Abstract: A propeller shroud or nozzle, made with airfoil section of high lift to drag ratio, increases thrust, speed and efficiency of a fixed or controllable pitch propeller operating inside the shroud. Shroud section is designed with continuously curved inside and outside surface to create maximum lift and minimum drag. For the larger propellers used on ships, and for lower cost of construction, shroud is fabricated using plates of steel and stainless steel or other suitable material, built as a number of straight airfoil segments forming a polygon approximating circular ring. Low shroud drag makes possible improving thrust and speed of vessels, even when operating at high speed, compared to optimally designed propeller without the shroud.

Abstract: A steering device, particularly attractive for use with power driven boats, is in the general shape of a cylinder positioned aft, or rearwardly, of the propeller employed, and is arranged to direct the flow of the propelled water in the direction in which the boat is intended to be turned, so as to afford an improved handling of operation. In a preferred embodiment, the diameter of the cylinder is selected to encircle the propeller driving the power boat.

Abstract: A motorized propulsion device for swimmers and scuba divers which is to be attached to the user's forearms. The battery, motor, propeller and propeller shroud are arranged in a compact, linear, hydrodynamic manner. The watertight housing may have one or more integrally shaped nesting protuberances to comfortably accommodate the user's forearm and thereby prevent slippage. The front end surface of the housing has a control panel within reach of the user's fingers.

Abstract: A propeller assembly, a so-called rotatable thruster, for propelling, manoeuvering, steering and/or positioning a watercraft, floating docks, pontoons and in particular offshore platforms, includes a propeller (1) having an embracing propeller shroud (2) and mounted on a propeller shaft journalled in a gear housing (3). The gear housing accommodates a bevel gearing through which the propeller shaft is connected to a drive shaft extending through a tubular support strut (4), which is connected at its lower end to the gear housing in order to support the same. The upper end of the support strut is arranged to be rotatably mounted in an opening in a bottom part of the hull of the watercraft, with the propeller shaft extending substantially horizontally, so that the drive shaft can be connected to drive machinery located within the hull and such that the assembly can be rotated about a rotational axis coinciding with the axis of the drive shaft, by means of rotational machinery located within the hull.

Abstract: A thrust augmenter for a propeller fluid drive (11) comprising a hollow substantially cylindrical body (12) having an open rear face (15) which is part circular or circular and is located closely adjacent and ahead of the propeller (11) wherein the outside diameter of the rear face (15) is larger than the propeller (11).

Abstract: A propeller duct assembly for use on water craft which enhances the thrust of the propeller, increases fuel efficiency, stabilizes boat handling, serves as a safety factor for swimmers, and which also serves to protect the propeller against submerged objects.

Abstract: The location of azimuth thruster propellers at the parallel hulls of semisubmersible offshore vessels, is arranged so the water jet from a propeller at one hull, which is occasionally directed towards the adjacent hull will pass mainly below last-mentioned hull. When thruster propellers are arranged in pairs the bottoms of the hulls will preferably be inclined upwardly/outwardly within the portion around a thruster propeller located outside of a longitudinal middle plane through the hull. In order to facilitate the docking of the vessel, the bottom plating in the fore and aft bodies of the hulls, where the thruster propellers are mounted, should be raised sufficient to prevent the propellers projecting below the base lines of the hulls.

Abstract: A towline connected tug and LT at sea is rearranged as an articulatively integrated tow in sheltered waters to moor the LT or to make sternway in channels with a fair tide by a stern thrustor pivotally mounted to the transom of the LT or for a horizontal above water stowed position at sea.

Abstract: A seagoing vessel comprises a hull having a forwardly projecting bulb at its bow. The bulb includes an upper periphery oriented substantially horizontally and exposed above the water surface when the vessel is stationary and in a fully loaded condition. A pair of side skegs extend rearwardly from an underside of the vessel at the stern end. Propeller shafts extend through the side skegs. The side skegs and propeller shafts converge in a rearward direction. Each side skeg includes a planar outboard surface and a bulbous inboard surface, the latter inducing an outboard flow of water through a top segment of the associated propeller in a direction opposite the direction of propeller rotation. A center skeg extends between the side skeg and includes downwardly converging and rearwardly diverging sides which induce an outboard flow of water through a top segment of a respective propeller in a direction opposite the direction of propeller rotation.

