Abstract: An all-terrain rover is provided in which the arrangement of flanges of one or more cylinders of first and second cylinder systems allow for forward and backwards motion, as well as turning and sideways motion of the roller. An all-terrain rover is further provided in which the flanges of the first cylinder system are oriented opposite to an orientation of the flanges of the second cylinder system such that, in counter-rotation, a forward or reverse motion results from contact between the flanges and a surface of travel.

Abstract: A gear mounting assembly is for causing rotation of a propeller on a marine drive. The assembly includes a driveshaft; a first bevel gear on the driveshaft, wherein rotation of the driveshaft causes rotation of the first bevel gear; a propeller shaft for supporting the propeller such that rotation of the propeller shaft causes rotation of the propeller; a gear hub on the propeller shaft; a second bevel gear on the gear hub, wherein the second bevel gear is engaged with the first bevel gear such that rotation of the driveshaft causes rotation of the gear hub, which thereby causes rotation of the propeller shaft; and an adapter facilitating relative rotation between the propeller shaft and the gear hub when the gear hub is caused to rotate by the driveshaft.

Abstract: An aircraft powerplant and a method for measuring thrust are described herein. A gas turbine engine has a turbine section for extracting energy from combustion gases and has a shaft mounted to the turbine section for converting the energy into rotary motion. A load cell is coupled to an end of the shaft and positioned to rotate with the shaft. The load cell is configured for generating a measurement indicative of propeller thrust. A propeller is coupled to the load cell and is configured for converting the rotary motion from the shaft and the load cell into the propeller thrust. The propeller thrust can be measured from the load cell as the propeller rotates.

Abstract: An apparatus is for supporting a marine engine and has a transom bracket having a body section, a head section extending transversely relative to the body section, a neck section disposed between the body section and the head section, and a transition portion along an inside surface of the neck section. A reinforcement member is connected to the neck section and relieves tensile stress on the transition portion when the transom bracket supports the marine engine.

Abstract: Boat (10) comprising a steering and propelling unit comprising at least one driving shaft (11, 11?) passing in an opening of the transom (12) for transmitting the motion from a motor to at least one propeller (21, 21?), at least one steering (14) provided at the top with at least one rotation pin (13), and a through-hull support (100) able to be associated with the opening and equipped with a plate portion (101) able to be fixed on the outside to the hull (12) of the boat (10) and with a through-hull tubular portion (102) for support of the at least one driving shaft (11, 11?), in which the through-hull support (100) also comprises at least one bush (103) passing through the plate portion (101) to support, in a rotary manner, the pin (13) bearing the steering (14) and in which the wall (12) of the hull where the passage opening of the at least one driving shaft (11, 11?) is formed is inclined from the top to the bottom in the direction of the stem of the boat (10).

Abstract: Lubricant oil (45) serving as second lubricant oil is supplied into an outer intermediate shaft (11c) by a lubricant oil supply unit (50) and accumulated therein, and thereby the lubricant oil (45) is supplied to a contra-rotating front seal unit (37). Thus, by bringing the front side of the contra-rotating front seal unit (37) (seal ring (37b)) into a wet state by the lubricant oil (45), it is possible to reduce heat generation and it is possible to extend the life of the contra-rotating front seal unit (37).

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

Abstract: A power transmission mechanism transferring a power output from an engine to a propeller includes a transmission planetary gear train that transforms the output power of the engine before it is transferred to the propeller. The transmission planetary gear train includes a transmission sun gear, a transmission double planetary gear set, and a transmission internal gear, in which the transmission sun gear is connected via the first clutch to the input end shaft extending into the engine, and the transmission sun gear is also connected via the second one-way clutch to the housing. In addition, the transmission double planetary gear set is connected via the second clutch to the input end shaft extending into the engine, and the transmission double planetary gear set is also connected via the first one-way clutch to the housing. Further, the transmission internal gear is connected to the output end shaft extending toward the propeller.

Abstract: A boat propulsion unit minimizes a shock upon switching of an engagement state of a clutch mechanism. The boat propulsion unit includes an upper clutch mechanism that is arranged on an axis of a lower drive shaft and that can be switched between an engagement state (first engagement state) in which driving force of an engine is transmitted to a downstream side, and a half clutch state in which the driving force of the engine is reduced and then is transmitted; and an advance-reverse drive that is disposed on an axis of a front propeller drive shaft and a rear propeller drive shaft and that can be switched between a forward travel engagement state and a reverse travel engagement state (second disengagement state) in which the driving force of the engine is transmitted to a front propeller and a rear propeller in order to propel a boat, and a disengagement state (second disengagement state) in which the driving force of the engine is disengaged.

