The present invention involves a method for manufacturing a blade (1) for a propeller, which blade (1) has a leading edge (2) and a trailing edge, the method comprising the steps of: forming a conduit in the blade (1), making a plurality of holes (7) through which the conduit (6) communicates with the exterior of the blade (1), and providing a blade blank having an edge part receiving surface (4) extending along at least a major part of the leading edge (2) of the blade (1) to be manufactured, wherein forming a conduit (6) comprises building up an edge part (3) onto the edge part receiving surface (4) by a wire-based additive manufacturing process, wherein the additive manufacturing process is adapted to form the conduit (6) at least partly delimited by the edge part (3) and extending along the leading edge (2) of the blade (1) to be manufactured.

A propulsion system for a marine vessel in a body of water includes an water intake formed in the hull, a impeller disc rotatable about a vertical axis for raising water and increasing the momentum of water in a plenum chamber, and a plurality of control gates located around the periphery of the hull. The impeller disc has a large outer diameter and is formed to enable efficient rotation by an electric motor. One or more of the water intake, the plenum chamber, the impeller disc and the control gates is designed to reduce acoustic noise generated by the marine vessel, direct the acoustic noise to avoid broadband acoustic noise, increase efficiency of the propulsion system and provide additional safety to passengers on the marine vessel and marine life in the body of water.

A propulsion system for a marine vessel in a body of water includes an water intake formed in the hull, a impeller disc rotatable about a vertical axis for raising water and increasing the momentum of water in a plenum chamber, and a plurality of control gates located around the periphery of the hull. The impeller disc has a large outer diameter and is formed to enable efficient rotation by an electric motor. One or more of the water intake, the plenum chamber, the impeller disc and the control gates is designed to reduce acoustic noise generated by the marine vessel, direct the acoustic noise to avoid broadband acoustic noise, increase efficiency of the propulsion system and provide additional safety to passengers on the marine vessel and marine life in the body of water.

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

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.

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 outboard motor includes a drive shaft extending vertically from an engine and is rotated by the engine. An upper case covers the drive shaft. A propeller shaft extends perpendicularly or substantially perpendicularly to the drive shaft. A lower case covers the propeller shaft. A front handle is disposed forward of the drive shaft and below an engine cover. A rear handle is disposed rearward of the drive shaft and below the engine cover. The rear handle is disposed in a position lower than a position of the front handle.

An outboard motor includes a drive shaft extending vertically from an engine and is rotated by the engine. An upper case covers the drive shaft. A propeller shaft extends perpendicularly or substantially perpendicularly to the drive shaft. A lower case covers the propeller shaft. A front handle is disposed forward of the drive shaft and below an engine cover. A rear handle is disposed rearward of the drive shaft and below the engine cover. The rear handle is disposed in a position lower than a position of the front handle.

A marine propeller has an outer hub having a central axis and a blade having a blade root attached to the outer hub and extending radially outward from the outer hub toward a blade tip. The blade has a leading edge and a trailing edge. The propeller has a diameter between about 15 inches and about 17 inches and a pitch between about 14 inches and about 24 inches. The blade has a progressive rake angle such that a first local rake angle at the blade root is less than a second local rake angle at the blade tip. A combination of the diameter, pitch, and progressive rake angle provides a marine vessel to which the marine propeller is coupled with minimum drag while the marine vessel is operating at less than a maximum vessel speed. A method of designing a propeller is also disclosed.