Patent Publication Number: US-2023132886-A1

Title: Stowable marine propulsion systems

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 17/185,289, filed Feb. 25, 2021, which is incorporated herein by reference in its entirety. 
    
    
     FIELD 
     The present disclosure generally relates to stowable propulsion systems for marine vessels. 
     BACKGROUND 
     The following U.S. Patents and Patent Applications provide background information and are incorporated by reference in entirety. 
     U.S. Pat. No. 6,142,841 discloses a maneuvering control system which utilizes pressurized liquid at three or more positions of a marine vessel to selectively create thrust that moves the marine vessel into desired locations and according to chosen movements. A source of pressurized liquid, such as a pump or a jet pump propulsion system, is connected to a plurality of distribution conduits which, in turn, are connected to a plurality of outlet conduits. The outlet conduits are mounted to the hull of the vessel and direct streams of liquid away from the vessel for purposes of creating thrusts which move the vessel as desired. A liquid distribution controller is provided which enables a vessel operator to use a joystick to selectively compress and dilate the distribution conduits to orchestrate the streams of water in a manner which will maneuver the marine vessel as desired. Electrical embodiments can utilize one or more pairs of impellers to cause fluid to flow through outlet conduits to provide thrust on the marine vessel. 
     U.S. Pat. No. 7,150,662 discloses a docking system for a watercraft and a propulsion assembly therefor wherein the docking system comprises a plurality of the propulsion assemblies and wherein each propulsion assembly includes a motor and propeller assembly provided on the distal end of a steering column and each of the propulsion assemblies is attachable in an operating position such that the motor and propeller assembly thereof will extend into the water and can be turned for steering the watercraft. 
     U.S. Pat. No. 7,305,928 discloses a vessel positioning system which maneuvers a marine vessel in such a way that the vessel maintains its global position and heading in accordance with a desired position and heading selected by the operator of the marine vessel. When used in conjunction with a joystick, the operator of the marine vessel can place the system in a station keeping enabled mode and the system then maintains the desired position obtained upon the initial change in the joystick from an active mode to an inactive mode. In this way, the operator can selectively maneuver the marine vessel manually and, when the joystick is released, the vessel will maintain the position in which it was at the instant the operator stopped maneuvering it with the joystick. 
     U.S. Pat. No. 7,753,745 discloses status indicators for use with a watercraft propulsion system. An example indicator includes a light operatively coupled to a propulsion system of a watercraft, wherein an operation of the light indicates a status of a thruster system of the propulsion system. 
     U.S. Pat. No. RE39032 discloses a multipurpose control mechanism which allows the operator of a marine vessel to use the mechanism as both a standard throttle and gear selection device and, alternatively, as a multi-axes joystick command device. The control mechanism comprises a base portion and a lever that is movable relative to the base portion along with a distal member that is attached to the lever for rotation about a central axis of the lever. A primary control signal is provided by the multipurpose control mechanism when the marine vessel is operated in a first mode in which the control signal provides information relating to engine speed and gear selection. The mechanism can also operate in a second or docking mode and provide first, second, and third secondary control signals relating to desired maneuvers of the marine vessel. 
     European Patent Application No. EP 1,914,161, European Patent Application No. EP2,757,037, and Japanese Patent Application No. JP20133100013A also provide background information and are incorporated by reference in entirety. 
     SUMMARY 
     This Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. 
     The present disclosure generally relates to a stowable propulsion system for a marine vessel. In certain embodiments, a base is configured to be coupled to the marine vessel. A shaft has a proximal end and a distal end with a length axis defined therebetween, where the shaft is pivotably coupled to the base and pivotable about a transverse axis between a stowed position and a deployed position, and where the distal end is closer to the marine vessel when in the stowed position than in the deployed position. A gearset is engaged between the shaft and the base, where the gearset rotates the shaft about the length axis when the shaft is pivoted between the stowed position and the deployed position. A propulsion device is coupled to the distal end of the shaft. The propulsion device is configured to propel the marine vessel in water when the shaft is in the deployed position. 
