Full-scale gate rudder performance obtained from voyage data

GATE RUDDER® system is a novel propulsion arrangement or Energy Saving Device (ESD) inspired by the new concept of elementary propulsive efficiency and its optimization in a ship’s wake to recover more energy. The performance of a GATE RUDDER® system in the hull wake, therefore, is important not only for the efficiency but also from the cavitation, noise and vibration point of view. The World’s first gate rudder has been installed on a 2500GT container ship in 2017 in Japan. Following the successful installation of the world’s first gate rudder on a 2500GT container ship (Lpp=102m), which was built by Yamanaka Shipyard of Japan, excellent manoeuvring performance has been recorded with a significant fuel saving over her sister ship fitted with a conventional rudder. The comparative manoeuvring characteristics of the two different rudder configurations obtained from the sea trials revealed that the resistance of the gate rudder during steering was extremely low compared with that of the conventional rudder. After some service experiences with both vessels, two important performance observations have been reported. One of these observations is the reduced sea margin requirement for the gate rudder driven vessel compared to the conventional rudder steered vessel. The other observation is the reduced speed-drop with the gate rudder driven vessel during manoeuvring in ports which makes the vessel’s berthing operation very easy and more efficient. This paper invesigate the reasons of the above-mentioned superior performance of the vessel fitted with the Gate Rudder system based on the performance data obtained from not only model test data but also voyage data which was collected from her delivery.