an even greater benefit since the shaft lengths on each side can be manipulated to provide cancelling torsional vibration frequencies on each side and then between side. The fact that this can’t be done with triple screws is as good a reason as any for not using the layout though there are many, many more.

Shafts can also generate transverse vibration by literally shaking in their tunnels. It is a lot to ask any foundry to produce a shaft 200 feet long that is perfectly dynamically balanced all the way down. Somewhere it won’t be and spinning at ship-applicable speeds, it’ll cause vibration. The next solution is to block the shaft at regular points and physically prevent the vibration from occurring. The blocks have to be resilient to absorb vibration or they will simply transfer it to the ship. Problem is, every block also absorbs power and the situation quickly develops where the resistance from the blocks is so high that the shaft won’t turn. The best solution to transverse shaft vibration is to keep the shaft as short as possible (this also reduces torsional vibration) and get it out of the hull as quickly as possible (there are, of course, many reasons why a designer might want to keep the shaft’s within the hull but that’s another matter). Which is why modern merchant ships have their machinery aft. I have always wondered if that consideration interested the designers of the British G-3 Battlecruiser? By putting the machinery aft, could they have had in mind (as a subsidiary benefit) cutting vibration??? By the way, this shows another problem with a centerline shaft - it has to be inside the hull for a lot of the way and also (nasties of nasties) runs right through the ship’s structural nodes - putting it in a perfect position to distribute vibration evenly throughout the aft section. Also, the gun turret supports are directly on top of it, wrapping the center shaft in a heavy carry-through structure that also serves to distribute the vibration (guns do not like being mounted on flexible supports).

Finally, we get to the end of the shaft and reach the witch’s cauldron - the screws. Hydrodynamically, the pressures on the screws change across the blade, along the length of the blade, following the contours of the blade and all of the above change in accordance with speed of rotation and the relative speed of the water impacting on the blades. For many years, people attempted to get a handle on this situation using uniformly continuous relational mathematics and failed. Today, the calculations use that are non-uniform and discrete. In general, each propeller blade has six components of displacement, three translations and three rotations and six corresponding force components at each nodal point. How many nodal points are there? As many as you want, friends, and the more you have the less inaccurate the answer. Scary isn’t it?

In general, the screws work best when the are rotating cleanly in smooth water. Thus vibration will be cut down if the water impacting on the screws is smooth - best achieved when it is faced with as few changes in direction as possible. The screws need to be far enough apart so that disturbance from one does not impact on another. They need to have large separation from the hull so that the water flow between the topmost tip on the screw and the hull plating is enough to permit smooth flow (very difficult on a centerline shaft and why merchant ships with single screws have that characteristic thumping feel on their fantails). Each blade of the screw has to be designed so it cuts the water cleanly, leaving it smooth for the next. As the blades get more numerous (essential to absorb power) they get less efficient. Each screw leaves a spiral race behind it - this causes vibration when it hits the hull and rudders (putting a rudder in a screw race does wonders for steering but there is a price to be paid for that in potential vibration.

Each prop generates its own resonance frequency. This is easy to calculate its the number of blades on the prop times the speed of rotation. Thus, a five-bladed prop turning at 300 rpm will generate vibration at 5x300=1,500 pulses per minute or 25 Hz. That’s easily detectable on passive sonar at long range. If the natural frequency of the hull component is 25 Hz, beware, trouble looms.

If there is a bar of turbulence in the water, every time a blade hits it, that blade will shake and transmit that shaking up the propshaft to the gearing from whence it will radiate forwards. This is called blade beat and is a bear. Nobody knew it existed until the 1950s when US submariners detected it and started to use it for ASW. It was crucially vital because, radiating forward, it revealed the position of a Russian submarine while it was approaching (most sonar-detectable noise radiates aft). The Russians didn't have a clue that blade beat even existed until the mid-1970s when the Walkers blew the secret. Scythe-shaped blades kill off blade beat very nicely since the curved edge of the blade hits the turbulence progressively (much as a curved sword slices flesh more efficiently than a straight edge).

There is a low pressure area on the edge of props that can be low enough to cause bubbles of water vapor to form. These expand and eventually collapse against the prop blade, striking it like a tiny hammer. There are thousands of them. They really start a propeller vibrating nicely. Cavitation can also form in the screw race. If the designers are really unlucky they get a thing called sheet cavitation where the blade generates a large bubble that envelopes the blade and part of the hub; this can rip of a blade without trouble. Sheet cavitation is a major design blunder. Small, fast running many-bladed props are much more prone to cavitation that slow-running, larger, fewer bladed ones.

Given all the possible sources of vibration, its no wonder that ships vibrate and sometimes that vibration exceeds acceptable limits. Those limits are much tighter now than they were 30 years ago because electronic equipment really does not like being thrown a few feet in the air a dozen times per second. If vibration is unacceptable, then the designers try new screws (hoping to change the natural vibration and get rid of resonance), add extra shaft blocks, brace things, change the water flow aft and swear that it is all the crew’s imagination (the latter never works but it might one day so is worth trying). Bad vibration can take years to correct - each item has to be checked and changed until the right combination is struck. Its called “running trials”.

