Abstract: A vortex generating exhaust component is installed in-line within a marine exhaust system downstream of the water can whereby a mixture of hot exhaust gas and entrained cooling water flows there through and vortex flow is enhanced by the component to increase cooling of exhaust gas by increasing the mixing of hot exhaust gas with entrained cooling water thereby resulting in enhanced exhaust gas cooling.

Abstract: An outboard motor includes an oil passage that through which an oil flows from the shift chamber to a gear chamber. A circular recessed portion is formed on an upper surface of the gear chamber. A rectangular recessed portion communicating with the circular recessed portion is formed on a portion of the upper surface adjacent to the circular recessed portion. The rectangular recessed portion includes a front surface facing a side surface of the circular recessed portion, a left surface located on a reverse side of a rotation direction of the drive gear with respect to the front surface, and a right surface located on a side of the rotation direction with respect to the front surface. An outlet of the oil passage is arranged on the front surface at a position closer to the left surface than to the right surface.

Abstract: A sea scooter has a main housing, a left arm pivotably attached to the left side of the main housing, a right arm pivotably attached to the right side of the main housing, a left barrel secured to the left arm, and a right barrel secured to the right arm. Each barrel has a fan and a motor for propelling the sea scooter through water. The left and right arms are locked by the first and second locking assemblies into a folded configuration against the left and right sides of the main housing when the sea scooter is not in use, and the left and right arms are pivoted away from the left and right sides of the main housing in a use configuration when the sea scooter is in use in the water. The motor is sand-proof and water-proof.

Abstract: A propeller device has a propeller hub which is elongated along the rotational axis and a propeller blade which radially extends from the propeller hub. The propeller hub and propeller blade are configured so that when the propeller device is forwardly rotated, a first portion of the propeller hub on a first side of the propeller blade encounters a positive pressure and a second portion of the propeller hub on an opposite, second side of the blade encounters a relatively lower pressure or suction, and further so that when the propeller device is reversely rotated, the second portion of the propeller hub encounters a positive pressure and the first portion of the propeller hub encounters a relatively lower pressure or suction. An exhaust vent hole is located in the first portion of the propeller hub and configured to vent exhaust gases from the marine drive via the propeller hub as the propeller device is reversely rotated, thereby enhancing reverse thrust performance of the propeller device.

Abstract: A circumferential locking mechanism, a battery securing device comprising same, a battery pack, and a vehicle are provided.

Abstract: A shock detector for determining the existence of a voltage gradient in a body of water, which may be remote from a structure and providing an alarm when the voltage gradient is a hazardous electrical condition that could injure or kill a person coming into contact with the body of water.

Abstract: In one embodiment of the invention, a robotic surgical system includes a combined laser imaging robotic surgical tool, a control console, and a laser generator/controller. The tool is mounted to a first robotic arm of a patient side cart. The tool has a wristed joint and an end effector coupled together. The end effector has a laser-emitting device to direct a laser beam onto tissue in a surgical site and an image-capturing device to capture images of the tissue in the surgical site. The control console, in communication with the tool, receives the captured images of tissue in the surgical site and displays the captured images on a display device to a user. The laser generator/controller is coupled to the tool and the control console to control the emission of the laser beam onto tissue of the surgical site.

Abstract: The present disclosure relates to a guiding arrangement for a retractable thruster assembly. The guiding arrangement may comprise a foundation plate, a first upper guide, a second upper guide, a first lower guide, and a second lower guide. The first lower guide and the second upper guide may be arranged such that an arc angle within the range from 25° to 75° is confined therebetween. Thus, flexibility regarding the implementation of the retractable thruster assembly as L-drive or Z-drive may be gained.

Abstract: A portable propulsion system for a watercraft may include a shaft, a propeller, an outer casing, and a flexible strap. The shaft may have a prop end section, a drive end section, and a rotational axis extending from the prop end section to the drive end section. The propeller may be connected to the prop end section of the shaft. The drive end section may be configured for removable connection to a driver for rotation of the propeller via rotation of the shaft about the rotational axis to propel the watercraft. The outer casing may be disposed around the shaft. The flexible strap may have first and second end sections connected to the outer casing in respective first and second regions.

Abstract: A novel retractable thruster unit for a marine vessel using a tunnel thruster includes a nozzle having an end, the end being provided with two closing plates, a top closing plate, and a bottom closing plate. The closing plates are arranged 180 degrees apart on opposite sides of the axis of the propeller and extend substantially axially from the end of the nozzle.