Abstract: A boat propulsion unit has a construction that prevents a structure near a drive shaft from becoming complicated and increased in size. The boat propulsion unit preferably in the form of an outboard motor includes a front propeller that is rotated together with a front propeller drive shaft during both forward travel and reverse travel of the boat, a rear propeller that is rotated together with a rear propeller drive shaft in an opposite direction of the front propeller during both of the forward travel and the reverse travel of the boat, and a forward-reverse drive that is arranged on an axis of the front propeller drive shaft and the rear propeller drive shaft, and that can be switched between a direction in which the front propeller drive shaft and the rear propeller drive shaft are rotated during the forward travel of the boat and a direction in which the front propeller drive shaft and the rear propeller drive shaft are rotated during the reverse travel of the boat.

Abstract: The invention relates to a propeller pod (14) having a body (16) which has a shaft (18) for attachment to a vehicle (10), in particular to a watercraft, wherein the shaft (18) extends along a shaft axis (AS) and has at least one cross section (Q) with a chord (S), and (b) at least one propeller shaft (20, 24) for attachment of a propeller (22), (c) wherein the chord (S) runs at a direction angle (?) with respect to a propeller rotation axis (AP) of the propeller shaft (20, 24). The invention provides that the direction angle (?) changes, at least in places, with the distance (r) from the propeller rotation axis (AP).

Abstract: An outboard motor includes a drive shaft including a pinion gear arranged at one end of the drive shaft, a first driven gear engaged with the pinion gear, a second driven gear engaged with the pinion gear, a first propeller shaft connected to a second propeller, a second propeller shaft connected to a first propeller, and a shift change mechanism arranged to selectively engage the first driven gear with the second propeller shaft, and to selectively engage the second driven gear with the first propeller shaft and with the second propeller shaft.

Abstract: A propulsion or pumping device which includes two counter-rotating shafts (3, 4) each carrying at least one impeller (7, 8), wherein each impeller (7, 8) can deflect by a predetermined amount in directions substantially perpendicular t to the longitudinal axis of the shaft (3, 4) on which the impeller (7, 8) is mounted.

Abstract: A cathodic protection system has electrodes disposed in a coolant passage of an engine filled with a conductive coolant. The electrodes are electrically insulated from the engine. A power supply device provides for a protective electric current to form from the electrodes to the engine through the coolant. The cathodic protection system reduces engine manufacturing and maintenance costs and provides an anticorrosive effect without increasing the size of the engine.

Abstract: An electrode for a cathodic protection device that has one or more electrode bodies formed of a conductive wire. The electrode includes a pair of films made of an insulating material which are bonded to each other while sandwiching the electrode body therebetween. Preferably at least one of the pair of films is bonded to an engine body. The electrode body is exposed to the outside through one or more through-holes formed in at least one of the films. The electrode is less susceptible to short-circuiting or wire breakage when bent and is also easier to manufacture than conventional electrodes.

Abstract: A propulsion or pumping device which includes two counter-rotating shafts (3, 4) each carrying at least one impeller (7, 8), wherein each impeller (7, 8) can deflect by a predetermined amount in directions substantially perpendicular t to the longitudinal axis of the shaft (3, 4) on which the impeller (7, 8) is mounted.

Abstract: An outboard drive for boats, having a steerable underwater housing (1) which has a wing-profiled portion (2). Projecting at an approximately 90 degree angle from the aft part of one side face (31) of the wing profile is a face portion (32), the lateral extent of which amounts to about 1–2% of its distance to the steering shaft (36) of the wing profile. As a result of this construction, a lifting force will be generated during forward travel in the water. The face portion is configured on that side of the profile which produces a lifting force counter-directional to a steering force, deriving from the motor torque, upon the wing profile.

Abstract: A pulling marine propeller (1) including multiple propeller blades (4) attached to a propeller hub (5). The propeller hub (5) is attachable to a propeller shaft (9) extending from a drive housing (10) located downstream of the propeller (1). The invention is especially characterized by the fact that the propeller hub (5) is provided with an annular, radially outwardly flared peripheral portion (11) at an aft end (12) thereof. The flared portion (11) is arranged to axially overlap a front end shoulder portion (13) of the drive housing (10).