Basics of Designing a Marine Propeller - A primer for Non Naval Architects : Part 1

2010-01-09T00:17:00.000-08:00

Marine Propellers are usually described as pushing against water in order to propel a ship forward. In fact, this isn’t quite the case. What a propeller does is apply an acceleration to a mass of water. According to Newton’s Law of Action and Reaction, the action of increasing the velocity of a mass of water in a given direction generates an equal and opposite reaction in the propeller/shaft assembly. This is described as the thrust of the propeller and it is this thrust that drives the ship forward.

The basic theory of how a propeller works was put together by three eminent Victorians, Rankine, Greenhill and RE Froude (son of our old friend William Froude) between 1865 and 1889. They envisaged an idealized propeller called a Rankine Disk Actuator which imparts a sudden uniform acceleration to all the fluid passing through it, the flow being frictionless and the water being present in unlimited quantities and the Rankine Disk working with 100 percent efficiency. In this idealized system, the energy imparted to the water by the Rankine Disk Actuator is

E = 0.5 x M x (V1-V0)(p2)

Where E is the energy required for the acceleration, M is the mass of water accelerated, V1 is the final velocity of the water and V0 is the initial velocity of the water. Due to the limitations of the text system here I can’t use superscripts so (p2) indicates squares, (p3) indicated cubes etc., etc. This is, of course, a slightly modified standard kinetic energy equation. Unfortunately, that’s the last easy bit of mathematics. Because adding any energy into the system changes the values of both V1 and V0, the equation has to be integrated between zero and t seconds where t is the time taken for the system to come to equilibrium.

Now, (V1-V0), the increase in velocity of the water, is determined by the design of the screw. Each turn of the screw accelerates a package of water from V0 to V1. Increasing the rate of revolution increases the number of those packages that goes through the Rankine Disk but does not increase the speed at which they leave the disk. This is important; it doesn’t matter how fast the screw turns or how large it is, it the design of the screw and that design only that determines the acceleration of the water. A good comparison is a road with a 55 mph speed limit - improving the quality of the road or widening it to include more lanes will increase the volume of traffic the road can handle but the speed of the traffic will only be increased by raising the speed limit.

M, the mass of the water passing through the Rankine Disk Actuator, is equivalent to the density of water times the volume of water passed. Increasing the volume (and thus the mass) of the disk can be achieved by using a larger disk and/or increasing the revolutions per minute of the propeller. In mathematical terms, the water passing through the Rankine Disk is a cylinder, the diameter of which is the diameter of the disk and the length of which (the number of packages transiting the disk) is determined by the speed at which the disk is turning. From an energy point of view, it doesn’t matter very much whether the cylinder is long and thin (a small prop running at high speed) or short and fat (a large prop running at slow speed). As long as the two cylinders contain the same volume of water being accelerated the same amount, they’ll demand the same amount of energy and yield the same level of thrust. (Remember these cylinders are mathematical constructs not physical reality).

This treatment gives us one very important lesson which takes some complex mathematics to prove because it seems so outrageous. Since we are accelerating a cylinder of water through a disk, fully half the thrust developed by the acceleration of that cylinder is delivered before the water ever touches the disk! In short, we seem to get the thrust before the water gets the acceleration. This is outrageous, ridiculous, unbelievable and perfectly correct - it is a major consideration in designing underwater hull forms.

Unfortunately, when we leave the idealized world of the Rankine Disk Actuator and enter the real world, life starts to get complex. Firstly, the cylinder isn’t a cylinder. Before the water hits the propeller it is being drawn along at speed above that of water outside the cylinder. Bernoulli’s law dictates that water will be drawn into the cylinder from outside, causing the cylinder to bulge outwards. The other side of the prop, the fact that acceleration is constant by the volume of water being pushed through is increased as the revolving speed of the prop goes up causes increased pressure areas aft of the prop. This causes a high-pressure bulge here too. (A simple experiment illustrates this - take a garden hose and set it running full blast. Now put your thumb over the nozzle). Eventually, this high-pressure region reaches the proportions where it breaks the surface, giving the famous rooster-tail effect. (It can also have a forward vector that has a propulsive effect on the ship). These two factors mean that the propeller isn’t at the center of a cylinder but a complex shape rather like an hourglass with the propeller at the thin neck. Again, the equations have to be integrated in order to get the “volume” (i.e. the energy content) of the system. If we were following the maths in detail, we would now be dealing with several layers of integrated equations.

Another problem is induced rotation. In the Rankine Disk Actuator, no axial rotation is applied to the water flow. At low transiting volumes, this is almost true, but as volumes get larger and the ratio of prop diameter to speed of rotation reaches critical values, the water leaving the propeller (the race) becomes more and more spiral in shape. This is purely awful - every drop of energy that goes into rotating the water instead of accelerating it is wasted (in effect it shortens our mathematical-construct cylinder). In mathematical terms the pitch of the spiral shortens as speed of prop rotation increases and the loss of energy is proportional to the square of that pitch.

Increasing prop size and speed of rotation are both good in that they increase the volume of water the prop accelerates. However, there are limits on both. Propeller size has physical limitations (we really do not want the blade tips hitting the hull plating), material restrictions (having the prop fly apart from metal fatigue is usually quite depressing) and also hydrodynamic restrictions which we’ll come to later. If speed of rotation is pushed too high, the propeller starts to hit the axial rotation problem described above and also starts to cavitate. This is by way of being an upper limit - reductions in propeller efficiency from cavitation quickly get so high that adding extra power will actually slow the ship down.

