Book Review- Larrie D. Ferreiro. Ships and Science: The Birth of Naval Architecture in the Scientific Revolution, 1600-1800.

Larrie D. Ferreiro. Ships and Science: The Birth of Naval Architecture in the Scientific Revolution, 1600-1800.

Ferreiro, Larrie D. Ships and Science: The Birth of Naval Architecture in the Scientific Revolution, 1600-1800. Cambridge, Mass.: MIT Press, 2007. 432pp. $45

This is the first in a planned two-volume history of the application of scientific theory to ship design. Larrie Ferreiro is well qualified to take this on, having both trained and worked as a naval architect and having earned a PhD in the history of science and technology.

The sailing ship was arguably the most complex mechanical system in common use prior to the Industrial Revolution. Thus a natural development of the scientific revolution of the seventeenth and eighteenth centuries was, for emerging "scientists," to try to explain the behavior of the ship at sea. The initial goals were to understand how it was that ships floated and were propelled through the water, with the ultimate objective of applying scientific principles to optimize the design of ships before they were actually built. Ferreiro traces the pursuit of this emerging ship science through the work of key individuals, most notably Pierre Bouguer, the "father of naval architecture." The book also takes a topical approach, focusing on efforts to develop the major concepts of ship design, including the proper configuration and placement of masts and sails, hull resistance in water, hull displacement, buoyancy, the center of gravity, and the metacenter. Running through this history is the evolving process of naval architecture through the end of the eighteenth century, including the development and standardization of terminology, ship models and plans, and experimental techniques.

This is ultimately a story of failure, a succession of scientific dead ends on the road to eventual enlightenment. Most of the baseline theoretical work of this period was later determined to be incorrect due to a variety of limitations inherent in early science, including inadequate mathematics, limited experimentation techniques, a lack of reliable means to spread ideas, and not least of all, dogged adherence to Aristotelian physics. It is nevertheless an instructive account of how early theorists came to understand the phenomena they were trying to explain.

Beyond the basic science, this is also an interesting story of the process of innovation within an established bureaucracy. Up until the nineteenth century there was virtually no demand for the application of scientific principles to ship design among those actually building or operating ships. Science was seen both as unnecessary and undesired by ship constructors, whose designs had proven quite adequate and whose livelihoods depended upon safeguarding their specialized and unwritten knowledge. Ferreiro's thesis is that the primary impetus for developing and applying standardized scientific techniques to ship construction was an effort by administrators outside shipbuilding to impose increasing control over warship design and production. Although little actual change was evident by the end of the eighteenth century, Ferreiro reveals the elements of the eventual shift in bureaucratic control over ship design from individual craftsmen (ship carpenters) to members of an entirely new profession (naval architects).

This book well serves its primary purpose as a general history of the beginnings of naval architecture. It is also valuable as a broader history of technological innovation, offering insight into the relationship between science and technology and the social impact of technological change. I look forward to the second volume (post-1800) of the series.

The Links to the book in the Web have been deleted as they violated Copyright laws.

Waterjets Propel Sweden's Visby to Success

When the first two Visby class corvettes enter service with the Swedish Navy at the end of 2009, they will mark the result of 20 years of naval stealth technology development by the Scandinavian country.

As the first operational stealth ship in the world, the corvettes are designed to be electronically undetectable at more than 13km in rough seas and at more than 22km in calm seas. This is partly thanks to a composite, non-magnetic hull that features large, flat surfaces and sharp edges to lower its acoustic and optical signatures.

The key element in the Visby's stealth abilities is the use of waterjet propulsion, which was favoured over traditional propellers.

The decision was sparked by a spate of incursions into Sweden's national waters in the mid-1980s by foreign submarines. This highlighted the need to create an anti-submarine and mine-hunting vessel that could operate close to its shore.

This is an area that contains hundreds of islands and archipelagoes that generate a complex underwater hydrological picture while presenting challenges in piloting and navigation, potentially forcing any such craft dangerously close to its quarry.

In this cluttered littoral environment the requirement was for a quiet and agile vessel. Patric Hjorth, technical manager at the Swedish Defence Materiel Administration (FMV) the prime contractor for the Visby programme, says: "It's very hard for a submarine to detect a waterjet vessel. It has a very different signature from a propeller-driven craft as it fades into the background. They're also very good for making tight turns and fast stops, so they give a lot more manoeuvrability."

A further reason for using waterjets is to reduce the vessel's draft in these shallow waters. Early trials suggest that using propellers will increase the draft by up to 0.65m. But it did mean standard hull design was out of the question. "You have to design the hull and stern of a vessel specifically for waterjet propulsion or you won't get the right water flow to the waterjet inlet – you have to channel the flow to the inlets," says Hjorth.

Minimising signatures

The plastics and carbon fibre used in the composite hull to give it stealth properties also help to make the craft very lightweight. The Visby displaces 600t of water, about half the weight of a conventional, steel-hulled corvette and this was a design parameter that led to another reason for choosing waterjets.

