A hydrofoil device is useable as a hydrofoil wing, propeller blade, etc. In a water flow, a relatively lower pressure is generated on a second surface (94) of the device compared with a first surface (96). Near the trailing end of the first surface a protrusion in the form of an adjustable interceptor (98) is provided. The face of this protrusion defines an included angle to the upstream direction of less than or equal to 90.degree. so that water flow thereat is deflected back on itself thereby ...

Flow modifying devices are simultaneously operative on the upper and lower surfaces of a fixed stabilizer foil on the submerged pod or hull of an ocean vessel to modify the lift hydrodynamically induced under control of pivotal flaps during propulsion of the vessel. The lift otherwise induced by the pivotal flaps is directionally reversed for all angular positions thereof by the spoiler devices.

The invention relates to hulls for planing or semi-planing water craft. The hull (4) has an abruptly down-swept trailing edge portion (18) which, in the preferred embodiment, is in the form of a flap extending across the full width of the transom of the hull and which projects beyond the level of an upswept portion of the underside (14) of the hull by only a small fraction of the length (L) of the hull. According to another aspect of the invention, a hull (4) having a lightly cambered nose porti...

In order to improve the trim of a power boat ready to accelerate toward "on plane" speed, a deflector plate is deployed by gravity from a substantially horizontal attitude toward a rearward-downward inclination, the deployed plate being located so that a predetermined portion only of the propeller backwash is intercepted. Latching mechanism locks the deflector plate at an optimum angle of deployment until the boat reaches a speed slightly in excess of "planing" speed at which juncture the deflec...

A wake reflector system attached to the hull of a surface or subsurface vessel attenuates the visible surface elements of a vessel's displacement wake, making the vessel less likely to be detected by passive observation means from above. The system consists of plates firmly mounted parallel to the longitudinal axis of the hull over a sufficient length and at a sufficient distance outboard from the hull to contain and affect at least the bow component of the displacement wake. The system may inco...

A hydrofoil craft having a pair of laterally spaced bow supporting planes carried by downwardly extending supports has a transverse roll stabilizer extending between the supports and structurally connected to them, the stabilizer being above the in-flight calm water line and above the space between the bow supporting planes.

A hydrofoil system for water-craft consisting of a bow hydrofoil and a stern hydrofoil of a surface-piercing transversely stabilizing type is described which does not require adjustment or trimming means when the craft is running. Each hydrofoil is approximately V-formed in both front and top views such that the pointed ends of the two V-forms face away from each other, pointing downward ahead and downward astern, respectively.

The present invention relates to a hydrofoil system attached to a hull of a vessel. The foil are attached to the hull of a vessel by means of non-lifting struts and each foil comprises a main lifting foil portion which consists of submerged middle section and two upwardly and outwardly inclined side sections which control the end position of the lift. In a spaced relation and parallel to the inclined sections, two auxiliary upper lifting foil portions are attached on each side of the hull for su...

The watercraft has a fore hydrofoil and an aft carried hydrofoil arranged in the "tandem" manner. The fore hydrofoil includes a central portion and two side portions of which the upper extremities are located above the water line corresponding to the cruising speed of the watercraft. The angles of deadrise, or lateral rise of the side portions of the fore hydrofoil are diminishing in the direction from the diametral central plane of the watercraft toward the sides thereof. This diminishing of th...

A power boat having an improved hull including concave aft sections, and which hull is capable of operations at a wide range of speeds with low relative horsepower for vessel weight and improved fuel economy is disclosed. In one exemplary embodiment, the boat is a 38 foot power boat having an improved hull which can achieve speeds of up to about 18 knots, with a 200 hp engine and which burns about 10 gals. per hour. The hull preferably includes a negative deadrise angle at the aft sections, the ...