Low-drag, high-speed ship

A low-drag lifting apparatus comprising a surface-piercing strut-like nose piece which lies at least partly under water and a lifting bottom plate which is attached near a bottom of the nose piece, further comprising an air filled cavity which lies behind the nose piece and which extends from the water surface down to the bottom plate.

The method of operating water vehicles comprising releasing gas from an underwater surface to form a cavity that extends rearward along the surface to reduce drag on the surface, further comprising pivoting a flap outward from the surface when gas is released from either under or behind the flap, and wherein the flap pivots about a region near its forward edge.

A method of reducing drag comprising supporting the weight of a moving submerged body by exhausting gas behind a discontinuity near a nose on an upper side of the body to from an essentially-constant, lower-pressure gas cavity that closes just ahead of a tail end of the body, and exhausting gas at a higher pressure behind a discontinuity near a nose on a lower side of the body to form an essentially-constant, higher-pressure gas cavity that closes just ahead of the tail end, and including an essentially horizontal fence on each side of the body to separate the two gas cavities.

A low drag flow apparatus for supporting a craft, comprising a submerged, dynamically-lifting foil body whose dynamic lift is greater than its displacement, further comprising a streamlined and continuous upper surface that includes an upper surface leading edge region that contains a leading edge of the foil body and an upper surface trailing edge region that contains a relatively-sharp trailing edge of the foil body, a streamlined and continuous lower surface that includes a lower surface leading edge region that contains the leading edge of the foil body and a lower surface trailing edge region that contains the trailing edge of the foil body, a spanwise discontinuity in the upper surface of the foil body in the leading edge region, and at least one source of gas connected to the foil body for releasing gas through the upper surface behind the upper surface discontinuity to form a gas cavity extending from the upper surface discontinuity to the trailing edge region, said foil body having no gas intakes in either surface.

A hydrofoil vessel comprising a hull, a propulsion system, and struts whose upper ends are connected to the hull and whose lower ends are connected to a fixed-sweep fully submerged dynamically lifting v-shaped hydrofoil in plan view, wherein said hydrofoil provides lift during operation at design speed, and has a leading edge that is swept back at least 45 degrees, and has at least one trailing edge flap for controlling vessel pitch and vessel roll.

A hydrofoil vessel comprising an above-water hull, a propulsion system, and at least one strut whose upper end is attached to the hull and whose lower end is attached to a fully-submerged dynamically-lifting hydrofoil, wherein the hydrofoil comprises an essentially upper continuous surface on a top side and an essentially continuous lower surface on the bottom side that join together at a relatively-sharp trailing edge of the hydrofoil, a spanwise inward step in one of the surfaces near a leading edge on at least one side of the hydrofoil to separate the water boundary layer from the hydrofoil surface, at least one gas source, a means to release gas behind the step to form a cavity that extends rearward from the step, further comprising means to limit the gas flow rate into the cavity to ensure that the cavity closes ahead of the trailing edge without having to remove gas from the cavity.

A hydrofoil vessel comprising an above-water hull, a propulsion system, and at least one strut whose upper end is attached to the hull and whose lower end is attached to a fully-submerged dynamically-lifting hydrofoil, wherein the hydrofoil comprises an essentially upper continuous surface on a top side and an essentially continuous lower surface on the bottom side that join together at a relatively-sharp trailing edge of the hydrofoil, wherein the hydrofoil is swept back at least 45 degrees, a spanwise inward step in one of the surfaces near a leading edge on at least one side of the hydrofoil to separate the water boundary layer from the hydrofoil surface, at least one gas source, a means to release gas behind the step to form a cavity that extends rearward from the step, further comprising means to limit the gas flow rate into the cavity to ensure that the cavity closes ahead of the trailing edge without having to remove gas from the cavity.

A hydrofoil vessel comprising an above-water hull, a propulsion system, and at least one strut whose upper end is attached to the hull and whose lower end is attached to a fully-submerged dynamically-lifting hydrofoil, wherein strut chord length is less at a lower end of a strut than at a water surface, wherein the hydrofoil comprises an essentially upper continuous surface on a top side and an essentially continuous lower surface on the bottom side that join together at a relatively-sharp trailing edge of the hydrofoil, a spanwise inward step in one of the surfaces near a leading edge on at least one side of the hydrofoil to separate the water boundary layer from the hydrofoil surface, at least one gas source, a means to release gas behind the step to form a cavity that extends rearward from the step, further comprising means to limit the gas flow rate into the cavity to ensure that the cavity closes ahead of the trailing edge without having to remove gas from the cavity.

A low drag cambered hydrofoil for supporting a vessel, comprising an essentially continuous upper surface on the top side and an essentially continuous lower surface on the bottom side which terminate at relatively-sharp trailing edge of the hydrofoil, a spanwise inward step in at least one of the surfaces near a leading edge on at least one of the sides, at least one gas source, a means to release gas behind the step to form a cavity that extends rearward from the step, and means to limit the gas flow rate into the cavity to ensure that the cavity closes ahead of the trailing edge without having to remove gas from the cavity, wherein the inward step is defined to include a wide range of angles relative to the adjacent surface.

A method of reducing drag comprising supporting the weight of a moving submerged body by exhausting gas at a lower pressure behind a projection near a nose on an upper side of the body to form an essentially-constant-pressure gas cavity that closes just ahead of a tail, and exhausting gas at a higher pressure behind a projection near a nose on a lower side of the body to form an essentially-constant-pressure gas cavity that closes just ahead of a tail, and further comprising an essentially horizontal fence on each side of the body to separate the two gas cavities.

A low drag submerged fin, comprising a symmetrical and essentially continuous surface on each side which terminate at a relatively-sharp trailing edge of the fin, a spanwise inward step on each side near a leading edge of the fin, wherein each surface behind the step is streamlined, further comprising a gas source, a means to release gas behind the step to form a cavity that extends rearward from the step, and means to limit the gas flow rate into the cavity to ensure that the cavity closes ahead of the trailing edge without having to remove gas from the cavity.

An underwater low-drag cambered blade, comprising an essentially continuous upper surface on the suction side of the blade, and an essentially continuous lower surface on the pressure side of the blade, wherein the surfaces terminate at a common essentially-sharp trailing edge, further comprising a spanwise inward step near a leading edge of the blade on at least one side of the blade, at least one gas source, a means to release gas behind the step to form a cavity that extends rearward from the step, and means to limit the gas flow rate into the cavity to ensure that the cavity closes ahead of the trailing edge.

A low-drag surface-piercing elongated body comprising a symmetrical and essentially-continuous surface on each side, a leading edge, a trailing edge, an upper body region with an upper trailing edge, a lower body region with a lower trailing edge, an inward step on each side near the leading edge in the upper body region to form an air-filled cavity that is open to the atmosphere and that extends rearward from the step past the trailing edge to merge into a single cavity, further comprising an inward step on each surface near the leading edge in the lower body region to form an air-filled cavity that closes ahead of the lower trailing edge.

The method of reducing drag on an underwater surface comprising the addition of at least one projection from an otherwise hydrodynamically smooth surface angled to the flow to cause the water boundary layer to separate, further comprising a means to release gas behind the projection to form a cavity downstream of the projection, wherein the downstream surface underlying the cavity is designed to lie within the predicted constant-pressure cavity, further comprising a means to control the gas flow rate into the cavity to control cavity size, and means to vary the height of the projection to change the height of the cavity to accommodate changes in operating conditions such as water speed and surface wave height and direction.