Abstract: Boat propeller drive unit with an underwater housing (5), which is solidly joined to a boat hull and has pulling propellers (15, 16) on the forward facing side of the housing. At the aft edge of the underwater housing, a rudder is mounted, comprising a first rudder blade (22a) mounted in the underwater housing and a second rudder blade (22c) mounted on the aft edge of the first rudder blade.

Abstract: An engine alignment jig assembly, which is used for installing an engine in a hull of a small watercraft via four engine mounts in such a manner that an output shaft of the engine is in alignment with a rotating shaft of a jet pump, is disclosed. The jig assembly includes an engine lower part dummy constructed to resemble a lower half of the engine. The engine lower part dummy includes a generally rectangular skeleton frame having substantially the same size in plan view as the lower half of the engine. Four screws are each provided at a respective corner of the rectangular skeleton frame and adapted to be threaded in a corresponding one of the engine mounts to attach the engine lower part dummy to the engine mounts. Two adjacent ones of the screws that are disposed on a bow side of the watercraft form left and right front screws, and the remaining two screws that are disposed on a stern side of the watercraft form left and right rear screws.

Abstract: A propeller attachment is disclosed including a body, the body including an anodic material, at least one projection projecting from the body, and a fastener coupled to the body. An anode is also disclosed including an annular body constructed from an anodic material, a fastener disposed centrally in the annular body, and at least one extension coupled to the annular body, the at least one extension is configured to allow for gripping of the anode. A fastener for coupling a propeller to a drive shaft of a lower unit is disclosed including a fastening portion configured to threadably engage the drive shaft and retain the propeller. The fastener further includes an anodic portion disposed around the fastening portion. The anodic portion is shaped to form at least one grip, and the anodic portion preferentially corrodes to prevent corrosion of the lower unit.

Abstract: A propulsion aggregate for boats of planing type is disclosed. The aggregate (10) comprises at least one inboard engine (5) disposed in a supporting frame (6), at least one first drive shaft (1) having a propeller (3), which shaft (1) extends through the boat hull (11) at the stern section of the boat, at least one rudder (12), and a second drive shaft (2) that extends through the stern section of the boat and drives a water turbine (4). The first drive shaft (1) is in direct connection with the power take-off (7) of the engine (5) via a releasable coupling (8) and said first drive shaft (1) is in operation during forward propulsion above a certain speed only, and the second drive shaft (2) is connected to the power take-off (7′) of the engine (5) and is arranged at a higher level than the propeller (3) and said second drive shaft (2) is in operation at forward propulsion at low speeds and at reverse motion.

Abstract: Disclosed is a personal watercraft comprising an engine capable of achieving a high power without increasing the diameter of an output shaft where a crankshaft-side sprocket is attached, and thus without increasing the diameter of the sprocket. The engine is configured such that an extended shaft that is separable from the crankshaft and has a diameter smaller than that of the crankshaft is connected to one end portion of the crankshaft so as to be coaxial with the crankshaft, and a sprocket is provided on the extended shaft. With such a structure, by forming the extended shaft of a material having relatively high strength, the diameter of the extended shaft can be made smaller than that of the crankshaft, and hence, the diameter of the sprocket provided on the extended shaft can be reduced. Since the diameter of a camshaft-side sprocket can be reduced, the size of the entire engine can be reduced.

Abstract: Torque fluctuations, which, on one hand, come from the engine, and on the other hand, come from the power take-off side due to the effect of the rudder and beating of the blade, and which are primarily caused by the typically low rotational speed in drives of watercraft, lead to intense vibrations in the hull and generate. noise. A device for transmitting torque in the power train of a watercraft damps torsional vibrations occurring in the power train of a watercraft and, therefore, ensures low-noise and low-vibration operation. The device includes an engine-side, primary flywheel mass, a secondary flywheel mass coupled at the power take-off to a gearbox driving the ship propeller, as well as a torsionally elastic connection disposed therebetween.

Abstract: A power transmission system for a marine propulsion unit includes an improved construction that can absorb a shock generated when a shift mechanism is operated. The propulsion unit has a powering element and a propulsion device. The power transmission system includes a first shaft driven by the powering element and a second shaft driven by the first shaft and driving the propulsion device. The first and second shafts have a common axis. A coupling assembly is mounted on both the first and second shafts so as to couple them for rotation together. A damper is disposed next to the coupling assembly. The coupling assembly includes a pair of coupling members. One of the coupling members is axially moveable along the common axis relative to the other coupling member to compress the damper at the moment the first shaft is rotated relative to the second shaft. In another arrangement, a lost motion mechanism operates when the first shaft is rotated relative to the second shaft such that the initial shock is damped.

