Abstract: A propeller shield to selectively shield rotating blades of a propeller. The propeller shield may include a shield element for placement adjacent to the propeller blades. The shield element may include multiple gates configured to open in response to water flow generated by the propeller. The gates may be configured to open away from the propeller in response to a forward movement of the boat, and to close towards the propeller in response to cessation of the forward movement.

Abstract: A watercraft propulsion device for protecting marine life includes a tube that is coupled to a hull of a marine vessel. The tube has a front end and a back end that are open. The front end is circumferentially larger than the back end so that the tube is tapered. An impeller assembly is positioned in the tube. The impeller assembly is operationally coupled to a drive shaft of the marine vessel. A power plant of the marine vessel is positioned to rotate the impeller assembly concurrently with the drive shaft to increase a pressure and a flow of water through the tube to generate thrust to propel the marine vessel. A grate is coupled to a front perimeter of the tube so that the grate covers the front end. The grate is configured to deter entry of a marine organism into the tube.

Abstract: A guard for protecting wildlife is mounted on an outboard motor having a propeller and keel below an anti-ventilation plate. The guard has a spaced pair of bars each with an upper section, a lower section and between them a midsection. The upper sections of the bars can be attached to opposite sides of the anti-ventilation plate in order to position the lower sections below the propeller and keel. The lower sections have a smooth, projection-free streamline for avoiding snagging on sea weed.

Abstract: The invention relates to a protective housing for a propeller of a submarine vehicle. The invention also relates to a connection system for a propeller-driven submarine vehicle with a submarine cable and such a protective housing. The invention further relates to the use of a protective housing for a propeller of a submarine vehicle for receiving a strain relief connection for a connecting cable. The invention enables low-cost communication between a propeller-driven submarine vehicle and a support platform by means of a connecting cable which is hydrodynamically streamlined and ensures strain-relief for the connecting cable. The connecting cable is fixed to the periphery of the protective housing, outside the working space of the propeller located on a propeller axis, and a strain-relief cable-holding fixture is arranged for a connecting cable on the submarine vehicle.

Abstract: The instant invention describes an anti-biofouling structure for placement onto structures or surfaces that are exposed to aquatic environments. Embedded within the anti-biofouling structure are agents that can diffuse out of the structure and prevent the formation and/or accumulation of plant and animal species build-up that creates biofouling. The instant invention also describes a system for preventing biofouling of an object stored in an aquatic environment which includes the anti-biofouling structure, and a protective cover element constructed and arranged to fit various structures, such as boat propellers.

Abstract: The invention relates to a protective housing for a propeller of a submarine vehicle. The invention also relates to a connection system for a propeller-driven submarine vehicle with a submarine cable and such a protective housing. The invention further relates to the use of a protective housing for a propeller of a submarine vehicle for receiving a strain relief connection for a connecting cable. The invention enables low-cost communication between a propeller-driven submarine vehicle and a support platform by means of a connecting cable which is hydrodynamically streamlined and ensures strain-relief for the connecting cable. The connecting cable is fixed to the periphery of the protective housing, outside the working space of the propeller located on a propeller axis, and a strain-relief cable-holding fixture is arranged for a connecting cable on the submarine vehicle.

Abstract: A system and apparatus are disclosed for improving safety and hydro-flow thrust from a hydro-drive device. The apparatus may include a shroud having a first opening for the ingress of water, and a second opening for the egress of water, a diverter connected with the shroud and angled in a direction selected to direct water to form a vortex as the water exits the shroud, and a screen connected with the second opening and configured to allow a substantially free flow of water and to prevent marine, plant, animal, and human life from contacting the hydro-drive device. The system may include a motor, a hydro-drive device coupled to the motor, and the apparatus.

Abstract: Arrangement for protecting an outboard motor. The arrangement includes a holding device which is made of steel and which is adapted to be detachably fixed to a shaft of the outboard motor. The holding device includes a ring element having U-shaped cross-sectional profile and at least one closure device. A protective cage includes at least one projecting part which projects radially outwards from an upper edge of the protective cage. The U-shaped cross-sectional profile defines an opening which is adapted to removably receive therein the at least one projecting part when the protective cage is fixed to the shaft of the outboard motor with the holding device. This Abstract is not intended to define the invention disclosed in the specification, nor intended to limit the scope of the invention in any way.

