Interactions Between the Hull and Rudder During Ship Maneuvering

Abstract

Maneuvering experiments, sponsored by the U.S. Coast Guard, were performed in the rotating arm and linear towing tank facilities at the Carderock Division of the Naval Surface Warfare Center. The experiments investigated the effect of the hull on the inflow to the rudder, and the effect of the rudder on the forces on the hull. A 1/24th scale model of a MARINER Class ship was used. The average inflow angle to the rudder was determined, at various yaw rates and drift angles, by an unbalanced flat plate rudder that was free to seek a neutral angle. In separate tests, the rudder inflow velocity and angle were determined by pitot tubes mounted at four spanwise locations on the leading edge of a rectangular rudder. In other tests, hull forces and moments were measured with the rudder stock passing through the hull but not attached, and compared to similar data taken without the rudder. These tests were used to quantify the hull force differential due to the presence of the rudder.