Abstract: A bearing body for rotatably supporting a drive shaft for driving an impeller on a watercraft body includes a bearing chamber containing bearing members rotatably supporting the drive shaft. Seal members are disposed on both sides of the bearing members and partition the bearing chamber by making contact with an outside circumferential surface of the drive shaft. The seal members are disposed so that grease in the bearing chamber does not leak out through the contact portions between the seal members and the outside circumferential surface of the drive shaft, and a breather passage is communicated with the bearing chamber. Two bearing members within the bearing chamber have a space formed between the bearing members, e.g., to form a grease reservoir between the bearing members. The aforementioned bearing structure reduces the necessity of maintenance, e.g., supplying grease to a drive shaft bearing portion, or at least the reduces the required frequency of maintenance.

Abstract: An impeller drive shaft in a vessel is supported on a vessel body at a midsection thereof by a bearing member. A driven side coupler to be coupled with a drive side coupler on the side of an engine output shaft is mounted on a front end of the impeller driving shaft, a collar having a diameter larger than the maximum diameter D of the shaft is detachably mounted on the rear of the mounting portion for the driven side coupler on the impeller driving shaft, and the driven side coupler is fixed with respect to the shaft so as not to be capable of movement from axial thrust by an abutment between the collar and the driven side coupler. The collar may also be divided into two or more pieces with respect to the circumferential direction. The aforementioned arrangement improves durability of the shaft at the mounting portion for the driven side coupler and facilitates ease of maintenance.

Abstract: To ensure that fitting a coupler rubber in a reverse condition will be prevented, and to ensure that the fitting direction of the coupler rubber can be visually checked even after the fitting. A driving-side coupler is provided on an end of an output shaft of an engine. A driven-side coupler is provided on an end of a drive shaft. A coupler rubber is disposed between the couplers. At least a portion of the coupler rubber is exposed between the couplers, and the exposed portion is provided with a mark indicating the fitting direction of the coupler rubber.

Abstract: A drive shaft support structure for a boat for preventing water from penetrating a boat body via a cylindrical portion through which the drive shaft passes. The cylindrical portion extends inwardly from outside the boat toward the engine. A support portion for supports a rubber dampered bearing body, which rotatably supports the drive shaft on the engine side. The rubber dampered bearing body includes a rubber damper portion and a rubber cylindrical portion formed integrally with the rubber damper portion and extending toward the cylindrical portion. The rubber cylindrical portion and the cylindrical portion are directly connected. The rubber dampered bearing body supports the rear end of a cover for a coupler for connecting an output shaft of the engine and the drive shaft.

Abstract: A propeller housing for a marine vehicle is provided which incorporates an improved locking structure for maintaining the propeller assembly on the drive shaft of the marine vehicle. The locking structure includes a spider washer having first and second ends and an aperture therebetween for receiving the propeller shaft therethrough. The spacer element includes a nose portion adjacent the first end thereof. A locking washer has an opening for receiving the nose portion of the spacer element therethrough and an outer periphery which maintains a propeller assembly on the propeller shaft. A locking element is mountable on the threaded end of the propeller shaft for retaining the spider washer thereon.

Abstract: A shaft guard for a watercraft is disclosed. The shaft guard is located inside a jet propulsion unit and at least partially surrounds the drive shaft. The drive shaft and the engine shaft are not substantially parallel. The shaft guard is attached to the housing of the jet propulsion unit at one end and may be attached to the drive shaft at the other end allowing for free rotation of the drive shaft.

Abstract: There is now provide an ocean-going ship, and an ocean-going vessel with a stern tube seal arrangement for sealing a stern tube for a propeller drive shaft, and an arrangement for sealing propeller drive shafts in an ocean-going vessel. In the seal arrangement there is provided a compensation to balance pressure fluctuations that arise in the lubricating oil chamber due to axial oscillations of the shaft. In this, the change of pressure is determined by a sensor and this actual value is passed to a comparator element. The comparator element controls a pressure valve so as to control the extent of filling of an annular tubular expandable body, whereby the expandable body impacts on the lubricating oil chamber. By way of a phase shift of 180 degrees in reference to the sensed pressure impulse in the event of an increase in volume of the expandable body, a minimized pressure fluctuation in the lubricating oil chamber can be controlled.

