Abstract: An improvement is made in terms of rolling of a semi-submerged glass boat whose hull is formed of the main hull and float tanks provided on the lateral sides of the upper part of the main hull, and anti-rolling fins each projecting outside of a straight line connecting the outer end part of the bottom of the float tank and the outer end part of the bottom of the main hull are provided on the opposite sides of the main hull respectively.

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: Disclosed is a semi-submerged ship comprising at least two lower hulls always located below the surface of water and arranged substantially in parallel to each other with respect to the direction of advance, struts mounted substantially vertically on the upper portion of each of all or at least two of the lower hulls along almost the entire length thereof and an upper hull supported by these struts and always located above the surface of water. In this semi-submerged ship, at least one opening is formed on each strut wherein the height of the opening is less than the height of the strut and a water-tight seal is formed between this opening and the interior of the strut. This ship is arranged so that the draft line of the ship is located on the openings of the struts while the ship is stopped. This semi-submerged ship is effectively used as a passenger ship, a cargo ship, a floating factory ship or the like and is especially suitable for stevedoring while stopping the ship in the wavy sea.

Abstract: The present invention relates to a ship with structural improvements which prevent factors causing an increase in the horsepower required for propulsion or an increase in propeller cavitation, hull vibration and noise, all of which result from the water turbulence and nonuniformity of flow field along the stern caused by corpulence of ship, and the present invention provides such a ship with a structural improvement comprising having a ring-shaped construction directly attached to the hull on each of the ship's stern and in front of the propeller.