Abstract
New transportation facilities may create new potential hazards and sometimes new safety measures are required. This paper provides an example of such safety measures. In these years, "girder-less type" cargo holds have been becoming popular for newly constructed container ships due to the advantage in capacity. On this type of a cargo hold, there are clear openings (gaps) between hatchway covers. Such clear gaps may create problems on safety such as ingress of water into cargo holds, leakage of fire extinguishing gas in case of fire and ingress of dangerous goods into a cargo hold in case of spillage of the dangerous goods from a container stowed on a hatchway cover. Recognizing these problems, the International Maritime Organization has considered safety measures for such ships and we have investigated on this issue. In this paper, we explain the outline of underlying principles for safety measures and propose some requirements.