     In certain embodiments, a marine vessel is configured to be propelled in a port-starboard direction. The marine vessel includes two or more pontoons coupled to a deck, where the two or more pontoons provide floatation for the marine vessel. A stowable propulsion system is configured to propel the marine vessel in the port-starboard direction. The system includes a base coupled to the marine vessel between two or the two or more pontoons. The system further includes a shaft having a proximal end and a distal end with a length axis defined therebetween, where the shaft is pivotably coupled to the base and pivotable about a transverse axis between a stowed position and a deployed position, and where the distal end is closer to the marine vessel when in the stowed position than in the deployed position. The system further includes a gearset engaged between the shaft and the base, where the gearset rotates the shaft about the length axis when the shaft is pivoted between the stowed position and the deployed position. The system further includes a propulsion device coupled to the distal end of the shaft. The propulsion device is configured to propel the marine vessel in water in the port-starboard direction when the shaft is in the deployed position. 
     Some embodiments include a stowable propulsion system for a marine vessel having two or more pontoons coupled to a deck. The system includes a base configured to be coupled to deck of the marine vessel between two of the two or more pontoons, where the two or more pontoons extend in a fore-aft direction. A shaft has a proximal end and a distal end with a length axis defined therebetween, where the shaft is pivotably coupled to the base, the shaft being pivotable about a transverse axis between a stowed position and a deployed position, and where the distal end is closer to the marine vessel when in the stowed position than in the deployed position. An electric actuator is coupled to the shaft and to the base, where the electric actuator pivots the shaft between the stowed position and the deployed position. A positional sensor is positioned to detect whether the shaft is in at least one of the stowed position and the deployed position. A gearset is engaged between the shaft and the base, where the gearset rotates the shaft 90 degrees about the length axis when the shaft is pivoted between the stowed position and the deployed position, where the gearset rotates the shaft in a first direction when the shaft is pivoted towards the deployed position and in a second direction that is opposite the first direction when the shaft is pivoted towards the stowed position. A control system is operatively coupled to the actuator and the positional sensor, where the control system is configured to control the actuator to pivot the shaft based on the positional sensor. A propulsion device is coupled to the distal end of the shaft, where the propulsion device comprises an electric motor that rotates a propeller, and where electricity is supplied to electric motor via a wire harness that extends through at least a portion of the shaft. The propulsion device is configured to propel the marine vessel in water in a port-starboard direction that is perpendicular to the fore-aft direction when the shaft is in the deployed position. 
     Various other features, objects and advantages of the disclosure will be made apparent from the following description taken together with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is described with reference to the following Figures. 
         FIG.  1    is an isometric bottom view of a marine vessel incorporating a stowable propulsion system according to the present disclosure; 
         FIG.  2    is an exploded isometric view of a system such as that shown in  FIG.  1    in a stowed position; 
         FIG.  3    is a sectional side view taken along the line  3 - 3  in  FIG.  2   ; 
         FIG.  4    is a rear view of the system shown in  FIG.  2   ; 
         FIG.  5    is a sectional view taken along the line  5 - 5  of  FIG.  2   ; 
         FIG.  6    is an isometric bottom view depicting the system of  FIG.  2    in a deployed position; 
         FIG.  7    is a sectional side view taken along the line  7 - 7  in  FIG.  6   ; 
         FIG.  8    is a rear view of the system of  FIG.  6    in the deployed position; 
         FIG.  9    is an isometric view of an alternate embodiment of system according to the present disclosure; 
         FIG.  10    is an isometric rear view of another exemplary stowable propulsion system according to the present disclosure; 
         FIG.  11    is an isometric rear view of another exemplary stowable propulsion system according to the present disclosure; 
         FIG.  12    is an isometric bottom view of the embodiment of  FIG.  11   ; and 
         FIG.  13    depicts an exemplary control system for controlling one of the embodiments of stowable propulsion systems according to the present disclosure. 
     
    
    
     DETAILED DISCLOSURE 
     The present inventors have recognized a problem with bow thrusters presently known in the art, and particularly those that are retractable for storage. Specifically, within the context of a marine vessel having pontoons, there is insufficient clearance between the pontoons to accommodate a propulsive device, and particularly a propulsive device oriented to create propulsion in the port-starboard direction. The problem is further exacerbated when considering how marine vessels are trailered for transportation over the road. One common type of trailer is a scissor type lift in which bunks are positioned between the pontoons to lift the vessel by the underside of the deck. An exemplary lift of this type is the “Scissor Lift Pontoon Trailer” manufactured by Karavan in Fox Lake, Wis. In this manner, positioning a bow thruster between a marine vessel&#39;s pontoons either precludes the use of a scissor lift trailer, or leaves so little clearance that damage to the bow thruster and/or trailer is likely to occur during insertion, lifting, and/or transportation of the vessel on the trailer. As such, the present inventors have recognized an unmet need to rotate the propulsion device in a fore-aft orientation when stowed to minimize the width of the bow thruster. Additionally, the present inventors have recognized a particular advantage for developing such a rotatable propulsion device that does not require additional actuators for this rotation, adding cost and complexity to the overall system. 