Abstract: To provide an output shaft structure of a personal watercraft, which is capable of enhancing the durability of the engine. An engine is mounted on a watercraft body with a crankshaft extending in the longitudinal direction of the watercraft body. A shaft of a propulsion device is coupled to a rear end of the crankshaft in such a manner as to be disposed on an extension of the crankshaft. The crankshaft is supported by an engine case via plain metal. An output shaft is provided separately from the crankshaft and is coupled to the rear end of the crankshaft. The shaft of the propulsion device is coupled to the rear end of the output shaft. The output shaft is supported by the engine case via rolling bearings immovable in a thrust direction. A spline is formed on or in each of the rear end of the crankshaft and the front end of the output shaft, and a spline to be engaged with these splines is formed in or on an inner surface of a connection pipe.

Abstract: To provide an output power shaft structure for a personal watercraft which is superior in durability. A shaft of a propulsion device is connected to a rear end of a crankshaft of an engine, which is carried on a watercraft body such that the crankshaft thereof is directed in a longitudinal direction of the watercraft body, on an extension line of the crankshaft. A rear end of the crankshaft is disposed in an engine case, and an output power shaft separate from the crankshaft is connected to the rear end of the crankshaft. The shaft of the propulsion device is connected to a rear end of the output power shaft. The rear end of the crankshaft and a front end of the output power shaft are connected to each other in a transmission chamber in which a transmission mechanism for transmitting power of the crankshaft to a camshaft is provided at a rear portion of the crankshaft. A driving sprocket wheel of the transmission mechanism is provided on the output power shaft.

Abstract: A watercraft includes an engine having an output shaft. A coupling structure is provided on one end of the output shaft. A driveshaft has an engine connecting axial end portion. The engine connecting end portion provides a first cooperating interlocking structure. A resiliently deformable cushioning structure has a second cooperating interlocking structure and is mounted to the engine connecting end portion with the first and second interlocking structures interlocking with one another to secure the cushioning structure on the engine connecting end portion. The coupling structure couples the output shaft and driveshaft together so that powered rotation of the output shaft is transmitted to the driveshaft. The cushioning structure is positioned between the engine connecting end portion and output shaft such that the cushioning structure prevents the engine connecting end portion from abutting directly against the output shaft during relative movement of the driveshaft and output shaft towards one another.

Abstract: An oil pump includes an oil supply pump and an oil recovery pump disposed on an extension line of a crankshaft of an engine. One joint member is provided at an end portion of the crankshaft, and another joint member is provided at an end portion of a pump shaft. The two joint members are coupled to each other on the same axial line within a front cover of an engine. The two joint members have alternating concave portions and convex portions. The convex portions of the two joint members include inclined faces and opposing driving transmission faces. The inclined faces of the convex portions guide the convex portions into the concave portion of the opposing joint member, so that the two joint members are meshed with one another. The crankshaft side joint member is fastened together with an ACG rotor. An oil tank connected to the oil pump is disposed above and very close to the oil pump.

Abstract: A drive system includes a drive shaft with first and second shaft sections connected by a diaphragm clutch having a diaphragm assembly. The radially outer end of the diaphragm assembly is connected to a disk having a first toothing arranged on one face of the disk. The first toothing engages in corresponding second toothing on a flange connected to the first shaft section when the diaphragm assembly is subjected to an axial preload. A contact-pressure device that is controllable by remote control in the stationary condition acts against the disk to produce the preload.

Abstract: A marine drive includes a drive shaft having an upper portion, a lower portion, and at least one waist portion between the upper and lower portions. The upper portion is adapted to be coupled to an engine crankshaft and the lower portion is adapted to be supported by bearings and drives a propulsion device through a transmission. The waist portion has a diameter of generally lesser size than the diameters of the upper and lower portions. The waist portion is tapered so that the diameter of the waist portion at its upper end is greater than the diameter of the waist portion at its lower end. The tapered geometry of the waist portion helps distribute impact forces that may occur when the propulsion device is suddenly locked in position when the engine is still running. As a result, failure and damage to the drive shaft waist portion is reduced.

