Abstract: An outboard motor cooling induction system. A pickup assembly is attached to a boat's transom proximate the keel. An uptake hose from this pickup assembly carries cooling intake water to one or more inlets on the outboard motor's lower unit. An intake plane is provided on the pickup assembly. This intake plane is preferably positioned so that the intake flow is optimized.

Abstract: Described herein are examples of stiffening shafts, which in some cases are adapted to couple to a marine vessel. An exemplary stiffening shaft can be used to extend a motor from the marine vessel or be used as a shallow water stick anchor. The exemplary stiffening shafts can include a plurality of linked vertebrae stacked to form a column and at least one inelastic tension element threaded longitudinally through the plurality of vertebrae. The shaft can have a flexible configuration when the at least one tension element is released and a stiffened linear configuration when the tension element is tensed to react to torque and bending moments. Alternatively, the stiffening shaft can be used as a shallow water stick anchor for a marine vessel by piercing the bottom of a marine environment (e.g., a sea bed, a lake bed, a river bed, etc.).

Abstract: A boat shaft seal system including a flexing gland configured to receive a boat drive shaft therethrough, the flexing gland having a first end configured to receive a shaft log fitting, and a second end configured such that the boat drive shaft extends therefrom, and a plurality of circumferential ribs formed along at least a portion of a length of the flexing gland and configured to allow limited flexing of the flexing gland.

Abstract: In an outboard motor, a damper includes a bushing fixed to a periphery of a propeller shaft. The damper includes a second pressing surface that presses a first pressing surface of an inner surface of a cylinder in a circumferential direction, an elastic member disposed around a portion of the bushing different from the second pressing surface of the bushing, and a reinforcer disposed between the first pressing surface and the second pressing surface.

Abstract: An assembly includes a plurality of seal shoes arranged about an axial centerline in an annular array. The assembly also includes a seal base and a plurality of spring elements. The seal base circumscribes the annular array of the seal shoes. A threaded base aperture extends axially through the seal base. Each of the spring elements is radially between and connects a respective one of the seal shoes with the seal base. The spring elements are formed integral with the seal base and the seal shoes as a unitary body.

Abstract: A propeller drive assembly includes a driveshaft for transferring a torque between an engine and a propeller of a water surface vessel, and a housing enclosing the driveshaft. The assembly includes, separately from the driveshaft, a first element and a second element, the first element extending through a first bore of the second element, wherein one of the first and second elements is fixed to the driveshaft and the other of the first and second elements is arranged to be stationary in relation to the housing, and the one of the first and second elements which is fixed to the driveshaft presents in the first bore a first elongated cavity forming a first helix along the first bore, so as to form with the other of the first and second elements a screw pump.

Abstract: An earthing contact for creating an electrical contact between an earthing cable and a component comprising an electroconductive component surface, comprises an electroconductive contact plate and a fixing element, the contact plate having a first contact surface for placing the contact plate on the component surface, a second contact surface for placing an earthing cable on the contact plate, and a passage for the fixing element, the fixing element comprising a fixing section for fixing the fixing element in the component, a pressure element for pressing the contact plate onto the component surface and a holding section for arranging in the passage of the contact plate, when the pressure element presses the contact plate onto the component surface, the first contact surface being tiltable in relation to the fixing section by a tilting angle of at least 6° when the holding section is arranged in the passage.

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 system for providing sealed shaft bearing is disclosed. The system can include housing and one or more end caps. The end caps can house one or more seals and one or more bearings for supporting a shaft. The housing can be watertight to prevent water from infiltrating the housing and to prevent lubricant, if any, from escaping the housing into the environment. The system can use a multi-piece design to facilitate repair and maintenance. The system can be easily retrofitted into systems, such as marine systems, that use conventional plain shaft bearings.

Abstract: The invention is directed to a waterjet propulsor. The propulsor includes a structure covering an impeller shaft. The implementation of the elongated structure results in reduced drag, increased thrust and increased craft speed. The elongated structure may be a sleeve that is mounted in a free-floating arrangement over the impeller shaft that self-aligns, the sleeve having an airfoil cross section for optimizing the flow of water over the shaft. The elongated structure may also be a fixed housing arrangement that includes an airfoil cross section for optimizing the flow of water over the shaft.

