A study on positive separating bulbous bow

The purpose of this paper is to introduce a novel method for ship design against collision accidents and to introduce a positive separating bulbous bow designed based on this method and also to study the effectiveness of this kind of bulbous bow compared with the conventional one. In this paper, the authors put forward a way to separate the bulbous bow from the striking ship so as to protect the cargo hold structure of the struck ship from being penetrated by partly using high tensile steel. The more real scenario supposing that the struck ship is navigating at a certain speed was considered. Nonlinear Finite Element Method (FEM) was used to study the effectiveness of the positive separating bulbous bow. Two bulbous bows with the same size and shape and one typical double hull structure in cargo hold area of a container vessel in service were modeled. One of the bow models is a prototype of the positive separating bulbous bow with part of the shell plate replaced by plate made of high tensile steel, and the other model is a conventional one. Collapse mechanism, force-time curve of the positive separating bulbous bow structure was investigated and compared with those of conventional bow structure. It is found from these investigations that the positive separating bulbous bow structure is expected to be efficient to reduce the risk of cargo leakage in case of ship collisions, and the method of using high tensile steel in ship collision accidents protection is reasonable.