Abstract: A watercraft (10) operates as a conventional displacement vessel or as an airborne craft. In the airborne mode water is drawn upward through a drogue (18) by operation of a pump (42) which is driven by a motor (44). Pressurized water from the pump (42) is directed downward as water jets by nozzles (64-70). The reaction force on the nozzles (64-70) serves to lift the watercraft (10) above the surface of a body of water (16). The watercraft (10) is further equipped with fore and aft nozzles (84, 90) as well as transverse nozzles (86, 88) to provide full directional control and propulsion for the watercraft (10). A control computer (100) operates through a bus (102) to position the drogue (18) as well as control the thrust produced by the nozzles (64-70) and (84-90). The altitude of the watercraft (10) is measured by altimeters (94, 96). The height of forereached waves is measured by a wave height radar (92).

Abstract: A water jet propelled boat that includes a source of pressurized air that by a single action control may be delivered to bow and stern portion positioned resilient bags to inflate the same to vary the contour of the wetted portion of the boat to a desired configuration. The boat includes a number of laterally spaced sponsons that have forward bottom surfaces that taper downwardly to merge into substantially straight rearward bottom surfaces on which the boat rides when traveling at high speed. Pressurized air is discharged from the source to flow rearwardly under the boat and impart a lift to the latter. The desired configuration of the bags is one which in combination with the action of the sponsons and the rearwardly flowing bubbles results in the boat moving through the water in a fuel efficient manner.

Abstract: Three-dimensional substrates having on at least one surface a coating formed of a polyurethane polyene composition obtained by reacting from about 10 to about 50 parts by weight of a polyene in the presence of about 100 parts by weight of a hydrophilic polyurethane resin. Transparent substrates are rendered antifogging by such coatings. The drag resistance of boat hulls may be decreased by a coating of the compositions and marine growth thereon may be inhibited by incorporating substances such as mercurous acetate in the coating.

Abstract: A propeller mount for deflecting ice away from the propeller of an icebreaker includes a wedge-shaped body, the front end of which is pointed, and the remainder of which flares rearwardly to direct ice outwardly away from the propeller assembly. By providing bubblers in the sides of the body near the front end thereof, outward deflection of ice by the mount is promoted. The rear of the body is also slightly wedge-shaped to provide a similr wedging action at the stern for steering ice away from propellers.

Abstract: A polymeric composition containing copper flake in sufficient quantities to render the entire thickness of the polymeric composition electrically conductive. The copper flake is treated to remove oxides and reacted with conventional epoxy resins modified with an epoxidized polyol (polyglycol). The formulation not only exhibits outstanding anti-fouling properties but also exhibits anti-sliming properties. The composition is useful as a gel coat and when utilized on ships, boats, and other water craft, a vessel results which requires no additional anti-fouling or anti-sliming treatment for several years. The composition can also be used to great advantage as a liner for pipes and conduits used to transport salt or fresh water where fouling of the pipes is a problem. In one embodiment of the invention, a composition is disclosed which will cure under water. This particular formulation can be used to great advantage in patching holes in copper clad hulls and the like while the vessel is in water.

Abstract: A submersible or semi-submersible structure, such as a boat, oil rig or pipeline, has an anti-fouling covering secured thereto. The covering comprises a mesh of copper or copper alloy embedded in a carrier, preferably of plastics material. The mesh has knuckles which on one surface are close to or protrude from the carrier so as to be accessible to sea water. The knuckles are spaced from the other surface so as to prevent contact between the structure and the mesh. A sea water permeable coating may be provided on the outer surface.

Abstract: A clean start backflush system provides a mode of operation in a suction inar flow control (LFC) vehicle in which low speed propulsion and backflush through surface apertures are simultaneously generated. The propulsion assists the transition from an at-rest state to the desired high-speed travel, while backflush in the low-speed regime ensures that ocean particles are not captured at the entrance to the flush suction slots.

