Nominal Speed Loss and Propulsive Performance of a Ship in Waves

Abstract

Nominal speed loss of a ship in a seaway is caused by the added resistance due to waves and wind. It is well known that the amount of nominal speed loss is influenced by the main engine characteristics. Therefore, the prediction method of nominal speed loss and the corresponding propeller load fluctuations in waves taking account of the main engine characteristics is studied. Self-propulsion tests in regular and irregular waves and overloaded self-propulsion tests in still water with a model of single screw high speed container ship are carried out by use of the engine simulated self-propulsion apparatus to confirm the validity of the prediction method. Fairly good agreement between the measured values and the calculated ones is observed.