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.

An autonomous water vehicle for moving above the water surface, part of the device being under water and part being lifted above the water surface. The water vehicle includes an underwater propulsion module, an upper platform and a vertical support, a power source and an electronic control unit. The propulsion module has a housing in which at least two propeller groups are preferably mounted, including electric motors and water screw propellers with two to five blades, such as the propeller groups are arranged symmetrically with respect to the central vertical axis of the housing and are designed to generate vertical thrust for lifting the upper platform plus maximum payload above the water surface. The rotational axes of the propeller groups are arranged vertically or at an angle to the central vertical axis of the housing.

An autonomous water vehicle for moving above the water surface, part of the device being under water and part being lifted above the water surface. The water vehicle includes an underwater propulsion module, an upper platform and a vertical support, a power source and an electronic control unit. The propulsion module has a housing in which at least two propeller groups are preferably mounted, including electric motors and water screw propellers with two to five blades, such as the propeller groups are arranged symmetrically with respect to the central vertical axis of the housing and are designed to generate vertical thrust for lifting the upper platform plus maximum payload above the water surface. The rotational axes of the propeller groups are arranged vertically or at an angle to the central vertical axis of the housing.

A marine propulsion system having a steering axis that allows pivoting of propellers along a first vertical axis directly beneath a gear box located inside the hull of a boat. A lower gear box can be placed within a vented or non-vented tunnel eliminating the need for a rudder and providing directional control of the boat by the orientation of the lower gear box. Surface piercing propellers and/or counter-rotating propellers may be used with the propellers pivoted around the vertical axis of the gear box. The offset steering axis allows pivoting around the first vertical axis wherein a secondary axis is moved with minimal drag providing superior maneuverability at both high and low speeds.

In a marine vessel, a propulsion system comprises at least one propeller having a direction of rotation about a drive shaft and a bulbus protrusion extending from the hull associated with each of the at least one propeller, each protrusion extending from the hull of the vessel, each protrusion receiving and rotatably supporting the at least one propeller. Each protrusion extends between leading and trailing ends and has a substantially circular cross section along a length between the leading and trailing ends having and a leading portion extending from the leading end wherein the leading portion is angled away from the centerline of the hull.

Invention relates to a thruster assembly for a marine vessel including a body including a duct having a longitudinal axis, and a first end and a second end, a support structure for a propeller including a propeller shaft at a centre line of the duct, a propeller, positioned into the duct and being attached to the propeller shaft, wherein the propeller including at least three blades and a boss which is supported to the shaft, and further a circular rim to which radial ends of the propeller blades are attached, wherein a circumferential slot is provided, opening inside the duct between the first end and the second end, into which slot the circular rim is arranged to extend radially, and at least one gas inlet arranged to open into the slot. Invention relates also to a transverse tunnel thruster and a steerable azimuthing thruster provided with the thruster assembly.

Invention relates to a thruster assembly for a marine vessel including a body including a duct having a longitudinal axis, and a first end and a second end, a support structure for a propeller including a propeller shaft at a centre line of the duct, a propeller, positioned into the duct and being attached to the propeller shaft, wherein the propeller including at least three blades and a boss which is supported to the shaft, and further a circular rim to which radial ends of the propeller blades are attached, wherein a circumferential slot is provided, opening inside the duct between the first end and the second end, into which slot the circular rim is arranged to extend radially, and at least one gas inlet arranged to open into the slot. Invention relates also to a transverse tunnel thruster and a steerable azimuthing thruster provided with the thruster assembly.

A watercraft propulsion system includes a bow thruster at a bow of a hull to generate a lateral propulsive force, at least two propulsion devices on a stern of the hull each having a variable steering angle, and a controller configured or programmed to control the propulsive force of the bow thruster and control the propulsive forces and the steering angles of the two propulsion devices to perform an azimuth control to control an azimuth of the hull. The azimuth control includes a bow thruster mode in which the bow thruster is controlled, and a combinational mode in which the bow thruster is controlled and the two propulsion devices are driven forward and in reverse, respectively. The controller switches between the bow thruster mode and the combinational mode based on a predetermined switching condition during the azimuth control.