Abstract: A system for facilitating movement of a shipping container uses a plurality of air bearing pontoons interposed between a shipping container and a h, soft or water surface. Each air bearing pontoon includes an inflatable skirt and its own controllable air supply that allows the skirt to float on a cushion of air above the surface.

Abstract: A system for reducing hydrodynamic drag and vortex-induced-vibration ("VIV") in a bluff hull. In a bluff hull that is designed to be at least partially submerged in a fluid, such as water, the hull has an internal area for holding or transferring fluid. When the hull is beset by a current present in the water, the surface of the bluff hull has an up-current side and a down-current side. The hull surface has at least one opening, preferably a slot-nozzle, for blowing the fluid from the internal fluid area of the bluff hull out of the hull surface and into the surrounding water at a velocity greater than the current velocity, so as to reduce flow separation of the current on the down-current side of the hull surface. Also, preferably, the fluid is blown out of the opening at an angle substantially tangential to the hull surface at the location of the opening and substantially in the direction of the current.

Abstract: A method for reducing skin-friction is based on generating bubbles by blowing gas into water from a selected location of a moving ship which are separated along the longitudinal direction by specific distances.

Abstract: Skin friction reduction on a surface moving relative to a fluid can be obtained by ejecting a polymer-water mixture/solution into the boundary layer. The efficacy of the ejected polymer-water mixture/solution is closely related to polymer dissipation out of the boundary layer and conditioning (i.e, lengthening, unwinding or stretching) of the polymer molecules by liquid shear forces immediately before ejection. The invention is a method and apparatus for conditioning and ejecting a polymer-water mixture/solution that improves drag reduction characteristics of the mixture/solution and maintains the mixture/solution in the boundary layer for as long as possible. By improving the drag-reduction characteristics of the polymer-water mixture/solution and by extending the time it remains in the near-wall region, the ejector can increase the performance and reduce the volume and storage requirements of a drag-reduction system.

Abstract: A polymer ejector system for reducing drag on an external surface of an urwater vessel includes a base portion mounted in an exterior surface of the underwater vessel, the base portion including an arcuate inner wall. A flexible lip portion is positioned above the base portion and spaced apart therefrom. The lip portion has an outer surface substantially coplanar with an outer surface of the underwater vessel, an arcuate inner wall, and is tapered at a distal end of the lip. This lip may be actively moved by means of MEMS deposited electrodes to control the passageway mentioned next. A passageway is formed between and defined by the inner wall of the lip and the inner wall of the base portion, such that the passageway terminates at the outer surface of the underwater vessel and substantially tangent thereto. The ejector may be constructed from single crystal silicon by so called MEMS (Micro-Electro-Mechanical Systems) methods.

Abstract: A tunnel-hulled boat that has a high degree of maneuverability at low and high speeds with decreased hydrodynamic drag is disclosed. The tunnel-hulled boat is maneuverable in shallow water and when proceeding in reverse. The tunnel-hulled boat is comprised of a hull having a generally square-nosed and notched aft and generally concave tunnel disposed from proximate amidships to the aft, with the concavity increasing as the tunnel proceeds aftward. A first set of bevels having increasing diameter extend along either side of the tunnel while a second set of bevels are each disposed within a respective one of the first set of bevels proximate the transom of the boat. A pair of sponsons are attached to the transom on either side of the tunnel.

Abstract: A method is provided for reducing skin-friction of a ship moving through bubbly flow fields generated in proximity of hull surfaces by jetting gas through a plurality of jet nozzles provided on hull surfaces of the ship. The gas flow rate is controlled so as to establish a peak void fraction in a turbulent boundary layer, by applying an observation that the location of a peak void fraction shifts away in a direction normal to the hull surface with increasing gas flow rate through the jet nozzles.

Abstract: Distribution pattern of bubbles produced from a bubble jet of a ship is analyzed by approximating the bubbly flow as a continuous flow of a gas phase and treating the bubbles as diffusing particles dispersing in a flow of the gas phase.

