On the Heaving of a Man with Life Vest in Regular Waves

Abstract

Fishermen aboard small fishing boats often fall overboard without a life vest and then lost their life. The primary reason why fishermen cannot put on a life vest is that a life vest interrupt their fishing work. However fishermen must keep their life vest on in preparation for a man-overboard. Therefore the new life vest which is light and safety is developed. It's buoyancy is 6.5kgf and it became possible to do fishing work smoothly. For the advance of studing on this field, we need information about characteristics of the human body motion in waves with the new life vest to ascertain safety of it. This paper describes some parameters that have strong influence on the human body motion in waves and relations among those parameters. We studied the heaving of a man with new life vest which as buoyancy under regulations in the process of development. As a result the main points of this study are summarized as follows ; 1. Specific gravity of human body and only head are measured. 2. The relationship between a weight of the head (y) and a head measurement is given in the following equation ; y=30.4x-0.925 x : the third power of a head measurement 3. The damping coefficient and restoring coefficient of heaving of the human body with life vest are measured. 4. The heaving of a man with life vest in regular waves is simulated. 5. It become clear that a man with new life vest can float enoughly and it is naturally as well as possible to be breathed in waves.