A convertible ducted fan engine and mounting system. The convertible ducted fan engine has a shroud encircling a mechanical fan. The convertible ducted fan engine includes a fluid-propulsion configuration in which the mechanical fan rotates freely with respect to the shroud to produce thrust through fluid flow, and a drive-wheel configuration in which the shroud rotates about the rotational axis. The mounting system includes at least one gimbal ring and may include a circular track system thereby enabling the convertible engine to be oriented in any direction.

A directed thrust propulsion system has a central hub and at least three blades that extends outward at a rake angle between about 20 to 70 degrees. Each blade is shaped as a portion of a cylindrical surface, in which concave side forms the blade face and is facing in direction of thrust generated by rotating the hub. The convex side of the blades minimizes drag in the water that resists forward motion while the concave shape and tilted end portions directs the thrust inward toward the extension of the hub's principal axis rearward. The directed thrust propulsion system may be deployed on inboard and outboard motors for all manner of watercraft to increase efficiency above 10 knots speed.

One or more propulsion arrangements for water vessels, and in particular propulsion arrangements that include flanking rudders with bidirectional high-lift sections to improve performance, particularly in the reverse direction. The flanking rudders are positioned adjacent a propulsor for directing a slipstream flow when the vessel is travelling in the reverse direction. Each flanking rudder has an elongated profile extending from a first edge to a second edge, and in which each elongated profile has a first bulb portion, a convex middle portion, and a second bulb portion.

Propulsion unit (11) for propulsion and maneuvering of a maritime vessel, which includes a nozzle (12) exhibiting a curved following edge (12) at outlet of the nozzle (12), which results in that length of the nozzle (12) is longer in upper part of the nozzle (12) and shortest at the outermost points of a horizontal central axis through the nozzle (12), when the nozzle (12) is seen from behind.

Propulsion unit (11) for propulsion and maneuvering of a maritime vessel, which includes a nozzle (12) exhibiting a curved following edge (12) at outlet of the nozzle (12), which results in that length of the nozzle (12) is longer in upper part of the nozzle (12) and shortest at the outermost points of a horizontal central axis through the nozzle (12), when the nozzle (12) is seen from behind.

To provide a gate rudder capable of reducing energy consumption during a voyage of a ship.

A gate rudder including a pair of rudders including a left rudder and a right rudder disposed left and right, respectively, of a propeller at a stern, wherein each of the rudders includes a first rudder portion extending in a horizontal direction and a second rudder portion linearly extending in a vertical direction in rear view, wherein a rudder chord length of the second rudder portion in a front-rear direction is 40 to 100% of a diameter of the propeller, wherein the propeller is provided within a range of 15 to 65% of the rudder chord length from a front edge of the second rudder portion in side view, and wherein a rudder shaft that drives each of the rudders is provided at a position within a range of 30 to 50% of the rudder chord length from the front edge of the second rudder portion in side view.

A support strut has an upper end rotatable supported at a bottom of a vessel and a lower end supporting a casing. A first electric motor within the casing drives a propeller via a first shaft. An annular nozzle surrounds an outer perimeter of the propeller and is fixedly supported on the casing, with a support construction comprising at least three vanes extending in the radial direction between the outer perimeter of the casing and the inner perimeter of the nozzle. A duct for water flow is formed through the interior of the annular nozzle. The propeller pulls the vessel in a driving direction. The vanes are positioned after the propeller in the driving direction of the vessel, whereby the vanes are optimized for redirecting rotational flow components of the flow produced by the propeller into axial thrust.

A support strut has an upper end rotatable supported at a bottom of a vessel and a lower end supporting a casing. A first electric motor within the casing drives a propeller via a first shaft. An annular nozzle surrounds an outer perimeter of the propeller and is fixedly supported on the casing, with a support construction comprising at least three vanes extending in the radial direction between the outer perimeter of the casing and the inner perimeter of the nozzle. A duct for water flow is formed through the interior of the annular nozzle. The propeller pulls the vessel in a driving direction. The vanes are positioned after the propeller in the driving direction of the vessel, whereby the vanes are optimized for redirecting rotational flow components of the flow produced by the propeller into axial thrust.

An accelerating ducted propeller system for propelling boats offers enhanced performance, having the front end of the nozzle disposed at a radial distance (H) between 0.045D and 0.082D from the inner radius of the nozzle, where D is the inner diameter of the nozzle. The front end of the chord of the axial profile of the nozzle has a larger radius than the rear end of the chord with respect to the axis of rotation of the propeller. The inner surface of the nozzle at the axial distance (J) of 0.025D from the rear end of the output edge of the nozzle is at a radial distance from the inner radius of the nozzle of more than 0.0040D and less than 0.0300D. The radial difference between the inner radius of the nozzle and the outer radius of the profile of the nozzle is less than 0.092D.

An accelerating ducted propeller system for propelling boats offers enhanced performance, having the front end of the nozzle disposed at a radial distance (H) between 0.045D and 0.082D from the inner radius of the nozzle, where D is the inner diameter of the nozzle. The front end of the chord of the axial profile of the nozzle has a larger radius than the rear end of the chord with respect to the axis of rotation of the propeller. The inner surface of the nozzle at the axial distance (J) of 0.025D from the rear end of the output edge of the nozzle is at a radial distance from the inner radius of the nozzle of more than 0.0040D and less than 0.0300D. The radial difference between the inner radius of the nozzle and the outer radius of the profile of the nozzle is less than 0.092D.