Energy efficiency design formula agreed

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 industry’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 Lloyd’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 IMO’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

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

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

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

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

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

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

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.