Abstract: A surface effect craft of simple construction achieving improved operational stability and performance at various speeds. The craft includes first and second main wing sections merge into the central hull to form a continuous aerodynamic wing structure. The wing structures are very thick with maximum thickness ratio of wing thickness to chord length on the order of 25-30% with the first and second wing sections being swept back, merging into first and second vertical side wall directional stabilizers, the wing shaped structure forming a generally U-shaped rear section (as best viewed from a rear plan or sectional view). The craft preferably includes an aft elevated secondary wing structure extending between the first and second vertical side wall directional stabilizers whereby both the main wing sections and the aft elevated secondary wing structure provide lift.

Abstract: A propulsion system for a large, nuclear-powered ship includes a number of steam expansion thrusters rearwardly directed from the stern portion of the ship above the water line, a number of water jet drivers rearwardly directed from the stern portion below the water line, and a number of water jet thrusters downwardly directed from the hull portion of the ship. The frictional drag effect on the ship may be reduced by providing a curtain of air bubbles adapted to flow rearwardly in contact with the hull portion.

Abstract: An energy efficient system for reducing the water friction on the hull of a marine vessel. The contact of water with the portion of the outer surface of the hull of a marine vessel which normally engages the water is reduced by the strategic induction of pressurized or compressed air or gas to cover that outer surface. The compressed air is retained on the outer surface by various grooves, channels or semi-flat surfaces running the length of the vessels bottom and in certain applications vertical sides, which prevent the flow of the compressed gas to the surface of the water. The pressurized air or gas is recaptured before exiting the stern or sides and recycled to the bow through an energy efficient circulation system, thus recovering the energy in the compressed air or gas which has flowed from bow to stern. The larger and the deeper the hull displacement, the greater is the efficiency realized by the recycling of the compressed air or other gas.

Abstract: An improved pressurized gas supported marine vehicle that is, in its preferred embodiment long and slender and stabilized by outrigger hulls, is presented. This vehicle, known as SeaLance because of its optimal very fine entry bow and narrow fine main hull, is also capable of full or partial airborne operation when equipped with sidewings. When waterborne, an artifically pressurized gas cushion is disposed in an open bottomed recess in the main hull. First and second, forward and aft, air cushions can be used to maintain a higher gas cushion pressure aft than forward which reduces water blowout at the bow and aids in trimming of the vehicle. Further, labyrinth seals can be disposed on recess intermediate and aft seals to aid in sealing of gas flow. An optional feature of SeaLance is one or more water stabilizers that can include hydrofoils and/or a small lifting body. The water stabilizer(s) would normally retract into an open bottomed recess in the main hull when not used.

Abstract: An improved multi-operational mode marine vessel is proposed that has blower pressurized air cushions that are utilized during high speed operations disposed in one or more secondary supporting hulls wherein said secondary supporting hulls are connected to a main hull by struts in the preferred embodiment of the invention and where, when the air cushions are not utilized, the secondary hulls are at least partially submerged thereby providing an exceptionally stable marine vehicle while stationary or at low speeds. This submergence of the secondary hulls can be enhanced by use of one or more water buoyancy tanks that would generally be disposed in the secondary supporting hulls. In the optional version of the invention, blower pressurized air is ducted from blowers in the main hull through the struts to the air cushion recesses in the secondary supporting hulls plus a duct connects separate air cushion recesses in separate secondary supporting hulls by way of the struts.

Abstract: A tri-hull using air and water collectively channeled and controlled through its design to enhance speed and stability of the tri-hull as it moves forward through the water. Structural wings connecting the two outer hulls to the middle hull comprise operational flaps which direct air in a desired direction along with the flow of air into air intake channels, the air exiting into hydrochannels beneath each outer hull where the interaction of the exiting air on the water moving through each hydrochannel provides an equalization or an upward force to the rear of the tri-hull and a resulting equalization or a downward force to the bow of the tri-hull which enhances the stability of the tri-hull at high speeds. The tri-hull also has adjustable air flow relief valves for controlling the flow of air into hydrochannels and sub fins beneath each outer hull to provide traction during turns.

Abstract: A multihulled partially gas supported marine vehicle that uses artificially pressurized gas cushion recesses in supporting hulls is presented.

