Investigation of the manoeuvrability characteristics of a Gate Rudder system using numerical, experimental, and full-scale techniques

The Gate Rudder is a recently introduced twin rudder system whose major advantages stem from its energy-saving properties. two foil-shaped blades of the rudder, placed aside propeller, act as partial duct in wake hull producing additional thrust. However, since primary safety device on any vessel, investigating manoeuvrability performance critical aspect that needs careful and detailed consideration. Owing to peculiar working principle location, standard prediction methods cannot produce reliable results they are applied rudders acting behind propellers. This paper presents first comprehensive investigation into system, which includes development modified MMG model, towing tank experiments full-scale measurements. model was conceived predict manoeuvring motions ship with system. A generalised method defined based this CFD analysis flow pattern around for commercial hull-forms. simulation validated by means tests trials. sea trials were conducted onboard sister container vessels, fitted first-ever second high-performance flap rudder. also allowed compare different steering systems.