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 is angled away from the centerline of the hull.

A thruster system for a marine vessel includes an electric motor having an output shaft. The thruster system also includes a housing having a first housing opening and a second housing opening, the first housing opening defining a water intake, the second housing opening defining a water discharge. The thruster system further includes a rotatable member operatively coupled to, and driven by, the output shaft of the electric motor, wherein rotation of the rotatable member results in water brought into the housing through the first housing opening and expelled through the second housing opening to generate a thrust force in a direction that is greater than 45 degrees relative to a propeller direction of the marine vessel.

In order to provide an arrangement with at least one rudder and with at least one accommodating space for a propeller, which accommodating space is formed in the direction of travel of the watercraft in front of the rudder and allows for a reduction of a propulsion power requirement of a watercraft with such an arrangement, it is proposed that, in the direction of travel in front of the accommodating space of the propeller, at least one pre-nozzle comprising at least one guide surface and at least one side fin is arranged on the rudder.

In order to provide an arrangement with at least one rudder and with at least one accommodating space for a propeller, which accommodating space is formed in the direction of travel of the watercraft in front of the rudder and allows for a reduction of a propulsion power requirement of a watercraft with such an arrangement, it is proposed that, in the direction of travel in front of the accommodating space of the propeller, at least one pre-nozzle comprising at least one guide surface and at least one side fin is arranged on the rudder.

Embodiments of the present invention are directed to devices adapted to enhance propulsion (i.e., propulsion enhancing devices) of watercraft such as, for example, personal watercraft and the like. To this end, a propulsion enhancing device in accordance with the disclosures made herein may be attached to or integral with (e.g., formed unitarily with a housing thereof) a propulsion unit of a watercraft. The propulsion unit generates a stream of water that provides for propulsion of the watercraft. A propulsion enhancing device in accordance with the disclosures made herein includes internal structures that enhance velocity and/or volumetric attributes of a stream of water generated by the propulsion unit by transforming non rotational flow at the inlet of the propulsion enhancing device to rotational flow at the outlet of the propulsion enhancing device.

What is provided is a propeller guard apparatus that may be readily configured to a variety of different boat motors. Described embodiments of the propeller guard apparatus comprise a cylindrical housing configured to circumferentially enclose a propeller from all sides in order to protect humans, pets, and aquatic wildlife from being entangled or cut by the propeller. Described embodiments of the propeller guard apparatus also comprise a protective structure, such as a skid plate comprising of at least two pieces of metal attached from the cylindrical housing to an end of the outer casing to form a folded T-shaped configuration. This type of configuration serves to protect the propeller from damage caused by submerged objects and aquatic wildlife found in shallow water. Also, the folded T-shaped configuration may push vegetation, weeds, manatees, and other aquatic wildlife away from the path of the moving boat and its propeller.

A protective device for a stern tube seal of a propeller-driven vessel, wherein an intermediate space is left open between a stern tube and a propeller hub, which intermediate space is covered by a tubular protective cover concentric with the propeller hub, which protective cover is fixedly anchored to the stern tube and axially overlies the propeller hub leaving an annular gap, wherein a ring concentric with the propeller hub and U-shaped in radial section is disposed inside the protective cover in the intermediate space between the stern tube and the propeller hub, the U-opening of which ring is directed radially outward, and wherein the ring is at least partially formed of a material that has a pourable consistency at 20° C.

The invention relates to an arrangement for multi screw vessels, in particular twin screw vessels, with external propeller shafts, as well as to a method for producing such an arrangement. The arrangement according to the invention is in particular suitable for a drive system of an above-mentioned multi screw vessel and to improve the energy efficiency thereof.

The invention relates to an arrangement for multi screw vessels, in particular twin screw vessels, with external propeller shafts, as well as to a method for producing such an arrangement. The arrangement according to the invention is in particular suitable for a drive system of an above-mentioned multi screw vessel and to improve the energy efficiency thereof.

A cutting device for coupling to a water vessel propelling device. The cutting device comprises a base extending between a proximal end and a distal end and is coupled to a shaft of the water vessel propelling device. An upper arm is coupled to the base. A lower arm is coupled to the base. A track extends along the base. A blade slidably engages within the track for displacing between the upper arm and the lower arm. An actuator displaces the blade relative to the track. A cutting edge is on the blade for severing a foreign object that is positioned between the upper arm and the lower arm of the base.