Capsizing and Restoring Characteristics of a Sailing Yacht in Oblique and Breaking Waves

Abstract

Recent years, many ocean going sailng yachts are constructed. Among those yachts, there are types that have poor stability performance especially at the capsized condition. The light displacement sailing yachts belong to this type. Sooner or later, capsizing phenomena can not be avoided for ocean going small vessels when hitted by a large plunging type breaking waves. So the most important point is the restoring characteristics from capsized condition. This paper investigated into the capsizing process of a 47-feet sailing yacht in a breaking waves taking into account the real hazard occured in 1991 and also studied on the restoring process mainly by model experiments. Plunging breaker in deep water is difficult to be generated in the experimental tank, so we applied Transient Water Wave Technique for the generation of such waves. This technique was developed at Yokohama National University more than twenty years ago. As the results, the relation between breaking wave height ,mast length, wave encounter angle and capsizing are obtained. The relation between the amount of water immersion and self restoration is also obtained.