An Experimental Study of a Tug Boat Form, Emphasizing the Astern Thrust

Abstract

The bollard pull tests of tug boat models with nozzle propellers are carried out, to study the possibility to increase the astern thrust. A buttock flow form (B-type ship) and a normal tug boat form (N-type ship) are compared. The experimental results are as follows: 1) At M.C.R., thrusts of the B-type ship are about 4.2% (for the ahead) and 4.0% (for the astern) larger than the N-type ship. 2) The effects of the inclinations of the nozzle centre line to horizontal plane and vertical plane are not significant.