The Effect of Icebreaking Bow on the Open Water Performance of a Large Arctic Ore Carrier

Abstract

The exploration of natural resources in the Arctic areas is the main drive behind recent research interest in its harsh environment. The high-quality iron ore in the Baffin Island area has attracted great interest among the mining and shipping communities. The shipboard transportation of the cargo poses numerous challenges since the vessel is required to be able to make shipments to ports in Europe year-round. The ship designer needs to keep a balance between good icebreaking performance and good seakeeping performance. The hull form of a good icebreaking bow typically requires a large flare near the waterline. However, this can cause severe wave impacts, causing increased structural loads. The hull structure is more likely to experience vibratory responses due to the increased wave impacts as the bow flare increases. This hydroelastic interaction of the hull girder in waves can cause increased bending moments and fatigue loads. This paper presents recent experimental and numerical studies of seakeeping, wave impact and hull girder responses of a large Arctic ore carrier. A series of model tests were undertaken at Samsung Ship Model Basin to investigate the global motion, hull girder loads and vibratory responses with three different bow shapes, including the icebreaking bow. A segmented model with an elastic backbone system was used to properly scale the hull girder stiffness and to simulate the vibratory responses. The effects of bow hull form on the global motion and hull girder loads were investigated. Numerical analyses were also carried out to simulate the hull girder vibratory responses in regular and irregular waves using the ABS nonlinear seakeeping program, NLOAD3D. Coupled with a nonlinear wave and slamming impact loads, it was demonstrated that the elastic beam model successfully simulates the observed hull girder vibratory responses in the time domain.