       FIG.  1    depicts the underside of a marine vessel  1  as generally known in the art, but outfitted with an embodiment of a stowable propulsion system  30  according to the present disclosure. The marine vessel  1  extends between a bow  2  and stern  3 , as well as port  4  and starboard  5  side, thereby defining a fore-aft plane FAP, and port-starboard direction PS. The marine vessel  1  further includes a deck  6  with a rail system  8  on top and pontoons  12  mounted to the underside  10  of the deck  6 . The marine vessel  1  is shown with a portion of a scissor type lift  20 , specifically the bunks  22 , positioned between pontoons  12  to lift and support the marine vessel  1  for transportation over land in a manner known in the art. As is discussed further below, the presently disclosed stowable propulsion device  30  has a propeller  284  that faces the underside  10  of the deck  6  when stowed, in contrast to during use to propel the marine vessel  1  in the water as a bow thruster. This orientation is distinguishable from propulsion devices known in the art, in which the propeller faces the pontoons. In prior art configurations, there typically is insufficient room between the propulsion device and the pontoons to fit the bunks of the scissor type lift without risking damage to the propulsion device while inserting the bunks, lifting the marine vessel, and/or traveling on the road. 
       FIGS.  2 - 3    depict an exemplary stowable propulsion system  30  according to the present disclosure, here oriented in a stowed position. The stowable propulsion system  30  includes a base  40  having a top  42  with sides  44  extending perpendicularly downwardly away from the top  42 . The sides  44  include an inward side  46  and outward side  48  and extend between a first end  65  and second end  67  defining a length  66  therebetween. A width  64  is defined between the sides  44 . A stop  80  having sides  82  and a bottom  84  is coupled between the sides  44  of the base  40 . A leg  68  having an inward side  70  and outward side  72  extends between a top end  74  and a bottom end  76 . The leg  68  is coupled at the top end  74  to the top  42  of the base  40  and extends perpendicularly downwardly therefrom. A stationary gear  92  having a mesh face  96  with gear teeth and an opposite mounting face  94  is coupled to the leg  68  with the mounting face  94  facing the inward side  70  of the leg  68 . As shown in  FIG.  4   , one or more support rods  140  may also be provided between the sides  44  and received within support rod openings  143  defined therein to provide rigidity to the base  40 . In the example shown, the support rod  140  is received within a bushing  144  and held in position by a snap ring  146  received within a groove defined within the support rod  140 . 
     Returning to  FIGS.  2 - 3   , the base  40  is configured to be coupled to the marine vessel  1  with the top  42  facing the underside  10  of the deck  6 . The base  40  may be coupled to the deck  6  using fasteners and brackets presently known in the art. A mounting bracket  60  is coupled via fasteners  62  (e.g., screws, nuts and bolts, or rivets) to the outward sides  48  of the sides  44  of the base  40 . The mounting bracket  60  is receivable in a c-channel bracket or other hardware known in the art (not shown) that is coupled to the deck  6  and/or pontoons  12  to thereby couple the stowable propulsion system  30  thereto. 
     As shown in  FIGS.  2 - 4   , the stowable propulsion system  30  includes a shaft  230  that extends between a proximal end  232  and distal end  234  defining a length axis LA therebetween. The proximal end  232  of the shaft  230  is non-rotatably coupled to a moving gear  100 . The moving gear  100  has a proximal face  102  and mesh face  104  having gear teeth, where the mesh face  104  engages with the mesh face  96  of the stationary gear  92  to together form a gearset  90  as discussed further below. The moving gear  100  further includes a barrel  106  that extends perpendicularly relative to the proximal face  102  and is coupled to the shaft  230  in a manner known in the art (e.g., via a set screw or welding). In this manner, the moving gear  100  is fixed to the shaft  230  such that rotation of the moving gear  100  causes rotation of the shaft  230  about the length axis LA. 
