Abstract: A marine vessel propulsion system includes multiple propulsion devices, multiple operation levers, and multiple lever position sensors arranged to detect the positions of the multiple operation levers, and a control unit. The control unit is programmed to control, based on detection results from the multiple lever position sensors, the shift states of the respective propulsion devices and to change the steering angle of at least one of the propulsion devices. The control unit may be arranged to change the steering angles of the propulsion devices to facilitate the behavior of the hull corresponding to the shift states of the respective propulsion devices.

Abstract: A steering system for a marine pod drive is disclosed. The system includes a driving pinion attached to a driving shaft. The system further includes a driven gear mounted to a driven shaft. Moreover, the system includes an intermediate gear mounted to an intermediate shaft and in mesh with the driving pinion. Furthermore, an intermediate pinion is attached to the intermediate shaft. The intermediate pinion is in mesh with the driven gear on the driven shaft. Moreover, the intermediate pinion may be fastened with the intermediate gear by a shear pin such that the intermediate pinion rotates with the intermediate gear. The shear pin may be configured to shear when a torque transmitted through the system exceeds a rated torque value, thereby causing the intermediate gear to rotate freely on the intermediate shaft.

Abstract: The gear case assembly has a gear case, a driveshaft and a propeller shaft mounted at an angle to the driveshaft, each at least partly disposed within the gear case, a transmission having forward and reverse gears and a shift rod, and an electric transmission actuator assembly having an actuation axis and an actuator end engaging the shift rod. The transmission is operatively connected the propeller shaft and the driveshaft selectively drives the propeller shaft via the transmission. An actuator chamber houses at least part of the actuator assembly. There is a gap between the actuator assembly and an actuator chamber wall in a direction perpendicular to the actuation axis. The gap is sized and shaped to permit a translation of the actuator assembly away from the shift rod for disengagement from the shift rod. A gear case, a marine outboard engine and a method of assembly is also disclosed.

Abstract: Disclosed are a ship propulsion device and a ship having the same. According to one embodiment of the present invention, the ship propulsion device includes a rear propeller fixed on a drive shaft; a front propeller supported on a drive shaft of the front of the rear propeller to be rotated; and a reverse rotary device having a plurality of gears which are provided on a rear side of the ship, and transmits rotation of the drive shaft after reversing the rotation to the front propeller.

Abstract: A watercraft propulsion system has a driveshaft, one of an impeller and a propeller, an overrunning clutch having outer and inner races, a driveshaft connector connecting the driveshaft to the outer race, an electric motor having a motor output shaft operatively connected to the outer race, and an internal combustion engine. The engine has a crankcase and a crankshaft operatively connected to the inner race. A lubricant pump supplies lubricant to the overrunning clutch via lubricant passages in the crankshaft. A watercraft having the propulsion system and a hybrid propulsion conversion system for a watercraft are also disclosed.

Abstract: An outboard marine drive with an engine is described. The marine drive may include a drive housing with an upper drive housing and lower drive housing. The drive housing may be configured to be attached to a transom of a marine craft. An upper drive assembly may be located in the upper drive housing. A lower gear drive assembly may be located in the lower drive housing. A cone clutch may be located in the lower drive housing to engage the upper drive assembly with the lower gear drive assembly.

Abstract: A transmission is structured to include a drive shaft, a counter shaft, a gear train bridged between each of a drive shaft input shaft and output shaft and the counter shaft, and a dog clutch mechanism selectively switching a high shift speed and a low shift speed in a transmission chamber. In a lower part of a lower bearing of the counter shaft in a bottom part of the transmission chamber, a lower reserve part of lubrication oil is provided, and a lubrication oil pump sending lubrication oil to respective parts of the transmission from the lower reserve part is provided.

Abstract: A gear case assembly for an outboard engine has a gear case, a driveshaft having a part disposed within the gear case, a bevel gear connected to the part of the driveshaft, a propeller shaft, and a transmission operatively connected to the bevel gear. The bevel gear selectively drives the propeller shaft via the transmission. The transmission has forward and reverse gears operatively connected to the bevel gear, and a shift assembly adapted for actuation by a shift actuator. The shift assembly has first and second rod portions and at least one resilient member. The at least one resilient member operatively connects the first rod portion to the second rod portion. The first rod portion is movable relative to the second rod portion.