Abstract: A system and method for reducing skin friction of an object in relative motion to a fluid. A skin forming a boundary between the object and the fluid, the skin having holes through which micro-blowing of air is blown and a transmitting mechanism for transmitting air through the skin. The skin has an inner layer and an outer layer, the inner layer being a low permeable porous sheet, the outer layer being a plate having high aspect ratio high porosity, and small holes. The system may further include a suction apparatus for suctioning air from the outer layer. The method includes the steps of transmitting air through the inner layer and passing the air transmitted through the inner layer to the outer layer. The method may further include the step of bleeding air off the outer layer using the suction apparatus.

Abstract: A discharge port 4 for discharging air into water is provided on the bottom of a craft behind the rear end of a strip 3 which is installed on the bottom of a small planing watercraft to protrude therefrom and extend in the longitudinal direction of the craft body. A pressure drop in a space behind the rear end of the strip 3 is used to suck in air outside of the craft and guide it through a discharge duct 5 to the discharge port 4, thereby decreasing the pressure resistance and friction resistance generated at the back of the strip 3 rear end. Ram pressure during running of the craft may also be used to take in air from the outside of the craft and guide it through the discharge duct 5 to the discharge port 4, thereby to discharge air from the discharge port 4 into water. The maximum craft speed and the craft acceleration performance is improved by sufficiently decreasing friction resistance at the back of strip rear end.

Abstract: A zero draft cargo vessel with high speed open sea operational capabilities, a catamaran type design with hovercraft systems capable of lifting the craft slightly out of the water and air lubricating the planing pontoon bottoms for greatly reduced water drag at all speeds. A surface effect ship (SES, twin hard sidewalls), design with flat bottom planning pontoons, (SEPPS). The soft Hovercraft air pad being contained and stabilized by the twin high speed surface planing pontoon reactions. A high speed cargo vessel capable of operating at two to three times the speeds of conventional cargo vessels having the same horse power to weight ratios. A high speed cargo vessel design of greatly increased fuel efficiency per ton mile due to its greatly reduced water drag. A fast cargo vessel traveling at near three times the speed with the same hourly fuel consumption of large conventional cargo ships. This equates to getting there in 1/3 the time and 1/3 the fuel.

Abstract: A ship's hull has a cargo deck which is located adjacent a waterline and which is intended to carry a number of barges. The cargo deck is open toward the stern of the vessel. An interior of the hull accommodates one or more ballast tanks and a device for emptying and filling the ballast tanks with water, either completely or partially, thereby enabling the hull to be brought to a shallow draft waterline or to a deeper draft waterline. An air-compressing device generates an air flow which can be delivered to the outer surfaces of the hull by a pipe system which discharges beneath the waterline. At least a part of the lowermost surface region of the hull is flat and extends horizontally. Arranged within this region is a downwardly open cavity of small height and large surface extension. The pipe system discharges at least into the cavity. Air bubbles that are generated will also reduce friction against side-related hull surfaces, even when the hull heels steeply in heavy swells.

Abstract: A marine pressure minesweeping and ship signature simulating vehicle having n inflated substantially doughnut shaped tubular float surrounding a pressurized air-filled cavity. The lower part of said float rides on the surface of the water and the upper part thereof is closed with a resilient membrane, upon the upper side of which is mounted water ballast container means, which is sufficiently open at the top to allow the water ballast to be ejected therefrom, as a result of a considerable increase in air pressure occurring in the aforesaid air filled cavity, due to a mine explosion. A motor driven fan maintains a suitable air pressure in said air-filled cavity at substantially all times, and drive and steering means are mounted on the vehicle in such manner as to enable it to be navigated along a desired course.

Abstract: A device for removing a vacuum bag from a ship stern includes a passageway and plural valve units fixed in holes of an outer wall of the stern. The passageway is formed by air entrances in a rear deck, and a space between an inner wall and an outer wall of the stern is divided into plural sections with vertical support plates bored with air holes, and holes bored in the outer walls of the stern. Each valve unit is fixed with each of the holes, normally closing the hole and opening it when the speed of water filling the vacuum bag is slower than the speed of a moving ship enabling open air to flow into the vacuum bag just behind the stern.