Abstract: A propulsion device of the ship includes a port side screw propeller; and a starboard side screw propeller provided in a forward or backward direction in a longitudinal direction of the ship from the port side screw propeller, such that a part of propeller wings of the starboard side screw propeller overlaps with propeller wings of the port side screw propeller. One of the port side screw propeller and the starboard side screw propeller, which is on a forward side in a longitudinal direction of the ship, is the forward screw propeller, and the other is the backward screw propeller. The forward screw propeller has a wing shape by which tip vortex cavitation is more difficult to be generated by the forward screw propeller than the backward screw propeller.

Abstract: Weed-trimmer outboard motor attachment has a lower shaft housing with a proximal coupling to correspondingly mate and engage a distal mid-shaft coupling of an upper part of a motorized weed-trimming device having a motor and a shaft that rotate a number of rotations per minute when operating; a distal termination thereto, which includes a propeller; and a rotation speed reduction unit to reduce a number of rotations of the propeller in relation to the number of rotations of the motor of the motorized weed-trimming device. The attachment can be assembled with the weed-trimming device to provide an outboard motor. A mount for mounting the weed-trimmer outboard motor to a boat can be provided as well.

Abstract: A buoyant structure having a hull, a planar keel defining a lower hull diameter, a lower cylindrical portion connected to the planar keel, a lower frustoconical portion disposed above the lower cylindrical portion with inwardly sloping wall at a first angle, an upper frustoconical portion directly connected to the lower frustoconical portion, and the upper frustoconical portion with outwardly sloping wall, the inwardly sloping wall abutting the outwardly sloping wall forming a hull neck with a hull neck diameter. The buoyant structure having a main deck, a moon pool, and propellers attached to the planar keel, which are operated by a motor or a generator. The buoyant structure connects over a chambered buoyant storage ring.

Abstract: A portable propelling system including a driver removably coupled to a drive end portion of a shaft, and a propeller connected to a prop end portion of the shaft. The shaft may extend through an outer casing. The driver may be configured to rotate the shaft and the propeller about a rotational axis of the shaft relative to the outer casing. One or more water-buoyant components, such as one or more sections of polymeric closed-cell foam, may be disposed around the outer casing. A flexible strap may be coupled to the outer casing. A first end portion of the flexible strap may be operable between a connected position and a towing position. The system may be a telescoping system operable between collapsed and extended positions along the rotational axis.

Abstract: A collapsible and disconnectible for storage yet extending for use emergency motor drive unit for a boat. A motor is secured to a hollow drive-shaft pipe segment. Another pipe segment is attached to the end of that pipe segment and has a propeller at its end. A drive shaft of the motor is coupled to the propeller by flexible tubing passing through the hollow bores of the pipe segments. A third, and possibly fourth and fifth, pipe segment(s) is(are) provided between the other two segments to extend the length of the overall device. At least one pipe segment has a vertical support post which allows the device to be selectively held in the receptacle of an anchor light receptacle, when needed. A clamp block and ball swivel allow for rotational, lengthwise, and angular movement of the pipe segments to adjust the motor and the propeller to maximize efficiency of use.

Abstract: A marine vessel comprising: a command module; first and second buoyant tubular foils; and first and second struts for connecting the first and second buoyant tubular foils to the command module, respectively; wherein the first and second buoyant tubular foils provide substantially all of the buoyancy required for the marine vessel; and wherein the marine vessel further comprises first and second engines enclosed within the first and second buoyant tubular foils, respectively, and first and second propulsion units connected to the first and second engines, respectively, for moving the marine vessel through the water.

Abstract: A propeller having a hub with a shaft hole at the center thereof, and a number of blades provided radially around the hub; a shaft connected at one end to a motor driving the marine vehicle, the shaft being adapted to the shaft hole, and having a threaded portion arranged at least partially in the longitudinal direction thereof; at least one bearing provided on the shaft for bearing the propeller to the shaft, the at least one bearing being rotatable in a single direction; a connection hub associated with the hub of the propeller, the connection hub comprising a threaded portion being screwable to the threaded portion of the shaft in the direction opposite to the rotatable direction of the at least one bearing, and being non-screwable to the threaded portion of the shaft in the rotatable direction of the at least one bearing.

