PREDICTION OF SHIP MOTIONS IN HEAD WAVES USING LINEAR STRIP THEORY

Abstract

Prediction of ship motions is an importance step in the ship design phases and considerable researches are related to this subject. It plays a unique role in main seakeeping characteristics such as maximum ship speed in sea waves, voluntary and involuntary speed reduction due to wave forces and added resistance as well as ship safety and ship routing, which affect transportation time, fuel consumption and total cost. This paper describes linear strip theory to predict quickly with sufficient accuracy ship motion characteristics in head wave, including added ship resistance, pitch and heave motion. The effects of environmental condition on calculation results is analyzed by performing some calculation with different wave parameter of JONSWAP spectra. The calculation results for the DTMB are examined by the comparisons with experimental data carried out at Ship Design and Research Centre's towing tank in Poland, and show good agreement, which demonstrates the ability of the present method to assess seakeeping characteristics at the initial ship design phases. The calculation is performed by using the commercial software MAXSURF.