Abstract: The ferry boat has a rectangular main deck with superstructure above and hull structure below. The superstructure is essentially rectangular in all views and has one or more decks with a plurality of traffic lanes on each deck in addition to those on the main deck. The lanes are straight and parallel and there are no deck-to-deck ramps. The hull structure has two sidewalls, one along each of the long sides of the main deck and two dams, one at each end of the main deck. The dams extend between the sidewalls and have vertical aft surfaces and front surfaces which slope downward and aft. The lower extremities of the sidewalls are further from the main deck than the apexes of the dams. The volume enclosed by the sidewalls, dams, main deck and water surface is filled with entrapped air which will compress to provide a major part of the support of the boat. There are two hydrofoils, one forward, one aft and extending between the sidewalls. Each foil is supported from the deck structure by several struts.

Abstract: An improved pressurized gas supported marine vehicle that is, in its preferred embodiment long and slender and stabilized by outrigger hulls, is presented. This vehicle, known as SeaLance because of its optimal very fine entry bow and narrow fine main hull, is also capable of airborne operation when equipped with sidewings. When waterborne, an artifically pressurized gas cushion is disposed in an open bottomed recess in the main hull. First and second, forward and aft, air cushions can be used to maintain a higher gas cushion pressure aft than forward which reduces water blowout at the bow and to aid in trimming of the vehicle. Further, labyrinth seals can be disposed on recess intermediate and aft seals to aid in sealing of gas flow. An optional feature of SeaLance is one or more water stabilizers that can include hydrofoils and/or a small lifting body. The water stabilizer(s) would normally retract into an open bottomed recess in the main hull when not used.

Abstract: A boundary layer polymer reservoir has bladder type side walls and is supted in a chamber in a vehicle that can be filled with sea water under pressure to provide external forces on the reservoir to eject the polymer through ports in the nose of the vehicle. The vehicle is a buoyant test vehicle that is drawn downwardly to a depth that produces a predetermined pressure in the chamber. The reservoir is elliptical with a support ring to which the elliptical side walls are peripherally attached, and which is itself attached to rails inside the vehicle.

Abstract: A system for positioning and sizing microbubbles in a liquid such as water. first source of acoustic energy produces a first acoustic signal in the liquid, and a second source of acoustic energy produces a second acoustic signal in the liquid. The first and second sources of acoustic energy are positioned and aligned so they produce a standing wave field in the liquid. The standing wave field creates forces which position microbubbles at the antinodes or nodes of the standing wave field. By selecting a frequency for the acoustic signal and a frequency for the second acoustic signal which are slightly different, the standing wave field can cause the positioned microbubbles to move towards or away from a surface region in contact with the liquid.

Abstract: An improved multi-hull gas cushion supported marine vehicle that is, in its preferred embodiment, capable of transition to airborne surface effect operation is presented. This marine vehicle, known as SeaCoaster, has optional elongated knife shaped bows that slice into waves, very fine entry and low angle of divergence supporting gas cushions, water rejecting steps that extend high onto the sidehulls, and retractable water stabilizers to insure optimum performance in heavy seas. The retractable water stabilizers are in the form of inverted-T hydrofoils and/or small boat shaped members. Several variations of hydrofoil configurations are presented. It also has special, normally inverted-V shaped, gas cushion and wetdeck aft seals to insure minimum effect of wave impacts in those areas. The gas pressurization system normally includes powered blowers where a flap-like sealing device can be installed to seal gas leakage.

Abstract: A method for reducing the frictional resistance of a navigating vehicle, and a method for generating micro-bubbles for reducing the friction of the navigating vehicle and an apparatus therefor. The friction reduction is achieved with the expenditure of a small amount of energy, thereby improving the overall energy efficiency for operating the ship. An air bubble/water mixture is injected towards the stern of the ship, at an inclined angle to the underwater surface, into a boundary layer formed in the vicinity of the underwater surface of the ship. The friction reduction is effectively performed because of the dynamic energy of the water, being a larger mass than air, enables the gas-including mixture to be injected over a longer distance into the boundary layer than in the case of air bubbles alone.

