Wärtsilä launches 2-speed marine gearbox

The product will serve vessels having multiple operational modes or reduced transit speed, including fishing vessels, RoPax ferries, offshore support vessels, and tug boats.

Compared to a single mechanical propulsion system, a fuel consumption reduction of eight per cent was verified with Wärtsilä’s 2-speed gearbox during sea trials. It is anticipated that further reductions of up to 15 per cent can be achieved, with a similar lowering of nitrogen oxide (NOx) and sulphur oxide (SOx) exhaust emissions.

These cost savings and environmental benefits are achieved by operating the ship’s propeller at low speed when maximum vessel speed or propeller thrust is not required. At the same time, the engine speed is kept constant, thereby allowing the electric power generation from the Power Take-Off on the gearbox to remain uninterrupted. Furthermore, the Wärtsilä 2-speed gearbox will reduce noise emissions by as much as 20dB both inside the ship and externally. This allows greater comfort for passengers and crew, while the reduced underwater radiated noise is important for fishing and seismic vessels, and is beneficial to marine life in general.

The first ship to utilise the new Wärtsilä 2-speed marine gearbox is a rescue vessel owned by the Rescue & Salvage Bureau of the People’s Republic of China’s Ministry of Transport, and sea trials have been successfully carried out at the Huangpu shipyard in China.

“This new propulsion solution is based on Wärtsilä’s proven gearbox technology and systems engineering. It offers considerable fuel cost savings, increased environmental sustainability, efficient utilisation of the main engine, a high degree of redundancy, retention of 100 per cent engine power at reduced propeller speeds, advanced functionality with low technical complexity, and much more”, says Arto Lehtinen, vice president propulsion, Wärtsilä Ship Power.

The Wärtsilä 2-speed gearbox will be available with a high degree of modularisation in the power range from 2 MW to 10 MW and Wärtsilä will continue to introduce this range throughout 2014 and 2015.