Abstract: A method of steering a planning V-bottomed boat with double individually steerable outboard drive units with underwater housings (6), which extend down from the bottom (1) of the boat. When running at planning speed straight ahead, the underwater housings are set with “toe-in”, i.e. inclined towards each other with opposite angles (alpha) of equal magnitude relative to the boat centre line (b). When turning, the inner drive unit is set with a greater steering angle than the outer drive unit.

Abstract: A marine vessel includes a rudder support structure attached to its hull and a rudder device attached to the rudder support structure in a manner allowing pivotal movement of the rudder device relative to the rudder support structure. A first drive train includes a first propeller shaft mounted in the hull and extending from the hull. A first propeller unit is attached to the first propeller shaft and is positioned forward of the rudder device. A second drive train includes a second propeller shaft that is mounted rotatably in the rudder support structure and a second propeller unit is attached to the second propeller shaft. The second propeller unit is aft of the first propeller unit and coaxially aligned therewith.

Abstract: A marine vessel includes a rudder support structure attached to its hull and a rudder device attached to the rudder support structure in a manner allowing pivotal movement of the rudder device relative to the rudder support structure. A first drive train includes a first propeller shaft mounted in the hull and extending from the hull. A first propeller unit is attached to the first propeller shaft and is positioned forward of the rudder device. A second drive train includes a second propeller shaft that is mounted rotatably in the rudder support structure and a second propeller unit is attached to the second propeller shaft. The second propeller unit is aft of the first propeller unit and coaxially aligned therewith.

Abstract: A water intake and transmission system for simultaneously driving dual jet units of a jet boat. According to a preferred embodiment, the water intake includes dual channels to allow the uptake of dedicated streams of water. Mounted to the intake is a housing having first and second jet units encased therein wherein each jet unit receives a dedicated stream of water from a respective channel of the water intake. A transmission is operatively coupled to each respective jet unit and is further connected to the driveshaft of the boat engine that is operative to simultaneously drive both jet units from a single driveshaft.

Abstract: Boat propeller drive with an underwater housing which is connected in a fixed manner to a boat hull and has tractor propellers arranged on that side of the housing facing ahead. Arranged in that end portion of the underwater housing facing astern is an exhaust discharge outlet for discharging exhaust gases from an internal combustion engine connected to the propeller drive.

Abstract: A hybrid gear/sprocket-based transmission is provided for driving a pair of coaxial, counter-rotating propellers in aircraft and airboats. A drive shaft couplable to an engine crank shaft extends rearward into the transmission case, and a pair of coaxial hollow driven shafts extend rearward out of the transmission case, to which are attachable a pair of propellers. A gear train, containing an even number of gears, reverses the rotational direction of the engine; a sprocket train, containing two sprockets and a chain connecting them, retains the rotational direction of the engine. Improved stability characteristics are imparted by supporting the drive shaft at two points within the case and also by positioning the drive and the driven shafts in vertical alignment. The adaptability of the transmission to being coupled with an automobile engine confers improved noise, reliability, and fuel efficiency characteristics.

Abstract: A marine propulsion unit supported from a vessel by a strut contains an electric motor within a housing and a forward propeller driven by the electric motor and having a diameter larger than that of the housing. Hydrodynamic vanes projecting from the surface of the housing counteract tangential flow generated by the forward propeller. An aft section with a pair of counter-rotating blade rows driven by the electric motor is mounted at the rear of the housing and including a shroud surrounding the aft blade rows. The shroud is spaced from the housing so as to receive the boundary layer of liquid passing along the surface of the housing to inhibit cavitation and improve efficiency. Rearward portions of the shroud are movable to form a clamshell causing a reversal of the flow of the liquid passing through the shroud.

Abstract: An improved hydraulic system for a twin propeller marine propulsion unit. A vertical drive shaft is operably connected to the engine of the propulsion unit and carries a pinion that drives a pair of coaxial bevel gears. An inner propeller shaft and an outer propeller shaft are mounted concentrically in the lower torpedo section of the gear case and each propeller shaft carries a propeller. To provide forward movement for the watercraft, a sliding clutch is moved in one direction to operably connect the first of the bevel gears with the inner propeller shaft to drive the rear propeller. A hydraulically operated multi-disc clutch is actuated when engine speed reaches a pre-selected elevated value to operably connect the second of the bevel gears to the outer propeller shaft, to thereby drive the second propeller in the opposite direction.