Abstract: A gear case assembly for a marine propulsion system has a gear case, a driveshaft, a propeller shaft, and a transmission chamber. A driveshaft passage fluidly connects to the transmission chamber. A lubricant return passage fluidly connects to the transmission chamber and the driveshaft passage. A pump is driven by the driveshaft. A first lubricant filling port fluidly communicates one of the lubricant return passage and the driveshaft passage with an exterior of the gear case. A second lubricant filling port fluidly communicates one of the lubricant return passage and the transmission chamber with the exterior of the gear case. First and second plugs are selectively disposed in the first and second lubricant filling ports respectively. A check valve is disposed in the lubricant return passage between the first and second lubricant filling ports. The check valve prevents lubricant to flow through the check valve away from the transmission chamber.

Abstract: A dog clutch mechanism incorporated in an outboard motor includes a sliding clutch dog member splined to a propeller shaft and having recesses on each end face thereof, and a row of gear teeth formed on an end face of each of a pair of driven gears rotatably mounted on the propeller shaft. Each of the recesses has a bottom surface stepped to provide a corner edge at a stepped portion thereof. Each of the gear teeth has a beveled surface formed at a rear edge as viewed from a rotating direction of the driven gear. When the gear teeth are in mesh with the recesses of the clutch dog member, the corner edge of the stepped bottom surface of each recess is in contact with the beveled surface of the mating gear tooth.

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: A gondola drive for a floating device has an underwater housing circulated around by water. The gondola drive contains a drive module which has a drive module housing and a shaft disposed therein, a transmission module with a transmission module housing and a transmission disposed therein and a propeller. The drive module and the transmission module are each configured as separate components connected to one another such that the drive module housing and the transmission module housing form at least a part of the underwater housing and that the shaft is coupled to the transmission for driving the propeller.

Abstract: A vessel propulsion apparatus includes a second shaft that is inserted in a first driven gear and in a second driven gear, that is connected to a dog clutch, and that is arranged to undergo a thrust. The vessel propulsion apparatus includes a first bearing disposed between the first driven gear and the second shaft, a second bearing disposed between the second driven gear and the second shaft, and a case to which a thrust applied to the second shaft is transmitted via the first bearing and the first driven gear or via the second bearing and the second driven gear. The vessel propulsion apparatus includes an adjusting member disposed between the second shaft and at least one of the first driven gear and the second driven gear and arranged to apply a preload onto the first bearing and the second bearing.

Abstract: This invention relates to an amphibious vehicle and especially to an amphibious vehicle having twin internal combustion engines propelling the vehicle in water with a pair of water jet drives and propelling the vehicle on land with one of the same engines having an automatic transmission controlling a pair of track assemblies with a pair of planetary gears, clutches and disc brakes.

Abstract: A hybrid power device for a marine vehicle is provided that has two hybrid prime movers, an electric motor and a combustion engine, that distribute power, for example torque, to a single or dual propulsor, such as surface drives with propellers. The prime movers can apply power singly or in unison, but maintain substantially optimum propulsive efficiency in all cases. The power outputs of the prime movers are in communication with a power transmitting device such as a gear box that may combine the power outputs to drive a single propulsor, or may have a power-splitting embodiment driving dual propulsors. In addition, multiple hybrid power devices may be deployed in other embodiments.

Abstract: A method and apparatus for limiting the torque from an engine to the drive train of a watercraft. A torque limiting clutch is mounted to the flywheel of the engine. The output of the clutch is connected to the drive train of the watercraft. The clutch allows all of the engine's torque to be delivered to the drive train during normal conditions and less than all of the engine's torque to be delivered to the drive train during conditions in which the drive train experiences periods of excessive force. When normal conditions return, the apparatus automatically delivers all of the engine's torque to the drive train.

Abstract: An outboard drive device (10) comprising a motor (11) having a crankshaft (16), wherein said outboard drive device (10) further comprises a propeller shaft (12) with a propeller which propeller is below the hull (13) of a boat when said outboard drive device (10) is operated, and a power coupling system for transferring power from the motor (11) to the propeller shaft (12). The motor (11) is an automotive motor or an industrial base engine, wherein the crankshaft (16) is substantially horizontal and substantially parallel to the propeller shaft (12) when said outboard drive device (10) is operated. The power coupling system comprises a power transfer device (17), a transmission (18) and a transmission drive shaft (19). The power transfer device (17) connects the crankshaft (16) with the transmission drive shaft (19) for transferring the output power from the crankshaft (16) to the transmission drive shaft (19).