     With reference to  FIGS.  2  and  5 - 6   , a pivot rotation device  150  is coupled to the shaft  230  near its proximal end  232 , below the moving gear  100 . The pivot rotation device  150  includes a main body  152  extending between a first end  154  and a second end  156  with an opening  153  defined therebetween. The shaft  230  is received through the opening  153  between the first end  154  and second end  156  of the main body  152  and rotatable therein. In the embodiment shown, a bushing  155  is received within the opening  153  of the main body  152  and the shaft  230  extends through an opening  157  within the bushing  155 . The bushing  155  provides for smooth rotation between the shaft  230  and the main body  152 . The shaft  230  is retained within the main body  152  via first and second clamp systems  210 ,  220 . The first clamp system  210  includes two clamp segments  212  coupled together by fasteners  216  received within openings and receivers therein, for example threaded openings for receiving the fasteners  216 . The clamp segments  212  are configured to clamp around the shaft  230  just above the main body  152 , in the present example with a gasket  213  sandwiched therebetween to provide friction. Likewise, clamp segments  222  of the second clamp system  220  are coupled to each other via fasteners  226  to clamp onto the shaft just below the main body  152 , which may also include a gasket sandwiched therebetween. In this manner, the shaft  230  is permitted to rotate within the main body  152 , but the first and second clamp systems  210 ,  220  on opposing ends of the main body  152  prevent the shaft  230  from moving axially through the main body  152 . 
     As shown in  FIGS.  2 - 3  and  5   , the shaft  230  is pivotable about a transverse axis (shown as pivot axis PA) formed by coaxially-aligned pivot axles  120 ,  121 . The pivot axles  120 ,  121  are received within pivot axle openings  52  defined within the sides  44  of the base  40 , with bushings  122  therebetween to prevent wear. Snap rings  126  are receivable within grooves defined  128  within the pivot axles  120 ,  121  to retain the axial position of the pivot axles  120 ,  121  within the base  40 . The interior ends of the pivot axles  120 ,  121  are received within the main body  152  of the pivot rotation device  150  coupled to the shaft  230 . The pivot axle  120  is received within a pivot axle opening  162  of the main body  152  such that the outer surface of the pivot axle  120  engages an interior wall  159  of the main body  152 . In the present embodiment, a gap  164  remains at the end of the pivot axle  120  to allow for tolerancing and bending and/or movement of the sides  44  of the base  40 , for example. 
     The pivot rotation device  150  further includes an extension body  170  that extends away from the main body  152 . The extension body  170  defines a pivot axle opening  178  therein for receiving the pivot axle  121 . As shown in  FIG.  5   , the pivot axle  121  has an insertion end  129  with threads  127  defined thereon, which engage with threads  173  of the pivot axle opening  178  defined in the extension body  170 . A slot  123  is defined in the end of the pivot axle  121  opposite the insertion end  129 . The pivot axle  121  is therefore threadably received within the extension body  170  by rotating a tool (e.g., a flathead screwdriver) engaged within the slot  123  defined in the end of the pivot axle  121 . A snap ring  126  may also be incorporated and receivable within grooves  128  defined in the pivot axle  121  to prevent axial translation of the pivot axle  121  relative to the sides  44  of the base  40 . 
     As shown in  FIGS.  2 ,  4 , and  6   , a face  176  of the extension body  170  defines a notch  177  recessed therein, which as will become apparent provides for non-rotational engagement with a pivot arm  190 . The pivot arm  190  includes a barrel portion  192  having a face  198  with a protrusion  179  extending perpendicularly away from the face  198 . The protrusion  179  is received within the notch  177  when the faces  176 ,  198  abut each other to rotationally fix the pivot arm  190  and the extension body  170 . It should be recognized that other configurations for rotationally fixing the pivot arm  190  and extension body  170  are also contemplated by the present disclosure, for example other keyed arrangements or fasteners. 
     With reference to  FIG.  2   , the barrel portion  192  of the pivot arm  190  further defines a pivot axle opening  199  therethrough, which enables the pivot axle  121  to extend therethrough. The pivot arm  190  further includes an extension  200  that extends away from the barrel portion  192 . The extension  200  extends from a proximal end  202  coupled to the barrel portion  192  to distal end  204 , having an inward face opposite an outward face  208 . A mounting pin opening  209  is defined through the extension  200  near the distal end  204 , which as discussed below is used for coupling the pivot arm  190  to an actuator  240 . 
