Experimental Investigation of the Behaviour of a Large Ship in Irregular Waves

Abstract

A towing tank experimental investigation was carried out using a segmented scaled model of a large ship prototype to study its behaviour when sailing in irregular head waves. The tests were carried out for typical sailing speeds and wave conditions that would be encountered by the large ship at sea. The vertical plane motion of heave, pitch, and the accelerations at bow and stern, and the vertical bending moment load responses of the ship were measured and analyzed. The significant amplitude values of motion and load response of the ship for the investigated wave conditions and speeds were determined by using spectral analysis. Slamming induced whipping loads were also investigated for the studied sailing conditions. In addition, the load response characteristics were evaluated in both time-domain and frequency-domain. Increasing the sea state had a greater effect on the motion and load responses of the large ship than increasing the sailing speed.