Abstract: A pivotal boat drive having a transmission unit (1) which is driven by a drive engine via a connection point (A). The connection point has an input shaft (11) of a drive device (10) that is rotatably positioned around a first rotational axis (5) and an output shaft (3) that is coupled with the input shaft (11) and rotatable around a second rotational axis (6). The rotational axes (5, 6) are neither parallel nor concentrically positioned with respect to one another. At least one additional connection point (B, C) is provided at the transmission unit (1), at which an additional drive device (20), driven by an additional drive engine, can be positioned to drive the output shaft (3).

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: Marine vessel transmission with an input drive shaft which extends along an input drive shaft axis and is designed to be connected to a marine engine, an output drive shaft which is designed to provide a torque to a propeller and has a gear reduction for the input drive shaft, a housing which partially surrounds the input drive shaft and the output drive shaft, a secondary output drive shaft having a torque introduction journal that protrudes from the housing and on which a secondary output drive gearwheel is arranged, which is located in the torque path behind the input drive shaft, and an electric generator which features a rotor which is interlocked with the torque introduction journal, whereby the rotor runs coaxially to the secondary output drive shaft and is borne mechanically determined onto the torque introduction journal.

Abstract: Disclosed herein is a trimmable pod drive assembly that includes a pod drive unit having a transmission assembly secured to a steering unit, a gear case assembly coupled to and rotatable by the steering unit about a steering axis, and a propeller rotatable about a propeller driveshaft axis extending through the gear case assembly so as to generate thrust along a thrust vector. The trimmable pod drive assembly further includes a trim assembly secured to the pod drive unit in a manner allowing for rotation of the pod drive unit about a trim axis that is substantially perpendicular to the steering axis, wherein actuation of at least one component of the trim assembly causes movement of the pod drive unit and the thrust vector about the trim axis.

Abstract: The present invention relates to an outboard drive device (10) comprising an outboard motor (11) having a crankshaft (16), wherein said outboard drive device (10) further comprises a propeller which propeller is below the hull (13) of a boat when said outboard drive device (10) is operated, and a power coupling system for transferring power from the motor (11) to the propeller. The power coupling system comprises a power transfer device (17) for transferring output power from the crankshaft (16) to a transmission drive shaft (19) of a transmission (18), and a power transfer means (20) for transferring output power from the transmission (18) to a drive shaft (21) of an endless loop flexible drive coupling (22) operatively connecting said transmission (18) to a propeller shaft (12) for driving said propeller, wherein the crankshaft (16) is substantially horizontal and substantially parallel to the propeller shaft (12) when said outboard drive device (10) is operated.

Abstract: An outboard engine unit includes a water pump disposed on a lower end portion of an input shaft of a transmission, and left and right cooling water feeding passages interconnecting the water pump and a cooling water inlet of an engine. The left and right cooling water feeding passages are disposed around a plurality of transmission gears disposed on the input shaft of the transmission. A cooling water drawn by the water pump is guided through the left and right cooling water feeding passages to the cooling water inlet.

Abstract: A propeller drive assembly, for steering and driving a ship (1), comprises a drive motor (2) and a transmission housing (4) secured to a ship hull and a control housing (7) secured to an exterior surface of the hull. The control housing (7) comprises a propeller (8) supported on a driven shaft (6) and the control housing (7) is pivotably coupled, via a steering shaft (10), to the transmission housing (4) for steering the ship (1). A transmission output shaft (5) is connected with the driven shaft (6) and a lubricant circuit of the transmission housing (4) is separate from a lubricant circuit of the control housing (7). At least one sealing element is provided, in a region of a shaft passage of the transmission output shaft (5) and in a region of a shaft passage of the steering shaft (10), for mutually sealing the transmission housing lubricant circuit and the control housing lubricant circuit.

Abstract: An outboard motor mounted on a stern of a boat is provided with a transmission and an oil pump. The transmission has a first-speed and second-speed gears, a first-speed gear clutch made of a mechanical dog clutch and a second-speed gear clutch made of a hydraulic clutch each adapted to engage the first and second-speed gears on a power transmission shaft, and a first-speed gear shift actuator adapted to couple the first-speed gear clutch with the first-speed gear. In the transmission, a first speed is established when the first-speed gear is engaged on the power transmission shaft and a second speed is established when the second-speed gear is engaged on the power transmission shaft while the first speed has been established such that power of the engine is transmitted to the propeller through the established speed.

Abstract: An outboard marine drive with an engine is described. The marine drive can include a drive housing with an upper drive housing and lower drive housing. The drive housing can be attached to a transom of a marine craft. An upper gear drive assembly can be located in the upper drive housing. A transmission can be provided with the upper gear drive assembly in the upper drive housing. In addition, a lower gear drive assembly can be located in the lower drive housing and coupled to the upper gear drive assembly. A propeller shaft may also be coupled to the lower gear drive assembly.

