Abstract: The present invention provides a ballast water treatment system including a reaction tank in which raw water and ozone are imported and made to react each other for a predetermined period of time to kill microorganisms existing in raw water, an ozone decomposer in which water containing residual ozone discharged from the reaction tank is imported and the residual ozone is decomposed, and a circulation pump installed between the reaction tank and ozone decomposer, forming a circulation system which removes the residual ozone by means of circulating the water containing the residual ozone between the reaction tank and ozone decomposer. Accordingly, this system dispenses with a deaeration tank which would require a wide space for installation, small cost and is able to be applied to existing ships easily.

Abstract: The present invention provides a ballast water treatment system including a reaction tank in which raw water and ozone are imported and made to react each other for a predetermined period of time to kill microorganisms existing in raw water, an ozone decomposer in which water containing residual ozone discharged from the reaction tank is imported and the residual ozone is decomposed, and a circulation pump installed between the reaction tank and ozone decomposer, forming a circulation system which removes the residual ozone by means of circulating the water containing the residual ozone between the reaction tank and ozone decomposer. Accordingly, this system dispenses with a deaeration tank which would require a wide space for installation, small cost and is able to be applied to existing ships easily.

Abstract: The present invention provides a ballast water treatment system including a reaction tank in which raw water and ozone are imported and made to react each other for a predetermined period of time to kill microorganisms existing in raw water, an ozone decomposer in which water containing residual ozone discharged from the reaction tank is imported and the residual ozone is decomposed, and a circulation pump installed between the reaction tank and ozone decomposer, forming a circulation system which removes the residual ozone by means of circulating the water containing the residual ozone between the reaction tank and ozone decomposer. Accordingly, this system dispenses with a deaeration tank which would require a wide space for installation, small cost and is able to be applied to existing ships easily.

Abstract: The present invention provides a ballast water treatment system including a reaction tank in which raw water and ozone are imported and made to react each other for a predetermined period of time to kill microorganisms existing in raw water, an ozone decomposer in which water containing residual ozone discharged from the reaction tank is imported and the residual ozone is decomposed, and a circulation pump installed between the reaction tank and ozone decomposer, forming a circulation system which removes the residual ozone by means of circulating the water containing the residual ozone between the reaction tank and ozone decomposer. Accordingly, this system dispenses with a deaeration tank which would require a wide space for installation, small cost and is able to be applied to existing ships easily.

Abstract: A ballast water intake and treatment system is disclosed, the system including a membrane treatment unit arranged in or on a ship hull for the separation of microorganisms of no smaller than a given size and organized to execute filtration during the intake of sea water or fresh water outside the hull into ballast tanks by the use of an intake pump installed consecutively with the membrane treatment unit. The system checks the invasion of microorganisms, etc. of no smaller than a given size during the intake of ballast water and allows ballast water free of microorganisms, etc. of no smaller than a given size to be fed into ballast tanks.

Abstract: The present invention provides a ballast water treatment system including a reaction tank in which raw water and ozone are imported and made to react each other for a predetermined period of time to kill microorganisms existing in raw water, an ozone decomposer in which water containing residual ozone discharged from the reaction tank is imported and the residual ozone is decomposed, and a circulation pump installed between the reaction tank and ozone decomposer, forming a circulation system which removes the residual ozone by means of circulating the water containing the residual ozone between the reaction tank and ozone decomposer. Accordingly, this system dispenses with a deaeration tank which would require a wide space for installation, small cost and is able to be applied to existing ships easily.

Abstract: A hull (5) of a planing boat (1) consists of front and rear hull portions (5a, 5b). A bottom part (2a) of the front hull portion (5a) forms one front planing portion (21a), and a recess (7) is provided so as to extend along the center line of the rear hull portion (5b), two bottom parts (2b') either of which is positioned on the left or right side of this recess (7) forming two rear planing portions (21b). When the speed of the planing boat (1) is low, it runs with the front and rear planing portions (21a, 21b) completely submerged, and, when the speed of the planing boat (1) is high, it floats and plans on the water surface with the hull (5) supported on three portions, one front planing portion (21a) and two rear planing portions (21b).

Abstract: In a propeller for use in a ship of the type comprising 4 or more even number blades, at least one of two adjacent blades is inclined forwardly or rearwardly or one inclined forwardly and the other rearwardly so as to make different the rake angles of the two blades. The pitch angle of the rearwardly inclined blade is made larger than that of the forwardly inclined blade. With this construction the mutual interference between adjacent blades is efficiently utilized to prevent decrease in the efficiency even when operating conditions and the diameter of the propeller vary.