Patent Publication Number: US-9849955-B1

Title: Marine surface propulsion device

Description:
BACKGROUND OF THE INVENTION 
     High-speed watercraft present a number of design challenges. In particular, to realize optimal thrust, the utilization of a variable pitch propeller is desirable. However, implementation of variable pitch propellers has entailed fixed propeller shaft tethering of the propellers to the watercraft. In turn, the performance of steering and/or trimming componentry has been compromised, thereby reducing maneuverability and/or performance. 
     SUMMARY OF THE INVENTION 
     The present disclosure is directed to improved devices for marine surface propulsion of a watercraft. In some embodiments, the device may include a support member supportably interconnectable to a watercraft transom and pivotable about at least a first axis, a propeller shaft supported by the support member for pivotable movement therewith about the first axis and rotatable relative to the support member, wherein a first end of the propeller shaft is interconnectable to a watercraft engine output for driven rotation thereby. The device may further include a hub body interconnected to a second end of the propeller shaft for co-rotation therewith, wherein the hub body is pivotable with the support member about the first axis, and a plurality of propeller blades projecting away from the hub body and interconnected to the second end of the propeller shaft for co-rotation therewith, wherein the plurality of propeller blades are pivotable with the support member about the first axis. Further, the device may include a variable pitch actuator, interconnected to the support member for pivotable co-movement therewith about the first axis, for adjustably controlling a pitch orientation of the plurality of propeller blades (e.g. relative to a longitudinal axis of the propeller shaft) and disposed for co-rotation with the propeller shaft. 
     As may be appreciated, the provision of a marine surface propulsion device having a support member that is supportably interconnectable to and pivotable about at least a first axis relative to a watercraft transom, and variable pitch actuator that is interconnected to the support member for pivotable co-movement therewith (e.g. co-rotation about a longitudinal axis of the propeller shaft), advantageously yields an arrangement that facilitates optimized propulsion by the variable pitch actuator in combination with at least one of steering and trimming control via pivotable adjustment of the support member relative to the first axis, wherein such steering and/or trimming control may occur concurrently with adjustable control of the pitch orientation of the plurality of propeller blades by the variable pitch actuator. Such arrangement facilitates further operative benefits as will be appreciated upon consideration of the various combinative features addressed hereinbelow. 
     In an embodiment in which the first axis is a reclined axis (e.g. a substantially horizontal axis or an axis that extends at an angle of +/−10° relative to horizontal), the device may further include a trimming actuator for adjustably pivoting the support member, propeller shaft, hub body, plurality of propeller blades and variable pitch actuator together about the reclined first axis, wherein the trimming actuator may be controlled concurrently with adjustable control of the pitch orientation of the plurality of propeller blades by the variable pitch actuator. In another embodiment in which the first axis is an upright axis (e.g. a substantially vertical axis or an axis that extends at an angle of +/−15° relative to vertical), the device may further include at least one or a pair of steering actuators for adjustably pivoting the support member, propeller shaft, hub body, plurality of propeller blades and variable pitch actuator together about the upright first axis, wherein the steering actuator(s) may be controlled concurrently with adjustable control of the pitch orientation of the plurality of propeller blades by the variable pitch actuator. In one arrangement, a first steering actuator may be interconnected between the support member and a watercraft transom or component supportably interconnected thereto on a first side of the upright first axis, and a second steering actuator may be interconnected between the support member and a watercraft transom or component supportably interconnected thereto on a second side of the upright first axis. 
     In some embodiments, the support member may be advantageously provided to be pivotable about both a first axis and a second axis, wherein the first axis and second axis are transverse and extend substantially within a common plane, and wherein the propeller shaft, hub body, plurality of propeller blades and variable pitch actuator are pivotable together with the support member about the first axis and about the second axis. In conjunction with such embodiments, the first axis may be an upright axis and the device may further include a gimbal member supportably interconnectable to and pivotable about the upright first axis relative to a watercraft transom. In turn, the support member may be supportably interconnected to and pivotable about the upright first axis with the gimbal member. 
     In some embodiments, the device may include at least one steering actuator interconnectable between a watercraft transom and the gimbal member for adjustably pivoting together the gimbal member, support member, propeller shaft, hub body, plurality of propeller blades and variable pitch actuator about an upright first axis. In some arrangements, a first steering actuator may be interconnected between the gimbal member and a watercraft transom on a first side of the upright first axis, and a second steering actuator may be interconnected between the gimbal member and a watercraft transom on a second side of the upright first axis. 
     In conjunction with such embodiments, the support member may be supportably interconnected to and pivotable about a reclined second axis relative to the gimbal member. In such embodiments, the device may further include a trimming actuator, interconnected between the gimbal member and support member, for adjustably pivoting the support member, propeller shaft, hub body, plurality of propeller blades and variable pitch actuator together about the reclined second axis. As may be appreciated, the provision of an arrangement having a variable pitch actuator interconnected to a support member for pivotable movement about both an upright first axis (e.g. for watercraft steering by one or more steering actuator(s)) and a reclined second axis (e.g. for watercraft trimming by a trimming actuator) yields an arrangement that facilitates optimized propulsion in dynamic combination with concurrent steering control and/or concurrent trimming control via selective pivotable adjustment of the support member. 