Abstract: An air cushion vehicle having a low drag, high stability non-scooping skirt system including closed loop finger sleeves. An enlarged bag combines to provide a more responsive skirt profile. The sleeves of this invention are trimmed at an angle to the supporting surface, thereby exposing the sleeve opening to the air cushion. The sleeve is maintained at the air cushion pressure unless the vehicle rolls enough to submerge and close the sleeve opening. A pressure build up occurs as the opening is submerged and a significantly greater differential pressure is obtained with an enhanced restoring moment. The interior wall of the sleeve that faces the air cushion is angled slightly inward on the bow and side seals to allow momentary collapse of the sleeve and release of an extraordinary force of a rough sea. In addition the effective air cushion area, the platform of the vehicle, is extended to its maximum to provide greater stability.

Abstract: Frictional resistance to motion of a boat is reduced by generating an unconfined layer of intermixed air bubbles and water adjacent at least a portion of the hull of the boat including at upcurving side surfaces of the hull. In the preferred form of the invention, an array of spaced apart airflow apertures in the hull extends outward and upward at each side of the keel at a plurality of locations along the hull. Air is forced through the apertures by a compressor or a forward facing air scoop or by a combination of both. In the preferred embodiment, barnacle inhibiting fluid may be released through the array of apertures when the boat is docked or at anchor.

Abstract: Trim compensation for a hovercraft having two engines (2,3) with flow outlet apertures. The two engines (2,3) are arranged laterally at the stern of the hovercraft to generate air jets for forward motion. The hovercraft also includes a compressor to generate an air cushion beneath the hovercraft. The trim compensation includes a tail plane arrangement located in the air jets in the two engines for directional control of the hovercraft by deflection of the air jets. The tail plane arrangement consists of a negatively arranged V-plane (7) with a middle upper section from which extends stabilizer surfaces (9,10) at both sides in a downward direction. The stabilizer surfaces (9, 10) are provided with rudder elements (11, 12) which are swingable in the same or opposite direction to deflect the air jets. The stabilizer surfaces (9, 10) and the rudder elements (11, 12) run centrally across the flow outlet apertures of the engines (2, 3).

Abstract: There is presented an underwater vehicle polymer ejection control valve ambly comprising a valve in communication with a polymer reservoir and in communication with ejection ports. The assembly further comprises a valve actuator including structure responsive to the vehicle in an ascending mode reaching a first predetermined depth in a water column to open the valve to place the polymer reservoir in communication with the ejection ports. The aforementioned structure is further responsive to the vehicle reaching a second and lesser predetermined depth to close the valve to interrupt communication between the polymer reservoir and the ejection ports.

Abstract: An apparatus for shielding the keel and/or bow of a watercraft is disclosed in one presently preferred embodiment comprising a protective cover member having an elongated body substantially tapered in cross-sectional thickness from a midsection to at least two opposing sides. Protective cover member is preferably configured having one or more elongated channels formed therein. Preferably, the elongated channels are integrally formed in an exterior surface of the protective cover member and longitudinally disposed substantially parallel to the linear length of the protective cover member from a first end to a second end thereof. The protective cover member is preferably formed having an opposing contacting surface comprising a fastening means preferably disposed thereover for securing the protective cover member over the keel and/or bow of the watercraft.

Abstract: The present invention provides a method of reducing the fluid friction drag of ships and fluid transport channels and prevent contamination and corrosion of a structure having an immersed portion. The method of forming an air layer over an immersed surface of a structure having an immersed portion, comprising the steps of: covering the immersed surface of a structure (hull 1) having an immersed portion with a coating layer 3, which has depressions 6 and projections 7 at the surface thereof and which has at least vertices 7' of the projections 7 formed of a water-repellent material 8; and supplying air a to the surface 10 of the coating layer to form an air film 12 between the coating surface 10 and water 13.

Abstract: A delta wing form body is provided having a central forward apex as well as rear opposite side apices. Each apex includes a vertical powered fan duct assembly extending therethrough and the rear of the wing form body includes forward thrust developing horizontal fan duct assemblies while the center of the body includes laterally and longitudinally shiftable weight structure for omnidirectional shifting of the center of gravity of the wing form body. The center and opposite side fan duct assemblies open downwardly into central and opposite side downwardly opening longitudinal tunnels, respectively, each including retractable and extendable front and rear flap assemblies. The wing form body also includes rear forward thrust developing propulsion fan duct assemblies and all of the fan duct assemblies are variably speed driven from a single power source.

