Quasi-Static Intact Stability Criterion for Ships with Well Decks

摘要

Many vessels have some probability of taking significant amounts of water onto the deck or over a bulwarkwhich can adversely affect stability. This type of water is typically termed a “green sea”. The probability depends on the environments the vessel is expected to operate in combined with the relative size of the vessel to the environment and its motions in that environment.rnContemporary stability criteria apply a still-water derived down flooding angle construct to limit the stability analysis to the “dry” case, but this cannot avoid the fact that green sea events can occur. It follows that stability criteria should address shipping of water if there is any realistic likelihood that such an event could occur.rnThere are a number of studies and research programs being progressed in Australia aimed at understanding aspects of the stability of landing craft. One of these research programs involved extensive captive model tests in beam seas together with ship motions and stability simulation analyses. This research program was based on a series of three models having different freeboards and a removable bulwark. The various hull/bulwark configurations were tested at three KGs in regular waves. In a substantial number of cases there was significant water on deck or into the well.The data obtained was used to examine the effects on stability of shipping water into a well with the aim of developing suitable stability criteria.rnPresented in this paper is a proposed intact stability criterion covering quasi-static green seas developed from this work.