The inefficiency of a small, fast running propeller is murderous. For example, if the efficiency of a prop was really that of a Rankine Disk Actuator, halving the diameter of a propeller could be compensated by increasing the speed of the propeller by a factor of four - the energy contents would be the same. In reality, the efficiency of the half-diameter quadruple-speed propeller would be only 61.8 percent of the full-size, slow speed version - it would provide less that 2/3 the thrust. So, mathematically, the Rankine Disk Actuator equations eventually show us that a large, slow-turning propeller is a better deal than a small, fast-turning one. As an insight into a science nobody had thought of a few years earlier, the Rankine Disk momentum theory isn’t bad for a group of Victorian gentlemen who had virtually nothing to work with except slide-rules and their own perceptive brilliance.

In effect we have a cycle by which the engines generate power, that power is used by the screws to accelerate water, the reaction to which is thrust which pushes the ship forward. Unfortunately, the limitations on prop size and speed of rotation plus the fact that the acceleration applied to the water by the props is fixed by the design of the props, means there is a limit to the energy the props can use (in mathematics, to the size of our hour-glass or cylinder depending on whether we are looking at reality or theory). Any extra power generated by the engines above that limit is so much deadweight. In reality, of course, this limit isn’t a sharp point but an area in which the efficiency by which the screws convert energy into thrust quickly drops to zero. Nonetheless, adding 500 tons of machinery to a ship that is already overpowered will not achieve anything at all.

We can’t do much about the density of water (well actually we can. The effects of pressure from depth are quite important - a propeller running at 45 feet will give measurably more thrust than the same prop at 15 feet due to water pressure. Also, the compressive effect of a heavy hull will have a beneficial effect on the effective mass of water going through the prop. These are, however, relatively minor effects in terms of the sort of gains we are looking for). If we are going to get a major gain in energy utilization out of the power train we have to improve the amount by which the propeller accelerates the water and design the prop so that cavitation is delayed as long as possible. Unfortunately, here the Rankine Disk ceases to be of help since the mechanism by which it accelerates the water is not considered. There are two theories that do deal with this, the Blade Element Theory (which evolved shortly after the pioneering work of Rankine, Greenhill and Froude) and the Circulation Theory (evolved by F.W. Lanchester for aircraft in 1907 and applied to ships by Betz and Prandtl some years later). Both involve mathematics of extreme complexity. The Circulation Theory in particular allows the acceleration applied to water by a blade of given shape to be calculated by a thing called the Kutta-Joukowski Equation. The fun question is, what is the ideal shape?

What makes this question difficult is the fact that the propeller works in the ship’s wake. What is normally called a wake isn’t; its a combination of the ship’s real wake and the race from the screws. Differentiating between the two is easy - the race travels backwards relative to the ship, the wake travels in the same direction as the ship but at a lower speed. The wake results from (a) the frictional drag of the hull which produces a following current, maximizing around the stern (b) the streamline flow past the hull causing increased pressure where the hull lines close also creating a following current and © the wave pattern formed by the ship on the surface in which the water packages have an orbital motion, the top being in the same direction as the movement of the ship and the bottom being in the opposite direction. The forward speed of the wake in proportion to that of the ship is called the Wake Fraction. This will significantly reduce the (V1-V0) value (by half for a wake fraction of 50 percent) with obvious effects on thrust. The three factors that create the wake give a hydrodynamic picture of unsurpassed complexity. Newton and Hadler did a whole series of studies back in 1960 on the performance of propellers using Fourier Analysis to create mathematical constructs of wakes using the computers then available. They produced a series of flow diagrams of single and twin-screw ships sections aft and of the props working in those flow conditions. These clearly showed that the twin-screw environment was much less chaotic than the single-screw situation. In a single centerline screw, the relative intensity of the wake/prop interaction (which should be constant for maximum efficiency) varied from 0.10 at the tip to 0.67 at the root of the blade. In a twin-screw, the same figures were 0.02 at the tip to 0.04 at the root. The study also showed that the effect on the wake form from a centerline screw was enough to badly disrupt the more favorable environment surrounding the wing screws. These experiments at last provided a reasonable explanation of why twin screws work better than single centerline props and lead to a concerted effort to relate hull design to wake characteristics.

In 1965, Van Manen produced a series of conclusions based on his extrapolation of Newton and Hadler’s work. These were that the wake pattern is largely a product of the aft body of the ship, that harmonic amplitudes (transverse vibration) are inherently more severe on ships with centerline screws, the finer the stern, the more efficient the props, that blade geometry has a significant effect on induced shaft vibration, that transom sterns are less prone to cavitation, that the rudder has little effect on the wake and that minor changes in speed, displacement, hull form and trim have major and completely unpredictable effects on the wake pattern and, therefore, screw performance. In 1972, Van Oossanen et al investigated these areas but failed to come up with meaningful answers as did Holden in 1980 (although he did have some success in predicting effects on wakes with low peak values). This whole area is still largely a mystery although Chaos Theory may provide some clues as to what is happening back there.