Abstract: Solutions of polyethylenimine or a hydrophilic derivative thereof and a hydrophilic acrylic polymer for coating watercraft below the waterline. The coating results in reduced drag by the water on the watercraft as it travels through the water. The coating also acts as a glaze coating which protects and increases the life of paint on the surfaces over which it is coated.

Abstract: A high strength, non-toxic, antifouling, marine coating composition is provided which comprises agar, a water soluble polyol plasticizer such as dipropylene glycol, a strengthening agent as, for example, potassium borate, and water.

Abstract: Wax coatings for underwater surfaces, e.g. ship's hulls, contain as biocidal component, an organo-tin ester (preferably a tribydrocarbyl tin ester) of an oxidized wax or an aliphatic fatty acid.The oxidized wax may be an oxidized petroleum wax and the fatty acid a C.sub.12 -C.sub.30 acid. The ester may form 5-100% of the finished coating and the other wax component, if present, may be a conventional petroleum wax.

Abstract: An effective antifouling result with respect to marine creatures such as barnacles is achieved by energizing a piezofilm layer carried on the outside of a vessel to cause mechanical vibration of the layer.

Abstract: A process for extending the life of an antifouling paint film which comprises applying onto an antifouling paint film a coating of a water-permeable graft polymer prepared by polymerizing one or more vinyl monomers in the presence of a hydrophilic polymer. The coating of the water-permeable graft polymer has an excellent water-resistance and a proper water-permeability by which an antifouling agent contained in the antifouling paint film can be leached into sea water and moreover the leaching rate can be controlled. As a result, the antifouling property of the paint film is exhibited for a long period of time.

Abstract: Improved molded drag reduction coatings which inhibit the degradation of g reduction properties of high molecular weight polymers such as polyethylene oxide. The moldings incorporate compatible anti-oxidants and/or lubricants and plasticizers in amounts that do not significantly decrease the drag reduction effectiveness of the polymer used.

Abstract: Coating formulations and method of making thereof for reducing the drag or riction encountered at the interface of a soluble drag reduction material coating and the liquid medium such as water in which the coating is being used. This is accomplished by adding various solid water-soluble materials as diluents and viscosity reducers, to a very high molecular weight drag reduction non-ionic polymer such as that of polyethylene oxide. The molded polymer with the added solid water-soluble material has less solubility and viscosity at and contiguous to the coating-water interface than that of the additive-free matrix under similar conditions.

Abstract: An anti-fouling overcoating composition for watercraft or stationary underwater structures precoated with hard-surface leaching-type anti-fouling paint consists essentially of an aqueous solution or dispersion of a carboxylated hydrophilic acrylic polymer, a cross-linking agent for the carboxylated hydrophilic polymer, polyethylenimine or a hydrophilic polyethylenimine derivative and an effective amount of an ultraviolet-absorbing agent.

Abstract: A method and composition for decreasing water resistance to movement by decreasing the surface tension and diminishing the contact angle between an object moving through water, and the water, and/or between water passing over an object and the object, thereby allowing the object to move at an increased speed with the same applied moving force or at the usual speed with less applied moving force. The method is accomplished by applying to the surface of the object which is to be moved through water a thin layer of a nonionic surface active agent which is water insoluble with the agent having a hydrophile-lipophile balance of about 7 to about 9.

Abstract: An automatic roll, pitch, and heave stability device for air-cushion-borne vehicles equipped with semi-rigid planing bow and stern seals, the latter which may be divided into separate port and starboard seals, and with rigid side-walls. Each seal at its trailing edge is mechanically linked to, and controls, a bypass duct valve. The linkage is arranged so that pressure in the seal increases as the seal is forced up due to a wave crest, and decreases as the seal drops away from the vehicle body in a wave trough. Vehicle stability in heave is achieved by the bow and stern seals operating in unison; in pitch, by the bow and stern seals operating oppositely; and in roll, by the split port and starboard seals operating oppositely. The system operates both while the vehicle is underway, and with changes in load on the vehicle in calm water.

