| 摘要 |
PURPOSE:To eliminate the increase in the cross-sectional area of a stern which is required for ensuring a necessary buoyancy, so that the performance of propulsion is enhanced, by recessing the stern to form an air sump of twin-hull stern shape so that the air sump is closed and fed therein with compressed air only upon cargo working, in order to provide a necessary buoyancy. CONSTITUTION:An air sump 9 of twin-hull stern shape is formed by recessing a stern, and is provided with, in its upper section, an air feed valve 10 for supplying compressed air in the air sump 9, and as well, an air shut-off gate 11 is vertically slidably arranged in the stern so that the rear end opening of the air sump 9 is made closable. On sail, the air shut-off gate 11 is retracted upward to open the rear end opening of the air sump 9. Meanwhile, upon cargo working, the air shut-off gate 11 is extended downward to close the rear end opening of the air sump 9, and as well compressed air is fed into the air sump 9 through the air feed valve 10 to give a necessary buoyance to the stern. In this way, a necessary buoynacy may be simply ensured without the cross-sectional area of the stern being made larger than that required for cruising, thereby the performance of propulsion may be enhanced. |
