Investigation into the propulsive efficiency characteristics of a ship with the Gate Rudder propulsion

Following the first successful application of the Gate Rudder® propulsion system on a 2500GT container ship (Lpp=102m) in Japan, excellent manoeuvring performance was reported with a significant fuel saving over her sister ship fitted with a conventional rudder propeller arrangement.
Based upon the investigations carried out by using model tests, CFD simulations and the full-scale data of two container vessels, this paper discusses the details of the propulsive efficiency characteristics of a vessel fitted with the GATE RUDDER® propulsion system in comparison those of the same vessel with the conventional rudder-propeller arrangement. In the paper the evolution history of the GATE RUDDER® concept is presented by tracing the development of the state-of-the-art energy saving devices (ESD) involving ducts since the GATE RUDDER® exploits the advantage of the duct effect. The components of the propulsive efficiency parameters, with an emphasis on the thrust deduction and effective wake parameters, are explored and discussed highlighting the differences for the hull with the GATE RUDDER® and the conventional rudder arrangements.