Abstract: A twin-skeg ship that allows for an improvement in propulsion performance (propulsion efficiency). A twin-skeg ship has a pair of left and right skegs on the bottom of a stern has reaction fins, each comprising a plurality of fins extending radially from a bossing fixed to a stern frame provided at a rear end of the skeg, or from a fin boss provided on the bossing, in a range where a flow immediately in front of a propeller attached to the skeg with a propeller shaft therebetween has a component in the same direction as a rotational direction of the propeller.

Abstract: A stern shape of a displacement-type marine vessel enables reduction of the hull resistance and prevents propeller cavitation. The displacement-type marine vessel which travels in a velocity range in which the Froude number is smaller than the last hump and the stern includes knuckle lines connecting knuckle points provided on the surface of the hull, from a starting point in front of a propeller to an end point behind the propeller. A portion of the stern located inside the knuckle line in the direction of the width of the hull has a dome shape with upward curvature, and the length of the portion which has the dome shape is set to 10% or more of the entire hull length or at least the diameter of the propeller.

Abstract: Provided is a twin-skeg ship that allows for a further improvement in propulsion performance (propulsion efficiency). A twin-skeg ship (10) having a pair of left and right skegs (3) on the bottom (2) of a stern has reaction fins 5, each comprising a plurality of fins 5a extending radially from a bossing (6) fixed to a stern frame (7) provided at a rear end of the skeg (3), or from a fin boss provided on the bossing (6), in a range where a flow immediately in front of a propeller (4) attached to the skeg (3) with a propeller shaft (4a) therebetween has a component in the same direction as a rotational direction of the propeller (4).

Abstract: In a displacement-type marine vessel which travels in a velocity range where the Froude number is smaller than the last hump, a stern shape includes knuckle lines connecting knuckle points, provided on the surface of the cross sections of the hull at the stern, continuously from a starting point in front of a propeller to an end point behind the propeller in the fore-and-aft direction of the hull, and a frame line located inside the knuckle line in the width direction of the hull which has a dome shape with upward curvature, the length of the hull portion which has the dome shape is 10% or more of the entire hull length or at least the diameter of the propeller, and the position of the starting point in the width direction of the hull is outside the position of the radius of the propeller.

Abstract: A ship has a main propeller 2 which can move the ship forward and reverse by normal rotation, reverse rotation or by changing the pitch angle. A drive unit drives the main propeller 2. A rudder 3 changes the course of the ship. At least one pod propulsion unit 10A, 10B is provided. As a result, the support mechanism and the turning mechanism of the pod propulsion unit, arranged separate from the main propeller, can be simplified and cost can be reduced.

Abstract: A propulsion apparatus for a vessel includes a main screw and a push type POD propeller which is provided rearward of the main screw. Furthermore, a plurality of grooves which extend along flow directions of a hub vortex generated by the main screw are provided on a front end portion of a casing of the POD propeller. According to this propulsion apparatus for a vessel, the hub vortex generated by the main screw rearward of the main screw is weakened by diffusing the hub vortex along the grooves, and therefore the propulsion efficiency of the propulsion apparatus for a vessel is improved.

Abstract: A ship of the invention comprises: a main propeller 2 which can move the ship forward and reverse by normal rotation, reverse rotation or by changing the pitch angle; a drive unit which drives the main propeller 2; a rudder 3 which changes the course of the ship; and at least one pod propulsion unit 10A, 10B. As a result, the support mechanism and the turning mechanism of the pod propulsion unit arranged separated to the main propeller can be simplified, and cost can be reduced.

Abstract: The propulsion apparatus for a vessel comprises a main screw and a push type POD propeller which is provided rearward of the main screw. Furthermore, a plurality of grooves which extend along flow directions of a hub vortex generated by the main screw, are provided on a front end portion of a casing of the POD propeller. According to this propulsion apparatus for a vessel, the hub vortex generated by the main screw rearward of the main screw is weakened by diffusing the hub vortex along the grooves, and therefore, the propulsion efficiency of the propulsion apparatus for a vessel is improved.

Abstract: The invention relates to a method for preventing the brightening effect of an optical brightening agent on a textile substrate comprising applying on the textile substrate a water-soluble, cationic, optical brightener quencher either before or together with a resin precursor and submitting the treated substrate to a heat treatment. This method imparts an antibrightening effect to goods when they are washed with an optical brightener containing detergent.