Abstract: A vessel propulsion apparatus includes a second shaft that is inserted in a first driven gear and in a second driven gear, that is connected to a dog clutch, and that is arranged to undergo a thrust. The vessel propulsion apparatus includes a first bearing disposed between the first driven gear and the second shaft, a second bearing disposed between the second driven gear and the second shaft, and a case to which a thrust applied to the second shaft is transmitted via the first bearing and the first driven gear or via the second bearing and the second driven gear. The vessel propulsion apparatus includes an adjusting member disposed between the second shaft and at least one of the first driven gear and the second driven gear and arranged to apply a preload onto the first bearing and the second bearing.

Abstract: A method of assembling an outboard engine is disclosed. The outboard engine has first and second driveshafts, each having a helical gear on a first end and a driving gear on a second end. A driven shaft has a driven gear. The method comprises: rotating the driven shaft; measuring an axial displacement of one of the first and second helical gears with respect to the engine casing; selecting a shim based at least in part on the measurement of the relative axial displacement; and placing the shim on the one of the first and second driveshafts at a position axially below the helical gear. A method of assembling a marine outboard engine comprising moving a height adjustment member from a first position to a second position based on the relative axial displacement is also disclosed. An outboard engine with first and second helical gears at different heights is also disclosed.

Abstract: An outboard motor for a marine vessel application, transmission devices for such an outboard motor, and related methods of making, operating, and modifying attributes of same, are disclosed herein. In at least one embodiment, the motor includes a horizontal-crankshaft engine in an upper portion of the motor, positioned substantially above a trimming axis of the motor. In at least another embodiment, first, second and third transmission devices are employed to transmit rotational power from the engine to propeller(s). In at least a further embodiment, the motor is made to include a rigid interior assembly formed by the engine, multiple transmission devices, and a further structural component. In further embodiments, the motor includes numerous cooling, exhaust, and/or oil system components, and/or other transmission features. In at least some additional embodiments, a transmission device of the motor is configured to facilitate gear ratio variation and/or includes an integrated oil pump.

Abstract: In a hybrid type marine propulsion device including a main engine and a motor, low fuel consumption is realized by a compact configuration and highly efficient drive control. A marine propulsion device includes a clutch 7 provided on an input shaft 6 of a main engine, a horizontal input/output shaft 8 connected to the clutch, a vertical shaft 11 connected to the input/output shaft through an upper bevel gear 9, a horizontal propeller shaft 13 connected to a lower end of the vertical shaft through a lower bevel gear 12, and a propeller 14 at the other end side of the propeller shaft, in which the propeller is revolved around the vertical shaft to set a propulsion direction, wherein a motor generator 20 is mounted on a floor 3, and connected directly to the other end side of the input/output shaft. In a low rotation region, motor propulsion is performed, and in a high rotation region, hybrid propulsion in which the main engine is assisted by the motor is performed.

Abstract: An outboard motor for a marine vessel application, and related methods of making and operating same, are disclosed herein. In at least one embodiment, the outboard motor includes a horizontal-crankshaft engine in an upper portion of the outboard motor, positioned substantially positioned above a trimming axis of the outboard motor. In at least another embodiment, first, second and third transmission devices are employed to transmit rotational power from the engine to one or more propellers at a lower portion of the outboard motor. In at least a further embodiment, the outboard motor is made to include a rigid interior assembly formed by the engine, multiple transmission devices, and a further structural component. In further embodiments, the outboard motor includes numerous cooling, exhaust, and/or oil system components, as well as other transmission features.

Abstract: An outboard motor for a marine vessel application, and related methods of making and operating same, are disclosed herein. In at least one embodiment, the outboard motor includes a horizontal-crankshaft engine in an upper portion of the outboard motor, positioned substantially positioned above a trimming axis of the outboard motor. In at least another embodiment, first, second and third transmission devices are employed to transmit rotational power from the engine to one or more propellers at a lower portion of the outboard motor. In at least a further embodiment, the outboard motor is made to include a rigid interior assembly formed by the engine, multiple transmission devices, and a further structural component. In further embodiments, the outboard motor includes numerous cooling, exhaust, and/or oil system components, as well as other transmission features.