So, having gotten the theory out of the way, how do we design a prop to convert more power into thrust and, thus, to make bigger battleships possible? If the ship design isn’t pushing the limits of practical, it’s quite simple. We take the desired prop diameter from the hull design, take the desired speed of revolution from the machinery design people and put the two figures into a pre-calculated graphical projection that will give us the “optimum” prop design for those conditions. This optimum isn’t really that, its the best commercial approximation that can be mass produced for those conditions. If we want anything better, its has to be custom-designed for that specific ship.

This involves massive tank-testing of hull forms to determine the wake characteristics at a wide variety of ship speeds and then the incorporation of those figures into a computer model to determine how a propeller will behave in those conditions. The geometry of each blade can then be designed (and redesigned and redesigned and ... you get the message) to try and reduce wake/prop interaction and to equalize that effect across the blade. This involves, slow, patient changes to leading and trailing edge configuration and blade cross section at varying points along the length of the blade (i.e. from root to tip). Blade area should be maximized to eliminate cavitation and the number of blades selected to give optimum results (usually that means as many as possible consistent with keeping flow conditions smooth). Typical selections these days are four, five and seven bladed props with nine-bladed units beginning to make an appearance. For some unfathomable reason, six-bladed props are more prone to exhibiting unfavorable characteristics than other configurations so are usually avoided (this is not an absolute). These days, much of this work can be done by computer simulation with the results confirmed by tank testing. Today’s customized propellers have extremely complex blade shapes, involving high skew and rake levels and extreme radial pitch changes and radical differences in cross section at each stage along the tip to blade axis. Throughout the design process one thing has to be kept in the back of people’s minds - can this prop actually be built? There is no point in designing the perfect propeller if it can’t be built!

Indian Shipbuilding Industry : A critique on KPMG Whitepaper

2009-12-25T20:37:00.000-08:00

The other day I was going through a report prepared by KPMG for FICCI “Indian Shipbuilding Industry: Poised for take off”, wherein they had mentioned India could be the next powerhouse in shipbuilding. You can read the report here.

The report seems to have been prepared by people whose understanding of the Shipbuilding Industry is naïve to put it politely. Not only have they got their facts wrong (by a huge margin!!!), but their conclusions seemed to be flawed.

Their report claims that the Indian Shipbuilding industry is poised to take off and India could emerge a worthy competitor to Japan, Korea and China. Their conclusions are based on the fact that Indian Shipbuilding industry would see an influx of Rs 200 Billion ($5 Billion) in the next 5-10 years. Moreover India with its cheap labor would be an attractive destination for competitive pricing of shipbuilding.

Global Shipbuilding has shown a CAGR of around 6 % from 1980-2007. This fact is nothing earthshaking, given the fact that during this period the Global GDP has also risen 6% annually. What this means is that on an average, every industrial activity has risen on an average of 6 % annually. Shipbuilding is no exception.

Because of the phase-out of Single Hull Tankers, the global shipbuilding orders have quadrupled in the last 5 years. This is as of 2007. I am sure 40 % of the orders would have got cancelled because of the ongoing recession due to the US sub-prime Mortgage crisis. Moreover with more emphasis on renewable energy sources, than the traditional petroleum products and with countries promising to cut their carbon emissions by atleast 20 % in the next five years, the scope for trading in Oil products is getting smaller and smaller.

Labor Cost : The report states that shipbuilding is a labor intensive activity (Wrong!!!) and labor accounts for 10 % of the total shipbuilding cost (Correct!!).

As rightly brought out in the report, labor accounts for 10 % of shipbuilding cost and hence is NOT a labor intensive activity. 90 % of the cost is associated with material costs, overheads and technological set up. To break it up further, 20 % of the total cost would be Steel, approximately 47 % is the cost of Finished Manufactured goods, 13 % costs are the overheads and the rest 10 % are the misc expenses. Thus even if we stick to the Report’s contention that Indian Labor is competitive compared to World’s markets, India is still competitive in only 10 % of the total costs.

Now let me come to the next assumption in the Report that ‘India’s labor cost is cheap’. As per Fig 7b ‘Cost of Labor in 2008’, the chart shows that India’s labor cost is 1.5 USD per day (i.e Rs 60/- INR). I am not aware where the Management Consultancy Firm KPMG got this absolutely crap figures from. Or is it, that they are fabricating the facts to support their contention. Most states in India, have Minimum basic Wages of 4 USD (Rs 200/- day). It is a known fact that the Minimum basic wages in the shipbuilding industry could touch somewhere between Rs 250- Rs 300 (5-7 USD). Taking this into account India’s labor cost is two and a half times China’s costs. So as far as the labor cost is concerned, India does not have edge over China.

Till now I have not taken into account, the labor productivity where India lags behind all the other shipbuilding nations. The labor productivity in terms of tons/mandays is 1/10 of Japan and ½ of China. Thus the contention that India is labor competitive compared to other nations is a myth.

Indian Shipyards have bagged huge quantum of International Shipbuilding orders: The report states that the Indian Shipyards, notably ABG Shipping and Bharti Shipping have bagged international orders in the last 2-3 years and their order books are already full till 2012. This could be true, but that does not mean that the shipyards which have bagged these orders have got it because of their competitive pricing. It is a known fact that the order books of Japanese, Korean and Chinese Shipyards are already full till 2015 with orders of Container Vessels, Super tankers and PANAMAX vessels and they have no further capacity to take any further shipbuilding orders, until and unless they upgrade or increase their shipyard facilities. Thus the ship owners were reluctantly forced to go to third world countries like India, Sri Lanka and Vietnam to augment their fleet size as none of the developed shipbuilding nations were willing to take up their orders.