     As shown in  FIGS.  2  and  4   , the pivot arm  190  is biased into engagement with the main body  152  of the pivot rotation device  150  via a biasing device, such as a spring  134 . In the example shown, the spring  134  is a coil or helical spring that engages the outward face  208  of the extension  200  of the pivot arm  190  at one end and engages a washer  124  abutting a snap ring  126  engaged within a groove of the pivot axle  121  at the opposite end. In this manner, the spring  134  provides for a biasing force engaging the pivot arm  190  and the main body  152  such that the faces  176 ,  198  thereof remain in contact during rotation of the pivot arm  190 , but also provides a safeguard. For example, if the shaft  230  experiences an impact force (e.g., a log strike), the presently disclosed configuration allows the protrusion  179  (shown here to have a rounded shape) to exit the notch  177  against the biasing force of the spring  134  to prevent the force from damaging other components, such as the actuator  240  coupled to the pivot arm  190  (discussed further below). 
     Referring to  FIGS.  2 - 4   , the stowable propulsion system  30  further includes an actuator  240  (presently shown is a linear actuator), which for example may be an electric, pneumatic, and/or hydraulic actuator presently known in the art. The actuator  240  extends between a first end  242  and second end  244  and has a stationary portion  246  and an extending member  260  that extends from the stationary portion  246  in a manner known in the art. The stationary portion  246  includes a mounting bracket  248  that is coupled to the base  40  via fasteners  252 , such as bolts, for example. At the opposite end of the actuator  240 , a mounting pin opening  261  extends through the extending member  260 , which is configured to receive a mounting pin  262  therethrough to couple the extending member  260  to the pivot arm  190  of the pivot rotation device  150 . The mounting pin  262  shown extends between a head  264  and an insertion end  266 , which in the present example has a locking pin opening  268  therein for receiving a locking pin  269 . The locking pin  269 , for example a cotter pin, is inserted or withdrawn to removably retain the mounting pin  262  in engagement between the actuator  240  and the pivot arm  190 . In the embodiment of  FIGS.  2 - 4   , it should be recognized that actuation of the actuator  240  thus causes pivoting of the shaft  230  about the pivot axis PA. 
     The stowable propulsion system  30  further includes a propulsion device  270  coupled to the distal end  234  of the shaft  230 . The propulsion device  270  may be of a type known in the art, such as an electric device operable by battery. In the example shown, the propulsion device  270  includes a nose cone  272  extending from a main body  274 . The main body  274  includes an extension collar  276  that defines a shaft opening  278 , whereby the shaft  230  is received within the shaft opening  278  for coupling the shaft  230  to the propulsion device  270 . The propulsion device  270  includes a motor  282  therein, whereby control and electrical power may be provided to the motor  282  by virtue of a wire harness  290  extending through the shaft  230 , in the present example via the opening  108  defined through the moving gear  100 ; however, it should be recognized that the wire harness  290  may enter the shaft  230  or propulsion device  270  in other locations. In some configurations, the wire harness  290  also extends through a gasket  291  that prevents ingress of water or other materials into the shaft  230 , for example (see  FIG.  9   ). The propulsion device  270  further includes a fin  280  and is configured to rotate the propeller  284  about a propeller axis PPA. The propulsion device  270  extends a length  286  and provides propulsive forces in a direction of propulsion DOP. With reference to  FIG.  4   , the propulsion device  270  has a width PW that is perpendicular to the length  286 , in certain embodiments the width PW being less than the width  64  of the base  40 . 
     As shown in  FIG.  6    and discussed further below, the propulsion device  270  is configured to propel the marine vessel  1  through the water in the port-starboard direction PS when the shaft  230  is positioned in the deployed position. It should be recognized that, for simplicity, the propulsion device  270  is described as generating propulsion in the port-starboard direction, and thus that the marine vessel moves in the port-starboard direction. However in certain configurations, the propulsion device  270  may accomplish this movement of the marine vessel in the port-starboard direction by concurrently using another propulsion device coupled elsewhere on the marine vessel  1 , for example to provide translation rather than rotation of the marine vessel  1 . 
