GATE RUDDER™ by Wärtsilä is an innovative energy-saving and manoeuvring device with a unique design formed of two foils on either side of the propeller. During transits, the resulting thrust performance is increased due to the beneficial hydrodynamic effects of the propeller and steering system. Unlike a traditional rudder arrangement, during transits the gate rudder foils can rotate their angular position, changing the hydrodynamic load on both the propeller and the foils. This is proven to have a positive effect on efficiency, particularly during changeable sea conditions, weather or currents. For manoeuvring purposes, the function of the foils changes the gate rudder from a thrust-generating to a thrust-directing device.
The resulting reduction in fuel consumption depends on the vessel type, its operational profile and on the reference propeller and rudder.
Vessels with highly loaded propeller systems, such as container or multipurpose vessels, can achieve the highest power savings. Power savings for any vessel can be estimated by Wärtsilä once the input parameters are known, but are typically significantly higher than 5%. The main application for gate rudder technology is singlescrew vessels. Gate rudder technology also improves manoeuvring performance by making it possible to decrease turning circles with higher turning speeds. Using the crabbing mode, thrust can be generated at angles of up to 80 degrees, which could eliminate the need to use tunnel thrusters in specific cases.
Wärtsilä supplies gate rudder technology as a complete system including:
- High-lift rudder foils, top plate, rudder stock and trunk
- Steering gear including hydraulics
- Rudder controls including control cabinet and interface to autopilot and bridge control
- Bridge controls
- The gate rudder system and propeller are designed together to ensure proper integration and optimal performance