Other problems with Indian Shipbuilding Industry

Lack of Creativity and Innovation : It is a known fact Indians are hardly known for their creative ideas/ innovation. The last great creative work done by Indians was the creation of Zero and that was way back in 1000 BC. This is not to say that, India has not progressed in the last three thousand years. They have progressed, but on the shoulders of other nations, not in their own capacity. Indians are good at solving equations once an equation is given to them, but poor at formulating equations or finding a practical use out of the equations. This is clearly seen in one of the achievements of Independent India, their so called Software Industry. The Indian Software Giants INFOSYS, Wipro and TCS are globally very competitive, but are not house hold names compared to Microsoft, Adobe, Macromedia, etc. Till date, these firms have yet to come up with an innovative product catering to the masses. These so called Software Giants are good at ‘one of a kind products’, not because they are competitive in that field, but because the actual Software Giants like Microsoft, Adobe , etc will not want to get into such ‘menial’ tasks or as Caste Indians term them ‘Shudra jobs’.

The same lack of creativity find a place in the shipbuilding industry. They cannot conceive of a new kind of vessel (For Eg, the Container Vessel). Their lack of creativity is amply shown in their lack of Design capabilities. The Indian Shipyards totally survive on Technology Transfers from Foreign Shipyards. Research & Development is an anathema to the Indian Shipbuilders.

Conclusion

Contrary to what the KPMG report claims, Indian Shipbuilding is nowhere near the class of Japanese, Korean or Chinese Shipbuilders. The Indian Cheap Labor cost is nothing but a myth. Their shipyards are what the US shipyards were a hundred years back. Most of the Indian Shipyards lack a CNC cutting machine, forget about robotic welders. Moreover India’s archaic labor laws would prevent the introduction of any labor saving technology. Lack of creativity is a bane of Indians and their creative spirit has not been shown in the past three thousand years.

But is all lost? Is India’s Shipbuilding Industry doomed for eternity in the backwaters of technological and creative primitivity. Need Not Be. As Ayn Rand rightly brought out in one of her novels “All it takes is for a few good men to take up the cudgels”. But will Indian Shipbuilding Industry find its Few Good Men???

Naval Construction in India - A History of Corp of Naval Constructors in India

2009-12-20T04:41:00.000-08:00

Naval Construction in India
By Cdr K.K. Varma

While browsing the Web, I came across the pdf version of this coffee table book. At first glace, the book looks impressive with a lot of ‘rare to get’ photographs, but on closer perusal it is more of style and less of substance. The Corp of Constructors should have employed the services of a professional editor rather than depend on the writing skills of a Naval Officer.

The first few pages talk about the history of shipbuilding in India. The contents are interesting and informative if not a bit jingoistic. After all, the world has not heard of any remarkable shipbuilders / ships from Ancient India.

The book then goes on to detail the progress of Naval Construction from its inception stages during the post independence era to the present days. It had started as a purely Civilian Corp akin to the Royal Corp of Constructors, but then to make it attractive to draw better talent, the brainwave decision was taken to make it a part of Uniformed Services, which in hindsight comes out as a very bad decision.

The book then speaks of the ‘so called achievements’ of the Constructor corp which are laughable and pale into insignificance when compared to the actual achievements in the field of Naval Architecture, the World over. The Indian Naval Constructors talk highly of a variant of the Leander Class which they were able to design. I had mentioned this in my previous blog on “The Autobiography of an Indian Naval Architect” about this, wherein the author had found that large ships of Similar Geometry could have lesser power requirements than a Slightly smaller ship, because of the cancellation of opposing wave fields generated by the forward and aft parts of the ship. This the author had stated as his “Eureka” moment. The other achievements of the Corp of Constructors are not worth mentioning in this review. The last few pages list out a list of achievements of officers from the Constructor Corp in local sporting and literary events of their local colleges which are hardly of any interest to anyone outside of their fraternity.

To summarize, the book gives a good background history of Shipbuilding in India in the days of yore and also the beginnings of the Corp of Naval Construction as an offshoot of RCNC. But the rest of the book is pure jingoism and not worth a read.

This book might not be of much interest to the Indian Naval Architects, but since it is freely available for download from the Net , one can peruse it , if one has the time and bandwidth.

Aspiring Naval Architects from India can go through the book to find out the “Challenging Environment” that Indian Navy offers for them to hone their skill and then to take the call whether to join the Indian Navy or hone their Naval Architecture skills elsewhere.

You can read it here.

Autobiography of an Indian Naval Architect

2009-12-18T07:47:00.000-08:00

Autobiography of an Indian Naval Architect

By Capt Mohan Ram (Indian Navy)

I came across this book, which was mailed to me by one of the readers of this blog site and I am not sure that the author has published it or not.