Abstract: An improved twin propeller marine propulsion unit. A vertical drive shaft is journaled in the lower gearcase and drives a pair of bevel gears. A pair of concentric propeller shafts are mounted in the lower torpedo section of the gearcase and each shaft carries a propeller. A slidable clutch is movable between a neutral, a forward, and a reverse position and serves to operably connect the outer propeller shaft with one of the bevel gears when the clutch is moved to the forward drive position. A gear is mounted for sliding movement in unison with the clutch and acts to operably engage the inner propeller shaft with the second bevel gear when the clutch is in the forward drive position so that both propellers are driven in opposite directions to provide forward motion for the watercraft.

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: An improved hydraulic system for a twin propeller marine propulsion unit. A vertical drive shaft is operably connected to the engine of the propulsion unit and carries a pinion that drives a pair of coaxial bevel gears. An inner propeller shaft and an outer propeller shaft are mounted concentrically in the lower torpedo section of the gear case and each propeller shaft carries a propeller. To provide forward movement for the watercraft, a sliding clutch is moved in one direction to operably connect the first of the bevel gears with the inner propeller shaft to drive the rear propeller. A hydraulically operated multi-disc clutch is actuated when engine speed reaches a pre-selected elevated value to operably connect the second of the bevel gears to the outer propeller shaft, to thereby drive the second propeller in the opposite direction.

Abstract: Angle gearing, especially a lower angle gearing between an intermediate shaft (2) and one or two propeller shafts (6, 7) in a marine outboard drive unit. A conical bevel gear (3) is pre-tensioned on the intermediate shaft against a cone (10) on the intermediate shaft by a nut (13) which is screwed onto a stud (21), which in turn is screwed into a central threaded bore (20) in the intermediate shaft end.

Abstract: An improved twin propeller marine propulsion unit. A vertical drive shaft is journaled in the lower gearcase and drives a pair of bevel gears. A pair of concentric propeller shafts are mounted in the lower torpedo section of the gearcase and each shaft carries a propeller. A slidable clutch is movable between a neutral, a forward, and a reverse position and serves to operably connect the outer propeller shaft with one of the bevel gears when the clutch is moved to the forward drive position. A gear is mounted for sliding movement in unison with the clutch and acts to operably engage the inner propeller shaft with the second bevel gear when the clutch is in the forward drive position so that both propellers are driven in opposite directions to provide forward motion for the watercraft.

Abstract: A marine propulsion system with counter-rotating propellers is provided with the capability of causing the propellers to rotate at different speeds. A first gear is attached to an inner propeller shaft and a second gear is attached to an outer propeller shaft. The inner and outer propeller shafts are arranged in coaxial and concentric relation for rotation about an axis of rotation. A driveshaft is connected to a pinion gear which engages the teeth of the fore and aft gears at different effective diameters. The pinion gear meshes with a first plurality of gear teeth on a beveled surface of the fore gear while a second set of gear teeth of the pinion gear mesh with a second plurality of gear teeth on a beveled surface of the aft gear. Because of the different effective diameters of the first and second pluralities of gear teeth, the inner and outer shafts rotate at different speeds.

Abstract: A propulsion system includes an improved propeller design which increases the durability of the propeller for enhanced rotational vibration damping, while simplifying the structure of the propeller. A rubber coupling is placed within a space that is secured between a propeller hub and an inner member of the propeller. The rubber coupling resiliently couples the propeller hub to the inner member with only the inner member and the propeller hub maintaining the space in which the rubber coupling is placed. The substantially constant size of the space generally isolates the rubber coupling from cyclic tension and compression stresses in the axiel and radial directions as the propeller rotates to improve the durability of the rubber coupling.

Abstract: A shifting mechanism for an outboard drive of a watercraft provides reduced coupling shock when the forward gears are engaged by a dual clutch assembly, as well as provides for consistent and quick engagement of the clutch assembly with the gear. The shifting mechanism involves a first gear and a corresponding first clutch, and a second gear and a corresponding second clutch. A plunger carries the first and second clutches which are arranged on the plunger at unequal distances from their respective gears. This nonuniform spacial relationship between the clutches and gears causes one clutch to engage its corresponding gear before the other clutch engages its corresponding gear. The staggered engagement decreases shock on the transmission and permits quicker engagement between the clutches and gears.

