Page 81: of Marine News Magazine (November 2012)

while still maintaining their operating temperature using keel cooling. ?This solution does not rely on sea or river water entering the engines for cooling, which is important because the silt- laden water of the Thames tends to block or damage cooling pumps and other systems,? said Alan Cartwright, the PLA?s head of marine engineering. The project for design and build of the innovative vessels was put to open bid and won by Alnmaritec, which is known for providing specialized commercial vessels to clients? demanding requirements. The engines were supplied by John Deere distributor E.P. Barrus Ltd, which conducts good business with both Alnmaritec and the PLA. ?E.P. Barrus provided modi cations to the exhaust manifold to prevent possible overheating of the engine, and ? to the PLA?s electrical systems design for the vessels -  tted larger on-engine auxiliary generators, providing all 230V AC power via an inverter. This prevented the need for a separate main generator and saved weight ? essential to vessel ef ciency.? Partnership Engineered for Success Alnmaritec designed the vessels based on PLA?s concept drawing and detailed speci cation, which focused on using ecologically-sensitive, energy-ef cient solutions. Specialists were called in to support the design process: the Marine Science Department of Newcastle University participated in the underwater form and propeller design, while specialist naval architects Amgram Limited optimized the vessel strength for minimum hull weight. The result was a 44 ft. (13.5m) deep-vee catamaran design, speci cally tailored for navigational patrol and pilotage tasks along the river. The ef ciency of the design is achieved through the combination of tremendous strength and seakeeping capability, at low displacement weight, ef cient hull form with matched propellers and very slippery Intersleek silicone anti- fouling, from International Paints Ltd. With their two John Deere engines, they can achieve top speeds of around 20 knots. The Lambeth was the  rst of class, built and used as a prototype, upon which the PLA crews, managers and engineers developed the design from lessons learned, in operational service. Southwark, Kew and Barnes were built to the rede ned speci cation, which incorporated a number of operational improvements. These included improved fendering, increased windscreen sizes, sliding wheelhouse doors, better instrumentation layout and revised alignment of the guardrails on the sides of the vessel, to help with pilotage operations. After two years in service, Lambeth was also re tted to the new speci cation. EfÞ cient Ð and Green, too During the service of the four vessels so far, it has become clear that the operational ef ciencies and advantages that were fundamental to the design concept have all been delivered. Compared to the older vessels being used in the same way, the new launches with John Deere engines use 52.4% less diesel fuel (based on aggregate monthly consumption). This is true even though the Bridge Class vessels in central London were put to particularly high use during the 2012 events and their preparation. Centofanti Marine SystemsDon?t settle for cheap imitations. Get the originalMark IV Air Clutch Control Panel Gear Mate Panel, Throttle Interlock, Governor Actuator, Chrome ?T? Handle Control Head And remember, just because you have installed electronic engines and gears doesn?t mean you have to give up the reliability of pneumatic controls. Contact us for more information on our PNELC System We are American Owned and American Made from Start to Finish Formerly Schrader Bellows Marine P.O. Box 1050 Uniontown, PA 15401 (724) 438-7666 [email protected] Type II Marine Sanita !on DeviceU.S. Coastguard Cer ed ? I.M.O. Cer ed1-606-561-4697711-C Colyer Road ? Bronston, KY 42518 www.envmar.com Booth #606Booth #1316 ? Constructed of HD High Density Polythylene ? Lightweight ? 4, 12, 16 & 32 Person Systems ? Corrosion free ? Maintenance Free ? Simple Installa !on? Operates as a Biological AerobicSewage Treatment, Elimina !ng Foul Odors ? Conforms to the Clean Water Act PROPULSION MN 81www.marinelink.com MNNov2012 Layout 66-81.indd 81MNNov2012 Layout 66-81.indd 8111/7/2012 11:21:40 AM11/7/2012 11:21:40 AM