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 marine vessel propulsion device includes an engine, a propeller shaft, a drive shaft that is rotated by power transmitted from the engine, a dog clutch that transmits rotation of the drive shaft to the propeller shaft, and an engine load generating unit. The engine load generating unit detects relative rotation speed between the drive shaft and the propeller shaft, and generates an engine load opposite in phase to the relative rotation speed detected therebetween.

Abstract: An outboard engine unit, where a drive shaft is connected to an engine and rotatably supported in a drive shaft chamber via a bearing and where a gear mechanism for transmitting rotation of the drive shaft to a propeller shaft is accommodated in a gear chamber, includes: a lubricant circulation section for returning lubricant oil, having lubricated the bearing, back to the gear chamber; an oil storage chamber for receiving the lubricant oil having lubricated the bearing; and a return passage communicating the oil storage chamber with the gear chamber. The lubricant oil guided to the oil storage chamber is returned back to the gear chamber via the return passage.

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 sealing unit longitudinally comprises first and second sealing sub-units disposed around first and second portions of a driveshaft of a marine propulsion system of a watercraft. The first sealing sub-unit is sealingly connected to a front wall of the hull and the engine casing. The second sealing sub-unit is sealingly connected to the driveshaft and a crankshaft. The second sealing sub-unit is disposed at least partially inside the first sealing sub-unit. An inside of the first sealing sub-unit is in fluid communication with a water intake ramp. An inside of the second sealing sub-unit is in fluid communication with an interior of an engine. The first sealing sub-unit prevents fluid communication between the water intake ramp and a portion of an inside of the hull. The second sealing sub-unit prevents fluid communication between the engine, the inside of the hull, and the water intake ramp.

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 watercraft propulsion apparatus is provided. The watercraft propulsion apparatus includes a watercraft having a hull, wherein the hull has at least an interior side and an exterior side. A motorized device is positioned proximate to the interior side of the hull. A shaft is connected to a propeller structure and positioned proximate to the exterior side of the hull. A drive structure is mechanically connected between the motorized device and the shaft, wherein the drive structure is at least partially positioned within an opening in the hull, wherein the opening is connected between the interior side and the exterior side.

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: 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 marine motor for shallow water boats that has a universal mounting bracket to fit all shallow water boats, the Mud Runner has a mid length drive system with a parallel shaft technology that has the most efficient forward thrust drive system for swallow water boats. The upper drive system is where the reverse drive system happens by way of gears and a drive shaft. The upper drive system and lower drive system are connected together by way of a drive belt. The lower drive system has an output drive shaft that comes down at an approximate 153 degree angle which then than transfers to a 0 degree angle. The 0 degree angle output drive shaft has a propeller attached to the shaft which gives this motor the forward thrust.

Abstract: A water jet propulsion watercraft includes a main engine body, a rotor chamber disposed at a rear portion of the main engine body, a crankshaft disposed so as to extend penetratingly through the rotor chamber such that a rear end portion thereof protrudes to an outer side of the rotor chamber, a rotor unit coupled to the crankshaft inside the rotor chamber, a drive shaft connected to the rear end portion of the crankshaft and rotated together with the crankshaft, and a jet propulsion unit, having an impeller that is coupled to the drive shaft, and arranged to suck in and jet out water. The crankshaft includes a flange portion that is integral with the crankshaft inside the rotor chamber. The rotor unit is fixed to the flange portion.

Abstract: A water jet propulsion watercraft includes, a main engine body, a rotor chamber provided at a rear portion of the main engine body, a crankshaft arranged such that a rear end portion of the crankshaft is disposed in the rotor chamber, the rear end portion having a first connection portion, an output shaft having a second connection portion at a front end of the output shaft, the second connection portion arranged to be connected to the first connection portion of the crankshaft such that the output shaft rotates together with the crankshaft about a rotational center axis of the crankshaft, a rotor unit housed in the rotor chamber and fixed to the output shaft, a fastening member arranged to fasten the first connection portion and the second connection portion, a drive shaft connected to a rear end portion of the output shaft.