Abstract: Frictional resistance to motion of a boat is reduced by generating an unconfined layer of intermixed air bubbles and water adjacent at least a portion of the hull of the boat including at upcurving side surfaces of the hull. In the preferred form of the invention, an array of spaced apart airflow apertures in the hull extends outward and upward at each side of the keel at a plurality of locations along the hull. Air is forced through the apertures by a compressor or a forward facing air scoop or by a combination of both. In the preferred embodiment, barnacle inhibiting fluid may be released through the array of apertures when the boat is docked or at anchor.

Abstract: A process for reducing skin friction and inhibiting the effects of liquid turbulence in a system involving the flow of a liquid along the surface of a body, e.g. a marine vehicle, includes injecting a drag reducing polymer into the valleys of adjacent, evenly spaced, longitudinal grooves extending along the length of the surface of the body, so that the rate of diffusion of the polymer from individual grooves into the liquid flow is predictably controlled by the groove dimensions. When the polymer has diffused over the tips of the grooves into the near wall region of the boundary layer, the polymer effectively reduces the turbulent skin friction. A substantial drag reducing effect is achieved with less polymer than must be used to lower skin friction when the surface of the body is smooth.

Abstract: An improved performance marine surface vessel that includes pressurized supporting gas cushions in multiple hulls, normally catamaran-like sidehulls, where such pressurized supporting gas cushions support a majority of boat weight in operation. The preferred embodiment of the invention utilizes long fine pointed bow catamaran-like sidehulls that are in mechanical communication with a connecting hull structure. The long fine sidehulls offer performance advantages over a single large supporting gas cushion. Sidehull gas cushion outer sidewalls are preferably wider and deeper than inner sidewalls which insures minimum resistance coupled with maximum transverse stability in roll. Further, sidehull gas cushion sidewalls optionally have angled to horizontal flatter surfaces forward and then transition to more rounded shapes aft which provides for good pitch stability and minimum hydrodynamic resistance.

Abstract: The high-speed hydrohull comprises a portion (1) having, in a longitudinal section, an airfoil profile with a low coefficient of aerodynamic resistance, having a convex upper surface (1B) in order to create, during the movement of the hydrohull, such lift as to raise the hydrohull over the surface of the water.

Abstract: An improved performance marine surface vessel that includes pressurized supporting gas cushions in multiple hulls, normally catamaran-like sidehulls, where such pressurized supporting gas cushions support a majority of boat weight in operation. The preferred embodiment of the invention utilizes long fine pointed bow catamaran-like sidehulls that are in mechanical communication with a connecting hull structure. The long fine sidehulls offer performance advantages over a single large supporting gas cushion. The invention may also include a center bow disposed between the sidehulls that adds to stability in rough seas and gives a racy yacht-like appearance. Recesses in the sidehulls may include, at least in part, fixed and/or movable seals. Fixed seals may include inset vented steps to reduce wetted surface area. The recess gas pressurization system may include a controller to control pressures in individual recesses which allows at least some control of boat motions in rough seas.

Abstract: An air cushion displacement hull water vehicle has a novel construction so s to defrictionize water flowing under the hull as the vehicle is propelled through the water. The hull includes a forward bow portion, an opposing aft end portion, a pair of sidewalls spaced from each other and extending between the forward bow portion and the aft end portion, and a bottom wall extending between the forward bow portion and the aft end portion and between the pair of sidewalls. The bottom wall of the hull is recessed to define an air cushion region. An air supply device positioned within the interior of the hull communicates with the air cushion region and is operable to supply pressurized air to the air cushion region to defrictionize water flow under the air cushion region.

Abstract: Methods and devices for generating gas bubbles including a microbubble generating cell having a microporous mat permeable to gas appied thereagainst under pressure which has a ultrasonic energy generator such as a piezoelectric transducer in wave energy communication therewith for promoting flow and impeding fouling thereof. Such mat is comprised of compressed corrosion-resistant metal fibers of a diameter of between 2 and 80 microns, has a density of less than 70% of the density of the fibers and an average pore diameter of between 5 and 100 microns. Such methods and devices are associated with a vessel and/or a foil for a vessel for generating and dispensing microbubbles along the hull surfaces to reduce friction and turbulence on the wetted surface. The foil is positioned forward of vessel bowpeak with its trailing edge confronting same and has a microbubble dispenser for dispensing microbubbles in the path of the hull of the vessel.