Abstract: In an ocean-going ship or vessel, a device is used to seal propeller drive shafts and has an inner bush that guides the drive shaft. The inner bush is for its part guided in an outer bush and has an inside diameter that is greater than an outside diameter of the drive shaft to be guided The inner bush has at least one oil or grease channel which is provided with at least one discharge opening in the vicinity of an inner side of the inner bush and can be connected to an oil or grease transport device.

Abstract: A propeller assembly that includes an interchangeable drive sleeve, a resilient inner hub having a bore in which the drive sleeve is inserted, and a propeller including an outer hub in which the drive sleeve and resilient inner hub are inserted, is described. In an exemplary embodiment, the drive sleeve includes a cylindrical shaped body and a plurality of splines extend from an outer diameter surface of drive sleeve body. A bore extends through drive sleeve, and a plurality of grooves are in an inner diameter surface of the drive sleeve bore. These grooves are configured to mate with splines on a propeller shaft. Resilient inner hub includes a cylindrical shaped body and a plurality of tapered grooves in an inner diameter surface of the inner hub body. Each groove is arranged to receive one drive sleeve spline. The inner hub also includes a drive flange at one end thereof.

Abstract: A marine jet drive with a wall structure forming an intake duct forward of a rotatable impeller, a drive shaft extending across part of the intake duct and coupling an engine to the impeller, a shaft sleeve secured to the wall structure, and a seal at the rear end of the shaft sleeve, the shaft sleeve and seal isolating the drive shaft from water and debris. Certain preferred embodiments include: a seal cartridge between the shaft sleeve and the impeller hub; a cooling feature; an annular-groove-and-pin cartridge-retention arrangement; a readily-releaseable sealing connection to the shaft sleeve; and a debris-cutting device.

Abstract: A marine propulsion system provides dual driveshafts which are connected in torque transmitting relation with associated propellers. In addition, a bow thruster is provided to provide a thrust on the bow of the marine vessel in the port and starboard directions. An output shaft extends from an engine in a forward direction, toward the bow, and two driveshafts extend from torque transmitting devices, which are also disposed forward from the engine, wherein the driveshafts extend in a rearward direction toward the transom. The driveshafts can be associated directly with propellers, in applications where the driveshafts extend through the transom or through a bottom portion of the hull. Alternatively, the driveshafts can be associated with stern drive units. Efficient maneuvering can be accomplished by selectably determining the magnitudes and directions of the three thrust vectors provided by the two propellers and the bow thruster.

Abstract: A roller bearing drive assembly for a marine mud motor with an elongated drive tube containing a lubricant, the drive assembly configured for rotatably receiving a drive shaft including a propeller on the end. The drive assembly comprises a drive assembly housing containing an outer seal to restrict lubricant flow from the housing cavity, an inner seal to provide a lubricant chamber for pressurizing the lubricant, a bearing to rotatably connect the drive assembly housing to the drive shaft, and a seal cap to protect the outer seal from the elements.

Abstract: A marine jet drive having a rotatable impeller, an impeller housing, an intake duct, a diffusor housing rearward of the impeller housing, an engine, and a unitary drive shaft extending from the engine to the impeller, and having a rear flexible coupling connecting the drive shaft to the impeller and a front flexible coupling connecting the drive shaft to the engine. Certain preferred embodiments include a shaft sleeve and rear seal assembly isolating the drive shaft from water and debris.

Abstract: A propeller assembly is provided for mounting on a rotatable propeller shaft of a marine vehicle. The propeller assembly includes a central hub mounted on the propeller shaft for rotation therewith. A generally tubular propeller housing is slidable on the central hub for rotational movement with the propeller shaft. The propeller housing includes an inner surface having a shoulder formed therein. A locking ring is mounted on the propeller shaft. The locking ring includes an outer rim for engaging the shoulder and preventing removal of the propeller housing from the central hub. A stop member may also be provided to limit movement between the propeller housing and the central hub.

Abstract: A watercraft includes an engine having an output shaft. A coupling structure is provided on one end of the output shaft. A driveshaft has an engine connecting axial end portion. The engine connecting end portion provides a first cooperating interlocking structure. A resiliently deformable cushioning structure has a second cooperating interlocking structure and is mounted to the engine connecting end portion with the first and second interlocking structures interlocking with one another to secure the cushioning structure on the engine connecting end portion. The coupling structure couples the output shaft and driveshaft together so that powered rotation of the output shaft is transmitted to the driveshaft. The cushioning structure is positioned between the engine connecting end portion and output shaft such that the cushioning structure prevents the engine connecting end portion from abutting directly against the output shaft during relative movement of the driveshaft and output shaft towards one another.