Abstract: A wakesurfing boat includes a hull. A bottom of the hull defines a W-shape in cross-section, the W-shape including a central inverted V-shaped portion. A ballast system includes a plurality of sets of ballast tanks. The boat has a plurality of modes: a cruising mode with ballast tanks empty, a first portion of the bottom in contact with the water, a stern-down trim ?1; a ballasted static mode with ballast tanks filled with ballast water, the hull displacing more water, a larger portion of the bottom in contact with the water, a bow-down trim ?2; and a dynamic surfing mode with ballast tanks filled with ballast water, an intermediate portion of the bottom in contact with the water, and an intermediate trim ?3. A wake wave, generated in the dynamic surfing mode is larger than a wake wave generated in the cruising mode.

Abstract: An attachment assembly quickly and securely mounts an outboard motor on a boat transom. Side frame members are disposed in a laterally spaced-apart relationship by two interconnected lateral frame members. A laterally extending cam member is rotatably connected to the side frame members and laterally extends the length between the side frame members. A cam rotating mechanism is connected to the cam member to selectively impart its rotational displacement and a lateral inverted-U-shaped transom channel is formed in the side frame members and is disposed adjacent to the cam member. The rotational displacement of the cam member effects an outward displacement of an outer surface of the cam member into the inverted-U-shaped transom channel to compressively engage and secure a transom by the cam member across the entire width of the motor.

Abstract: A propulsion device of the ship includes a port side screw propeller; and a starboard side screw propeller provided in a forward or backward direction in a longitudinal direction of the ship from the port side screw propeller, such that a part of propeller wings of the starboard side screw propeller overlaps with propeller wings of the port side screw propeller. One of the port side screw propeller and the starboard side screw propeller, which is on a forward side in a longitudinal direction of the ship, is the forward screw propeller, and the other is the backward screw propeller. The forward screw propeller has a wing shape by which tip vortex cavitation is more difficult to be generated by the forward screw propeller than the backward screw propeller.

Abstract: A marine propulsion assembly comprises or consists of a marine engine, a pair of parallel laterally spaced propeller shafts and a pair of marine propellers with one of the propeller fixed to each of the shafts for rotation. Each of the propellers includes a hub and four equally spaced blades and wherein the hub has a forward portion having the shape of a frustum of a cone with a decreasing radius from a forward edge thereof to the middle of the hub and a rear or second continuous portion having the shape of a frustum of a cone with an increasing radius from the middle of the hub to the rear of the hub. The bases or larger ends of the frustums are of equal size as are the tops of the frustums. In addition, each of the blades has a complex concave shape.

Abstract: An underwater propulsion device includes a number of modules allowing it to be used in a range of configurations including a tow/pull type scooter 300, a thigh strap configuration 700, a calf strap configuration 1100, a push configuration 1200, a tank mount configuration 1300. The device may include an underwater changeable battery canister 1600, a hand controller 216 that senses movement about the radius bone to generate direction and speed control signals and/or a front mounted headlight 224.

Abstract: The invention relates to a method for improving the propulsion efficiency of vessels. The improvement is obtained by utilizing wave induced variations in propeller inflow, i.e. the speed of water flowing towards the propeller. The wave induced water speed variation is used to calculate the propeller speed in a way so that the propeller speed is optimal with respect to the total propulsion efficiency. The optimal propeller speed is determined by solving an optimization problem formulated as the maximization of the ratio of energy delivered by the propeller and the energy delivered to the propeller. The method may be used for vessels with one or more propellers.

Abstract: There is described a watercraft (1), comprising a hull (6) pivotally mounted for rotation about a longitudinal axis (10) relative to a float assembly (2, 3) having only two stable floating positions. The float assembly may comprise two spaced floats extending longitudinally of the watercraft and joined by transverse spars (4, 5), the hull being mounted between the transverse spars. Alternatively, the watercraft may comprise a first float assembly (27) mounted to a forward end of the hull and a second float assembly (33) mounted to an aft end of the hull, each float assembly comprising a pair of floats (28, 29; 35, 36) spaced transversely from the longitudinal axis of rotation of the hull.

Abstract: The present invention relates to a rim driven propeller unit for a vessel, where a number of permanent magnets (4) are arranged round the propeller unit's rotatable rotor housing (1), comprising a number of propeller blades (3), and a number of permanent magnets round the propeller unit's external, stationary casing (2) housing the rotatable rotor housing, where the permanent magnets round parts of the rotatable rotor housing and the external, stationary casing's circumference are provided located above one another with like polarity, while other parts of the rotatable rotor for housing and the external, stationary casing are provided located facing one another with opposite polarity, whereby the rotor housing and the stationary casing are repelled by and attracted to one another respectively, thereby being prevented from coming into contact with one another.