Abstract: Underwater surfaces are protected against weed and/or shell growth with a wax coating containing one or more biocides effective against weed and/or shell growth when dissolved or dispersed in wax. The biocides are preferably sea-water insoluble and may be fresh water soluble also. They are preferably thermally stable up to 150.degree. C and soluble in wax. Suitable biocides are Cu, Zn, Ni, Co, Mn or Sn salts of carboxylic acids or polyacrylic acids, or organic compounds having an active structure containing S, Cl, N or O.The coating may be 5-500 micrometers thick.

Abstract: A cargo vessel hull bow configuration comprising a horizontal forwardly projecting bow wave making bottom plate disposed substantially coplanar with the bottom surface of the hull proper, of a transverse maximum width approximately one-third the hull width and carried in that position by central support means conducive to a flow pattern extending over the plate diverging both laterally to merge smoothly with laminar flow along the tapered bow sides and downwardly to merge smoothly with laminar flow along the hull bottom. Reduction in transverse width of said wave making plate aft of its fore-and-aft point of maximum width cooperates in the formation of such laminar flow pattern, and, in conjunction with a secondary bow wave formed by the hydrodynamic effect of the plate superimposed on the normal bow wave effect of the hull proper minimizes the resultant bow wave and greatly reduces resistance to forward movement of the composite hull.

Abstract: Hydrophilic polymers, i.e., hydrophilic cellulose esters, hydrophilic cellulose ethers, hydrophilic polyurethanes, hydrophilic vinyl lower alkyl ether polymers, vinyl alcohol group containing polymers, partially hydrolized polyacrylonitrite, ethylene-maleic anhydride copolymer, stryene-maleic anhydride copolymer, proteins, high molecular weight polyalkylene oxides or phenoxy resins, having encapsulated therein either or both anti-fouling agents or pigments is applied as a coating to underwater portions of a marine structure so as to reduce the drag of said structure.

Abstract: A surface effect-type ship has vertically depending sidewall skirts that define a shock receiving cavity. A compound keel member is pivotally mounted to the forward end of the bow and is adapted to dampen the shock of waves incident thereon. The keel member includes a skeletal structure over which is clad a resilient and deformable skin. That skin deforms due to the wave pressure so as to present a concave surface to the incident waves. This surface partially diverts those waves into horizontal and vertical components. The vertical components may be cushioned by means of an air bag suitably positioned in the cavity behind the keel member. The vertical forces are transferred to the sidewalls and to some extent are canceled since each side of the keel acts to divert waves. Off center waves are dampened by the feature of the entire keel member being pivotable about its longitudinal axis. The keel is provided with such spring loaded means in constant contact with the sidewalls.

Abstract: An amphibious vehicle is adapted to be propelled in water with a minimum of wet hull drag. The vehicle includes a semi-flexible frame and an engine fixed to the frame. Parallel sets of tandem rollers are mounted on the opposite sides of the body on which pairs of pontoon assemblies are mounted. Each pontoon assembly includes a plurality of circumferentially superimposed endless layers or plies of buoyant material so that the pontoons support the body on both land and water. A propulsion device is provided for propelling the load-carrying body in water, the preferred propelling means being a finned belt driven by the engine. An engine is also provided for driving the pontoon rollers so that the linear velocity of the endless layers is approximately equal to the velocity of the body when it passes over water to minimize the occurrence of wet hull drag.

Abstract: A hull construction especially suited to inhibit marine growth and a method for forming same is provided. The hull construction includes an outer surface having alternating metallic areas and fiber glass areas defining the entire outer hull surface. The metal forming the metallic areas is of the type which inhibits marine growth.

Abstract: In order to control the boundary layer of air over the outer surface of an airframe and to recover some of its energy, portions of this boundary layer are sucked at a multiplicity of locations distributed over this surface and thereafter discharged rearwardly as a jet contributing to propulsion. Such suction takes place through orifices having inlets directed towards the rear and the sucked flow is adjusted so as to draw off only a part of the boundary layer whose velocity relative to the airframe is but a minor fraction of the absolute velocity of the latter, thereby leaving a substantial thickness of boundary layer.