compatible ferry transport in the UK by way of the groundbreaking scheme launched by Caledonian Maritime Assets(CMAL) for two new vessels incorporating a hybrid power and propulsion system. With Ferguson Shipbuilders having recently been contracted to construct the two double-enders, the project could see a resumption of commercial shipbuilding on the Clyde aſter a gap of several years. Ferguson will work alongside Glasgow-based ship designer Seatec and electrical specialist Tec-Source in realising the programme for CMAL’s fleet operator Caledonian MacBrayne(CalMac). Intended for short crossings at service speeds


of 9knots on CalMac’s Clyde and Hebridean network, each ferry will accommodate 150 passengers plus 23 cars or two heavy goods vehicles. Power will be derived from four main gensets, feeding a 400V split main switchboard, delivering energy to two propulsion motors driving respective, offset propulsion units at each end of the hull. In addition, two lithium-ion battery banks with a total capacity of 700kW/h will also supply power to the propulsors, reducing fuel consumption and CO2


emissions by at least 20%. Te batteries will


be charged overnight from the mains when the vessels are berthed. Te installation will allow the ferries to run


in diesel generator, diesel generator plus battery, or battery-only mode, allowing power delivery to be matched to precise, overall energy needs at any point, whether sailing, manoeuvring or alongside. Aside from the battery-engendered gains, it is estimated that the vessel design and power configuration will realise 19-24% savings in power input to the propulsion units, compared to a conventional diesel-mechanical solution, with correspondingly less emissions.


Lower maintenance costs A recent endorsement of the diesel-electric mode by prominent US operators is the selection of Siemens BlueDrive propulsion systems for two platform supply ships ordered from Bay Shipbuilding Company by New Orleans-based Tidewater Marine. Te diesel- electric vessels will employ Z-drive propulsors, and the integral BlueDrive low-voltage, multi-drive system promises enhanced reliability through failsafe provisions, lower maintenance costs, increased efficiency and ease of operation. Siemens’ scope of supply also encompasses


the main generators, main propulsion and thruster motors, switchboards, power


for the project management, engineering and commissioning of the complete diesel- electric system. Tis year also saw ABB win a contract to


Northern Lights is offering a hybrid propulsion system combining its Lugger engines with BAE Systems’ HybiDrive technology.


management system and Siship IMAC automation system. Te vessels are slated for delivery from the Sturgeon Bay yard in Wisconsin towards the end of 2012 and during 2013 respectively, and will be constructed to DP2 dynamic positioning standard and PC7 ice class. BlueDrive technology also figures in


Ostensjo Rederi’s platform supply vessel newbuild project at Astilleros Gondan in Spain. Te ship’s diesel-electric plant will be based on four MaK M25C-series medium- speed diesels, comprising two six-cylinder and two nine-cylinder models. The environmental credentials of this


prospective 2012 fleet entrant, as regards both CO2


and NOx, will reflect the operational


optimisation conferred by a diesel-electric configuration, together with the use of SCR(selective catalytic reduction) units for each engine, and the first-time application of the engine builder’s new air injection system. Meanwhile, Siemens has devised a


compact, hybrid system tailored to small vessels and craſt that have traditionally relied on mechanical drives. Designated Siship EcoProp, the diesel-electric hybrid propulsion solution allows small ships, fishing vessels, public authority, agency craſt and workboats to reap the benefits of increased efficiency across the vessel’s operating profile, greater cruising range, enhanced reliability, reduced maintenance, lessened emissions and quieter running. An added advantage of the system and its standardised modules is a suitability for installation in tight spaces. Siship EcoProp has been nominated for


a 65m supply vessel to be delivered in 2012 to the Italian coastguard service by Cantieri Navali Megaride. Siemens is responsible


Ship & Boat International January/February 2012


supply twin 6.5MW Azipod propulsors for each of two 99m icebreaking, multifunctional supply ships ordered in Finland by Sovcomflot. The vessels have been designed for Arctic conditions and operations in driſting ice of up to 1.7m thickness. Sovcomflot intends to use the pair for a gas field development project off Sakhalin Island in the Russian Far East. Deliveries are scheduled in 2013 from the Arctech Helsinki Shipyard.


Biofuel options A further example of the growing reach of electric propulsion technology is provided by the latest fleet development project initiated by Finnish heavy freight and transport group Meriaura. Te company’s newbuild project cargo carrier and multipurpose vessel Aura II, just over 100m in length, will be the first dry cargo ship in the Baltic to incorporate the double-acting concept, enabling propulsion astern or ahead in ice. The diesel-electric plant will be based


on three main gensets driven by Wärtsilä 6L20 engines, which will have the added distinction of enabling operation on various types of liquid biofuels as well as marine diesel oil. Besides the ice-going and ice-forcing attributes of the double-acting mode, the high manoeuvrability conferred by two electric propulsors and two bow thrusters will be a major asset in close-quarter berthing situations and when positioning for cargo offloading in offshore waters. Te capability for ‘crabbing’, or moving


sideways in open water, is also salient to the vessel’s oil spill recovery tasks. Te diesel- electric power and propulsion system thereby supports the operational flexibility demanded of the vessel, while also meeting the compact installation space criteria imposed by the design. Good torque characteristics and


controllability, especially at low speeds, continue to make electric propulsion systems an attractive alternative to conventional solutions in a whole range of vessels, a choice reinforced by considerations relating to specific operating profiles, technical design and through-life efficiency issues, and the environmental backdrop. SBI


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