Abstract: A marine vessel comprising a command module, first and second buoyant tubular foils, and first and second struts for connecting the first and second buoyant tubular foils to the command module, respectively, wherein the first and second buoyant tubular foils provide substantially all buoyancy required for the marine vessel, and wherein the marine vessel further comprises first and second engines enclosed within the first and second buoyant tubular foils, respectively, and first and second propulsion units connected to the first and second engines, respectively, for moving the marine vessel through water, and means for reducing drag on the vessel as the vessel moves through water.

Abstract: The main propulsion and drive system of a merchant vessel such as a freighter or tank vessel, or a military vessel is supplemented by an auxiliary propulsion and drive system that includes at least one, but preferably a pair of auxiliary propellers that flank the main propeller at port and starboard positions and each of which are attached via a drive shaft through a gear train, which can optionally include a clutch mechanism, to an auxiliary motor or motors. In order to reduce the drag when the main propeller is disabled, segments of a wake field modifying propeller duct are mounted for repositioning to form at least a partial housing or cowling that diverts the water over the exterior surface of the duct and minimizes contact with the stationary blades of the main propeller as the vessel moves through the sea when powered by the auxiliary propulsion system.

Abstract: The present invention allows for the replacement of polluting and inefficient diesel-based marine propulsion systems. A natural-gas burning power plant in combination and at least one renewable energy source are combined to drive a ship's propulsion during times when the power plants are not in use for other activities including desalination and oil exploration. Renewable energies are used judiciously to reduce fossil fuel requirements but the present invention does not fully rely on renewable energy, which is not always available.

Abstract: A propeller unit for a marine vessel propulsion device includes an inner cylinder arranged to be fixed to the propeller shaft, an outer cylinder, a first driving force transmitting member, and a second driving force transmitting member. The propeller unit for marine vessel propulsion device further includes a pair of first engaging portions, and a pair of second engaging portions provided on the outer cylinder and the second driving force transmitting member. The pair of second engaging portions are arranged such that the mutual engaging of the respective second engaging portions is disengaged when a driving force is not transmitted to the propeller shaft and are arranged such that the respective second engaging portions become mutually engaged in a driving force transmittable manner by elastic deformation of the first driving force transmitting member when a driving force that is not less than a reference driving force is transmitted to the propeller shaft.

Abstract: Advanced foil design method and structure for multi speeds mainly adds a constraint according to a needed pressure distribution of the advanced foil after building an advanced foil environment. Thence, a step of optimization could be applied for analyzing the advanced foil by flow characteristics to achieve a shaped profile, so that a weight calculation weighted calculation would be further operated base on a proportion of the advanced coil applied to multi speeds. Accordingly, a preferable profile of the advanced foil and the environment parameter combination can be obtained to enhance a higher operative efficiency with the preferred benefit of the Supercavitating propeller while applied to a higher speed and with the profit of a stable competence while applied to a lower speed.

Abstract: A propeller assembly is provided for mounting on a rotatable propeller shaft of a watercraft. The propeller assembly includes a housing structure extending along a longitudinal axis. The housing structure includes an outer surface and an inner surface defining a cavity having a polygonal-shaped cross-section defined by at least one corner and at least one sidewall. A bushing assembly is receivable in the cavity of the housing structure. The bushing assembly includes a spindle having an inner surface defining a passageway for receiving the propeller shaft therethrough and an outer surface having a plurality of circumferentially spaced fin pairs extending therealong. Each fin pair includes a first fin extending from the outer surface of the spindle and a second fin extending from the outer surface of the spindle at a predetermined angle to the first fin. The bushing assembly also includes a bushing positioned between the spindle and the inner surface of the housing structure.

Abstract: An outboard motor includes an engine, an engine cover, a partitioning member, an intake device, and a fan. The engine is arranged to support a crankshaft extending along an up-down direction. The partitioning member is arranged to partition the inside of the engine cover into a lower chamber accommodating the engine and an upper chamber. In the partitioning member, a communication hole which is arranged to cause the upper chamber to communicate with the lower chamber is provided. Also, the engine cover has an air inlet arranged to cause the upper chamber to communicate with the atmosphere, and an air outlet arranged to cause the lower chamber to communicate with the atmosphere. The air inlet is arranged in an upper portion of the engine cover. The air outlet is arranged at a lower end portion of the engine cover. The intake device is connected to the engine. The intake device has an air suction port arranged to communicate with the upper chamber. The fan is arranged inside the engine cover.

