| Energy-saving Technology |
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| Technologies enabling fuel saving by improving the propulsive efficiency |
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Kawasaki RBS-F (Rudder Bulb System with Fins)
"Kawasaki RBS-F" (patented) is an energy saving device installed on a rudder. It consists of a streamline-shaped rudder bulb and airfoil-shaped fins.
The rudder bulb brings smooth inflows to the propeller, and the fins produce thrusts in the rotational flows generated by the propeller. As a result, Kawasaki RBS-F reduces the required propulsive power by 2% to 7%. |
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| Kawasaki RBS-F has been installed on more than 100 ships including LNG carriers, LPG carriers and bulk carriers. |
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| Kawasaki OLP (Overlapping Propeller) System |
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"Kawasaki OLP System" (patent pending) is a suitable propulsion system for large LNG carriers. It utilizes bilge vortices to obtain a high propulsive performance.
Twin bilge vortices arise around the propeller, which are generated along the aft part of the hull. In Kawasaki OLP System, two propellers are overlapped and located around the center of the port and starboard bilge vortices. Since the rotational directions of the two propellers are contrary to the bilge vortices, the energy of the bilge vortices can be utilized efficiently. Furthermore, the two propellers reduce the propeller load, compared with single propeller, and increase the propulsive efficiency.
By locating the two propellers close to the ship’s centerline, additional resistance caused by the shaft brackets, etc. can be reduced to a negligibly low level, compared with the conventional twin propeller system.
Ships with Kawasaki OLP System achieve an about 12% energy saving against the conventional single propeller ships. |
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| Kawasaki SDS-F (Semi-Duct System with contra Fins) |
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"Kawasaki SDS-F" (patented), which is fitted in front of the propeller, is an energy saving device. It consists of contra fins and a semi-duct.
The contra fins produce reverse rotational inflows in the propeller rotating direction and reduce the rotational flows behind the propeller, resulting in the improvement of the propulsive efficiency. The semi-duct produces thrusts in the oblique downward flows of bilge vortices and also prevents the flow separation at the stern position.
Kawasaki SDS-F achieves 3% to 7% energy saving, and by fitting it along with our another energy saving device, Kawasaki RBS-F, further energy saving can be expected.
Kawasaki SDS-F has already been installed on five oil tankers. |
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