Abstract: A marine propulsion system includes a gearbox housing that is attached to the stern of a vessel hull, a pivot casing that can pivot relative to the gearbox housing for trim/tilt and a lower unit that can pivot relative to the pivot casing to steer. The gearbox housing houses an input shaft, which is connected via a gear set to an intermediate shaft, which is connected via a bevel gear set to a transverse shaft, which extends into the pivot casing. Inside the pivot casing, a drive shaft is connected to the transverse shaft via a clutch assembly and the drive shaft extends from the pivot casing to the lower unit, where it drives a propeller shaft. The pivot casing pivots about the axis of the transverse shaft to trim/tilt and the lower unit pivots about the axis of the drive shaft to steer.

Abstract: An outboard motor for a marine vessel application, and related methods of making and operating same, are disclosed herein. In at least one embodiment, the outboard motor includes a horizontal-crankshaft engine in an upper portion of the outboard motor, positioned substantially positioned above a trimming axis of the outboard motor. In at least another embodiment, first, second and third transmission devices are employed to transmit rotational power from the engine to one or more propellers at a lower portion of the outboard motor. In at least a further embodiment, the outboard motor is made to include a rigid interior assembly formed by the engine, multiple transmission devices, and a further structural component. In further embodiments, the outboard motor includes numerous cooling, exhaust, and/or oil system components, as well as other transmission features.

Abstract: An outboard motor for a marine vessel application, and related methods of making and operating same, are disclosed herein. In at least one embodiment, the outboard motor includes a horizontal-crankshaft engine in an upper portion of the outboard motor, positioned substantially positioned above a trimming axis of the outboard motor. In at least another embodiment, first, second and third transmission devices are employed to transmit rotational power from the engine to one or more propellers at a lower portion of the outboard motor. In at least a further embodiment, the outboard motor is made to include a rigid interior assembly formed by the engine, multiple transmission devices, and a further structural component. In further embodiments, the outboard motor includes numerous cooling, exhaust, and/or oil system components, as well as other transmission features.

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: An outboard motor for a marine vessel application, and related methods of making and operating same, are disclosed herein. In at least one embodiment, the outboard motor includes a horizontal-crankshaft engine in an upper portion of the outboard motor, positioned substantially positioned above a trimming axis of the outboard motor. In at least another embodiment, first, second and third transmission devices are employed to transmit rotational power from the engine to one or more propellers at a lower portion of the outboard motor. In at least a further embodiment, the outboard motor is made to include a rigid interior assembly formed by the engine, multiple transmission devices, and a further structural component. In further embodiments, the outboard motor includes numerous cooling, exhaust, and/or oil system components, as well as other transmission features.

Abstract: An outboard motor includes an engine that generates power and a transmission device arranged to change the speed of rotation of the engine and to transmit the rotation to a propeller. The transmission device includes a planetary gear type transmission mechanism arranged to shift to any of a plurality of speed positions, and the planetary gear type transmission mechanism is controlled to shift such that a sun gear and planetary gears unitarily rotate when a speed position is a normally used speed position. The outboard motor achieves a reduction in load normally caused by engagements between gears in a normally used speed position and also achieves significant improvement in durability of the gears.

Abstract: A hybrid marine power train system is provided that facilitates selective use of one of multiple prime movers for powering and driving a boat. The multiple prime movers can include an internal combustion engine and an electric motor which can itself be part of a motor/generator assembly. The system further includes a power-take-in assembly that can have either an active or passive clutching device for selectively importing power from the prime movers into the transmission. The system is configured so that the second prime mover occupies relatively little space within an engine compartment of the boat, for example when compared to an amount of space occupied by the first prime mover and transmission. Since the second prime mover occupies relatively little space within the engine compartment, the system can be readily retrofitted to existing marine power train systems.

Abstract: In an apparatus for controlling operation of an outboard motor mounted on a boat and having a torque converter equipped with a lockup clutch, it is configured to regulate a trim angle relative to the boat by trim-up operation and trim-down operation; calculate a speed ratio of the torque converter based on an input rotation speed and output rotation speed of the torque converter; and control operation of the trim angle regulator based on the calculated speed ratio. With this, it becomes possible to mitigate a deceleration feel to be generated after the acceleration is completed, and easily sets a trim angle of after the trim-up operation to an optimal value.

Abstract: In an apparatus for controlling an outboard motor having an internal combustion engine to power a propeller, and a torque converter interposed between the engine and a drive shaft and equipped with a lockup clutch, it is configured to have a throttle opening detector that detects throttle opening of a throttle valve of the engine, a throttle opening change amount calculator that calculates a change amount of the calculated throttle opening, and a clutch ON unit that makes the lockup clutch ON when the calculated change amount is equal to or greater than a predetermined value, and keeps the lockup clutch ON during a predetermined time period. With this, it becomes possible to improve acceleration performance immediately after the engine speed is accelerated.