The book is an interesting read, though it doesn’t cover much that is relevant to the naval architecture field. The author Mohan Ram was an ex-captain in the Indian Navy and was one of the earliest officers to join the Corp of Naval Constructors of Indian Navy, which is an offshoot of Royal Corp of Naval Constructors (UK), after India got its independence. An alumnus of the prestigious Indian Institute of Technology, Kharagpur, the author served the Indian Navy for a span of twenty five years. During this brief span the author had the distinction of serving in various capacities in the Dockyards and the Naval Design organizations. Though the author claims, he is one of the foremost naval architects of India, I am pretty sure that not many in the Naval Architectural world would have heard of him. He has not published any papers or made any theoretical contribution in the field of Naval Architecture. But considering the primitive state of naval architecture in India during those days, it is possibly true that the author could have been India’s foremost Naval Architect.

Notwithstanding the above, the book is an interesting read, especially from the point of historical development of India’s indigenous capabilities in the designing of ships.

The primitive state of Indian Navy’s Naval Architectural capabilities is brought out in one of the eureka moments which the author had……….

“ On a wet Saturday afternoon I was doodling on a piece of paper at home and idly wondered “what would happen, if I powered the new ship with the same power plant- two turbines of fifteen thousand horsepower each, without any change. How much would the speed drop? Was there any chance of convincing the naval staff that a small sacrifice in top speed would make the ship more economical and easier to construct?” I did a quick back-of-the envelope calculation to estimate the speed loss. To my utter surprise, the answer came out that the ship did not lose speed at all. On the contrary it would go a full knot faster, at 29 knots which the naval staff wanted! I checked the numbers again and again and could not find any mistakes in the calculation. I tried other methods for estimating the power required and found that the answer came out the same. I was elated. Perhaps this was a brilliant solution for meeting the navy’s requirement without any additional investment, using equipment being manufactured in India. I was so excited about my discovery that I could hardly sleep the whole weekend.”

“I rushed to the office on Monday and announced my discovery. No one believed me at first. I was greeted with a stony silence and most of my colleagues, thought that I had gone out of my head. I could not blame them, as my findings were totally counter-intuitive.”

“Without sounding too technical, let me simply explain how this came about. Further analysis revealed that at lower speeds the resistance to ships’ motion was primarily due to friction, in which the larger ship with about 20% greater wetted surface area (area exposed to the water) was at a disadvantage. Above 22 knots, the resistance to motion from wave making due to the ship cleaving through the sea became much more prominent than friction. If the interference between the waves created by the bow (front) of the ship and the stern (rear) of the ship were positive, resulting in a crest at the rear end, resistance due to wave making would be lower. If the interference between the bow and stern wave systems resulted in a trough at the stern, the resistance due to wave making would be higher. The interference is a function of a factor called Froude number, which relates the square of the speed of the ship to the length of the ship. In the case of the Leander at 28 knots, the interference caused a trough at the stern increasing the wave making resistance. But in the new longer ship, the interference resulted in a crest. This resulted in a lower wave resistance in the bigger ship, which more than compensated the increased drag due to greater area. Overall this led to the bigger ship going faster. Once we had done this detailed analysis the picture became a lot clearer. We also found that the same principle was being adopted in ‘jumboizing’ super tankers to by adding a new mid section, making the ships longer to carry more crude without losing speed.”

The very fact, that the obvious result that larger ships (of similar Geometric proportions) could have lesser resistance compared to ships of smaller length, because of the cancellation of the wave fields (a fact taught in the basic courses of Resistance of Ships), was such a shocking eye-opener to the Stalwarts of Indian Naval Architecture Community speaks volumes of their technical ignorance of Basic Naval Architecture and goes on to show that Mohan Ram, when he claims himself to be one of the foremost Naval architects of India, could indeed be speaking the truth.

The second half of the book deals with the author’s life as a non-practicing naval architect in the Indian Industry. Interesting, but not relevant to Naval Architects. The author claims that he was responsible for the turnaround of some loss making companies and offers some management platitudes.

“I expect this story to be of interest to senior managers of organizations facing severe competition and loss of market share and running into decline and sickness. It should provide useful insights, as it spans my experience of working in all three sectors, government, PSUs and the private sector. It should also be useful to academic institutions and students of management, as the book brings live Indian cases to light. Management consultants might find some of the events and solutions relevant and interesting. Multinational corporations and foreign institutional investors may find the narrative useful in getting a clearer understanding of the Indian psyche and corporate scene, some of its unique problems and possible approaches to their solutions.”

Overall a good book, especially for those in India in the Naval Architectural profession.

The book is not openly available in the internet as of date. I had read it, courtesy, one of my blog readers who had emailed it to me. He is one the members of a yahoo group called “Constructor County” which is a group which caters to the Naval Architecture Fraternity of India (only??? I am not sure).

However surprisingly while browsing the net, I found it here.

The author would have possibly uploaded it.

Theory of Submarine Design

2009-12-16T18:31:00.000-08:00

Theory of Submarine Design
Yuri N. KORMILITSIN, Oleg A. KHALIZEV

Hardcover: 340 pages
Publisher: Riviera Maritime Media (1 Aug 2001)
Language English
ISBN-10: 0954144600
ISBN-13: 978-0954144609

This book has been written based on the textbook "Submarine Design,which has been recommended by the Ministry of Education of the Russian Federation for students at institutions of higher education, specializing in "Shipbuilding". It is published in the year of a centenary anniversary. of submarine professional design in Russia.
The book is published with the permission of the authors and the consent of the St.Petertsburg State Maritime Technical University. The book explores methodological issues, theory of submarine design, general methods of submarine displacement and its trimming determination, architectural aspects and determination of principal particulars as well as some othcr issues related to submarine specific features.

