Power System for Environmentally Safe Tankers

Wärtsilä will supply the complete marine power system for the first of a series of environmentally safe 40,000 dwt chemical/product tankers building at the San Marco shipyard in La Spezia, Italy. As the Ship Power Supplier, Wärtsilä is responsible for the complete functionality of the system. In addition to supplying the hardware, Wärtsilä is providing the shipyard with all the functional drawings and will be supervising the plant's installation, commissioning and sea trials.

Model of the 40,000 dwt chemical/product tanker being built by the San Marco shipyard in Italy
Schematic of the auxiliary propulsion drive (APD)

The 171.6 m long ship will be equipped with Wärtsilä 6L64 medium-speed diesel engine providing 12,060 kW output at 333 rev/min, a 6200 mm diameter controllable-pitch Lips type propeller, shafting and a reduction gear. Electrical power will be supplied by 1800 kW generator driven off the reduction gear and three Wärtsilä 6L20 auxiliary engines with output 1020 kW each. The Wärtsilä 6L64 main engine gives vessel a top speed of about 17 knots on 10.3 m draft, and a service speed of 16 knots. Redundancy is provided by an auxiliary propulsion drive (APD) in which the shaft generator can be used as a motor to drive the propeller when powered by the diesel generating sets. This APD provides speed of about eight knots.

Environmental friendliness and safety are ship’s important characteristics. Apart from having the auxiliary propulsion drive, the vessel is of double-hulled construction in the cargo area, and all fuel tanks are separated from the hull by cofferdams. Wärtsilä engines were chosen because of their low NOx emission levels. Wärtsilä 64 main engine has particularly low fuel consumption and thus also lower carbon dioxide (CO2) release into the atmosphere.