This invention provides improvements in the efficiency of a sailing vessel through the use of flaps, hydrofoils, or members on the keel of a sailing vessel. One or more are positioned at the top, or root of the keel of the vessel, which primarily generate a force in the windward direction to provide a counter-leeward drift force. One or more are located at the bottom, or tip of the keel of the vessel, which primarily generate a force in the leeward direction to provide a counter-heeling moment. Among other benefits, operation of these flaps, hydrofoils, or members during sailing increases the vessel's efficiency, in particular its velocity made good. Further, since they are mounted on one appendage, sailing vessels of a rudder and keel design can be equipped with counter leeward-drift and counter-heeling attributes without the need for additional appendages.

A boat with a foam material filled keel structure comprising: a buoyant body, which is a U-shaped tube; a bottom plate, set on the bottom of the buoyant body; a tail plate, set at the rear of the buoyant body and the bottom plate; and a keel structure, set on the bottom of the bottom plate; wherein the keel structure is downward depressed, hence a convex part on the bottom and a groove on the top are formed; wherein in the groove of the keel structure is filled with foam material, Thereby it is achieved that water seepage in the keel structure is avoided.

The present disclosure provides a platform system for a boat, including a wake tow tower, a platform supported on the wake tow tower, a safety rail above the platform, and a stabilizing fin supported at least partially below a waterline adjacent a major side of the hull to resist uncontrolled movement of the boat during usage of the platform by a person.

The present disclosure provides a platform system for a boat, including a wake tow tower, a platform supported on the wake tow tower, a safety rail above the platform, and a stabilizing fin supported at least partially below a waterline adjacent a major side of the hull to resist uncontrolled movement of the boat during usage of the platform by a person.

Disclosed is a motorised wave-piercing ship with hull with a deck, the ship including a conning tower and, under the hull, a weighted keel, the keel being removable and being able to be placed in a low position and a high or extracted position. According to the invention, the ship can sail as a monohull or as a trimaran, the hull including a device for removable attachment of an anti-roll stabilisation system including an elongated connection arm terminated at its two lateral ends by two floats, the connection arm including an attachment member, the attachment member being configured to be removably attached on the attachment device in order to transform the ship into a trimaran, and the ship is monohull in the absence of the anti-roll stabilisation system.

Disclosed is a motorised wave-piercing ship with hull with a deck, the ship including a conning tower and, under the hull, a weighted keel, the keel being removable and being able to be placed in a low position and a high or extracted position. According to the invention, the ship can sail as a monohull or as a trimaran, the hull including a device for removable attachment of an anti-roll stabilisation system including an elongated connection arm terminated at its two lateral ends by two floats, the connection arm including an attachment member, the attachment member being configured to be removably attached on the attachment device in order to transform the ship into a trimaran, and the ship is monohull in the absence of the anti-roll stabilisation system.

It is an object of the present invention to reduce a restriction caused by a water depth of an area available for sailing. The ship has a hull part and is configured to be able to sail on water. The hull part has: a fuselage extending in the longitudinal direction of the hull part; a keel and a rudder arranged on the fuselage to receive water flow when the ship sails; a first posture switching mechanism for switching the postures of the keel and the rudder between a first posture and a second posture; and a first power source. The first posture is in the keel and the rudder respectively extending to the lower side of the fuselage. Compared with the first posture, the second posture is shorter in the length of the keel and the rudder when extending toward the lower side of the fuselage.

The present disclosure provides a platform system for a boat, including a wake tow tower, a platform supported on the wake tow tower, a safety rail above the platform, and a stabilizing fin supported at least partially below a waterline adjacent a major side of the hull to resist uncontrolled movement of the boat during usage of the platform by a person.

The present disclosure provides a platform system for a boat, including a wake tow tower, a platform supported on the wake tow tower, a safety rail above the platform, and a stabilizing fin supported at least partially below a waterline adjacent a major side of the hull to resist uncontrolled movement of the boat during usage of the platform by a person.

The present disclosure provides a platform system for a boat, including a wake tow tower, a platform supported on the wake tow tower, a safety rail above the platform, and a stabilizing fin supported at least partially below a waterline adjacent a major side of the hull to resist uncontrolled movement of the boat during usage of the platform by a person.