"The need for agility and a high top speed meant that a light weight was an essential factor throughout the entire programme," says Hjorth. "You actually need waterjets for these vessels, as they're more efficient than propellers at high speeds."

The waterjets themselves, from Rolls-Royce subsidiary Kamewa, are standard 125SII units customised for navy use. They produce a low hydro-acoustic signature in any case – about 10–15dB less than a prop-driven equivalent – but to obtain the even lower signature specified in the design, the impellors use seven blades instead of the usual five and the blades themselves are skewed.

This allowed the main inlet to be light and small with some components being remade in bronze instead of the usual stainless steel to minimise their magnetic signature.

They are driven by a combined diesel or gas – CODOG – system designed for the Visby by its builder, Swedish shipwright Kockums, which consists of two MTU diesel engines and four Verico marine gas turbines.

At low speeds the waterjets are powered by the diesel engines while the turbines are used for higher speeds, which can exceed 35 knots. Power is fed to the waterjets through a pair of gearboxes, with one diesel and two turbines connected to each one. "The gearing had to be specific to the waterjets to allow the Visby to move slowly for hunting submarines or detecting mines, then switch to higher speeds for other roles," Hjorth explains.

He adds that CODOG was chosen over CODAG (combined diesel and gas) because it allows for a simpler gearing arrangement and therefore does its bit to save weight too. "The choice of power unit and waterjets is governed entirely by the vessel's operational profile," he says. Although CODAG is used in similar craft such as the South African Navy's Valour class of frigates, Hjorth points out its use is more appropriate there because the Valour vessels operate on the open sea and hence tend to operate at intermediate speeds where CODAG propulsion is more efficient.

Multipurpose vessels

Originally there were to have been six Visby corvettes divided into two classes, one for surface combat and the other for submarine hunting and mine detection. However, cutbacks in the early 1990s saw the fleet reduce to five vessels in all and in a single, multifunction class.

As a result, the standard configuration is a mixture of equipment. But, Hjorth says, all is not lost. "Although the vessels can switch from one role to another while out at sea, if needed they can return to port to be refitted with specific modules to optimise them for a particular role."

There has been a great deal of interest in the Visby from around the world, particularly from the US in relation to its own Littoral Combat Ship programme – the first product being the experimental Sea Fighter that serves as a testbed vessel and is powered by the same Kamewa waterjets as the Visby.

Hjorth admits it is still early days for the Visby and believes potential buyers will wait until the corvettes have run up some operational time before coming forward with orders. Some may view this as ironic as Sweden's historic neutrality has led to a long tradition of developing its own technology and as such has been pioneering waterjet propulsion since the 1980s, notably in Visby's predecessors the Göteburg class.

"Waterjet technology has worked brilliantly for us over the years," says Hjorth. "There has been no giant leap for us with Visby – they were the obvious choice."

Visby Class - Stealth Ship Of The Swedish Navy

Golden State (PC-1 Class Product Tanker)

The ship, named the Golden State, was built by General Dynamics NASSCO, a wholly-owned subsidiary of General Dynamics, and was delivered to U.S. Shipping Partners LP. The Golden State is the lead ship of a new line of product tankers, disignated the PC-1 class. Construction began in August of 2007 and was completed six months ahead of schedule and under budget, making it a excellent first-of-class ship spearheading the Product Carrier program at NASSCO. It is the first of 9 product tankers to be delivered to U.S. Shipping Partners LP.

At a length of 600 feet, the Golden State has a cargo capacity of approximately 331,000 barrels and will be used to carry petroleum and chemical products between U.S. ports. The ship is named in honor of the State of California, where General Dynamics NASSCO is located.

The PC-1 class of product tankers will be 183 meters (600.4 feet) in length and 32.2 meters (105.6 feet) in beam, with a design draft of 11.8 meters (38.7 feet). The ships will be double hulled, displace 49,000 dead weight tons (DWT) and have a cargo capacity of 331,000 barrels. Also, they will have a single crew, be diesel-powered and have a target operating speed of 14.8 knots. The PC-1 class will replace single-hulled and aging double-hulled ships that carry refined petroleum products among U.S. ports.

CLICK HERE for a PC-1 Product/Chemical Tanker Fact Sheet (PDF)