     In some approaches, the device may further include an input shaft that is supported by the support member for pivotable movement therewith about the first axis and the second axis, wherein the input shaft may be interconnectable to a watercraft engine for driven rotation thereby. In conjunction with such embodiments, the device may also include a plurality of meshing gears, wherein a first gear of the plurality of meshing gears is fixedly interconnected to the input shaft for co-rotation therewith, and wherein a second gear of the plurality of meshing gears may be disposed to rotate in response to rotation of the first gear. In turn, the first end of the propeller shaft may be fixedly interconnected to the second gear for co-rotation therewith. In conjunction with such arrangements, the first gear and second gear may be disposed at different elevations, e.g. the first gear may be elevated relative to the second gear, thereby facilitating positioning of the propeller shaft and interconnected propeller blades at an optimal position relative to the surface of a water body. Further, the number and/or relative sizes of gears of the plurality of meshing gearings may be selected to obtain desired over-speed and/or under-speed ratios. 
     In related embodiments, the device may include a first universal joint supportably interconnectable to a watercraft transom and rotatably interconnectable to a watercraft engine output for rotation thereby, and second universal joint supported by the support member for pivotable movement therewith about the first axis and about the second axis, and rotatably interconnected to the first universal joint for co-rotation therewith. In such embodiments, the first universal joint and the second universal joint may be interconnected free from direct connection with the gimbal member. In that regard, the first universal joint and second universal joint may be interconnected to extend through opposing side portions of the gimbal member, e.g. the interconnected first and second universal joints may extend through a yoke-configured portion of the gimbal member. 
     In some embodiments, the variable pitch actuator may comprise a linear actuator (e.g. a hydraulic linear actuator) that includes a housing fixedly interconnected to the support member, and a piston member having an end (e.g. a piston head portion) slidably disposed within the housing for linear and rotational movement relative thereto (e.g. linear movement along and rotational movement about a longitudinal axis of the propeller shaft), wherein the linear actuator is actuatable to control linear movement of the piston member and thereby adjust the pitch orientation of the plurality of propellers. In such embodiments, the device may include a force rod having a first end interconnected to the piston member (e.g. a piston rod portion that extends out of the housing) of the variable pitch actuator for linear and co-rotational movement therewith, and having a second end interconnected to the second end of the propeller shaft for co-rotation therewith, wherein the pitch orientation of the plurality of propellers (e.g. relative to a longitudinal axis of the propeller shaft) is adjustable in response to the linear movement of the force rod by the piston member of the variable pitch actuator. 
     In some implementations, the device may further include a pitch control member that may be fixedly interconnected to the second end of the propeller shaft for co-rotation therewith and to the second end of the force rod for linear and co-rotational movement therewith (e.g. linear movement along and rotational movement about a longitudinal axis of the propeller shaft). In turn, the pitch orientation of the plurality of propellers may be adjustable in response to the linear movement of the pitch control member by the force rod and the piston member. In some arrangements, the plurality of propellers may engage different corresponding ones of a plurality of guide surfaces provided by the pitch control member so as to rotate the plurality of propellers about corresponding axes to adjust the pitch orientation thereof in response to linear movement of the pitch control member by the force rod and piston member. 
     In some approaches, at least a portion of the propeller shaft may be tubular. In turn, the force rod may extend through at least a portion of the tubular portion of the propeller shaft to facilitate linear movement of the force rod and interconnected piston member relative to the propeller shaft. In that regard, in some approaches, the force rod may extend through a tubular propeller shaft from the first end to the second end thereof. 
     In contemplated embodiments, the device may further include a controller for automatically controlling operation of the variable pitch actuator that may be operated concurrent with operation of either or both of the at least one steering actuator(s) and trimming actuator. By way of example, the controller may comprise a computer processor configurable by preprogrammed instructions that utilize control algorithms to control the operation of the variable pitch actuator (e.g. to obtain optimal thrust) in relation to a watercraft engine throttle sensor output signal (e.g. to obtain optimal acceleration or de-acceleration to a desired speed), and optionally, concurrent with operation of the at least one steering actuator(s) and/or trimming actuator. In certain implementations, pitch magnitude may be automatically established by the control algorithms of the controller as a function of both a difference between a desired watercraft engine speed and an actual watercraft engine speed, in addition to the actual pitch position, or orientation, of the propeller blades as reflected by a sensor output signal indicative of a linear position of the piston member of the variable pitch actuator along a longitudinal axis of travel (e.g. relative to a longitudinal axis of the propeller shaft). The desired engine speed may be determined as a function of a position of either a throttle control or a throttle plate of an internal combustion watercraft engine, as indicated by an associated sensor output signal, and the actual engine speed may be determined as a function of a tachometer output signal. In that regard, controller functionality may be provided as described in U.S. Pat. No. 6,379,114, the entirety of which is incorporated herein by reference. 
     Further, in some embodiments the controller may be provided with preprogrammed instructions that utilize control algorithms to control the operation of the variable pitch actuator in relation to a trimming sensor output signal indicative of a positioning of a trimming actuator, and optionally, in co-relation to a watercraft engine throttle sensor output signal. The trimming sensor output signal may be provided by a sensor that senses operation/position of a trimming control device (e.g. a rocker switch controllable by a watercraft operator) and/or a sensor that senses a position of a piston member of a trimming actuator. 