Abstract: A joint 10 is shown for transmission of torque between an input shaft 12 and an output shaft 14. In the form shown, the joint 10 comprises an outermost helical coil spring 16 and an innermost helical coil spring 18, both of which are connected at their respective opposite ends to the input shaft 12 and to the output shaft 14. The innermost helical spring 18 is arranged to be entirely located within, and co-axially aligned with, the outermost helical spring 16 along the same centerline. The springs 16, 18 are arranged to be counter wound relative to one another to provide delivery of torque in a stabilised manner reflected in a significant reduction in the vibration observed within the joint 10 during use. The joint 10 is also arranged for transmission of thrust (or axial force) between the input shaft 12 and the output shaft 14.

Abstract: An outboard motor that is capable of reducing a trolling noise includes an engine which has a crank shaft extending in an up-down direction; a drive shaft extending downward from the crank shaft and including a torsion bar spring; a propeller shaft; a propeller provided in the propeller shaft; a forward/backward switching mechanism arranged to connect the drive shaft and the propeller shaft with each other; and a vibration damper which includes a first cylindrical body and a second cylindrical body which are penetrated by the torsion bar spring. The first cylindrical body and the second cylindrical body are coaxial with each other. The first cylindrical body has its upper end portion connected with an upper end portion of the torsion bar spring whereas the second cylindrical body has its lower end portion connected with a lower end portion of the torsion bar spring. A viscous fluid is filled between the first cylindrical body and the second cylindrical body.

Abstract: Marine propulsion system and ship outfitted therewith, wherein the marine propulsion system has a propulsion element for propelling a ship, a driving engine which is to be flexibly mounted at a hull of the ship for driving the propulsion element, a thrust bearing which is to be rigidly mounted at the hull and which has a thrust bearing shaft having a first end and a second end, a driving engine drivetrain for connecting the driving engine to the first end of the thrust bearing shaft, and a propulsion element drivetrain for connecting the second end of the thrust bearing shaft to the propulsion element, wherein the driving engine drivetrain rigidly connects the driving engine to the first end of the thrust bearing shaft.

Abstract: An engine is provided to facilitate installation of a compressor on an engine. The engine can include a crankshaft, a front end, and an installation structure, and can be disposed in an engine compartment having an opening for accessing the engine. The installation structure can comprise an installation mount that can be disposed at the front end of the engine. The installation mount can extend substantially parallel to the crankshaft of the engine. The installation mount can include a surface configured for mounting the compressor. Further, the installation mount can be configured with the surface thereof facing toward the opening of the engine compartment. Additionally, the installation structure can be configured to facilitate meshing engagement of the crankshaft with a drive shaft of the compressor.

Abstract: A marine vessel propulsion unit includes an engine, a drive shaft, a propeller shaft, a propeller, an intermediate shaft, a forward-reverse switching mechanism, and a shock reduction mechanism. The intermediate shaft is arranged on a central rotation axis of the propeller shaft. The intermediate shaft is arranged to transmit rotation between the drive shaft and the propeller shaft. The forward-reverse switching mechanism is arranged to switch a rotational direction of the propeller shaft to a forward drive direction or a reverse drive direction. The shock reduction mechanism includes a plurality of spring members and a pair of stopper portions. The shock reduction mechanism is arranged on the central rotation axis of the propeller shaft. The plurality of spring members are arranged to absorb a force in the rotational direction by elastically deforming in the rotational direction when the force in the rotational direction is applied to the intermediate shaft.

Abstract: A boat includes a connection structure that connects couplings via a transfer shaft on a rear end portion of a crankshaft extending rearward from an engine. The crankshaft and the transfer shaft are connected by screwing an external thread and a front internal thread, and the transfer shaft and the couplings are connected by screwing an external thread and an internal thread. There are provided an inner bolt that strengthens the connection between the external thread and the front internal thread, an end bolt that strengthens the connection between the transfer shaft and the couplings, and an outer nut that strengthens the connection between the crankshaft and the transfer shaft. The boat can prevent movement between the crankshaft and an intermediate member and between the intermediate member and a coupling both in a rotational direction and in an axial direction without causing an increase of processing time or processing cost.