US Navy saves $3M by using Water Bags for load testing

The Navy has recently begun using water bags accomplishing periodic weight tests of boat davits. A result of a teaming effort between NAVSEA, NAVSEA Philadelphia-SSES and FTSCLANT, this innovation will save the Navy over $3 million per year compared to traditional methods. In the past, tests using concrete block or steel weights required a pier side or barge crane plus four-six individuals, cost as much as $20 thousand and required up to eight hours. Using water bags is simple. A flexible container is filled with water, acting as the test weight. Water supplied from the ship fire main fills the bag to the required weight. (Remember "A pint's a pound the world around"?) A wireless load cell shackle connected between the bag master link and the davit hook provides an accurate reading as the bag fills. Adding or draining water adjusts the weight. Once the operation is complete, the container is drained and packaged for storage. Since it can be packed up at the relatively small size of 175 - 300 lbs, the process requires no crane supporting or positioning the bags on the davit. Only about three workers are needed over a three-hour job. Cost savings constitute the greatest advantage. The Navy spends between $3.6 and $5.2 million per year for weight tests. Estimated annual costs will decrease approximately $560K per test by eliminating the need for a crane plus reduced labor and time, producing savings of over $3 million. Safety is enhanced, as physical handling of large weights is no longer necessary. Scheduling flexibility increases for the testing activity and the TYCOM, ship's force and FTSC. Without the need to schedule a crane, tests can be accomplished with very little advanced notice. Greater flexibility generates additional savings that defy accurate calculation. Funding obtained from NAVSEA's Engineering for Reduced Maintenance Program enabled the teaming effort between NAVSEA, NSWCCD-SSES and FTSCLANT. The first step called for identifying a manufacturer whose product was safe, functional and reliable. Water Weights Inc. was quickly identified. The second step entailed resolving physical size constraints for the bags because of unique test requirements associated with boat davits. Unlike many other hull and deck machinery systems, boat davits must inhaul the test weights to the fullest inboard point, ensuring the davit winch and structural members are subjected to loading experienced during actual conditions. This brings the weights within the shell of the ship, requiring shapes small enough to avoid deck obstructions. Water Weights Inc. was able to modify "off the shelf" bags to fit. The final step was development of operational and maintenance procedures for incorporation into manuals and a training video. It shows the principle of operation as well as the test. The footage was taken and the operational and maintenance procedures "proofed in" during actual tests on USS GEORGE WASHINGTON (CVN 73), USS BARRY (DDG 52), and USS MOUNT WHITNEY (LCC 20). - (By Tom Warring, Public Affairs Officer, Naval Station Warfare Center, Carderock Division)

Water Weights: Proof load testing of lifting equipment

In many countries proof load testing of lifting equipment such as cranes is a mandatory requirement. Such requirements are legal minimums and many companies and industries set rigorous standards.
For the first time in India, FAFECO (Furnace & Foundry Equipment Co.), a leading manufacturer of high capacity cranes and other material handling equipment, has introduced Water Weights, a specialised, innovative, safe and unique method for load testing cranes and other MH equipment and structure. FAFECO has teamed up with Water Weights, a division of IMES, UK, the pioneers of the system of specialised load testing through use of water filled proof load bags.
Proof load testing is an essential part of any inspection, repair and maintenance programme. In India, annual proof load testing of lifting equipment is a statutory requirement. A successful proof load test instills confidence in customer, operator and owner.
Water Weights load testing involves the use of lightweight, empty, poof load bags that are made up of specially developed super-strong PVC, are suspended from or placed on the equipment/structure to be tested, and then gradually filled with water to systematically build up the load to the required level. These bags have a simple system of manual release of the water permits the load to be withdrawn immediately whenever required to avoid mishaps, in case at any point of testing it appears that the equipment may not be able to withstand the load.
Water Weights water filled proof load bags is designed to provide a test load instead of traditional solid weights. This highly engineered and certified system allows a safe, practical and economical method for load testing. The development of Water Weights bags has increased greatly the practicality, economy and safety of providing proof load testing in marine, industrial and engineering applications.

Applications
Marine: Offshore installations, shipbuilding and repair companies and docks and harbours use Water Weights for testing applications like cranes, davits, derricks, winches, lifeboats, ramps and lifts, and pad eyes.
Industrial: Power stations, refineries, factories and crane companies use Water Weights for testing overhead cranes, beams, gantries and elevators.
Engineering: Specialised Water Weights products and services are used by structural engineers, construction companies, naval architects and engineers, and logistics management companies for floor and bridge tests, ballast and counterweight, water and liquid storage, tanks and liners, load measurement, and cargo manifesting and data logging.

Advantages
Safe: Water Weights water bags have a physically proven factor of safety in excess of 6:1 and are proof load tested to over 2:1 prior to being taken into services. When performing load test, gradual application of the load allows many problems to be identified prior to attaining maximum load.
Economical: Water Weights bags weigh less than 2 per cent of achievable load allowing for considerable savings in transport, storage and labor cost.
Flexible: A wide range different sizes of Water Weights bags is available. Bags can be hung in combinations to achieve large loads.
Simple: Water Weights bags are very light, aiding handling. These bags are fully rigged and ready to hang and fill.
Certified: All Water Weights bags are certified to the UK Health and Safety Executive Safety Requirements and the American Bureau of Shipping. Even Water Weights are approved to ISO 9001:2000.
Says Shyam M. Gurnani, Partner, Fafeco, "With the introduction of Water Weights in India, the company can now ensure more safety to people that work in conditions where any negligence on the part of the authorities or the manning of the equipment can result in huge amount of losses, both of tangible value and reputation."