     In one embodiment, at least two marine surface propulsion devices having features as described herein may be provided for supportable interconnection to and pivotable movement about a first axis and/or second axis relative to a watercraft transom. For example, a first propulsion device may be provided for interconnection to a watercraft transom on a first side (e.g. a port side) of a longitudinal axis (e.g. a lengthwise axis) of a watercraft, and a second propulsion device may be provided for interconnection to a watercraft transom on a second side (e.g. a starboard side) of the longitudinal axis of a watercraft. In turn, control algorithms may be provided so that the controller may automatically control the variable pitch actuators of the first and second propulsion devices to control the pitch orientation of each corresponding plurality of propeller blades in relation to operator steering and/or slowing of the watercraft. 
     For example, preprogrammed instructions may be provided that use control algorithms so that, in response to a watercraft engine throttle sensor output signal indicative of operator slowing of a watercraft, the controller may automatically control the first and second variable pitch actuators to reduce the magnitude of the pitch orientation of the propeller blades to a lower pitch orientation as a function of the desired degree of slowing. Further, the preprogrammed instructions may be provided with control algorithms so that, in response to processing of a steering control sensor signal (e.g. a signal indicative of a position of a watercraft steering wheel and/or a signal indicative of a position of a piston member of a steering actuator) indicative of operator steering of a watercraft to the left (i.e. to the port side), the controller may automatically control the first and second variable pitch actuators so that the propeller blades of the first variable pitch actuator automatically assume a first predetermined pitch orientation in relation to the desired steering moment and the propeller blades of the second variable pitch actuator automatically assume a second predetermined pitch orientation in relation to the desired steering moment, wherein the second predetermined pitch orientation is higher than the first predetermined pitch orientation. Conversely, the preprogrammed instructions may be provided with control algorithms so that, in response to processing of a steering control sensor signal (e.g. a signal indicative of a position of a watercraft steering wheel and/or a signal indicative of a position of a piston member of a steering actuator) indicative of operator steering of a watercraft to the right (i.e. to the starboard side), the controller may automatically control the first and second variable pitch actuators so that the propeller blades of the first variable pitch actuator automatically assume a first predetermined pitch orientation in relation to the desired steering moment and the propeller blades of the second pitch actuator automatically assume a second predetermined pitch orientation in relation to the desired steering moment, wherein the second predetermined pitch orientation is lower than the first predetermined pitch orientation. 
     Numerous additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the embodiment descriptions provided hereinbelow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates one embodiment of a marine surface propulsion device operatively interconnected to a watercraft engine. 
         FIG. 2  is a cross-sectional view of the marine surface propulsion device embodiment of  FIG. 1  supportably interconnected to a transom of a water craft. 
         FIG. 3  is a side perspective view of the marine surface propulsion device embodiment of  FIG. 1 . 
         FIG. 4  is a side view of the marine surface propulsion device embodiment of  FIG. 1  as positioned for operative use relative to the surface of a body of water. 
         FIG. 5  is a side cross-sectional view of a variable pitch actuator comprising the marine surface propulsion device embodiment of  FIG. 1 . 
         FIG. 6A  is a rear perspective view of the marine surface propulsion device embodiment of  FIG. 1  with portions of a support member and variable pitch propeller thereof cut away. 
         FIG. 6B  is a front perspective view of the marine surface propulsion device embodiment of  FIG. 1  with a forward support member of a support member thereof removed. 
         FIG. 6C  is a front perspective view of a rearward support member of the support member shown in  FIGS. 6A and 6B . 
         FIG. 7A  is side perspective view of a variable pitch propeller of the marine surface propulsion device embodiment of  FIG. 1  with portions of a hub body thereof cut away. 
         FIG. 7B  is a side perspective view of the variable pitch propeller illustrated in  FIG. 7A . 
         FIG. 7C  is another side perspective view of the variable pitch propeller illustrated in  FIG. 7A  with different portions thereof cut away. 
         FIG. 7D  is another side perspective view of the variable pitch propeller illustrated in  FIG. 7A  with different portions thereof cut away. 
         FIG. 7E  is another side perspective view of the variable pitch propeller illustrated in  FIG. 7A  with different portions thereof cut away. 
         FIG. 7F  is a rear view of the variable pitch propeller illustrated in  FIG. 7A  with a portion of the hub body thereof cut away. 
         FIG. 8  is a propulsion force delivery diagram for the marine surface propulsion device embodiment of  FIG. 1 . 
         FIG. 9A  is a schematic illustration of an embodiment that includes embodiments of two marine surface propulsion devices, each as described in relation to  FIGS. 1-8 , interconnected to a watercraft on different sides of a longitudinal axis thereof, wherein the variable pitch actuators of the two marine surface propulsion devices may be selectively and automatically controlled to facilitate steering of the watercraft. 