Here is the link:
http://rapidshare.com/files/321721512/Theory_of_Submarine_Design.pdf.html

Analysis and Design of Marine Structures By Carlos Guedes Soares, P.K. Das

2009-12-13T00:22:00.000-08:00

About the Book

Author(s): Carlos Guedes Soares, P.K. Das
Publisher: CRC
Date : 2009
Pages : 564
Format : PDF
OCR : Y
Quality :
Language : English
ISBN-10 : 0415549345
ISBN-13 : 978041554934

Book Description

From the Back Cover

This book is a collection of papers from MARSTRUCT 2009, the second International Conference on Marine Structures, held in Lisbon, Portugal, 16-18 March 2009, and contains the latest progress made in structural analysis of marine structures.

The MARSTRUCT series of conferences started in Glasgow, UK in 2007, and has the aim of becoming a bi-annual specialised conference dealing with Ship and Offshore Structures. The initial impetus and support for this series was given by the Network of Excellence on Marine Structures (MARSTRUCT), which brings together 33 European research groups and is now in its 6th year of funding by the European Union.

'Analysis and Design of Marine Structures' explores recent developments in methods and modelling procedures for structural assessment of marine structures:

- Methods and tools for establishing loads and load effects;

- Methods and tools for strength assessment;

- Materials and fabrication of structures;

- Methods and tools for structural design and optimisation;

- Structural reliability, safety and environment protection.

The book is a valuable reference source for academics, engineers and professionals involved in marine structures and design of ship and offshore structures.

You can download the book from here

The Wave Resistance of Ship By J.H. Michell

2009-12-12T03:41:00.000-08:00

John Henry Michell (1863-1940) published scientific papers only between 1890
and 1902, but included in his 23 papers from that short but productive period are some of the most important contributions ever made by an Australian mathematician.
In this blog I shall concentrate on the extraordinary 1898 paper "The wave resistance of a ship," Phil. Mag.(5) 45, 106-123. There are many reasons why this paper was an astounding achievement, but perhaps the most remarkable is that the resulting formula has not been improved upon to this day. In the computer age, many efforts have been made to do so, but with little success so far. The formula itself involves a triple integral of an integrand constructed from the offset data for the ship's hull, and even the task of evaluating this triple integral is not a trivial one on today's computers; another reason for admiration of Michell's own heroic hand-calculated numerical work in the 1890's. Lack of a routine algorithm for Michell's integral has inhibited its use by naval architects and ship hydrodynamic laboratories, and there has been a tendency for it to receive a bad press based on unfair comparisons, e.g. comparison of model experiments (themselves often suspect) with inaccurate computations or computations for the wrong hull, etc. The original integral is in fact quite reasonable as an engineering tool, and some new results confirming this are shown. Improvement beyond Michell is however needed in some important speed ranges, and indications are given of recent approaches that may be promising.

I had searched for this paper everywhere, and luckily I found a website (a Russian one that too!) and I dont think it is available anywhere.
The Link is here.

Other Options for a Naval Architect

2009-12-10T07:03:00.000-08:00

Not interested in design??? But still interested in the field of Naval Architecture!!!!!

No Problems!!!!!

Here are the other options

Construction and Repair

The task of the ship and boat builder and offshore constructor is to convert drawings and detailed specifications into real structures. A Naval Architect specialising in construction usually holds a management post, taking responsibility for the management of the whole yard or for sections of it such as planning, production or the complex operation of fitting out. There is a continuous striving to make savings with existing techniques and equipment through the adoption of new processes and practices and by better training for the work force. The Naval Architect must also organise the supply of materials and components, inspection and testing as well as the vital resources of manpower.

Repair work has much in common with construction. Naval Architects in this field become professional managers who, like the builders, need to master modern management and associated techniques. Emergency repair work often offers opportunities for ingenuity and on-the-spot improvisation, and in the offshore engineering world in particular repair frequently involves underwater technology.

Employers of Naval Architects in construction and repair include both large and small shipbuilders and repairers, and those involved in the maintenance and repair of naval ships and submarines. A large proportion of senior technical managers and executives in the UK maritime industry are those who have been educated and trained as Naval Architects.

Consultancy

As consultants, Naval Architects provide clients with engineering solutions, technical and commercial guidance, support and project management for concept design studies, new vessel constructions, refits and conversions. The variety of work provides a rewarding challenge to the Naval Architect.

Marketing and Sales

Naval Architects are employed to give professional advice and technical support to customers of the maritime industry.

Operations

Many shipping companies have technical departments in which Naval Architects are responsible for the many phases of ship and equipment procurement and for solving problems affecting the economics of maritime operations.

Regulation, Surveying and Overseeing

Naval Architects employed by Classification Societies as Ship Surveyors are engaged world-wide in evaluating the safety of ships and marine structures using the Society's Rules and those of intergovernmental organisations such as the International Maritime Organisation. Plans of ships to be built and eventually classed with the Society are scrutinised, and aspects of design such as strength, stability, and lifesaving approved before construction.