Abstract: A shaft coupling for an outboard motor includes an improved construction that can be held under a good lubricative condition. The outboard motor includes an engine. An engine body defines a first aperture through which a crankshaft extends and is journaled. A recessed portion of the crankshaft defines inner spline grooves. A support member that supports the engine body has a second aperture. A driveshaft extends through the second aperture toward the recessed portion. The driveshaft has a tip portion defining outer spline grooves that are coupled with the inner spline grooves. A first seal member is disposed between an outer surface of the output shaft and an inner surface of the first aperture. A second seal member is disposed between an outer surface of the driveshaft and an inner surface the second aperture. The engine body, the support member, the output shaft, the driveshaft and the first and second seal members together define a lubricant chamber to enclose lubricant.

Abstract: A marine drive transmission includes an improved shock-absorbing coupling mechanism. Engine power is transmitted to a propulsion device through a drive shaft and driven shaft. The drive shaft is coupled to the driven shaft by a coupling arrangement which has a first coupling mechanism and a second coupling mechanism. The second coupling mechanism is spaced apart from the first coupling mechanism in a direction along a common axis of the shafts. The shafts are coupled with each other selectively by one of the first and second coupling mechanisms. The first coupling mechanism desirably includes an elastic member or a viscosity coupling. The second coupling mechanism desirably includes a toothed mechanism, which functions as the primary coupling between the drive and driven shafts (i.e., overrides the first coupling) once a predetermines load has been applied to the drive shaft.

Abstract: A sealing member for a propeller shaft is provided with a heat shield to prevent damage from occurring to an elastomeric portion of the sealing member when exposed to hot exhaust gases. The exhaust gases can flow in thermal communication with the elastomeric portion of the sealing member when the marine propulsion unit is operated in reverse gear. A heat shield is provided by extending a metallic portion of the sealing structure toward the outer cylindrical surface of the propeller shaft and rounding the edge to avoid direct contact between the heat shield and the propeller shaft.

Abstract: An assembly and techniques for facilitating assemblage of a drive unit to a gimbal housing in a boat are provided. The assembly uses a universal joint (U-joint) in the gimbal housing for pivotally engaging the drive unit to the gimbal housing. The U-joint includes an input shaft that receives driving power and an output shaft connectable to the drive unit. The assembly further uses an alignment subassembly configured to support the U-joint in an alignment position while its output shaft is being connected to the drive unit.

Abstract: A roller bearing drive assembly for a marine mud motor with an elongated drive tube containing a lubricant and for rotatably receiving a drive shaft including a propeller on the end. The drive assembly comprises a drive assembly housing having an upper end, lower end, and housing cavity. An outer seal is mounted in the lower end of the drive assembly housing and structured to stop lubricant flow from the housing cavity. A seal cap is mounted to protect the outer seal from the elements. An inner seal is provided, between the outer seal and the upper end of the drive assembly housing, and spaced apart from the outer seal to provide a lubricant chamber for pressurized lubricant. The pressurized lubricant in the lubricant chamber cannot escape because the two seals are installed in opposing directions allowing pressurized fluid to enter but not escape the lubricant chamber.

Abstract: A center bearing for a shaft, in particular a propeller shaft, has a rolling bearing arranged on the propeller shaft and a bearing housing surrounding the center bearing. A slide ring in which the rolling bearing is axially displaceable is arranged over the outer periphery of the rolling bearing. A decoupling element is arranged between the slide ring and the bearing housing.

Abstract: A water jet apparatus having a single drive shaft rotatably supported by a pair of bearings installed in an inlet housing. The impeller is securely mounted on a splined end of the drive shaft which extends out of the inlet housing in the aft direction. The drive shaft is not supported by the stator housing, thereby eliminating the need to install bearing inside the stator housing during assembly. Oil seals are arranged between the drive shaft and an inlet housing projection which extends into a cavity formed in the front end of the impeller.