         FIG. 9B  is a schematic illustration of an embodiment that includes embodiments of two marine surface propulsion devices, each as described in relation to  FIGS. 1-8 , interconnected to a watercraft on different sides of a longitudinal axis thereof, wherein the variable pitch actuators of the two marine surface propulsion devices may be selectively and automatically controlled to facilitate slowing of the watercraft. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-8  illustrate one embodiment of a marine surface propulsion device for use with a watercraft, e.g. a high-speed watercraft. As will be described, the propulsion device comprises a variable pitch propeller which may be steered for directional control of a watercraft and tilted for enhanced thrust and attendant propulsion of a watercraft (i.e. “trimming”). A closed-loop control system may be utilized with the propulsion device to optimize pitch and trim for either maximum performance or best fuel economy, based upon a position of a throttle for controlling the output of an operatively interconnected watercraft engine. The described embodiment is not intended to be limiting and various described features may be implemented in modified arrangements. 
     With reference to  FIG. 1 , an embodiment of propulsion device  1  may be provided for operative interconnection to a watercraft engine  100  that may be fixedly mounted within the hull of a watercraft to provide an output to rotate a variable pitch propeller  60  of the propulsion device  1 , and more particularly, a hub body  61  and plurality of propeller blades  62  comprising variable pitch propeller  60 , to propel the watercraft on a body of water. By way of example, mount brackets  110  may be interconnected to the watercraft engine  100 . In turn, with reference to  FIG. 2 , the mount brackets  110  (not shown) may be fixedly mounted in a rear aspect of a watercraft  120 , e.g. mounted to hull stringers  122 . 
     With further reference to  FIGS. 1 and 2 , propulsion device  1  may include a transom mount member  10  that may be fixedly interconnectable to an aft surface of a transom  124  of the watercraft  120 , e.g. interconnectable via a mount bracket assembly  11  that comprises a plurality of mounting bolts extending forwardly from an outer frame-like portion  10   a  of the transom mount member  10  for securement to transom  124 . The frame-like portion  10   a  of the transom mount member  10  may present a flat forward surface for flush interface with a flat aft surface of the transom  124 . 
     As shown in  FIGS. 1, 2 and 3 , propulsion device  1  may further include a gimbal member  20  supportably interconnected to the transom mount member  10  for pivotable movement about an upright axis AA and relative to transom mount member  10  and transom  124 . For such purposes, the transom mount member  10  may comprise rearwardly projecting arms  12  to which gimbal member  20  may be supportably interconnected for pivotable movement about upright axis AA. For example, each rearwardly extending arm  12  may be provided with a bearing ring member  13  for receiving a complimentary, bearing pin member  21  of the gimbal member  20 . 
     As shown in  FIGS. 1 and 3 , propulsion device  1  may further include one or more steering actuator  30  (e.g. one on each side of upright axis AA) interconnected between transom mount member  10  and gimbal member  20  for selective, controlled pivoting of the gimbal member  20  about upright axis AA for steering the watercraft  120 . In the illustrated embodiment, steering actuators  30  may be hydraulic linear actuators. 
     With reference to  FIGS. 2 and 3 , propulsion device  1  may further include a support member  40  supportably interconnected to the gimbal member  20  for pivotable movement about the upright axis AA together with the gimbal member  20 . For such purposes, support member  40  may include one or more forwardly extending arms  41  (e.g. one on each side of upright axis AA) that may be supportably interconnected to gimbal member  20  and pivotable relative to gimbal member  20  about a reclined axis BB, as shown in  FIG. 3 . For example, each forwardly extending arm  41  may be provided with a bearing ring member  42  for receiving a complimentary, bearing pin member (not shown) of the gimbal member  20 . 
     With further reference to  FIGS. 2 and 3 , propulsion device  1  may also include a trimming actuator  80  supportably interconnected between the support member  40  and gimbal member  20  for pivotable movement about the upright axis AA together with gimbal member  20  and support member  40 , variable pitch actuator  50  and variable pitch propeller  60 . The trimming actuator  80  may be provided for selective, controlled pivoting of the support member  40 , and variable pitch propeller  60  and variable pitch actuator  50  supportably interconnected thereto, about the reclined axis BB and relative to transom mount member  10  and transom  124 . 
     In the illustrated embodiment, trimming actuator  80  may be a hydraulic linear actuator. In turn, trimming actuator  80  may comprise a housing  81  supportably and pivotably interconnected to a downward extending arm  22  of the gimbal member  20 . For example, downward extending arm  22  may be provided with a bearing ring member  23  for receiving a complimentary, bearing pin member of the housing  81  of trimming actuator  80 . Further, and as best shown in  FIG. 2 , trimming actuator  80  may comprise a piston member  82  supportably and slidably interconnected at a first end within housing  81  and supportably and fixedly interconnected at a second end to support member  40 . 
     As shown in  FIG. 2 , propulsion device  1  may also include a variable pitch actuator  50  operatively interconnected to the variable pitch propeller  60 , wherein the variable pitch actuator  50  and variable pitch propeller  60  are supported by the support member  40  for pivotable movement therewith about the upright axis AA and about the reclined axis BB. The variable pitch actuator  50  may be provided for adjustably controlling a pitch orientation of the propeller blades  62 . In the illustrated embodiment, variable pitch actuator  50  may be a hydraulic linear actuator. In turn, variable pitch actuator  50  may comprise a housing  51  and piston member  52  supportably interconnected to support member  40 , as will be further described. 