Abstract: A device that when fitted to a motor vessel's existing propulsion gear improves the performance and reduces potential damage and wear of underwater propeller shaft bearings, commonly referred to as “cutlass bearings” that are used on boats, ships, etc. Designed with radially mounted impeller blades around the periphery of the propeller shaft, the device creates a forced flow of water by centrifugal pumping action, which creates suction along the shaft abaft the cutlass bearing, thereby increasing the flow of water through the cutlass bearing. The device also greatly diminishes the probability that fouling around a propeller shaft will severely restrict water flow through the cutlass bearing.

Abstract: An improved bearing assembly includes one unique shaft washer (158) rather than using separate forward and aft shaft washers as in the prior art; a slight lengthening of the forward roller (174) as compared to the aft roller (176); an increase in the diameter of the forward roller relative to the aft roller; an increase in the number of rollers; improved materials, particularly in the shaft washer (158) where fewer inclusions are present in the metal; and an osculation configured to provide less space and unconstrained movement between the rollers and runways. The improvements result in decreased movement or play between the shaft washers, the bearings/rollers, and the outer rings. The improvements and changes provide a compact design that fits within existing pod propulsion systems.

Abstract: In an outboard motor, a lower casing is located below an upper casing, and an engine with a vertically-arranged crankshaft is mounted above the upper casing. The rotation of the crankshaft is transmitted to a drive shaft pivotally supported in the upper casing, has its speed changed by a transmission mounted on the drive shaft, and is transmitted to a propeller shaft pivotally supported in the lower casing. The upper casing includes an upper-side casing and a lower-side casing, and mating surface portions of the upper-side casing and the lower-side casing are laterally wider than an upper section and a lower section of the upper casing.

Abstract: A device that when fitted to a motor vessel's existing propulsion gear improves the performance and reduces potential damage and wear of underwater propeller shaft bearings, commonly referred to as “cutlass bearings” that are used on boats, ships, etc. Designed with radially mounted impeller blades around the periphery of the propeller shaft, the device creates a forced flow of water by centrifugal pumping action, which creates suction along the shaft abaft the cutlass bearing, thereby increasing the flow of water through the cutlass bearing. The device also greatly diminishes the probability that fouling around a propeller shaft will severely restrict water flow through the cutlass bearing.

Abstract: The present invention relates to a propulsion arrangement for a marine vessel, which propulsion arrangement comprises an internal combustion engine, a shaft arrangement and a steerable thruster unit. The marine vessel further comprises an electric generator or a combined electric generator and motor in connection with the propulsion arrangement. In order to reduce space requirements and required equipment as well as to raise efficiency, the shaft arrangement comprises a main shaft extending from the internal combustion engine to a first angle gear and a drive shaft extending from the first angle gear to a second angle gear in the steerable thruster unit. The electric generator or the combined electric generator and motor is connected to the drive shaft of the shaft arrangement after the main shaft and the first angle gear are connected thereto.

Abstract: A drive joint for transmission of rotary motion between a drive unit a propeller shaft with a propeller for propulsion of a boat, where the drive joint (1) comprises a flexible joint (3) which is enclosed by a housing (2) and is designed to sustain thrust forces from the propeller during operations. At the exit shaft (4) of the joint (1) an attachment ring (16) is attached at the inner or free end of the shaft (4) and is dimensioned in order to sustain full forces from the propeller during operations. The housing (2) is provided with an opening (17) above the inner or free end of the exit shaft (4) for direct access to the locking ring (16) during assembly and disassembly of the drive joint.

Abstract: A device that when fitted to a motor vessel's existing propulsion gear improves the performance and reduces potential damage and wear of underwater propeller shaft bearings, commonly referred to as “cutlass bearings” that are used on boats, ships, etc. Designed with radially mounted impeller blades around the periphery of the propeller shaft, the device creates a forced flow of water by centrifugal pumping action, which creates suction along the shaft abaft the cutlass bearing, thereby increasing the flow of water through the cutlass bearing. The device also greatly diminishes the probability that fouling around a propeller shaft will severely restrict water flow through the cutlass bearing.