Abstract: The marine vessel propeller has vanes or blades containing outer edges which are bounded by circularly domed outer surfaces which coact with a spherical zone of a spherical surface formed at the inner surface of the nozzle. The common central point of the spherical zone and of the circularly domed outer surfaces of the vanes or blades is located at the intersection point of the vane axes and about each of which vane axis the related propeller vane or blade is pivotable. The intersection point of such vane axes is located on the propeller axis.

Abstract: A marine vessel propulsion assembly includes at least one propeller nozzle unit having a rudder associated with it. The propeller nozzle unit has a shroud laterally surrounding the propeller and the shroud is supported so that it can be pivoted about two different axes each extending transversely of the flow direction. In the desired angular position, the shroud can be locked in position. The two pivot axes of the shroud extend perpendicular to one another. The shroud is connected to a shaft extending in the direction of one of the pivot axes and the shaft can be interlocked with shaft guide means. The shroud and the rudder each include the same angle of pitch of at least two degrees relative to the propeller shaft.

Abstract: A propeller mount for deflecting ice away from the propeller of an icebreaker includes a wedge-shaped body, the front end of which is pointed, and the remainder of which flares rearwardly to direct ice outwardly away from the propeller assembly. By providing bubblers in the sides of the body near the front end thereof, outward deflection of ice by the mount is promoted. The rear of the body is also slightly wedge-shaped to provide a similr wedging action at the stern for steering ice away from propellers.

Abstract: Propulsion unit for a marine vessel intended for operation under severe ice conditions comprises a multi-bladed propeller, which may be of fixed or controllable pitch, a stationary duct, which may take the form of a nozzle, within which the propeller runs and is protected peripherally against ice damage, and, at the forward and aft ends of the duct, water-guide members in the form of vanes and/or blades which are more massive than is required by their water-guiding functions and which restrict the size of ice masses that can encounter the propeller by entering the duct at its opposing ends. The duct may embrace the propeller peripherally around the full 360.degree.. The water-guide members may be secured at their outer ends to the duct and at their inner ends to ring members co-axial with the propeller. The upper quadrant of the duct may be secured to the hull of the vessel and the lowest portion of the duct to a skeg extending beneath the duct.

Abstract: Propulsion apparatus for an undersea vehicle comprises a pair of counter-ating low speed impellers driven from a spider shaft rotating at relatively high speed. The reduction is accomplished by a variable speed reducing and torque transmitting device which allows infinite resolution for speed control including a zero speed setting while maintaining a constant high speed at the input spider shaft. Attitude of the vehicle is controlled by a plurality of regulated inlet ports and roll control is regulated by increasing the speed of one impeller and decreasing the speed of the other. The sea water utilized for the attitude is also used for propulsion. Control systems within the vehicle utilize an electro-pneumatic-hydraulic system complex.

Abstract: The present invention relates to a ship with structural improvements which prevent factors causing an increase in the horsepower required for propulsion or an increase in propeller cavitation, hull vibration and noise, all of which result from the water turbulence and nonuniformity of flow field along the stern caused by corpulence of ship, and the present invention provides such a ship with a structural improvement comprising having a ring-shaped construction directly attached to the hull on each of the ship's stern and in front of the propeller.

Abstract: The marine propulsion device includes a lower unit normally submerged in water, a propeller carried by the lower unit, and an annular shroud surrounding the propeller blades and defining a passageway through which water flows. The shroud, which can be in the form of a Kort-type nozzle for augmenting propeller thrust, has a trailing edge located rearwardly of the travel path of the propeller blade tips. The trailing edge of the shroud includes an annular recess through which either engine exhaust gases or atmospheric air is delivered to ventilate the low pressure area created behind the trailing edge of the shroud during forward movement of the lower unit through water.

Abstract: A tubular duct is provided for ship propellers with blade tips having barrier plates extending transversely therefrom. The tubular ducts are effectively arranged to extend the barrier plates in a manner which, in operation, directs a fluid stream in substantially shock-free contact with such plates.