Ballast-free ship

Abstract

By adjusting the amount of air supplied from compressed-air supply piping, a seawater level in an air cushion chamber is adjusted. Accordingly, even in a case of a ballast-free ship, there is secured a function to adjust a hull equivalent to an adjusting function of a ship having ballast tanks. One end of the compressed-air supply piping is opened to the air cushion chamber divided by horizontal and vertical partition plates. Below the horizontal partition plate, a current plate is disposed with a space through which seawater passes therebetween. In an air chamber provided inside a side wall, the other end of a vent pipe is provided in an opened manner at the same position in the height direction as an upper face of the current plate. One end of the vent pipe is opened at a seawater surface outside of the side wall.

1 . A ballast-free ship, comprising
 air chambers provided in lower portions of right and left side walls of a hull;   a chamber which has a flat ship bottom along a vertical centerline of the hull covering a bow side to a stern side and, with the vertical centerline of the hull being an axis of symmetry;   air cushion chambers whose lower ends are opened on both the right and left sides of the chamber and provided in a recessed manner at opposing positions;   vertical partition plates provided along a moving direction of the hull to a bottom shell in the air cushion chamber;   two or more mutually parallel horizontal partition plates provided vertically to the bottom shell perpendicularly to the moving direction of the hull,   wherein the air cushion chamber is partitioned by using the vertical and horizontal partition plates as partition walls, a lower edge position of the horizontal partition plate is set so that it may be located above a horizontal position of a lower edge of the vertical partition plate and, at a lower position of the horizontal partition plate, a space through which seawater passes is provided so as to horizontally dispose a current plate;   wherein a lower surface of the current plate, lower edges of the right and left side walls of the hull, and an external surface position of the ship bottom of the chamber are set at the same horizontal position in the height direction;   a compressed-air supply piping having first and second ends, wherein said first end is connected to a compressed-air supply unit for supplying and discharging compressed air to and from the partitioned air cushion chamber, wherein said second end opened to and in communication with the air cushion chamber or the air chamber;   a vent pipe having a first and second open end, said first end opened above the surface of water, the second end is opened at the same position as an upper end face of the current plane in the height direction in the air chamber;   wherein the air chambers are communicated with the air cushion chambers so that a seawater level in the air cushion chamber is kept from becoming below the opening position of the second end of the vent pipe and the air quantities in the air cushion chambers is equalized.   
     
     
         2 . A ballast-free ship, comprising
 air chambers provided in lower portions of right and left side walls of a hull;   air cushion chambers whose lower portions are opened and provided at a ship bottom of the hull in a recessed manner covering from a bow side to a stern side;   vertical partition plates provided along a moving direction of the hull to a bottom shell in the air cushion chamber;   two or more mutually parallel horizontal partition plates provided vertically to the bottom shell perpendicularly to the moving direction of the hull,   wherein the air cushion chamber is partitioned by using the vertical and horizontal partition plates as partition walls, a lower edge position of the horizontal partition plate is set so that it may be located above a horizontal position of a lower edge of the vertical partition plate and, at a lower position of the horizontal partition plate, a space through which seawater passes is provided so as to horizontally dispose a current plate;   wherein an undersurface of the current plate and lower edges of the right and left side walls of the hull are set at the same horizontal position in the height direction;   a compressed-air supply piping having first and second ends, wherein said first end is connected to a compressed-air supply unit for supplying and discharging compressed air to and from the partitioned air cushion chamber, wherein said second end is alternately opened to and in communication with the air cushion chamber or the air chamber;   a vent pipe having a first and second open end, said first end opened above the surface of water, the second end is opened at the same position as an upper end face of the current plate in the height direction in the air chamber; and   wherein the air chambers are communicated with the air cushion chambers so that a seawater level in the air cushion chamber is kept from becoming below the opening position of the second end of the vent pipe and the air quantities in the air cushion chambers is equalized.