Abstract: An outboard motor with an engine where the exposed ends of the crankshaft and camshaft project downward toward the bottom surface of the engine. An accommodation chamber is recessed within the bottom surface of the engine. A chain driven camshaft drive mechanism fits within this accommodation chamber. An oil pump, mounted below the accommodation chamber, is driven by the crankshaft. The bottom end of the crankshaft is sandwiched between the bottom surface of the engine and an oil seal housing. The oil seal housing fits within a recessed opening in a plate-like engine holder positioned below the engine. A plurality of positioning and fastening bosses are used to align and fix the oil seal housing to the engine. When the engine is removed from the outboard motor, its bottom surface is flat enabling the engine sit upright on a workbench.

Abstract: A drive system includes a drive shaft with first and second shaft sections connected by a diaphragm clutch having a diaphragm assembly. The radially outer end of the diaphragm assembly is connected to a disk having a first toothing arranged on one face of the disk. The first toothing engages in corresponding second toothing on a flange connected to the first shaft section when the diaphragm assembly is subjected to an axial preload. A contact-pressure device that is controllable by remote control in the stationary condition acts against the disk to produce the preload.

Abstract: A housing for an outdrive is installed with a replaceable tower support for a ball bearing race through which the drive shaft rotates. When the bearing race becomes worn, rather than replacing the entire housing and installing a new bearing race, only the tower support and worn bearing race is removed and replaced, which represents a considerable cost saving.

Abstract: An inboard/outboard boat drive having a housing with first and second ends and a cavity passing between the housing first and second ends. The first end of housing is pivotally mounted on the boat stern. The drive includes an input drive shaft for coupling to an engine mounted within the boat, an intermediate drive shaft disposed within the housing cavity, a first universal joint coupling the input device shaft and the intermediate drive shaft, together with an output drive shaft coupled to a propulsion element and a second universal joint coupling the intermediate drive shaft and the output drive shaft.

Abstract: A propeller assembly that includes, in an exemplary embodiment, a cantilever spring for securing a propeller to a propeller shaft is described. In the exemplary embodiment, the propeller assembly includes a thrust bearing which tightly fits to an inclined surface of the propeller shaft. The thrust bearing includes an annular slot which forms a tight fit with one end of a hub of the propeller and one end of the spring. The propeller hub has a cylindrical shape, and a plurality of blades extend from an outer surface of the hub. A bore extends through the propeller hub, and the spring extends into the hub bore. The assembly further includes a washer and a nut which engages to a threaded end of the propeller shaft.

Abstract: In an outboard engine, a support member for supporting a drive shaft and an exhaust pipe within an extension case can be cooled by outside water pumped by utilizing the exhaust pressure from the engine. The inside of the extension case is divided, by the support member for supporting the drive shaft and the exhaust pipe, into an upper chamber communicating with the open air, and a lower chamber into which outside water is introduced, so that the exhaust gas from the exhaust pipe is discharged into the lower chamber. Both the upper and lower chambers are in communication with each other through a communication pipe. Thus, during operation of the engine, the support member and the depending members are cooled by the outside water forced up from the lower chamber through the communication pipe into the upper chamber.

Abstract: Several embodiments of personal watercraft having very compact construction, in particularly embodying a compact propulsion system wherein the engine and a number of its accessories all define a very compact area. This permits the center of gravity to be located at the desired location and maintain good balance for the watercraft regardless of the number of passengers who occupy it.

Abstract: In a marine propulsion system comprising: a drive shaft operably connected to an engine and carrying a drive bevel gear; a propeller shaft carrying a propeller; and a pair of driven bevel gears meshing with the drive bevel gear and selectively engageable with the propeller shaft via a clutch member, the propeller shaft is provided with an axially facing annular shoulder surface which faces a corresponding axially facing surface of one of the pair of driven bevel gears to determine an axial position of the propeller shaft, and a rolling thrust bearing is disposed between the mutually facing surfaces of the propeller shaft and the one of the pair of driven bevel gears. The rolling thrust bearing reduces the friction between the mutually facing surfaces of the propeller shaft and the one of the driven bevel gears when they rotate in opposite directions to each other, to thereby improve the durability of these component parts.