     As noted above in relation to  FIGS. 1 and 2 , propulsion device  1  may be provided for operative interconnection with watercraft engine  100 . In that regard, watercraft engine  100  may provide for driven rotation of an output member, e.g. driven rotation of a drive flange  102 , wherein the drive flange  102  may be selectively driven in a clockwise direction or in a counter clockwise direction. In turn, propulsion device  1  may comprise a drive assembly interconnectable to the drive flange  102  for driven rotation of the variable pitch propeller  60 . The drive assembly may include a transom throughput shaft  70  having a forward flange  70   a  that may be interconnected to the output drive flange  102  for co-rotation therewith either directly or utilizing an optional drive line member  71  as illustrated in  FIG. 1 . 
     As shown in  FIG. 2 , the transom throughput shaft  70  may extend through a forward projecting portion  10   b  of the transom member  10  that projects through an opening  112  through transom  124 . In turn, the throughput input shaft  70  may be interconnected to a double universal joint assembly comprising a first universal joint  72  supported by the transom mount member  10  and interconnected to a second universal joint  73  supported by the support member  40 , wherein driven rotation of transom throughput shaft  70  effects co-rotation of first universal joint  72  and second universal joint  73 . The double universal joint assembly may be located proximate an intersection of the upright axis AA and reclined axis BB, and enables drive power transmission from the transom throughput shaft  70  during steering and/or trimming operations. A forward extending shaft  72   a  of the first universal joint  72  may comprise external, longitudinal splines which telescope into an internally-splined, hollow shaft portion of the transom throughput shaft  70 , thereby allowing a sliding interconnection to accommodate small axial displacements of the propulsion device  1  as the propulsion device  1  is trimmed or steered. 
     As shown in  FIG. 2 , the second universal joint  73  may be fixedly interconnected to an input shaft  74  for driven co-rotation of the input shaft  74 , wherein the second universal joint  73  and input shaft  74  may be supported by and rotatable relative to the support member  30  for pivotable movement therewith about upright axis AA and reclined axis BB. In turn, the input shaft  74  may be interconnected to a plurality of meshing gears  75  and a propeller shaft  76  for driven rotation thereof, wherein the plurality of meshing gears  75  and propeller shaft  76  are also supported by and rotatable relative to the support member  40 , and pivotable with support member  40  about the upright axis AA and reclined axis BB. As shown in  FIG. 2 , the double universal joint assembly may extend through an opening of a yoke-configured portion of the gimbal member. In turn, and as shown in  FIG. 3 , a flexible tubular outer sleeve member  49  may extend around the universal joint assembly through the opening of the gimbal member  20 , wherein a first end of the sleeve member  49  may be sealably interconnected to a rearwardly projecting annular flange portion  10   c  of the transom mount member  10  (See  FIG. 2 ) and a second end of the sleeve member  49  may be sealable interconnected to a forwardly projecting annular flange portion  40   a  of the support member  40  (See  FIG. 2 ). In that regard, sleeve member  49  may define an enclosed water-free volume (e.g. a sealably enclosed volume), and the transom mount member  10  and support member  40  may each define corresponding enclosed, water-free volumes (e.g. sealably enclosed volumes), wherein the various illustrated and described componentry may be housed in the interconnected and enclosed, water-free volumes, including for example, transom throughput shaft  70  and associated bearings, and sensors  94  and  96  (described below) within transom mount member  10 , the double universal joint assembly within sleeve member  49 , and the input shaft  74  and associated bearings, meshing gears  75  and associated bearings, propeller shaft  76  and associated bearings, and at least a portion of variable pitch actuator  50  and associated bearings within support member  40 . 
     In the illustrated embodiment, the plurality of meshing gears  75  includes a first gear  75   a  fixedly interconnected to the input shaft  74  for co-rotation therewith, and a second gear  75   b  fixedly interconnected to a first end of propeller shaft  76  (e.g. a tubular or hollow shaft) for driven rotation of the propeller shaft  76 . The plurality of meshing gears  75  may further include a third gear  75   c  meshed with the first gear  75   a  and second gear  75   b  and may function as an idler gear. 
     In the illustrated arrangement, driven rotation of the first gear  75   a  in a first direction (e.g. clockwise) effects driven rotation of the third gear  75   c  in a second direction (e.g. counterclockwise) to effect driven rotation of the second gear  75   b  in the first direction (e.g. clockwise). The plurality of meshing gears may be provided to obtain desired over-speed or under-speed ratios, e.g. 1:1.5 overspeed or 1.4:1 speed reduction. 
     As illustrated, the second gear  75   b  and third gear  75   c  may be disposed at locations lower than the location of the first gear  75   a , thereby facilitating interconnection of the second gear  75   b  with propeller shaft  76  at a “dropped” location relative to input shaft  74 . Such arrangement facilitates driven rotation of the propeller blades  62  at the surface of a water body with rudder  17  extending below the water surface, as shown in  FIG. 4 . For example, the propeller blades  62  may be located to successively enter in to and pass out of the water as they rotate with hub body  61 . 
     With further reference to  FIG. 2 , the hub body  61  and propeller blades  62  of variable pitch propeller  60  may be interconnected to a second end of the propeller shaft for co-rotation therewith. More particularly, a pitch control member  63  may be fixedly interconnected to the second end of the propeller shaft  76  for co-rotation therewith, and each of the propeller blades  62  may comprise corresponding flanges captured between the hub body  61  and corresponding guide surfaces provided by the pitch control member  63 , as will be further described. 