Abstract: A propulsion chain (8) for a ship (6) including a main heat engine (18); at least one secondary electrical power house (26) powering a distribution panel (34); at least one transmission line (16) provided with an end propeller (14) and mechanically coupled to the main heat engine (18) to drive the latter; at least one rotating electrical machine (22) mechanically coupled to the transmission line (16) and powered from the distribution panel (34), a mechanical coupler (20) able to be freed from the main heat engine (18) and the rotating electrical machine (22) arranged on the transmission line (16), between the rotating electrical machine (22) and the main heat engine (18).

Abstract: A marine propulsion system includes a gearbox housing that is attached to the stern of a vessel hull, a pivot casing that can pivot relative to the gearbox housing for trim/tilt and a lower unit that can pivot relative to the pivot casing to steer. The gearbox housing houses an input shaft, which is connected via a gear set to an intermediate shaft, which is connected via a bevel gear set to a transverse shaft, which extends into the pivot casing. Inside the pivot casing, a drive shaft is connected to the transverse shaft via a clutch assembly and the drive shaft extends from the pivot casing to the lower unit, where it drives a propeller shaft. The pivot casing pivots about the axis of the transverse shaft to trim/tilt and the lower unit pivots about the axis of the drive shaft to steer.

Abstract: A power transmission system of a marine propulsion system includes a transmission arranged to change the speed of an output from an engine and then to transmit the output to a propeller shaft. Wet-type multi-plate clutches provided in the transmission include a plurality of clutch plates fitted to a clutch rotating body for axial movement with the clutch rotating body. The clutch rotating body includes an oil reservoir in its inner bottom portion and arranged to hold lubricating oil and a peripheral wall arranged to cover the oil reservoir from the radial outside and fit to each of the clutch plates to permit axial movement of the clutch plates. Communicating holes are arranged on the peripheral wall such that they communicate the oil reservoir side to the outside of the clutch rotating body in the radial direction.

Abstract: A vertical power unit includes: an engine having a vertically arranged crankshaft; a vertically arranged output shaft provided below the crankshaft; and a torque converter providing a connection between the crankshaft and the output shaft. The torque converter is arranged so as to be offset from the crankshaft toward a cylinder block of the engine. A transmission device is provided between the crankshaft and the torque converter. The output shaft is arranged coaxially with the torque converter. Thus, the center of gravity of the vertical power unit is positioned as close as possible to the central portion of the engine, thereby minimizing bias of the center of gravity due to the weight of the torque converter and the output shaft to facilitate the handling of the vertical power unit.

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.

Abstract: A boat propulsion system includes a power source, a propulsion section, a shift position switching mechanism arranged to switch among a first shift position, a second shift position, and a neutral position, a gear ratio switching mechanism, an actuator, and a control section. When switching is to be performed from the neutral position to the first shift position and the high-speed gear ratio, the control section is arranged to cause the actuator to, maintain the low-speed gear ratio, switch to the first shift position, and then establish the high-speed gear ratio when the current gear ratio of the gear ratio switching mechanism is the low-speed gear ratio, and cause the actuator to establish the low-speed gear ratio before switching to the first shift position, switch to the first shift position, and then establish the high-speed gear ratio when the current gear ratio of the gear ratio switching mechanism is the high-speed gear ratio.

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: In an apparatus for controlling operation of an outboard motor mounted on a boat and having a torque converter equipped with a lockup clutch, it is configured to have a clutch controller that controls the lockup clutch to ON when a speed ratio of the torque converter is equal to or greater than a reference value, the clutch controller being configured to determine whether a throttle valve is at about a fully-opened position and to control the lockup clutch to ON when the speed ratio becomes equal to or greater than a predetermined value set smaller than the reference value before the speed ratio reaches the reference value, and the throttle valve is discriminated to be at about the fully-opened position. With this, it becomes possible to reliably make a lockup clutch ON when the acceleration is completed, so that the boat speed can reach the maximum speed.

Abstract: An outboard motor includes a transmission mechanism mounted between an output shaft of an engine and a propeller drive shaft. The transmission mechanism includes a clutch. An oil pump for generating a hydraulic pressure so as to switch the clutch is disposed underneath a lowermost one of transmission gears closely thereto. An oil pan is disposed underneath the oil pump and is placed inside an exhaust channel of a gear case.