Development of Constructive Measures to Reduce the Consequences of Ship Collisions

An analysis of the damage caused to vessels by collisions shows that the wreck of most struck ships is mainly due to underwater damage developed because of the accident. Such damage is caused, as a rule, by the presence of bulbs on striking ships that have high longitudinal rigidity and strength exceeding the load-bearing capacity of the framing system several times. Scientists in many countries are looking for ways to reduce the consequences of collisions with ships that have bulbs. Based on the results of the research, schemes for modernizing the forward end of ship hulls by installing bulbs with increased longitudinal compliance to reduce the consequences of ship collisions were proposed, and recommendations were developed for the selection of their characteristics, which make it possible to avoid underwater holes on a struck ship. Bulbs with increased longitudinal compliance were designed using methods of plastic limit analysis. The effectiveness of a modernized deformable bow structure was studied using ANSYS LS-DYNA non-linear finite element method computations. The developed technical solutions ensure that in case of collision in the underwater part of a struck vessel, the deformations of the framing systems will remain insignificant, thereby avoiding the appearance of damage below the waterline.