     The support member  40  may include a forward support member  41  and a rearward support member  42  removably interconnectable to the forward support member  41 . The forward support member  41  and rearward support member  42  may define the sealed internal volume within support member  40  for housing the plurality of meshing gears  75  and other interconnected componentry. In that regard, and as illustrated in  FIGS. 6A, 6B and 6C , oiling of the plurality of meshing gears  75  and various associated bearings within the support member  40  may be accomplished with a gerotor pump  90  located in the rearward support member  42 . Use of an oil circulating pump reduces the volume of oil required for lubrication of the various gears and bearings. It also reduces parasitic losses due to oil drag within the gear train defined by the plurality of meshing gears  75 . The gerotor pump  90  comprises an inner rotor  91   a  and an outer rotor  91   b . The inner rotor  91   a  is driven by a pin  92  that is rotated by an extension of the input shaft  74 . As the gerotor set rotates a suction side of the gerotor pump  90  draws lubricating oil through an oil channel  93  from the bottom of the internal volume of the support member  40 . The pressure side of the gerotor pump  90  routes pressurized lubricant through two channels, a first channel  94   a  in the rearward support member  42  and, utilizing a cross-over port  95 , a second channel  94   b  in the forward support member  41 . Cover plates  97  are provided on a forward facing side of the rearward support member  42  and on a rearward facing side of the forward support member  41 , to enclose the first channel  94   a  and second channel  94   b , respectively. In turn, small holes or jets  97   a  are located in cover plates  97  so as to spray oil from the pressurized oil channels  94   a ,  94   b  into the teeth comprising the plurality of meshing gears  75  on both sides thereof. At the end of the first channel  94   a  and the rearward support member  42 , an over-pressure discharge port  98  and a pressure regulator  99  may be provided, thereby providing for the return of excess oil to the bottom of the internal volume of the support member  40 . 
     With further reference to  FIG. 2 , the variable pitch actuator  50  may include a housing  51  fixedly interconnected to the support member  40  to maintain a sealed internal volume there within, and a piston member  52  disposed within a cylinder portion of the housing  51  for rotational and linear movement relative thereto. In turn, the piston member  52  may be interconnected to a force rod  55  that extends through the first end of a hollow propeller shaft  76  and is interconnected at a second end to pitch control member  63 , wherein linear movement of the pitch control member  63  adjusts the pitch orientation of the propeller blades  62 , as will be further described. 
     Reference is now made to  FIG. 5 . As shown, piston member  52  may include a piston head portion  52   a  and an integral piston rod portion  52   b  (e.g. of one-piece construction) that slidably and sealably extends through an aperture of housing  51  for interconnection with the force rod  55  shown in  FIG. 2 . In that regard, piston rod portion  52   b  may be through-broached, e.g. to define a hex keyway  57 . In turn, and as shown in  FIG. 2 , force rod  55  may be milled with wrench flats  55   a , wherein the piston rod portion  52   b  may be threaded in to the force rod  55 . As noted above, the force rod  55  may extend through the propeller shaft  76  (e.g. through an internal bore), and through the hub body  61 . 
     With further reference to  FIG. 5 , the piston member  52  may include a plurality of piston rings  53  partially disposed within a corresponding plurality of grooves  52   c  with exposed portions disposed to slidably engage an inner surface  51   a  of the housing  51 , thereby providing both rotational and linear sealing of the variable pitch actuator  50 . To provide for linear displacement of the piston member  52 , variable pitch actuator  50  may comprise a first hydraulic fluid inlet/outlet port  55   a  located in a foreward portion of the housing  51 , and a second hydraulic fluid inlet/outlet port  55   b  located in aftward portion of the housing  51 . As may be appreciated, flexible hydraulic fluid lines  56  may be interconnected to a hydraulic fluid control unit (e.g. located on a watercraft) to selectively control the passage of hydraulic fluid in to and out of chamber regions of the cylinder portion of housing  51 , fore and aft the piston head portion  52   a  of piston member  52  to effect a desired linear positioning of the piston member  52 , and in turn, pitch control member  63  to thereby control the pitch orientation of the propeller blades  62 . Such pitch positioning may be completed while the propeller blades  62  are rotating with hub body  61 , propeller shaft  76  and piston member  53 , and during trimming and/or steering operations. 
     More particularly, reference is now made to  FIG. 7A-7F  which illustrate additional features of the variable pitch propeller  60 . As shown in  FIG. 7A , hub body  61  may comprise a foreward section  61   a  and an aftward section  61   b  that meet along a plane defined by the pivot axes of the propeller blades  62 . The foreward section  61   a  may have an internal tubular boss  64  that extends aftward to a terminus to the aft of the plane of the pivot axis of the propeller blades  62 . The pitch control member  63  may be attached to the force rod  55  and secured axially by a complimentary nut  65  and rotationally by a polygonal outer configuration of the pitch control member  63  (e.g. pentagonal in the illustrated embodiment), or by a key and force rod keyway. The complimentary nut  65  may be tightened to the piston rod portion  52   b  and force rod  55  via a hex or square socket  65   a  in the complimentary nut  65  and via the hex keyway  57  in the piston rod portion  52   b  that may be accessed through an aperture  51   b  in the variable pitch actuator housing  51 , as shown in  FIG. 5 . 