Abstract: Vessels with improved performance capability and methods for improving such performance and foils which may be associated with a vessel for providing this improved performance capability. Additionally, a method and device for improving flow through a microporous barrier and a diffuser cell for generating gas bubbles, both of which may be associated with a vessel and/or a foil for a vessel for improving its performance. The foil is positioned forward of the vessel bowpeak with its trailing edge confronting same to impart momentum to water in the outboard direction to each side of the bowpeak while maintaining a streamline water flow, thereby reducing friction and turbulence on the wetted surface of the bow. The foil may have means of heating the surface of the leading section to reduce friction. The foil may have generators of and dispensers for friction reducing agents such as gas bubbles to distribute such agents into the path of the bow, advantageously from the trailing section of the foil.

Abstract: Method and arrangement for the reduction of the resistance to rotation of the propeller (3) of a ship (1) going in ice when the ice increases the resistance to rotation of the propeller to a level higher than when sailing in open water. When the resistance to rotation increases, gas is passed to the propeller (3), and the supply of gas is adjusted when the resistance to rotation is changed. The supply of gas may be continual, but as a rule it is used only for short periods in order to correct the speed of rotation of the propeller to the appropriate level.

Abstract: A process for reducing skin friction, inhibiting the effects of liquid turbulence, and decreasing heat transfer in a system involving flow of a liquid along a surface of a body includes applying a substantially integral sheet of a gas, e.g., air, immediately adjacent to the surface of the body, e.g., a marine vehicle, which has a longitudinally grooved surface in proximity with the liquid and with a surface material having high contact angle between the liquid and said wall to reduce interaction of the liquid, e.g., water, with the surface of the body, e.g., the hull of the marine vehicle.

Abstract: A device for movement over a viscuous or liquid medium, such as a water ski, has a textured contact surface which includes the bottom and side edges of the ski. The texture is formed of shallow dimples.

Abstract: The method and the apparatus for removing ice from a ship's channel or from around the ship, to ease its navigation. The invention is characterized in that the propeller stream is used for removing the ice by turning the propeller stream up to the surface where the ice is. The removing influence of the stream can be further strengthened by diverting it also to the sides. Turning up the stream can be done for instance by mixing air into the propeller stream. Mechanical foils (8), for instance tilted ploughing rudders (9,10), can be used for turning the stream up and to the sides. The same air blowing apparatus can be used also for other applications, as loading the payload, or for biological aeration of water.

Abstract: A method and apparatus for reducing friction at the interface between a liquid and a solid. A solid interface member includes a plurality of apertures over the entire surface which are to be in contact with the liquid. The apertures are of a size and dimension such that the surface tension of the liquid will not allow the liquid to pass through the apertures, but which will allow a gaseous material with less surface tension than the liquid to pass therethrough. The gaseous material is thereafter motivated through the apertures to interpose a gaseous layer at the liquid solid interface which reduces the drag coefficient therebetween, which would otherwise result from relative motion between the solid interface member and the liquid.

Abstract: An improved performance marine surface vessel that includes a pressurized gas cavity in its underside that is restrained by hull structure and hull seals supports some 80 to 90 percent of vessel weight which results in much greater hull efficiencies. The gas cushion is normally supplied with pressurized gas by mechanical apparatus such as a powered blower.

Abstract: A boat hull having a bow, an underside and also including at least one transverse step extending at least partly across the hull underside. The boat hull is characterized in the provision of a venting tube which extends from the transverse step substantially adjacent or contiguous with the hull underside to form an outlet adjacent to the bow. Suitably the venting tube does not communicate with the interior part of the hull and also the venting tube defines at least partly the longitudinal axis of a keel of the boat hull.

Abstract: A means and method for simultaneously reducing drag and noise of a high-sd underwater vehicle is provided. Water is admitted through a water intake scoop in the nose of the vehicle and a polymer powder-gas combination is injected into the water stream in the scoop. The water, polymer and gas are mixed in a mixing chamber into which the scoop empties and are ejected through a circumferential ejector disposed at the minimum pressure point.