     It should be recognized that when transitioning the shaft  230  and propulsion device  270  from the stowed position of  FIG.  3    to the deployed position of  FIG.  6   , the shaft  230  pivots 90 degrees about the pivot axis PA from being generally horizontal to generally vertical, and the propulsion device  270  rotates 90 degrees about the length axis LA of the shaft  230  from the propeller axis PPA being within the fore-aft plane FAP ( FIG.  1   ) to extending in the port-starboard direction PS. The present inventors invented the presently disclosed stowable propulsion systems  30  wherein pivoting of the shaft  230  about the pivot axis PA automatically correspondingly causes rotation of the shaft  230  about is length axis LA without the need for additional actuators (both being accomplished by the same actuator  240  discussed above). With reference to  FIGS.  2 - 3   , this function is accomplished through a gearset  90 , which as discussed above is formed by the engagement of the stationary gear  92  and moving gear  100 . 
     As discussed above, the stationary gear  92  is fixed relative to the base  40  and the moving gear  100  rotates in conjunction with the shaft  230  rotating about its length axis LA. In this manner, as the shaft  230  is pivoted about the pivot axis PA via actuation of the actuator  240 , the engagement between the mesh face  96  of the stationary gear  92  and the mesh face  104  of the moving gear  100  causes the moving gear  100  to rotate, since the stationary gear  92  is fixed in place. This rotation of the moving gear  100  thus causes rotation of the moving gear  100 , which correspondingly rotates the shaft  230  about its length axis LA. Therefore, the shaft  230  is automatically rotated about its length axis LA when the actuator  240  pivots the shaft  230  about the pivot axis PA. It should be recognized that by configuring the mesh faces  96 ,  104  of the gears accordingly (e.g., numbers and sizes of gear teeth), the gearset  90  may be configured such that pivoting the shaft  230  between the stowed position of  FIG.  4    and the deployed position of  FIG.  6    corresponds to exactly 90 degrees of rotation for the shaft  230  about its length axis LA, whether or not the shaft  230  is configured to pivot 90 degrees between its stowed and deployed positions. It should be recognized that other pivoting and/or rotational angles are also contemplated by the present disclosure. 
     The present inventors invented the presently disclosed configurations, which provide for stowable propulsion systems  30  having a minimal width  64  ( FIG.  2   ) when in the stowed position, clearing the way for use of a scissor type lift  20  or other lifting mechanisms for the marine vessel  1 , while also positioning the propulsion device for generating thrust in the port-starboard direction PS when in the deployed position. 
     As shown in  FIG.  6   , certain embodiments include stop  80  within the base  40  for stopping, centering, and/or securing the shaft  230  in the stowed position. In the embodiment shown, a centering slot  86  is defined within the bottom  84  of the stop  80 . This centering slot  86  is configured to receive a tab  308  that extends from a clamp  306  positioned at a midpoint along the shaft  230 . When the shaft  230  is pivoted and rotated into its stowed position as shown in  FIG.  2   , the tab  308  of the clamp  306  is received within the centering slot  86  of the stop  80 , whereby the bottom  84  of the stop  80  itself prevents further upward pivoting of the shaft  230 , and whereby the centering slot  86  prevents lateral movement of the propulsion device  270  when in the stowed position. 
     The embodiment of  FIG.  6    further depicts a positional sensor  300  configured for detecting whether the stowable propulsion system  30  is in the stowed position. The positional sensor  300  shown includes a stationary portion  302  and a moving portion  304 , whereby the stationary portion  302  is a Hall Effect Sensor positioned adjacent to the centering slot  86  of the stop  80 , which detects the moving portion  304  integrated within the tab  308 . In this manner, the positional sensor  300  detects when the shaft  230  is properly in the stowed position, and when it is not. 
     It should be recognized that other positional sensors  300  are also known in the art and may be incorporated within the systems presently disclosed. For example,  FIG.  3    depicts an embodiment in which the positional sensor  300  is incorporated within the actuator  240 , such as a linear encoder, that can be used to infer the position of the shaft  230  via the position of the extending member  260  of the actuator  240  relative to the stationary portion  246 . An exemplary positional sensor  300  is Mercury Marine&#39;s Position Sensor ASM, part number 8M0168637, for example. 