Abstract: The root shape of a flash formed in the friction-welded joint is controlled by introducing an upset delay time interposed between termination of the friction step and commencement of the upset step and by controlling the upset displacement speed. This provides a friction-welded joint having a tensile strength and a fatigue strength which are comparable with those of TIG- or MIG- welded joints and enables aluminum alloy hollow members to be produced by friction welding instead of TIG or MIG welding. Typically, the upset delay time is 0.4 to 0.8 sec and the upset displacement speed is 5.0 to 70.0 mn/sec to form a flash having a flash root radius of 0.5 mm or more and a flash root angle of 75.degree. or less.

Abstract: A vibrational damper reduces torsional vibration within a crankshaft of a marine engine. The vibrational damper is located on an end of the crankshaft opposite of the flywheel and includes an inertia ring that adds additional mass to this opposite end. In addition, the vibrational damper includes an elastic member that suspends the inertia ring about the crankshaft. The elastic member effectively dampens torsional vibrations. The torsional damper desirably is cooled by an air flow so as to maintain it's dampening efficiency. A ventilation duct, which is positioned directly above the vibrational damper, supplies the cooling air. Cooling is enhanced by locating a bilge system inlet below and slightly behind the vibrational damper. An air flow stream occurs between the duct and the bilge inlet and across the torsional damper to cool the torsional damper.

Abstract: A system for propelling a marine vessel having a hull. The propulsion system including a first propeller assembly positioned to extend from the hull and along starboard side of the vessel, the first propeller assembly including a propeller positioned outside the hull and a second propeller assembly positioned to extend from the hull and along a port side of the vessel, the second propeller assembly including a propeller positioned outside the hull. An engine is mounted within the hull and connected to both the first and second propeller assemblies for imparting rotation to both the first and second propellers. The engine is connected to the first propeller assembly by a first rotating unit connected between the engine and first propeller assembly for rotating the first propeller. The engine is connected to the second propeller assembly by a second rotating unit connected between the engine and second propeller assembly for rotating the second propeller.

Abstract: Hub assembly for the journalling of an impeller (4) or drive shaft end (3) in the pump housing (2) of a water jet propulsion unit for propulsion of a vessel. The hub assembly forms a separate, integrated assembly (6) which as a single unit can be assembled and dismounted from the stem without requiring the pump housing, impeller or drive shaft to be removed from the vessel. The hub assembly is joined together by means of a tightening nut (15), screwed onto a sleeve (9), with an inwardly positioned bearing plate (16) axially holding the sleeve in a bearing housing (8) while concurrently clamping the bearings (10, 11) between said bearing plate and a radially extended flange (17), arranged in the front end of the sleeve, so that the bearing housing, the bearings and the sleeve form a separate, integrated unit.

Abstract: This invention relates to a marine jet drive having improved operation, especially in regard to having efficient adaptation to propulsion engine and hull design; having a drive shaft with flexible coupling at each end, internal to the jet drive; having through-the-nozzle engine exhaust; having simplified, combined means of steering and reversing; having controllable nozzle aperture and trim control; having combination reverse flow deflector and trim plane; having means to disengage the engine from the jet to obtain true neutral; having protection from and removal of debris in the water intake duct; generally having fewer overhauls, easier serviceability and lighter weight.

Abstract: A ship propulsion system in which the ship's propeller is connected with its propeller shaft directly to a drive mechanism. A thrust bearing in the drive mechanism receives directly the thrust of the propeller shaft. An auxiliary drive with an electrical machine is operable selectively as a motor or as a generator, and a coupling is provided between the electrical machine and transmission linkage in the auxiliary drive. A gear on the transmission surrounds the propeller shaft, and a flexible coupling connects the transmission to the propeller shaft. Mounted on a separate section of the propeller shaft between the transmission and the drive mechanism, is a shiftable coupling which is free of play and transmits torque from the drive mechanism to the propeller shaft as well as the thrust of the propeller shaft. An auxiliary thrust bearing is connected to the shiftable coupling and is actuated when the ship is in auxiliary or emergency operation during which the propeller shaft has a reduced thrust.

Abstract: A propeller device includes a shaft rotatably supported in a marine engine, and a hub secured to the shaft and having three or more axially extending keys. A propeller housing includes three or more pairs of lobes for forming keyways and for engaging with the keys of the hub. The keyways include a narrower outer end for preventing the housing from disengaging from the hub. Three or more stops are disposed between the pairs of lobes. A retainer disc includes a number of angularly spaced ears for engaging with the lobes and the stops and for preventing the propeller housing from being disengaged from the propeller shaft.