During construction, Ship Surveyors carry out inspections to ensure that the quality of the workmanship and materials used is in accordance with the Rules and Regulations. Once the vessel or structure is in service, Ship Surveyors will continue to carry out inspections to ensure that any serious defects arising from operation are made good and that a safe and seaworthy structure is maintained. Government Departments employ Naval Architects who deal mainly with the framing of safety regulations and the surveying of ships and equipment from the safety point of view.

Ship operators and the Ministry of Defence employ Naval Architects to oversee the construction and repair of their vessels.

Research and Development

Maritime research in the UK enjoys a high reputation world-wide and Naval Architects, many with post-graduate qualifications, are engaged in research in universities and industry throughout the country. Classification Societies also devote resources to Research and Development employing Naval Architects in this field.

Education and Training

Careers in engineering demand a sound education. Consequently, there is a need to attract Naval Architects with above average qualifications into Universities and Colleges as professors and lecturers.

Creativity in Naval Architecture: Ship Design

2009-12-10T06:59:00.000-08:00

Are You creative?????
Naval Architects are by necessity creative people. They must have an understanding of the many facets of ship design - function, appearance and especially important at sea, safety. They must be team leaders, able to integrate the inputs of many others to achieve a balanced and coherent whole. Apart from the architectural aspects of ship form and layout, they must be able to use complex mathematical and physical models to ensure that the design is satisfactory technically and that it meets the safety rules and standards laid down by Classification Societies and Government Agencies.

A ship, boat or offshore structure must be stable, seaworthy and have adequate strength in all weathers as well as the hydrodynamic (and, for sailing craft, aerodynamic) performance to give economic propulsion and safe and comfortable motion in all sea states. The design process demands the extensive employment of computer based information and communication systems.

Employers of Naval Architects involved in design work include ship and boat builders, offshore constructors, design consultants, and for the ships and submarines of the Royal Navy, the Ministry of Defence. Major equipment manufacturers also employ teams of engineers, including Naval Architects, on the design of such products as propulsion systems, auxiliary systems, subsea production systems and control systems.

Career Options for a Naval Architect

2009-12-10T06:57:00.000-08:00

Naval Architects have a wide range of employment opportunities, both in the UK and world-wide. They are involved in such a wide variety of work that it is difficult to categorise it comprehensively. However, the main areas are as follows:

Design
Construction and Repair
Consultancy
Marketing and Sales
Operations
Regulation, Surveying and Overseeing
Research and Development
Education and Training

Each type of work has its own distinctive character and offers opportunities for initiative and imagination in a wide variety of technical and managerial posts as well as opportunities for foreign travel. The work place may be a large company, a small group, a consultancy or a government department.

Depending mainly on the type of qualifications held and personal inclination, Naval Architects may become specialists in one field or develop broad experience in several. Eventually they may find themselves in senior executive positions using their knowledge and experience of general management as well as their professional skills in engineering and project leadership. Indeed, aided by the breadth of their education, training and experience, professional Naval Architects are successful in top management posts in government, industry and commerce quite outside the maritime field.

What's so different about being a naval architect

2009-12-10T06:50:00.000-08:00

Why be a Naval Architect?? ?

What's so special in being a naval architect???

Why can't I be a normal software nerd??? and be a millionaire???

Well here are the answers!!!!

A Naval Architect is a professional engineer who is responsible for the design, construction and repair of ships, boats, other marine vessels and offshore structures, both civil and military, including:

Merchant ships - Oil/Gas Tankers, Cargo Ships, Cruise Liners, etc
Passenger/Vehicle Ferries
Warships - Frigates, Destroyers, Aircraft Carriers, Amphibious Ships, etc
Submarines and underwater vehicles
Offshore Drilling Platforms, Semi Submersibles, FPSOs
High Speed Craft - Hovercraft, Multi-Hull Ships, Hydrofoil Craft, etc
Workboats - Fishing Vessels, Tugs, Pilot Vessels, Rescue Craft etc
Yachts, Power Boats and other recreational craft

Some of these are among the largest and most complex and highly valued moveable structures produced by mankind. Without them to provide for the safe and efficient transport and recovery of the world's raw materials and products, modern society as we know it could not exist.

Modern engineering on this scale is essentially a team activity conducted by professional engineers in their respective fields and disciplines. However, it is the Naval Architect who integrates their activities and takes ultimate responsibility for the overall project. This demanding leadership role requires managerial qualities and ability to bring together the often conflicting demands of the various professional engineering disciplines involved to produce a product which is "fit for the purpose".

In addition to this vital managerial role, the Naval Architect has also a specialist function in ensuring that a safe, economic and seaworthy design is produced.

To undertake all these tasks the Naval Architect must have an understanding of many branches of engineering and must be in the forefront of high technology areas such as computer aided design and calculation. He or she must be able to utilise effectively the services provided by scientists, lawyers, accountants and business people of many kinds.

A Naval Architect requires a creative, enquiring and logical mind; the ability to communicate clearly in speech and writing with others inside and outside the engineering profession; sound judgment and qualities of leadership. The education and training given to the Naval Architect are designed to develop these skills and to lead him or her to recognised qualifications and professional status.