     The present disclosure contemplates other configurations of stowable propulsion systems  30 . For example,  FIG.  9    depicts an embodiment having two pivot arms  190  coupled directly to the main body  152  of the pivot rotation device  150 . The actuator  240  is then pivotally coupled to the two pivot arms  190  in a similar manner as that discussed above. In certain examples, the two pivot arms  190  are integrally formed with the clamp segments  212  of the first clamp system  210 , for example. The gearset  90  of the embodiment in  FIG.  9    also varies from that discussed above. Specifically, the mesh face  96  of the stationary gear  92  includes openings  97  rather than gear teeth. These openings  97  are configured to receive fingers  105  that extend from the mesh face  104  of the moving gear  100 , generally forming a gear and sprocket type system for the gearset  90 . The embodiment shown also includes a stop rod  81  for preventing the shaft  230  from rotating too far, or in other words past the deployed position. 
       FIG.  10    depicts another alternative embodiment of stowable propulsion system  30  according to the present disclosure. Among other distinctions, this embodiment differs with respect to the pivot rotation device  150 . The stowable propulsion system  30  of  FIG.  10    includes a slide system  720  that causes rotation of the shaft  230  about the length axis LA in conjunction with this rotation of the pivot axle  120  about the pivot axis PA. The pivot rotation device  150  of  FIG.  10    includes a clamp  700  having extensions  702  that extend in opposing directions therefrom. The clamp  700  is secured onto the shaft  230  in a manner previously described or otherwise known in the art. A yoke  704  extends along an arc  708  between opposing ends  707  with a slide connection  710  at a midpoint therebetween. Extension openings  706  are defined near the ends  707  of the yoke  704 , which receive the extensions  702  of the clamp  700  therein such that the yoke  704  is pivotable on the extensions  702  about a clamp pivot axis  703  defined by the extensions  702 . 
     A slide system  720  is coupled to the slide connection  710  of the yoke, for example via welding, integral formation, and/or other techniques known in the art, and extends between the yoke  704  and the base  40 . The slide system  720  includes a rod  722  extending between a proximal end  724  and distal end  726  defining a slide axis  728  therebetween. The slide system  720  further includes a housing  730  that extends between a proximal end  734  and distal end  736 . An opening  738  is defined within the housing  730 , extending inwardly from the distal end  736  to a backstop  739 . The rod  722  is received within the opening  738  of the housing  730  and permitted to translationally slide therein. The housing  730  is anchored to the base  40 , presently shown to be coupled via a arm  750  coupled to the base  40  via a bracket  752  coupled thereto. It will be recognized that the bracket  752 , and base  40  may be coupled via fasteners, welding, adhesives, and/or other techniques known in the art. 
     In the embodiment shown in  FIG.  10   , the distal end  736  of the housing  730  is coupled to the arm  750  via a ball joint  740 . In particular, a ball  742  is coupled to the distal end  736  of the housing  730 , which may be integrally formed or coupled thereto using techniques presently known in the art. The ball  742  is received within a socket  744  defined within the arm  750 , allowing limited rotation of the housing  730 , and thus the slide system  720 , relative to the arm  750 . In certain examples, the angle  745  is a maximum of 45 degrees on either side of center (other examples being 50 degrees, 30 degrees, or others). It should be recognized that the fully extended and fully compressed lengths  747  of the slide system  720 , along with the allowable angles  745 , depend upon the mounting locations of the slide system  720  (e.g., the bracket  752 , dimensions of the base  40 , and specific location of the pivot axle  120  therein) to ensure the intended rotation about the shaft  230  when the pivot axle  120  rotates about the pivot axis PA. 
     In this manner, the limited rotation of the slide system  720  relative to the arm  750 , as well as the limited length  747  of the slide system  720 , is particularly configured such that a 90° rotation of the pivot axle  120  about the pivot axis PA causes pivoting of the yoke  704  about the clamp pivot axis  703 , and therefore provides equivalent rotation of the shaft  230  about the length axis LA. In certain embodiments, the angle  745  and length  747  of the slide system  720  are configured such that 1° of rotation about the pivot axis PA causes 1° of rotation about the length axis LA. However, other configurations are also anticipated by the present disclosure, including those in which the stowed position is other than 90° different than the deployed position for the stowable propulsion system  30 . 
     More generally, it should be recognized that the slide system  720  provides restricted movement of the yoke  704 , and therefore rotation about the length axis LA of the shaft  230  in conjunction with pivoting about the pivot axis PA of the pivot axle  120 . 
