PURPOSE: To economize fuel, by providing side tanks on both the sides of a main ship body so that the tanks are connected to each other over the main ship body and can be moved up and down and by placing the side tanks in an upper position to put only the main ship body in water at the ballasted voyage.
CONSTITUTION: Side tanks 13 are provided on both the sides of a main ship body 14 integrated with the bow and stern, so that the side tanks are connected to each other over the main ship body and can be moved up and down. In full loading, cargo oil is put in the tank of the main ship body 14 and the side tanks 13. At that time, the side tanks 13 are placed in a lower position so that navigation is effected in a normal integrated ship form. In ballasted navigation, the side tanks 13 are made empty and placed in an upper position and ballast water is put in the tanks of the main ship body 14 to place only the main ship body in water to decrease the displacement to economize fuel.
MATSUMURA TAKAO
NAKAMURA SHIGEO