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: An outboard motor S has a first drive shaft 31 directly interlocked with an engine E, a second drive shaft 32, an intermediate gear mechanism 33 interlocking the first drive shaft 31 and the second drive shaft 32, an output gear mechanism 50 driven by power transmitted thereto through the second drive shaft 32, a propeller shaft 17 driven for rotation by power transmitted thereto through the output gear mechanism 50, and a gear case 13 holding the output gear mechanism 50. The second drive shaft 32 extends downward beyond a vertical position corresponding to the lower end of the first drive shaft 31. The gear case 13 is provided with water intakes 98 through which a water pump 90 sucks water in a space between the first drive shaft 31 and the output gear mechanism 50 with respect to a vertical direction on the front side of the second drive shaft 32. The space for the water intakes 98 can be easily secured because the second drive shaft 32 is disposed on the rear side of the first drive shaft 31.

Abstract: A boat has a hull, a deck having a deck floor, and an engine disposed in the hull. A top of the engine is disposed vertically below the deck floor. The engine includes a crankcase, a crankshaft, a pair of cylinder banks connected to the crankcase at an angle relative to each other. A transom extends generally vertically upwardly from a rear portion of the hull. A stern drive unit is connected to the transom and is operatively connected to the engine through the transom. In another aspect, a marine engine has a crankcase, a cylinder block, and a crankshaft. An output shaft is disposed vertically above the crankshaft. The output shaft is disposed at least partially internal to the engine. A drive, internal to the engine, is operatively connected to the crankshaft and the output shaft. A driveshaft coupling is disposed on the output shaft.

Abstract: A propulsion system is provided for an underwater vehicle such as a Remote Operated Vehicle (ROV). Two propellers are independently driven by motors, while the orientation of the propellers is simultaneously controlled by a third motor. A means is provided for reprogramming the control electronics that can be disabled when the vehicle is underwater. The control electronics also provides that all signals including video are transmitted to a base station without requiring coaxial cable.

Abstract: In an outboard motor S, a first drive shaft 31 and a second drive shaft 32 are interlocked by an intermediate gear mechanism 33 including a drive gear 34 mounted on the first drive shaft 31 and a driven gear 35 mounted on the second drive shaft 32. The second drive shaft 32 is supported in an upper bearing 38 and a lower bearing 39 disposed on the upper and the lower side of the driven gear 35. The upper bearing 38 supports an upper end part 32a of the second drive shaft 32 extending upward from the driven gear 35 and the upper bearing 38 is at a vertical position coinciding with that of the drive gear 34. The lower bearing 39 is placed at a position on a lower end part 32b of the second drive shaft 32. The lower end part 32b extends between the driven gear 35 and an input gear 51 included in the output gear mechanism 50.

Abstract: A sealing member can include a radially-working lip which contacts a drive shaft in a radial direction to seal a gap between the drive shaft and the housing in the radial direction, an axially-working lip extending in an axial direction, and a contact member which contacts the axially-working lip to seal the gap between the drive shaft and the housing in the axial direction. The contact member can be fitted to the drive shaft to rotate with the drive shaft.

Abstract: A propulsion system is disclosed for moving a hull of a watercraft through a body of water. The propulsion system includes a power transfer unit that comprises a housing with an interior, an input gear positioned in the interior for being rotated by the engine, and an output gear positioned in the interior and being rotatable by the input gear. The input gear is rotatable about a first axis and the output gear is rotatable about a second axis, and the second axis is oriented at a non-zero angle to the first axis. A primary output shaft is mounted on the output gear and extends from the interior of the housing to an exterior of the housing. An adjustable propeller assembly may be included that includes a propeller, with the propeller assembly being configured to enable adjustment of a direction of thrust provided by the propeller along an axis of rotation of the propeller.

Abstract: A device that when fitted to a motor vessel's existing propulsion gear improves the performance and reduces potential damage and wear of underwater propeller shaft bearings, commonly referred to as “cutlass bearings” that are used on boats, ships, etc. Designed with radially mounted impeller blades around the periphery of the propeller shaft, the device creates a forced flow of water by centrifugal pumping action, which creates suction along the shaft abaft the cutlass bearing, thereby increasing the flow of water through the cutlass bearing. The device also greatly diminishes the probability that fouling around a propeller shaft will severely restrict water flow through the cutlass bearing.

