The Wärtsilä 2-speed gear is designed to serve vessels having multiple operational modes or reduced transit speeds. These vessels can gain notable economic & environmental benefits:
‑ fishing vessels
‑ rescue tugs
‑ offshore support vessels
‑ seismic support vessels
The Wärtsilä 2-speed gear is available with a high degree of modularization in the 2 MW to 13 MW power range.
Fuel savings of up to 15% can be achieved compared to a single speed mechanical propulsion system, thanks to the key feature of the 2-speed gearbox: the option to reduce the propeller speed while the vessel speed remains constant.
All Wärtsilä gears can be supplied with one or more PTOs for driving the shaft alternator, compressor or pump. For single vertical and horizontal gears, the standard PTO is primary driven. For double gears, the PTO is optionally primary or secondary driven.
A primary driven PTO rotates whenever the engine is rotating.
A secondary driven PTO rotates whenever the propeller shaft is rotating.
Based on the standard Wärtsilä gear types, customized solutions can be delivered upon request.
Most Wärtsilä gears can be supplied with a combined PTO/PTI. In PTI mode the shaft alternator can also be used as an electric motor. PTI is normally used for the following operational modes:
PTI “Booster” mode is used when the main power of the engine is insufficient in order to increase the total propulsion power. For this mode, no clutches are required on the gear.
PTI “Take me home” mode is used in case of emergency should the prime mover be inoperable. For this mode a minimum of 2 clutches are required on the gear.
Most Wärtsilä gears are purpose-designed with an integrated hydraulic system for both the gear and the CP propeller. As a separate hydraulic power unit for the CP propeller is superfluous, both installation costs for the yard and operational costs for the owner are reduced. For safety reasons the gear mechanically drives the main pump for the propeller. All gears can also be interfaced with a separate hydraulic power unit.
The introduction of a gear, able to select from two propeller speeds while the engine speed remains constant, results in excellent propulsion efficiency at varying loads.
Fuel savings of up to 15% with the Wärtsilä 2-speed gear”
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Wärtsilä is a global leader in advanced technologies and complete lifecycle solutions for the marine and energy markets. By emphasising sustainable innovation and total efficiency, Wärtsilä maximises the environmental and economic performance of the vessels and power plants of its customers.