One of the two engine rooms of the MAN 48/60CR-powered ro-pax ferry for Tunisia
MAN Diesel & Turbo reports that it has received an order for four medium speed engines from Daewoo Shipbuilding & Marine Engineering of Korea, for a new large ro-pax ferry.
The ship, to be operated by Cotunav (Compagnie Tunisienne de Navigation) of Tunisia, will measure 210m long and 30m wide, with the capacity for 3,200 passengers and 1,060 vehicles. MAN believes this will make it the largest ferry in operation; the ship will service Cotunav’s routes between Tunisia, Italy and France. The design speed of the ferry is 27.5 knots, and the accommodation will include a shopping centre, restaurants, swimming pool and multiple entertainment facilities. Delivery is due in the first half of 2012.
The 48/60CR engines feature MAN’s common-rail fuel system and will each be rated at 14,400 kW. The common-rail technology allows independent setting of injection timing, duration and pressure for each cylinder, and has been well proven on cruise ships among other vessels. The flexibility of operation is said to allow optimisation of fuel consumption, NOx and smoke emissions at any point on its operating profile, especially at part-load.
MAN says that its common-rail system is based on an intelligently designed safety concept that features screened or double-wall high-pressure pipes, and flow-limiting valves to prevent uncontrolled injection. The system has redundant high-pressure pumps as well as twin-type pressure and speed sensors to ensure engine operation, even in the event of failures, so safety is a prime consideration.
The 48/60CR is equipped with MAN Diesel & Turbo’s SaCoSone engine-management system. Benefits claimed for the system include:
- integrated self-diagnosis functions;
- maximum reliability and availability;
- simple use and diagnosis;
- quick exchange of (plug-in) modules; and
- trouble-free and time-saving commissioning
MAN says that NOx emissions are tightly controlled in the 48/60CR engine through the use of retarded injection timing, which delays combustion-heat release, thus lowering combustion chamber temperature peaks and NOx emission. A new piston design provides a higher compression ratio and faster temperature reduction after ignition, further reducing NOx formation. Variable valve timing enables variations in the opening and closing of the inlet valves, thus providing an additional contribution to the minimisation of adverse effects on SFOC as a result of NOx reductions.
MAN is additionally supplying two Alpha CP propellers of type VBS1800-ODF, with a diameter of 5.6m and a power density corresponding to 1,169 kW/m2. Each propeller is driven by a twin-in/single-out gearbox. The ferry is designed with two separate engine-rooms with the propeller shaft-lines having differing lengths of well over 40 m. The final propeller-blade design will be hydro-dynamically optimised and carefully balanced with a special focus on propulsion efficiency, low noise, and cavitation levels.
Propulsion control and manoeuvring will be managed by MAN’s Alphatronic PCS system, featuring control consoles in the engine-control room, the forward bridge and the bridge wings.
MAN dual-fuel medium speed engines power the LNG carrier Castillo de Santisteban, recently delivered by STX Offshore & Shipbuilding of South Korea to Empresa Naviera Elcano of Spain.
Five MAN 8L51/60DF engines, each rated for 8,000 kW at 514 rpm, will power the 300m, 173,600 m3 ship. The newbuilding has been assigned by charterer Repsol to the Peruvian Camisea/Pampa Melchorita gas project, the first natural-gas liquefaction plant in South America.
MAN says that entry into service of the Castillo de Santisteban represents a milestone for the company in that the order for the ship’s dual-fuel engines, registered in 2007, was the very first received for this engine type. The engine is especially designed for propulsion systems for LNG carriers and gas-fuelled ships, and focuses on safety requirements stipulated by classification societies for gas operation. The propulsion system is designed to give the ship a high degree of redundancy in terms of maintenance while sailing.
The engines were built by MAN Diesel & Turbo’s at its works in Germany. They can run on gaseous (e.g. vaporised LNG) or liquid fuels of a wide range of qualities (HFO/MDO/MGO) and are designed for low emission levels. At 1.5 g/kWh (IMO cycle E2) in gaseous-fuel operating mode, the 51/60DF is claimed to comply with future IMO Tier 3 limits for NOx by a considerable margin without the need for exhaust-gas treatment or any other countermeasures.
The 51/60DF dual-fuel engine offers a 1,000 kW/cylinder output at 514 rpm in both its gaseous and liquid-fuel operating modes. For marine applications, it is offered in inline versions with 6, 7, 8 and 9 cylinders and V- configuration versions with 12, 14, 16, and 18 cylinders in a power range from 6,000 to 18,000 kW. It uses a common-rail micro-pilot fuel-injection system for liquid fuel, that is necessary when running on gas to ignite the air-gas mixture. This system ensures independent control of injection timing, injection pressure and injection volume. When running on liquid fuel, the 51/60DF works with a conventional fuel system, injecting the fuel through a separate main injector in a camshaft-actuated pump-line-nozzle system. The fuel injection control is integrated within the engine’s SaCoSone control system, designed to offer safe engine operation in both liquid and gas mode with optimal fuel consumption and exhaust-gas emissions, and avoiding incomplete-ignition, misfiring and knocking which can sometimes occur in gas-only operation.
A further prominent contract for MAN Diesel & Turbo comes from China, and involves two large rescue ships. Each ship will be supplied with twin-screw propulsion packages based on 6L48/60CR engines, Renk RSHL reduction gears and Alpha Mk 5 propellers.
The ships are to be built by the CSSC GuangZhou HuangPu Shipbuilding Company. The 117m, 22 knot newbuildings are to operate for the Chinese Ministry of Transport’s BeiHai Rescue Bureau and DongHai Rescue Bureau.
The 48/60CR engine offers 1,200 kW per cylinder output at 500 rpm. In this application the 6-cylinder engines power RSHL1000 reduction gears from MAN Diesel & Turbo’s sister company Renk. The Renk gears feature shaft alternators driven from 2,400 kW primary PTOs. Completing the power train, are twin four-bladed 4.0m Alpha VBS1020 CP propellers to a new high-efficiency Mk 5 design. Tail shafts of 20m and three 8.5m intermediate shafts are specified.
Two Alphatronic 2000 propulsion control and management systems are to be provided for the engine control room, main bridge and aft bridge control stations.
According to Goetz Kassing, general manager of MAN Diesel Shanghai:“The 48/60CR engines have been chosen for these rescue vessel newbuildings due to their wide operational flexibility and their combination of favourable fuel efficiency, low emissions levels and invisible smoke under part-load operation. With flexible control of injection pressure, timing and rate shaping, common rail fuel injection allows emissions and fuel consumption to be optimised over the engine’s entire load range.”