Abstract: An outboard motor which includes a driving motor, a switching device, an impeller and a blade casing. The switching device switches rotation of a drive shaft of the driving motor between normal and reverse directions. The impeller is rotated with a driven shaft connected to the switching device. The blade casing includes a first duct member and a second duct member. The first duct member has first opening through which water is sucked from the outside when the impeller is rotated in the normal direction. The second duct member connected to the first duct member encloses the impeller, and has a second opening through which water is sucked from the outside when the impeller is rotated in the reverse direction.

Abstract: An air suction device for a surface boat having a filter element of paper type arranged in an air suction passage of an engine. The filter element is composed of a core made of a filter material and a permeable waterproof sheet arranged at the upstream side surface of the core in the air suction passage.

Abstract: The Propeller Safety Guard is a wire mesh type enclosure covering the perimeter of the propeller as well as the rear plan of the propeller. The upper section of the guard is bolted to the underside of the outboard motor anticavitation plate. The lower section of the guard is bolted to the skeg of the outboard motor by a connection mounting bracket which has along gated holes to allow for adjust ability in order to locate the ideal position on the motor skeg for mounting the guard. This guard encloses the propeller from the two most dangerous exposures, the propeller tips rotating and the rear of the propeller. The forward section of the propeller is to some extent protected by the lower leg of the outboard motor.

Abstract: The Propeller Safety Guard is a wire mesh type enclosure covering the perimeter of the propeller as well as the rear plan of the propeller. The upper section of the guard is bolted to the underside of the outboard motor anticavitation plate. The lower section of the guard is bolted to the skeg of the outboard motor by a connection mounting bracket which has along gated holes to allow for adjust ability in order to locate the ideal position on the motor skeg for mounting the guard. This guard encloses the propeller from the two most dangerous exposures, the propeller tips rotating and the rear of the propeller. The forward section of the propeller is to some extent protected by the lower leg of the outboard motor.

Abstract: A marine propulsion assembly comprises a drive shaft, a first propeller fixed to the drive shaft and turnable therewith in a first direction, an annular array of gear teeth disposed on the first propeller and turnable therewith, a second propeller aligned with the first propeller, and an annular array of gear teeth disposed on the second propeller. Bevel gears are disposed between the first and second propellers and engaged with the first and second annular arrays of gear teeth. The bevel gears transmit rotation of the first propeller to the second propeller, such that the second propeller turns in an opposite direction relative to the first propeller.

Abstract: A propulsion apparatus is mounted on at least one end of a flexible tubular flotation member which is mountable about the body of the user. The propulsion apparatus is capable of propelling the tubular member and the user in the water. In one embodiment, a housing containing a motor driven propeller is fixedly mountable over one end of the tubular member. A guard containing an open mesh surrounds the propeller. In another embodiment, the housing and the propulsion means are mounted in a bore in the end of the tubular member, with the propeller projecting outward from the end of the tubular member.

Abstract: A propeller guard for use in association with a boat propulsion propeller driven by an outboard motor or an inboard/outboard rear motor drive unit. The propeller guard may be constructed of injection molded plastic, fiber reinforced resin, metal such as aluminum or other materials having strength characteristics to provide necessary protection and constructed to minimize hydrodynamic resistance. The propeller guard will protect swimmers, aquatic mammals and other sea life from coming into contact with the propeller thereby preventing injury and at the same time protect the propeller from damage by engagement with floating or submerged debris.

Abstract: A screen system for marine thrusters is devised having directionally streamlined screens with geometrically-shaped contoured gratings capable of imparting thrust-enhancing effects, thereby permitting high operational efficiency and the ability to operate with little or no reduction in thrust due to cavitation.

Abstract: A guard for a marine propeller utilizing a flange found on the lower drive unit or power leg, thereof. The guard includes a cage which at least partially encloses the propeller and a support member for holding the cage to the lower drive unit. A support member includes a bracket having a pair of legs with an intermediate portion between the two legs. The bracket is joined to the cage and fixed to the flange found in the lower drive unit of the marine engine having the marine propeller.