     As illustrated in  FIG. 7B , the foreward section  56  and aftward section  57  of the hub body  61  may be adjoined by bolts  66 , thereby capturing blade flanges  62   a  of each of the propeller blades  62 , as shown in  FIG. 7C . In that regard, each of the propeller blades  62  may extend radially from a corresponding blade flange  62   a  and are received by corresponding mounting sockets  61   c  defined by the foreward section  61   a  and aftward section  61   b  of the hub body  61 . Axial outside o-ring seal members  67  may be provided and are compressed during assembly while axial inside o-ring seal members  68  may be placed flush with each blade flange  62   a . During operation, centripetal force radially displaces the inside o-ring seal members  68  on the inside surface of the corresponding blade flange  62   a  for a positive seal. Relief passageways  62   b  may be provided through blade flanges  62   a  to prevent blocking of the o-ring seal members in the groove (e.g. blocking that may otherwise occur due to suction forces sufficient to prohibit centripetal radial movement and subsequent sealing), as shown in  FIG. 7A . 
     As shown in  FIG. 4 , the external surface of the hub body  61  may be of a streamlined configuration. At higher speeds, the propeller blades  62  may be designed to super cavitate within the outside diameter profile of the hub body  61  spinning above the water surface, with the propeller blades  62  entering and exiting the water surface each revolution of the propeller shaft  76  for minimum drag. 
     As shown in  FIG. 7D , the complimentary nut  65  may be received in and sealed to the aftward hub section  61   b  by sealing rings  69 . An eccentric crank pin  62   c  may project inwardly in to the cavity of the hub body  61  from the blade flange  62   a  of each of the propeller blades  62 . In the neutral (i.e. near-zero pitch) settings of the propeller blades  62 , the crank pins  62   c  may be offset circumferentially from the blade pivot axes and centered substantially on the plane of the pivot axes. 
     As noted above, the force rod  55  extends through the propeller shaft  76  from the variable pitch actuator  50  to move pitch control member  63  foreward and aftward. As shown in  FIG. 7E , the pitch control member  63 , may include a round base portion  63   a  and a tubular portion  63   b  extending forward from the perimeter of the base portion  63   a . The tubular portion  63   b  may transform to a polygonal portion  63   c  having a polygonal configuration (e.g. pentagon in the illustrated embodiment) at its peripheral surface. At the location of each of the crank pins  62   c  each section of the polygonal portion  63   c  may be provided with a slideway  63   d  oriented transversely of the axis CC of the propeller shaft  76 , and each slideway  63   d  may receive a cross slide  79 . In turn, each cross slide  79  may receive a crank pin  62   c  of a corresponding propeller blade  62 , as further shown in  FIG. 7D . 
     In a right-hand rotation drive arrangement, when the force rod  55  and pitch control member  63  are pulled forward from a neutral position by the variable pitch actuator  50 , the propeller blades  62  may be rotated clockwise, which will adjust the propeller blades  62  to deliver astern thrust. That is, forward positioning of variable pitch actuator  50  and clockwise blade rotation decreases pitch and thrust. Conversely, when the force rod  55  is pushed aftward by the variable pitch actuator  50 , the propeller blades  62  may be pivoted to deliver decreased pitch and lesser astern thrust. That is, aftward positioning of variable pitch actuator  50  and counter clockwise blade rotation increases pitch and thrust. In that regard, the variable pitch actuator  50  may be suitably controlled to provide a continuum of settings between maximum and minimum pitches for astern thrust. In the case of reverse thrust at an idling speed when the variable pitch propeller  60  is submerged, water deflectors  47  (shown in  FIG. 4 ) may be provided to direct water flow beneath the hull of a watercraft rather than in to the aft transom surface, for reverse authority. In a left hand rotation drive arrangement, when the force rod  55  and pitch control member  63  are pushed aftward from the neutral position by the variable pitch actuator  50 , the propeller blades  62  may be rotated counter-clockwise, which adjusts the propeller blades  62  to deliver increased pitch and greater astern thrust. Pressure to the variable pitch actuator  50  may be supplied via the hydraulic lines  56  and pressure ports  55   a ,  55   b  noted above in relation to  FIG. 5 , and transfer blocks  91  shown in  FIG. 6C  from an interconnectable pump and reservoir provided on board a watercraft. 
     With further reference to  FIG. 7D , travel of the pitch control member  63  is limited in the forward direction by contact between the base portion  63   a  and the tubular boss  64 . Travel of the pitch control member  63  is limited in the aftward direction by contact of the base portion  63   a  with internal ribs  61   c  of the aftward propeller hub  61   b . Alternatively, travel could be limited by the length of the slideways  63   d  for cross slides  79  and, thereby, restrict cross slide travel and blade rotation. At one extreme of travel, the propeller blades  62  are nearly feathered at a very low pitch, which enables extremely low speed progress. At the other extreme of travel, the propeller blades  62  are almost paddle-wheel-like at infinite pitch, which enables lateral movement of a watercraft when used in conjunction with a bow thruster. As shown in  FIG. 7E , the force rod  55  and pitch control member  63  need not be rotationally fixed to the hub body  61  or propeller shaft  76  because the hub body  61  imparts rotation to them through engagement of the peripheral surface of polygonal portion  63   c  of the pitch control member  63  on the propeller blade flanges  62   a  of the propeller blades  62 . 
