A portable propulsion system for a watercraft may include a shaft, a propeller, an outer casing, and a flexible strap. The shaft may have a prop end section, a drive end section, and a rotational axis extending from the prop end section to the drive end section. The propeller may be connected to the prop end section of the shaft. The drive end section may be configured for removable connection to a driver for rotation of the propeller via rotation of the shaft about the rotational axis to propel the watercraft. The outer casing may be disposed around the shaft. The flexible strap may have first and second end sections connected to the outer casing in respective first and second regions.

A marine propulsion system for shallow waters, swamps, savannahs and the like includes a rotating propeller shaft supporting a propeller. An anti-cavitation body defines a partial cylinder having a longitudinal axis adjacent to the propeller. The propeller generates a vacuum between the anti-cavitation body and a surface of a water body. First and second wings adjacent to edges of the anti-cavitation body are generally planar and operatively angled towards the bottom of a water body. The first and second wings are adjusted to run below the water body surface and seal the anti-cavitation body to maintain generated vacuum. A first thread is cut in a first helical direction at an end of the rotating propeller shaft adjacent the propeller, and slightly more distal therefrom a second thread is cut in a second helical direction opposed to the first thread helical direction. The second thread drives matter away from the bearing.

A marine propulsion system includes a water intake guide block with a flow guide passage, a propulsion device including a housing connected to the water intake guide block and a propeller mounted in the housing, a fixed nozzle connected to the housing of the propulsion device, a swinging nozzle connected to the fixed nozzle and biasable leftward and rightward relative to the fixed nozzle, and a contra type bossing pivotally connected to the fixed nozzle and biasable up and down relative to the fixed nozzle. When rotating the propeller, water is sucked into the flow guide passage and propelled by the propeller to eject backward through the fixed nozzle, and the swinging nozzle is biased leftward/rightward to control leftward/rightward turning of the boat, and the contra type bossing is biased upward/downward to control the pitch angle of the boat and forward/backward movement of the boat.

A propeller guard including inner circumferential component defining a multi-angled band formed of a plurality of independently radiused sections and an outer fluid amplifier extending along sides of the inner circumferential component. The band may also include a plurality of evenly spaced ports therethrough. The propeller guard is designed to improve the performance characteristics, specifically acceleration, planing, speed and steering, of the motor. The outer fluid amplifier increases flow of fluid through the ports of the inner circumferential component and further improves performance characteristics of the boat and motor to which the propeller guard is attached.

A portable propulsion system for a watercraft may include a shaft, a propeller, an outer casing, and a flexible strap. The shaft may have a prop end section, a drive end section, and a rotational axis extending from the prop end section to the drive end section. The propeller may be connected to the prop end section of the shaft. The drive end section may be configured for removable connection to a driver for rotation of the propeller via rotation of the shaft about the rotational axis to propel the watercraft. The outer casing may be disposed around the shaft. The flexible strap may have first and second end sections connected to the outer casing in respective first and second regions.

A propeller guard including inner circumferential component defining a multi-angled band formed of a plurality of independently radiused sections and an outer fluid amplifier extending along sides of the inner circumferential component. The band may also include a plurality of evenly spaced ports therethrough. The propeller guard is designed to improve the performance characteristics, specifically acceleration, planing, speed and steering, of the motor. The outer fluid amplifier increases flow of fluid through the ports of the inner circumferential component and further improves performance characteristics of the boat and motor to which the propeller guard is attached.

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.

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.

The presently disclosed subject matter is directed to an adaptor that can be used to eliminate the gap present between the motor housing and the propeller in conventional trolling motors. Particularly, the disclosed adaptor comprises a first shell and a second shell that attach together and surround the base of the trolling motor propeller therebetween. As shown, the propeller blades extend from one or more apertures in the adaptor. The adaptor attaches to the trailing end of the motor housing and is maintained on the drive shaft through the use of one or more fasteners.

An outboard drive assembly for a work boat is provided. In embodiments, an outboard drive assembly includes a lower outdrive assembly including: a housing extending between a first and end a second end and having a motor housed therein; a propeller mounted to the first end of the housing; first and second fins extending horizontally from opposing side portions of the motor housing; a third fin extending vertically from the housing; respective cutting blades attached to respective end portions of each of the first, second and third fins adjacent the propeller; an upper outdrive assembly including mounting brackets configure to connect the upper drive assembly to a deck of a work boat; and a drive arm assembly pivotally mounted to the lower outdrive assembly at a first end of the drive arm assembly and mounted to the upper outdrive assembly at a second end of the drive arm assembly.