Abstract: A marine outboard motor has a rotary bearing on the vertical drive shaft intermediate its ends. This bearing is mounted in a housing that joins the power head to the lower unit. The bearing prevents failure that may occur when the shaft has an unbalance that causes bowing and whipping of the shaft at certain speeds. The bearing is supplied with water from a water pump in the lower unit.

Abstract: A lubricant circulating system has a lubricant passage formed in a propeller shaft. The lubricant passage extends axially along the propeller shaft from a bevel gear mechanism to a position proximate to a journal of the propeller shaft. The journal of the propeller shaft is rotatably supported by a bearing. The lubricant passage further extends radially of the propeller shaft and communicates with an area proximate to the bearing. The lubricant circulating system is adapted such that lubricant circulates through the lubricant passage between an upstream opening of the lubricant passage at or around the bevel gear mechanism and a downstream opening of the lubricant passage in the vicinity of the bearing.

Abstract: A propeller for a boat includes a propeller shaft having a shaft hole, a shaft sleeve mounted in the shaft hole of the propeller shaft and provided with a metal core with a through hole for insertion of a driving shaft of the boat, and a shock-absorbing member covering an outer surface of the metal and having an outer surface contacted with an inner surface of the propeller shaft that surrounds the shaft hole; and a lock unit mounted on the driving shaft for fixing the driving shaft in the through hole of the shaft sleeve, so that the propeller is rotatable by the driving shaft. When the propeller bumps hard things during rotation to result in vibration to the propeller, the shock-absorbing member can absorb the vibration so as to protect the driving shaft from damage.

Abstract: A sealing member can include a radially-working lip which contacts a drive shaft in a radial direction to seal a gap between the drive shaft and the housing in the radial direction, an axially-working lip extending in an axial direction, and a contact member which contacts the axially-working lip to seal the gap between the drive shaft and the housing in the axial direction. The contact member can be fitted to the drive shaft to rotate with the drive shaft.

Abstract: A paper tube of a propeller tube 12 is made by winding a single faced corrugated fiberboard 16 in which a wavy corrugating medium 16b is fixed to one side of a flat linerboard 16a so that the corrugating medium 16b is oriented outwards, and the corrugating medium 16b contacts with an inner surface of the propeller tube 12, so as to enhance a vibration controlling function. When winding the single faced corrugated fiberboard 16, since the single faced corrugated fiberboard 16 cannot be wound in a direction oblique to a direction of ridges of the corrugating medium 16b, there are no fears that the shape of the single faced corrugated fiberboard 16 is collapsed to taper axially, thereby it becomes possible to prevent a reduction in vibration controlling function that would otherwise be caused due to a change in the shape of the paper tube.

Abstract: A coupling joint structure for a boat where the output of an engine can be securely transmitted to a propeller shaft and centrifugal force can be reduced. The structure includes a first coupler on the driving side to an output shaft, a second coupler on the driven side to a propeller shaft, and a damper member interposed between the second coupler on the driven side and the first coupler on the driving side. The first coupler on the driving side and the second coupler on the driven side each include pawl pieces. In a first curved part of each of the pawl pieces on the driving side, the base (wall thickness t1) is made thicker than the end (wall thickness t2). In a second curved part of each of the pawl pieces on the driven side, the base (wall thickness t1) is made thicker than the end (wall thickness t2).

Abstract: In an outboard drive or an inboard-outboard drive, power generated by a single engine is transmitted in left and right directions from a main drive shaft, thereby finally causing left and right propellers to be rotated, the left and right propellers being arranged about the main drive shaft so as to be spaced apart from the main drive shaft at approximately equal distances from the main drive shaft and facing a travel direction of a marine vessel, the outboard drive or inboard-outboard drive being provided with left and right shift cam assemblies for causing rotation situations of the propellers to be controlled dependently from each other, the rotation situations including normal rotation, reverse rotation and non-rotation situations of the propellers.