An aeration control system and method for a marine vessel. The system includes a valve configured to be coupled to an aeration conduit of a marine vessel. The valve is configured to be responsive to a valve control signal having a first value so as to be open and to provide air to the aeration conduit, and the valve configured to be responsive to the valve control signal having a second value so as to be closed and not provide air to the aeration conduit. The aeration control system also includes a control device, electrically coupled to the valve, that provides the valve control signal to the valve

One embodiment of submerged superventilated blades (101) that provide hydrodynamic force to a vessel or aircraft (117) that can lift it above the surface of the water (106) at high speed by creating thrust with a wetted high pressure surface (111), the low pressure surface (112) being covered with a gas filled void in the liquid, thus preventing sudden loss of lift as speed increases due to cavitation or surface venting. Other embodiments are described and shown.

An apparatus and method for use with a marine vessel having a first steerable propeller and a second steerable propeller is disclosed. The apparatus and method providing for movement of the first and second steerable propellers relative to each other and also maintains a minimum distance between the first and second steerable propellers so as to prevent the first and second steerable from contacting each other. Also disclosed is a control system and method to control the first steerable propeller and the second steerable propeller to provide the fixed distance between the first and second steerable propellers and so as to individually control the first steerable propeller and the second steerable propellers to allow the first steerable propeller and to the second steerable propeller to move relative to each other.

A lower unit for a marine propulsion device includes a gearcase housing defined along a longitudinal center axis between a fore end and an aft end. A propulsor shaft extends through the gearcase housing along the longitudinal axis. A driveshaft extends non-parallel to the propulsor shaft and rotates in a direction of rotation when powered by an engine. The driveshaft is coupled in torque-transmitting relationship with the propulsor shaft. A skeg projects from a bottom surface of the gearcase housing proximate at least the aft end thereof. The skeg or the gearcase housing is cambered such that a moment acting in a direction opposite the driveshaft's direction of rotation is induced on the skeg or the gearcase housing as the lower unit moves through water. A marine propulsion device is also disclosed.

One embodiment of submerged blades (101) that provide hydrodynamic force to a vessel or aircraft (117) that can lift it above the surface of the water (106) at high speed by creating thrust with a single wetted high pressure surface (111), the low pressure surface (112) being covered with a gas filled void in the liquid, thus preventing sudden loss of lift as speed increases due to cavitation or surface venting. Other embodiments are described and shown.

An improved boat and drive assembly intended for a boat used in a primary shallow water environment has a hull with an integrated closed internal engine heat exchanger and a drive assembly that includes a ring-within-a-ring steering mechanism and an obstacle resistant shoe plate. Stabilizer fins positioned above the shoe plate at a position forward of the spinning propeller allow air and water to exit from the rear of the stabilizer fins away from the spinning propeller. The heat exchanger assembly may include an axillary cooling tank and open heat dissipation system having a raw water reservoir continuously filled with raw water drawn directly from the waterway on which the boat is propelled to enhance the cooling capacity of the integrated internal engine heat exchanger.

An aeration control system and method for a marine vessel. The system includes a valve configured to he coupled to an aeration conduit of a marine vessel. The valve is configured to be responsive to a valve control signal having a first value so as to be open and to provide air to the aeration conduit, and the valve configured to be responsive to the valve control signal having a second value so as to be closed and not provide air to the aeration conduit. The aeration control system also includes a control device, electrically coupled to the valve, that provides the valve control signal to the valve

An apparatus and method for use with a marine vessel having a first steerable propeller and a second steerable propeller is disclosed. The apparatus and method providing for movement of the first and second steerable propellers relative to each other and also maintains a minimum distance between the first and second steerable propellers so as to prevent the first and second steerable from contacting each other. Also disclosed is a control system and method to control the first steerable propeller and the second steerable propeller to provide the fixed distance between the first and second steerable propellers and so as to individually control the first steerable propeller and the second steerable propellers to allow the first steerable propeller and the second steerable propeller to move relative to each other.

A propeller propulsion system for a watercraft includes at least one electric motor and a propeller which can be driven by the electric motor. The propeller is a surface piercing propeller. The propulsion system includes a box-like body having a side wall on which the electric motor is fixed and a cover part on which an outdrive of the surface piercing propeller is applied. The side wall and the cover part include holes through which a shaft of the motor and a shaft of the outdrive respectively pass. The box-like body includes means for transmission of motion from the drive shaft to the outdrive shaft, and the propulsion system includes means for fixing the box-like body to a transom of the watercraft.

An improved boat and drive assembly intended for a boat used in a primary shallow water environment has a hull with an integrated closed internal engine heat exchanger and a drive assembly that includes a ring-within-a-ring steering mechanism and an obstacle resistant shoe plate. Stabilizer fins positioned above the shoe plate at a position forward of the spinning propeller allow air and water to exit from the rear of the stabilizer fins away from the spinning propeller. The heat exchanger assembly may include an axillary cooling tank and open heat dissipation system having a raw water reservoir continuously filled with raw water drawn directly from the waterway on which the boat is propelled to enhance the cooling capacity of the integrated internal engine heat exchanger.