Page 42: of Maritime Reporter Magazine (November 2013)

42 Maritime Reporter & Engineering News ? NOVEMBER 2013 Marine Propulsion ? RepowerWhile many owners discuss ideas to suitably maintain maritime service while slashing operating costs, Seasteak LLC, owners a 43m fast ferry Wall Street, put words into action with a dramatic pro-pulsion switch that saw the company maintain sailing schedule and speed while reducing fuel consumption 30% and CO2 emissions 50%. Wall Street, a 43m fast ferry owned by Seastreak LLC of Atlantic Highlands, NJ, was originally built by Gladding-Hearch Shipbuilding and launched in 2003, the third of four sister vessels. As built, Wall Street was equipped with four KaMeWa A50 waterjets powered by four Cummins KTA50 diesel engines of 1424kW each and a total output of 5696 kW. At the time of construction, the vessel was state-of-the-art, and the four-engine package was selected with an emphasis on speed and reliability on the Atlantic Highlands, NJ, to Manhat- tan service.As the equipment aged and fuel prices skyrocketed, however, the decision was taken to investigate repower options for the ferry, as the owner sought a reduction in both emissions and fuel consumption, as well as reduced maintenance cost and reduced wake during operation.Seastreak?s director of vessel engineer- ing developed estimates based on Ser- vogear?s Eco ß ow Propulsor concept. In cooperation between Servogear, Nor- way, Incat Crowther Design (the vessel?s original designer) and Seastreak, the re-powering was studied.With the assistance of a U.S. govern- ment energy efÞ ciency improvement loan Seastreak made the decision to remove one ferry from service and reÞ t it from a quadruple engine/water jet vessel to a twin engine twin screw Servogear CPP propulsion system. In addition, the owner decided to power the vessel with a pair of MTU 16V4000M53 diesel engines rated 1840 kW each. In looking at the vessel?s oper- ational proÞ le, Servogear?s controllable pitch propellers, tunnel design and rud-ders promised a signiÞ cant fuel saving at the vessel?s 32 knot operating speed. With Incat Crowther providing a com- prehensive design service, preparing detailed drawings and documentation including revised Coast Guard submis-sions, the contract to perform the work was awarded to Midship Marine in Loui-siana. The engine re-powering entailed a re-conÞ guration of the vessel?s aft. The topsides and the undersides of the hulls were removed from the waterline down, from the forward engine room bulk-head aft. New engine beds, longitudinal stiffeners and plating were fabricated to support the MTU-engines and ZF-gear- boxes. Servogear designed tunnels lower hull resistance and provide optimal in-ß ow of water to Servogear?s propellers and rudders.Together with interior and exterior modiÞ cations, Wall Street today is 15 tonnes lighter than when originally built. At sea trials the vessel recorded speeds of 36 knots, and at equivalent dead-Fast Ferry Gets a New Power Package Fast Ferry Gets a New Power Package Wall Street Wall Street Seastreak?s Wall Street Seastreak?s Wall Street Repower Synopsis Repower Synopsis Installed power: Reduced from 5696 kW to 3680 kW (35%) Fuel consumption: Reduced 30% (est. $500,000/year) Weight: Reduced 15 tonnes CO2 emissions: Per-passenger value halved MR #11 (42-49).indd 42MR #11 (42-49).indd 4211/12/2013 10:54:12 AM11/12/2013 10:54:12 AM