Abstract: A propeller thrust transmission device includes a taper portion of a propeller shaft that is fitted in a spacer divided into a first half and a second half. A thrust force acting on a propeller is received by the taper portion of the propeller shaft through the spacer. The first half includes a taper hole having an inner surface which corresponds in shape to an outer surface of the taper portion and in which the taper portion is fitted. The second half has a smaller diameter portion extending from one side of a ring-shaped wall portion closer to the propeller and fitted in a hole of an attachment device spaced from the propeller shaft, and a larger diameter portion extending from the other side of the ring-shaped wall portion and fitted on an outer peripheral surface of the first half.

Abstract: There is provided a ship, in particular a cargo ship. It has a plurality of Magnus rotors, wherein associated with each of the plurality of Magnus rotors is an individually actuable electric motor (M) for rotating the Magnus rotor, wherein associated with each electric motor (M) is a converter (U) for controlling the rotary speed and/or the rotary direction of the electric motor (M).

Abstract: A transportable outboard drive for a boat has a head, a pylon, a shaft connecting the head and the pylon, an electric motor and a cable running inside the shaft. The shaft has at least two shaft sections and wherein the head, shaft and pylon can be arranged in a working configuration or in a transport configuration. In the working configuration, the head, the shaft and the pylon are rigidly connected to each other. In the working configuration and the transport configuration, the cable and shaft are differently positioned with respect to each other, whereas, in its transport configuration, the shaft sections are separated from each other.

Abstract: A watercraft (1) includes at least two oar handles (3a, 3b) which are designated to be actuated by a passenger of the watercraft in order to propel the same. A considerably expanded functionality is achieved in such a way that the oar handles (3a, 3b) are connected to a control unit which controls at least one power-actuated driving motor (6a, 6b; 7; 16a, 16b; 26a, 26b) of the watercraft depending on the actuation of the oar handles (3a, 3b).

Abstract: A propeller assembly is provided for mounting on a rotatable propeller shaft of a watercraft. The propeller assembly includes a housing structure extending along a longitudinal axis. The housing structure includes an outer surface and an inner surface defining a cavity having a polygonal-shaped cross-section defined by at least one corner and at least one sidewall. A bushing assembly is receivable in the cavity of the housing structure. The bushing assembly includes a spindle having an inner surface defining a passageway for receiving the propeller shaft therethrough and an outer surface having a plurality of circumferentially spaced fin pairs extending therealong. Each fin pair includes a first fin extending from the outer surface of the spindle and a second fin extending from the outer surface of the spindle at a predetermined angle to the first fin. The bushing assembly also includes a bushing positioned between the spindle and the inner surface of the housing structure.

Abstract: A hybrid propulsion and energy management system for use in marine vessels and other variable demand propulsion applications monitors and draws energy from various energy sources dynamically to implement multiple operating modes and provide efficient system operation across a range of propulsive demands, altering the operation and output of various energy sources in response to propulsive load demands, hotel loads and auxiliary energy demands. The propulsion system incorporates at least two propulsive sources, including at least one main propulsive engine and at least one motor-generator unit arranged to drive a common output shaft, and the energy management system dynamically shifts operation of each of the two sources to satisfy propulsive demands. The main propulsive engine and the motor-generator unit are capable of driving the common output shaft both independently and simultaneously.

Abstract: An assembly for retrofitting the hull of a watercraft is presented, which includes an elongated panel which defines a longitudinal channel and at least one chamber housing. The chamber housing defines at least one chamber extending through the panel and an upper chamber opening and a lower chamber opening. The panel is sized and configured to attach to the hull at an opening in the hull, and to form a seal between the panel and the hull at the hull opening. The chamber housing of the assembly is sized and configured to receive a detachably attached propulsion device. Also presented is a watercraft having integral thereto the assembly, and a method for retrofitting a watercraft to provide a location for detachable attachment of a propulsion device such as a trolling motor.

Abstract: A marine propulsion support system incorporates a vibration isolation structure which comprises a plurality of elastomeric support components, or mounts. The vibration isolation structure is disposed between a marine vessel and a propulsion drive mounting transom to which a marine propulsion component, such as an outboard motor, can be attached. Support of the propulsion drive mounting transom by the marine vessel extends through the vibration isolation structure so that elastomeric portions of the elastomeric support components can damp any vibration emanating from a marine propulsion device, such as an outboard motor, and a deck of a pontoon boat or other marine vessel.