Abstract: An improved twin propeller marine propulsion unit. A vertical drive shaft is journaled in the lower gearcase and drives a pair of bevel gears. A pair of concentric propeller shafts are mounted in the lower torpedo section of the gearcase and each shaft carries a propeller. A slidable clutch is movable between a neutral, a forward, and a reverse position and serves to operably connect the outer propeller shaft with one of the bevel gears when the clutch is moved to the forward drive position. A gear is mounted for sliding movement in unison with the clutch and acts to operably engage the inner propeller shaft with the second bevel gear when the clutch is in the forward drive position so that both propellers are driven in opposite directions to provide forward motion for the watercraft.

Abstract: A transmission for a dual, counter-rotational propeller system incorporates a shift assistor to yieldably cushion transmission engagement. The shift assistor desirably operates between one clutch of a dual clutch assembly and a clutch actuator. The shift assistor specifically yieldably couples the clutch to the actuator. The yieldably coupling permits relative movement between the shift assistor and the clutch during the shifting operation in order to allow the clutches to engage the corresponding gears separately (i.e., at different times). The shift assistor thus reduces coupling shock when shifting the transmission either into a forward or a reverse drive condition.

Abstract: An exhaust system for an marine drive discharges exhaust gases between front and rear propellers of a counter-rotating propeller system. The discharge of exhaust gases between the propellers produces a cavitation effect about the rear propeller when accelerating from low speeds. As a result, the drive of the propellers accelerates more rapidly. At high speeds, however, the velocity of the exhaust gases carries the gases over the rear propeller principally in the vicinity of the rear propeller hub. No substantial cavitation effect occurs about the blades of the rear propeller at high speeds. As a result, the discharge of exhaust gases between the propellers causes no significant loss of propulsion efficiency when traveling at high speeds.

Abstract: A propeller drive installation in a boat has two propeller drive units (8, 9) which extend out through individual openings (4, 5) in the bottom (1) of a V-bottomed boat, so that the legs are inclined relative to each other. The leg of one drive unit can be set to turn the boat in one direction at the same time as the leg of the other drive unit can be set to turn the boat in the opposite direction, so that the horizontal counteracting forces acting on the legs cancel each other, while the vertical forces are added to each other to trim the running position of the boat in the water.

Abstract: A bearing carrier and ring nut of a marine outboard drive both attach to a lower unit of the drive by rotating them in the same direction. The bearing carrier includes a threaded front end which screws into a threaded aperture within the lower unit. A ring nut locks the bearing carrier in place by screwing into a hole on the rear face of the lower unit. A locking tab washer desirably locks the ring nut in place. Because the threads on the bearing carrier and the ring nut are of the same hand, the ring nut does not loosen the bearing carrier when threaded into the hole of the lower unit rear face.

Abstract: A seal arrangement for controlling any large bearing clearance in the vicinity of a propeller shaft, such as for a propeller drive system for ships with two concentric propeller shafts rotating in opposite directions, has a housing ring for supporting the sealing lips and a supporting ring for supporting the housing ring and defining a clearance therebetween. This clearance can be sealed, and maintained by means of elastic ring walls disposed between and interconnecting the housing to the supporting ring, so that compensation can be achieved for changes in the clearance during rotation of the propeller shaft.

Abstract: A jet propulsion unit for a watercraft that employs a pair of counter rotating impellers that are disposed immediately adjacent each other so that the need for straightening vanes is eliminated. The impellers are driven by a bevel gear transmission to rotate in opposite directions, which bevel gear transmission is contained within the jet propulsion unit outer housing but forwardly of the flow path of water therethrough. This bevel gear transmission is driven by a single input shaft through a flexible coupling.

Abstract: A transmission system for a counter-rotational propulsion device is easily incorporated into an existing outboard drive of a watercraft to convert the outboard drive from a single propeller drive to a counter-rotational dual propeller system. The transmission system involves a first transmission which selectively couples an inner propulsion shaft with an existing drive shaft of the outboard drive. The inner propulsion shaft in turn drives a rear propeller. A second transmission of the transmission system is provided between the inner propulsion shaft and an outer propulsion shaft. The second transmission reverses the rotational drive direction input by the inner propulsion shaft so as to drive the outer propulsion shaft in an opposite rotational direction. The outer propulsion shaft drives a front propeller which spins in an opposite direction to that of the rear propeller, but asserts a thrust in the same direction as the rear propeller.

