Ship & Boat International: eNews September/October 2018
A cocktail of LNG and battery power is intended to provide the crucial brew for an innovative, next-gen, diesel engine-free purse seiner. To be built at Turkey’s Cemre Shipyard, with a scheduled delivery date of Q2 2020, the design for the forthcoming Libas was supplied by Norwegian naval architect Salt Ship Design, which has been enjoying much success in the aquaculture sector of late.
Libas will be delivered to Liegruppen, a Norway-based, family-run fisheries service provider and fleet operator. The ship will measure 86.1m x 17.8m and feature a deadweight of 4,190tonnes and accommodation for up to 16 persons. MAN Diesel & Turbo will supply the vessel’s single dual-fuel engine and LNG tank (as well as associated tank equipment), while Corvus Energy will equip her with a battery arrangement rated 500kWh in total. Wärtsilä, meanwhile, will provide the ship’s dual-fuel auxiliary engine.
The batteries will provide a means of peak-shaving in transit. Egil Sandvik, Salt Ship Design chairman, tells Ship & Boat International: “All peaks in the ship system will be taken by the batteries. A dual-fuel engine can be slower in reaction, and this particular problem for a fishing vessel is taken care of by the batteries.” He adds: “The batteries can be used when the vessel is in harbour mode, but Libas will also feature an LNG boiler that can also be used in harbour to avoid emissions. The batteries can be charged using excess power from the engine when shooting the trawl, or from an onshore connection.”
MAN Diesel & Turbo’s supply package to Libas will comprise: a MAN 6L51/60DF main engine, rated 6,000kW; a Renk gearbox; a MAN Alpha propeller system; and MAN’s in-house-developed Cryo fuel-gas supply system.
This latter system includes a 350m³ vacuum-insulated, cylindrical C-type tank, and features: a tank connection space (TCS)/coldbox, which contains the process equipment necessary for tank operation; an emergency shut-down system; and a bunker station, for the supply of LNG to the tank. MAN comments: “The system is designed for temperatures down to -163⁰C. The tank stores LNG at the lowest possible temperature and pressure until it is evaporated and supplied to the dual-fuel main engine, as consumption demands.”
The vessel is expected to maintain a speed of 16.5knots in loaded mode. Another feature, Sandvik adds, is the inclusion of “turbines in the roll reduction tank”. “The energy from these turbines can also be used for the ship’s onboard needs, or to charge the batteries,” he says.
Libas will be able to store up to 2,800m³ of refrigerated seawater (RSW) in dedicated storage tanks and will be equipped with two RSW pumps, each rated 1,000m³ per hour. The vessel will also be fitted with two 4.2m³-capacity vacuum pump systems. Additionally, Rapp Marine will install three trawl winches, three net drums, purse sein winches and an electrical fish pump aboard the vessel. The vessel’s crane package will be handled by Karmøy Winch, while MMC will fit her with a water separator unit.