Abstract: A Portable Dry Dock (PDD) system designed for commercial servicing of recreational vessels (RVs) in inland waterways (IW). This PDD is disassembled and transported from one IW to another. This PDD was designed specifically to improve the efficiency in the most typical maintenance jobs in RVs. The convenient layout of the equipment and the closed environment of the PDD reduce the execution time and improve the working conditions. The isolated environment created by the superstructure, deck and roof of the PDD significantly reduces the environmental impact. The isolated environment inside the PDD is controlled in temperature and humidity. The air filtering and waste water collection systems remove dust and other substances coming from the operation, stopping pollutants from getting into the IW.

Abstract: A watercraft includes a hull having a hull bottom with an opening and a trunk surrounding the opening. The watercraft also includes a propulsion device pivotally mounted to a portion of the hull other than the trunk. The propulsion device can include a transmission and a propeller on an end of the transmission, and can be movable between a deployed position and an onboard stowed position. In the deployed position, the transmission extends through the trunk and through the opening such that the propeller is positioned below the hull bottom. In the onboard stowed position, no portion of the transmission or the propeller is located within the trunk or below the hull bottom.

Abstract: An improved propeller design is provided herein. One embodiment includes a propeller with a housing having a diameter sufficient to encloses at least a portion of the propeller blades. The housing may be secured to the ends of the propeller blades. The housing may include a forward facing edge that is flared outwardly. In addition, the housing generally tapers inward aft of the propeller blades reducing the diameter of the housing to form a general funnel shape. In one embodiment, the housing has a rear portion with a substantially constant diameter located aft of the end of the tapered section. Outer blades may be secured to the outer portion of the housing. These outer blades may be useful to, for example, provide additional rear thrust when the boat is shifted into reverse.

Abstract: A propelling system for a boat includes a housing adapted to be mounted to a stem of the boat and having a receiving chamber inside and a waterway at a bottom side thereof, a propeller rotatably disposed in the waterway of the housing, a driving device mounted in the receiving chamber of the housing and having a driving member and a linking member pivotally coupled to the driving member, and a guide ring connected to the linking member of the driving device and located in the waterway of the housing in such a way that the guide ring surrounds blades of the propeller and is pivotable relative to the propeller. Thus, the propelling system has the advantage of increasing the utilization of the internal space of the boat.

Abstract: A generally Mo-free, ferrite-austenite duplex stainless steel has a ferrite phase area ratio of about 20 to about 60% and a composition containing, in mass %, not more than about 0.08% of C, about 0.5 to about 1.5% of Si, not more than about 1.0% of Mn, about 4.0 to about 8.0% of Ni, about 23 to about 27% of Cr, about 2.0 to about 6.0% of Cu, about 0.05 to about 0.3% of N, and the balance being Fe and generally unavoidable impurities.

Abstract: A propeller for watercraft having excellent abrasion resistance includes a propeller body having a blade and a hub portion, the propeller body being molded from an aluminum alloy by casting, and an anodic oxide coating of the aluminum alloy provided so as to cover a surface of the propeller body. The anodic oxide coating has a thickness of about 20 ?m or more in a thinnest portion and a hardness of about 330 HV or more at a near-surface level in a thickest portion.

Abstract: A boat hull comprises a hull body having two lateral flanks linked by a bottom surface, and at least two propulsion compartments provided in two bulges protruding below the bottom surface of the hull body. Each propulsion compartment lodges a propulsion engine located below the bottom surface of the hull body. The propulsion engines are located at the deepest position in the hull and below the water plane.

Abstract: A boat propeller system, consisting of propeller blades attached to the forwardmost portion of a cylindrical housing extending aftward from the propeller blades for increasing the propulsion of the propeller system.

Abstract: A marine propulsion unit having an oil circulation system is provided. In the oil circulation system, lubricant is delivered from a bevel gear mechanism adjacent a drive shaft through an oil passage defined in a lower casing to a journal bearing supporting the drive shaft. From the drive shaft journal bearing, the lubricant flows through a gap between the drive shaft and the inner peripheral wall of a drive shaft chamber in the lower casing and then returns to the bevel gear mechanism.

Abstract: The present invention relates to a boat propeller and the assembly method therefor. The propeller comprises a hub and a plurality of separated blades to be integrally coupled with corresponding seats that are formed in the hub. Advantageously, during the assembly stage of the propeller, the blades can be orientated in the respective seats, each about its own axis. The method for assembling the propeller comprises the steps of orientating the blades according to a determined pitch angle before they are definitely fixed to the hub.