Abstract: A low-aspect ratio propeller system is provided with a multiple ring structure formed with a plurality of circular or non-circular, annular, narrow equivalent air foil rings which are held by rails in a predetermined relationship with the propeller blades. The upstream ring is located downstream from the tip vortex of the propeller within the axial span of the propeller. One or more additional downstream-located rings are used so as to provide at least one annular multiple ring-defined pump aperture through which peripheral vortices generated by the propeller blades or fan blades may enhance the mass flow. In one propeller system, a low-aspect-ratio propeller is employed with high blade angles of attack and non-stall capability to generate strong vortices which enhance the beneficial effect of the multiple ring structure. These vortices increase thrust because their induction action on the rings increase beneficial ring flow circulation.

Abstract: The present invention relates to a propeller enclosure for enclosing a skeg and propeller. The invention includes a fence portion which defines a first chamber. The first chamber is designed for receiving the skeg of a watercraft motor. The fence portion allows the passage of water therethrough. The invention also includes a solid band portion which defines a second chamber. The second chamber receives the propeller. A first end of the solid band portion is attached to the fence portion. So that the first chamber communicates with the second chamber. The invention also includes a cover which is mounted on a second end of the band portion. The cover allows the passage of water therethrough. The cover includes means for causing trim-tab-like action. The propeller enclosure of the present invention is intended for mounting to a cavitation plate.

Abstract: A device to protect the propellor of a boat from damage caused by striking underwater obstacles, when the boat is moving in any direction relative to the obstacles, and to improve the movement of the boat along the water.

Abstract: Two angle brackets secure a severely swept plastic wing-like propeller guard to the sides of the motor housing or skeg. The left and right wing-like projections have a horizontal center wing segment oriented parallel the axis of propeller rotation, and upturned outer wing segments that are provided in the plane of propeller rotation.

Abstract: A propeller guard for an outboard or stern drive motor having increased rigidity and stiffness is disclosed. The guard comprises an arcuate main spine, a plurality of side ribs and an upright brace. The spine comprises a channel adapted to engage the leg of the motor and clamping strap means for attachment of the guard to the motor.

Abstract: The propeller and lower unit protector is made from a high grade steel and has a spring like U-shaped top member for sliding in a generally horizontal direction over an outboard engine cavitation plate from a front to a back portion of the engine. A generally ring shaped member depends downwardly from a first end of the top member and is attached thereto. The ring member is spaced apart outwardly from the outer edges of the propeller blades. The opening in the front of the U-shaped top member is closed by a bolt through a bore in the first end of the top member to secure the top member in a tight grip around the lower engine housing. The closed end of the top member is attached to a strut depending downwardly and backwardly to attach to a bottom portion of the ring member. Port and starboard side struts also connect the downwardly depending strut to a middle portion of the ring member.

Abstract: The propellor guard described herein is designed primarily for the protection of manatee but is also useful in protection against injury to other animals and larger fish which might come in contact with a boat's propellor. This guard is tapered toward substantially a point at the front end and is substantially circular at the rear end so as to encircle the region in which the propellor is rotated. The guard has a V-bracket at the front which is securely pressed against a propellor support and is supported at the rear in the circular portion by a pair of clamps which engage and are bolted tightly onto the cavitation plate.

Abstract: A propeller guard is provided with replaceable ribs that form a cage is placed around the propeller of an outboard marine propulsion unit. The ribs are suspended from a flat upper plate adapted to be bolted to a cavitation plate above the propeller. The ribs are maintained in spaced relation to each other around the propeller by the support plate and a longitudinally extending bottom bar bolted at one end to the skeg of the propulsion unit. In the event of damage to any of the ribs of the cage, the damaged rib can easily be replaced with a new one.