Abstract: A small watercraft powered by twin jet propulsion units, each driven by a respective engine. The engine is concealed within a hatch cover that has a larger portion which is removable for removal of the engine and a smaller portion which is pivotal for servicing of the engine without removing the larger portion. A centrally positioned operator's seat has a seat back with a handle so as to facilitate mounting of a rear deck and facilitate a passenger standing on the rear deck during operation. There are disclosed a pair of driving engines positioned within a V-hull in a central location so as to improve stability and yet permit extreme maneuverability. A fuel tank supplies fuel to the engines and is separated from the engines by a bulkhead with both the fuel tank and the engines being accessible when the smaller hatch cover is opened.

Abstract: A simple structured propeller shaft assembly for a counter-rotating propeller system of a watercraft outboard drive prevents fishing line, weeds and like debris from entangling on a shaft of the propeller system and damaging the lubricant seals of the shaft assembly. The shaft assembly includes a nut which threads partially onto an end of an outer propeller shaft of the propeller shaft assembly. A thrust washer, carrier by an inner propeller shaft, includes a front hub which partially inserts into the nut adjacent to the end of the outer shaft. The nut, thrust washer and outer shaft end together define a labyrinth path into the space occupied by the lubricant seals between the inner and outer shafts. This labyrinth path inhibits weeds and like debris from wrapping around the inner shaft at a point adjacent to the lubricant seals.

Abstract: A transmission for a counter-rotating propeller system of a watercraft outboard drive includes a reduced friction coupling between the inner and outer shafts which permits transfer of the thrust loading on the inner shaft to the outer shaft under a reverse drive condition. The inner and outer shafts include opposing transverse surfaces which are separated by a pair of anti-friction washers. The washers allow the shafts to rotate in opposite directions with minimum friction, while allowing the opposing surfaces to act on each other through the washers to transfer the trust loading when the watercraft is driven in reverse.

Abstract: An improved transmission bearing assembly for a counter-rotating propeller system of a marine outboard drive directly journals the driven gears of the transmission on the propulsion shafts of the outboard drive. The hub of one driven gear is journaled between a portion of an inner propulsion shaft and a hollow end of the outer propulsion shaft. The bearing assembly also supports the hollow end of the outer propulsion shaft at a front end of a bearing carrier and supports a rearward section of the outer shaft at a rear end of the bearing carrier. The span between the bearing assemblies journaling the outer propulsion shaft within the bearing carrier is increased by positioning the bearing assemblies at the ends of the bearing carrier. The positions of the bearing assemblies at the ends of the bearing carrier thus improves the stability of the outer propulsion shaft.

Abstract: A propulsion unit for watercraft that employs a pair of counter-rotating propellers disposed one in front of the other in order to improve the performance upon acceleration, a cavitation effect is generated around at least one of the propellers at least during acceleration. Various ways in which this can be done employing the exhaust gases from the powering internal combustion engine for driving the propellers are illustrated.

Abstract: In a marine drive (10), a nonrotational thrust sensing device (202 or 204) is placed between the stationary housing (26') and rotating propeller shaft (40' or 42') to measure the thrust output of a propeller (12 or 14) by measuring the equal and opposite force applied to the housing by the propeller shaft (40' or 42'). A thrust bearing (214 or 248) is situated between the rotating shaft and the nonrotating thrust sensing device. A thrust ring (246) and adapter (250) provide adoption of the thrust sensing device to a particular housing and shaft configuration. In a marine drive having counter rotating coaxial propeller shafts, first and second thrust sensors individually sense the thrust of inner and outer propeller shafts, respectively, to provide separate sensed thrust for each.

Abstract: A shifting mechanism for an outboard drive of a watercraft provides reduced coupling shock when the forward gears are engaged by a dual clutch assembly, as well as provides for consistent and quick engagement of the clutch assembly with the gear. The shifting mechanism involves a first gear and a corresponding first clutch, and a second gear and a corresponding second clutch. A plunger carries the first and second clutches which are arranged on the plunger at unequal distances from their respective gears. This nonuniform spacial relationship between the clutches and gears causes one clutch to engage its corresponding gear before the other clutch engages its corresponding gear. The staggered engagement decreases shock on the transmission and permits quicker engagement between the clutches and gears.

Abstract: A propeller has a hub affixed to a propeller shaft so as to rotate therewith. The hub is axially locked by a locking arrangement consisting of a lock nut screwed on to the shaft and a lock screw screwed into the end of the shaft to lock the nut. The screw is tightened more than the nut in order to cause the thread on the nut to load the opposite thread flank on the shaft. A portion of the nut which is deformed during tightening of the screw holds the nut and screw together during subsequent removal of the propeller.