Natural gas-fuelled ferry VIKING GRACE

The PaxCar ferry VIKING GRACE is the largest LNG fuelled passenger ship. Built in STX Turku yard, the ship is designed for efficient year-round service on the trans-Baltic route linking the southwest Finnish port of Turku with Stockholm.

To ensure self-reliance and scheduling in Baltic winter conditions, the hull has been strengthened to Finnish/Swedish 1A Super ice-class criteria. The cruise-standard ferry has been laid out for 2800 passengers, with a total of 880 cabins. The maximum ro-ro freight payload equates to the 1275m lane of main deck loading capacity, complemented by some 550m lane for cars, with provision of a similar capacity on the intervening hoistable deck level.

The dual-fuel electric propulsion is based on Wärtsilä 50DF-type machinery. Four eightcylinder 50DF engines drive ABB alternators delivering power to the main switchboards for two 10,500kW ABB propulsion motors and other shipboard consumers. With two independent engine rooms and two drive lines the propulsion system offers a high degree of redundancy.

LNG fuel is carried in two 200m3 stainless steel, vacuum-type tanks located in an open area right aft, above the stern ro-ro ramp. The tanks and associated bunker handling equipment, safety and automation systems constitute the integrated LNGPac solution developed by Wärtsilä.

Wärtsilä’s patented Cold Recovery System utilises the latent heat of LNG in air conditioning systems, reducing the amount of electricity consumed in cooling compressors. Significant operational savings and an increase in overall vessel efficiency are the result.

In addition, Wärtsilä supplied two 2300kW bow thrusters and a 1500kW stern thruster, two stainless steel fixed-pitch built-up-type main propellers and complete propeller shaft lines with shaft-line seal systems.

The main functions of the Gas Valve Unit are to regulate the gas feeding pressure to the engine, and to ensure a fast and reliable operation and shut down of the gas supply. GVU-EDTM  is standard part of Wärtsilä’s gas propulsion package.

Wärtsilä Compact Silencer System minimises noise emissions from the engines, being particularly effective in the abatement of disturbing low frequency impulses. Furthermore, the Wärtsilä propellers have been designed with the lowest possible pressure impulses.

Length, oa: 218.60m, Length, bp: 135.40m, Breadth, mld: 31.80m, Depth to main deck: 13.80m, Design draught: 6.80m, Gross tonnage: 57,700GT, Service speed: 21.8 knots, Maximum speed: 25.6 knots, Lane metres: cargo 1275 m, cars 500m on Deck 4 plus 500m on Deck 5, Propulsion: 4 Wärtsilä dual fuel (LNG/diesel) 8L50DF engines, Combined output: 30,400 kW.

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