Abstract: In a marine drive (10), a propeller shroud is provided by a cage (24) having internal spoke structure (26, 28, 38, 40, 46, 48) and having retainer structure (50, 74) mounting the cage (24) to the gearcase (12) and engaging the gearcase (12) and driveshaft housing (11) in a particular manner such that impact force on the cage (24) is transmitted to(1) the junction of the lower skeg (20) and the torpedo-shaped portion (14) of the gearcase (12,)(2) the leading edge of the gearcase (12) at the front edge (31) of the strut portion (23) and the front edge (33) of the skeg (20),(3) the underside of the anti-ventilation plate (22), and(4) the rearwardly extending portion (52) of the driveshaft housing (11) above the anti-ventilation plate (22) and the splash plate (13).

Abstract: A portable personal floatation device for water sports such as fishing and the like is constructed of a light material such as styrofoam and has a horizontal main panel with an opening for a user to fit through so the floatation device surrounds the user. The device is designed to be easily accessible for the user, with a door provided on a side panel. The central opening in the main panel of the device accommodates the occupant to carry the device and wade into the water, and as the device begins to float, the occupant may sit on the main panel of the device.

Abstract: A propeller protector (26) is provided by a two piece hub structure (28, 30). Each piece has an inner arcuate portion (32, 34) substantially conforming to the side of the torpedo housing (14) of the marine drive. Each piece has a pair of fins (40 and 42, 44 and 46) extending radially outwardly from the inner arcuate portion and spaced axially forward of the propeller (20). Top rear, bottom rear and front clamps (48, 50 and 52) mount the two pieces (28 and 30) to the torpedo housing on opposite sides (36, 38) thereof.

Abstract: A self retracting screen for turbomachinery comprised of a number of interlocking wires, the wire ends being pivotally attached to the periphery of the normal inlet of the turbomachinery. Preferably, the wires are elliptical, or streamlined, in cross-section such that the major diameters of the elliptical cross-section of the wires when the screen is closed are substantially parallel to the turbomachinery inlet stream.

Abstract: An upper and a lower blade are fixed together at an adjustable angle and have means for mounting same on the leading edge of the propeller drive housing of an inboard/outboard motor to cut kelp and other seaweed which would otherwise foul the prop and clog the cool, sea water input vents. The cutter has adjustable brackets which will accommodate a wide variety of different types of propeller drive housings, and will accommodate outboard motors as well as inboard motors, and will even fit on the advance edge a sailboat keel. In one embodiment, it has a combination brace/mesh screen which extends from the cutter to the propeller drive housing in front of the cooling water inlets to keep bits of seaweed and other debris from entering and clogging the cooling system, causing overheating the destruction of the motor.

Abstract: A propeller guard includes a rigid U-shaped sleeve which has a pair of legs extending on either side of the lower housing in the motor. The cavitation plates on the lower housing are received within a U-shaped channel formed in the sleeve for mounting the guard upon the motor. A cylindrical shield having an open inlet end and an open outlet end is secured to the sleeve and encircles the propeller to protect the propeller from contact with foreign objects. A frame member extends downwardly from the forward edge of the sleeve to the lower portion of the inlet end of the shield and engages the leading edge of the lower housing to provide structural support for the guard. A plurality of horizontally disposed ribs extend from the frame member to the shield to further protect the propeller from contact with foreign objects. A gridwork is pivotally mounted over the open outlet end of the shield to further protect the propeller from contact with foreign objects.

Abstract: A vessel, in particular a ferry, intended for use in ice-filled waters, is provided with a propeller guard having the form of a rigid grid construction and being arranged to enclose one or several propellers acting in the front part of said vessel and/or below the keel line of said vessel. The width of the guard at its upper edge at the hull of the vessel is at least substantially equal to the greatest width of the guard. At its front end, the guard has an oblique front edge which, in a longitudinal section, is at least to its major part, inclined relative to a horizontal plane at the most 50.degree., preferably at the most 45.degree..

Abstract: The device comprises an assembly of three principal components, a member for embedding in the rear wall of a tabular iceberg at some depth below the water line, a support structure projecting therefrom and a propulsion unit. It preferably includes a shield to transmit the thrust to a sufficiently large surface of the iceberg wall to avoid creep problems. The propulsion unit may be an electric motor.