Study and development of a stability assessment system for fishing vessels to prevent capsizing during navigation

Abstract

Fishing is well known for being a very hazardous activity. Most of the accidents, in particular those with the worst consequences, are caused by stabil-ity failures (static or dynamic). Small and medium sized ˝shing vessels, which represent the largest percentage of the ˛eet, are the most a˙ected due to the crew lack of training in this matter. The use of stability guidance systems has been proposed by several authors, administrations and other stakeholders, as a feasible solution to help the skipper to objectively identify potential risks, to support his decision making process and to reduce the probability of accident. The main objective of this PhD. thesis is to contribute to the development of such a stability assessment system, which could estimate in real-time and with minimum need of crew interaction the level of stability of a vessel. Furthermore, it could provide useful information to the skipper and warning messages in case of potential risk. In order to evaluate the stability level two novel methodologies have been developed. They automatically compute in real-time the current metacentric height from the analysis of roll motion and detect changes on this parameter. The performance of these proposals has been validated with roll motion data from di˙erent vessels, obtained by mathematical model simulations, towing tank tests and sea trials of a real ship. Such a system could contribute to increase the safety not only of the ˝shing sector, but also of other ship types where crews need simple and easy to under-stand stability information. Although this dissertation represents a large step in the development of stability guidance systems, further work is still needed to have a robust operational system. Stability estimation algorithms, information and guidance interfaces and communication systems should be fully integrated and ready to be installed on board.