Heuristic Solution Strategy for the Sequential Ballast Water Exchange Problem

Abstract

The sequential ballast water exchange problem is characterized by its combinatorial and computational complexity that must be resolved in transoceanic ship design and involves key technologies. Solving the problem is subjected to many safety criteria including ships’ intact stability, hull girder strength, fore and aft drafts, and bridge visibility, et cetera. The combinatorial and computational complexity of the problem grows exponentially with the growth of the problem’s scale. It has been verified that current existing approaches are not adequate in solving the problem for ships with small design margins of the sequential exchange performances. This paper presents a heuristic solution strategy for the problem that has been tested to be applicable to double hull tankers and bulk carriers with small sequential exchange design margins. A simplified algorithm is developed and presented in this paper. Numerical simulations are conducted using a 50,000 deadweight (DWT) double-hull product tanker. The results show that, compared with existing approaches, the proposed approach is superior in flexibility and capability of automatically obtaining improved solutions with better key performances of the ship.