     The cavity of the hub body  61  may be suitably sealed and filled with grease through a plugged grease hole  61   d , as shown in  FIG. 3 . As shown in  FIG. 7F , the round base  63   a  of the pitch control member  65  may have holes  63   e  through it to allow the movement of the pitch control member  63  through the grease. Grease can also readily displace through openings  93  between the forward hub section  61   a  cavity walls and the pitch control member  63 . 
     As shown in  FIG. 5 , the axial position of the piston member  52  of the variable pitch actuator  50  may be read by a sensor  94 , e.g. Hall effect sensor  94  passing through a magnet  94   a  within the piston member  52 . Because the piston rod portion  52   b , force rod  55  and pitch control member  63  are secured along the longitudinal axis CC, piston member  52  position correlates to blade pitch position. Similarly, another sensor  96  may communicate the position of piston member  82  of trim actuator  80 . In that regard, sensor  94  and/or sensor  96  may provide a corresponding sensor output signal(s) that may be processed by a computer processor configured by preprogrammed instructions that utilize control algorithms to automatically control the operation of the variable pitch actuator  50  to position the propeller blades  62 . 
     As shown in  FIG. 2 , supply voltage and position voltages are transmitted through water sealed electronic cables  87 . Watertight thru hull fittings  98  pass cable to an on-board microcomputer. Control algorithms may set and maintain propeller pitch and/or trim geometry for optimal acceleration or fuel economy depending on throttle position and engine rpm, torque and fuel consumption profiles. 
     With reference now to  FIG. 8 , propulsive reaction to propeller thrust is transmitted sequentially through the propulsion device  1  as follows: 
     a) from the blade flanges  62   a  and sockets  61   c  to the hub body  61 ; 
     b) to the propeller shaft  76 ; 
     c) to the tapered roller bearing  78 ; 
     d) to the variable pitch actuator housing  51 , from which the force divides along two paths, e1 and e2; 
     e1) to the support member  40  into the gimbal member  20 ; and, 
     e2) to the trimming actuator  80  into the gimbal member  20 ; 
     f1) from the gimbal member  20  through arms  12  of the transom member  10 ; and, 
     f2) from the gimbal member  20  through steering actuator(s) member  30  to the transom housing member  10 ; and, 
     g) from the transom member  10  to the watercraft transom  124 . 
     Reference is now made to  FIGS. 9A and 9B , in which at least two marine surface propulsion devices having features as described herein may be provided for supportable interconnection to and pivotable movement about a first axis and/or second axis relative to a watercraft transom. For example, a first propulsion device may be provided for interconnection to a watercraft transom on a first side (e.g. a port side) of a longitudinal axis (e.g. a lengthwise axis) of a watercraft, and a second propulsion device may be provided for interconnection to a watercraft transom on a second side (e.g. a starboard side) of the longitudinal axis of a watercraft. In turn, control algorithms may be provided so that the controller may automatically control the variable pitch actuators of the first and second propulsion devices in relation to steering and/or slowing, (e.g. “breaking”) of the watercraft. 
     For example, and as illustrated in  FIG. 9A , preprogrammed instructions may be provided with control algorithms so that, in response to processing of a steering control (e.g. a signal indicative of a position of a watercraft steering wheel and/or a signal indicative of a position of a piston member of a steering actuator) indicative of operator steering of a watercraft to the left (i.e. to the port side), the controller may automatically control the first and second variable pitch actuators so that the propeller blades of the first variable pitch actuator automatically assume a first predetermined pitch orientation in relation to the desired steering moment and the propeller blades of the second variable pitch actuator automatically assume a second predetermined pitch orientation in relation to the desired steering moment, wherein the second predetermined pitch orientation is higher than the first predetermined pitch orientation. Conversely, the preprogrammed instructions may be provided with control algorithms so that, in response to processing of a steering control sensor signal (e.g. a signal indicative of a position of a watercraft steering wheel and/or a signal indicative of a position of a piston member of a steering actuator) indicative of operator steering of a watercraft to the right (i.e. to the starboard side), the controller may automatically control the first and second variable pitch actuators so that the propeller blades of the first variable pitch actuator automatically assume a first predetermined pitch orientation in relation to the desired steering moment and the propeller blades of the second pitch actuator automatically assume a second predetermined pitch orientation in relation to the desired steering moment, wherein the second predetermined pitch orientation is lower than the first predetermined pitch orientation. Further, and as illustrated in  FIG. 9B , preprogrammed instructions may be provided that use control algorithms so that, in response to a watercraft engine throttle sensor output signal indicative of operator slowing of a watercraft, the controller may automatically control the first and second variable pitch actuators to reduce the magnitude of the pitch orientation of the propeller blades to a lower pitch orientation as a function of the desired degree of slowing. 
     The foregoing description of the present invention has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modifications commensurate with the above teachings, and skill and knowledge of the relevant art, are within the scope of the present invention. The embodiments described hereinabove are further intended to explain known modes of practicing the invention and to enable others skilled in the art to utilize the invention in such or other embodiments and with various modifications required by the particular application(s) or use(s) of the present invention. It is intended that the appended claims be construed to include alternative embodiments to the extent permitted by the prior art.