     Another embodiment of stowable propulsion system  30  providing the general functionality of the gearset  90  previously discussed is shown as the slot system  790  of  FIGS.  11  and  12   . It should be recognized that the term “gearset” is used herein to generally describe all embodiments for transferring a pivoting of the pivot axle  120 ,  121  to also cause rotation of the shaft  230 , including the slot system  790 . In this example, the stationary gear  92  previously described is replaced with a curved plate  792  that defines a slot  791  having an edge  796  therein. Likewise, the moving gear  100  previously described is replaced with a pin  800  coupled to the shaft  230 . As the shaft  230  is pivoted about the pivot axles  120 ,  121  (e.g., by an actuator such as discussed above), the pin  800  slides within the slot  791  between a starting point A corresponding to the deployed position, and an ending point Z corresponding to the deployed position. The slot  791  is not linear, but includes an angled portion  793 . Due to the angled portion  793  of the slot  791 , and the shape of the curved plate  792  (i.e., being generally curved about the pivot axis PA), the pin  800  is caused by engagement with the contoured plate  792  to rotate the shaft  230  coupled to the pin  800  as the pin  800  passes through the angled portion  793  to the end point Z. In the embodiment shown, the pin  800  is coupled to the shaft  230  so that the two extend non-coaxially, but are nonetheless substantially parallel, for example via an extension portion  799  that extends away from the shaft  230 . This extension portion  799  creates a moment arm by which the engagement between the curved plate  792  and pin  800  within the slot system  790  causes rotation of the shaft  230  between the stowed and deployed positions. Other configurations for causing this rotation are also anticipated by the present disclosure, specifically without requiring actuation devices beyond those providing the pivoting of the shaft  230 . 
       FIG.  13    depicts an exemplary control system  600  for operating controlling the stowable propulsion system  30 . Certain aspects of the present disclosure are described or depicted as functional and/or logical block components or processing steps, which may be performed by any number of hardware, software, and/or firmware components configured to perform the specified functions. For example, certain embodiments employ integrated circuit components, such as memory elements, digital signal processing elements, logic elements, look-up tables, or the like, configured to carry out a variety of functions under the control of one or more processors or other control devices. The connections between functional and logical block components are merely exemplary, which may be direct or indirect, and may follow alternate pathways. 
     In certain examples, the control system  600  communicates with each of the one or more components of the stowable propulsion system  30  via a communication link CL, which can be any wired or wireless link. The control system  600  is capable of receiving information and/or controlling one or more operational characteristics of the stowable propulsion system  30  and its various sub-systems by sending and receiving control signals via the communication links CL. In one example, the communication link CL is a controller area network (CAN) bus; however, other types of links could be used. It will be recognized that the extent of connections and the communication links CL may in fact be one or more shared connections, or links, among some or all of the components in the stowable propulsion system  30 . Moreover, the communication link CL lines are meant only to demonstrate that the various control elements are capable of communicating with one another, and do not represent actual wiring connections between the various elements, nor do they represent the only paths of communication between the elements. Additionally, the stowable propulsion system  30  may incorporate various types of communication devices and systems, and thus the illustrated communication links CL may in fact represent various different types of wireless and/or wired data communication systems. 
     The control system  600  of  FIG.  13    may be a computing system that includes a processing system  610 , memory system  620 , and input/output (I/O) system  630  for communicating with other devices, such as input devices  599  and output devices  601 , either of which may also or alternatively be stored in a cloud  602 . The processing system  610  loads and executes an executable program  622  from the memory system  620 , accesses data  624  stored within the memory system  620 , and directs the stowable propulsion system  30  to operate as described in further detail below. 
     The processing system  610  may be implemented as a single microprocessor or other circuitry, or be distributed across multiple processing devices or sub-systems that cooperate to execute the executable program  622  from the memory system  620 . Non-limiting examples of the processing system include general purpose central processing units, application specific processors, and logic devices. 
     The memory system  620  may comprise any storage media readable by the processing system  610  and capable of storing the executable program  622  and/or data  624 . The memory system  620  may be implemented as a single storage device, or be distributed across multiple storage devices or sub-systems that cooperate to store computer readable instructions, data structures, program modules, or other data. The memory system  620  may include volatile and/or non-volatile systems, and may include removable and/or non-removable media implemented in any method or technology for storage of information. The storage media may include non-transitory and/or transitory storage media, including random access memory, read only memory, magnetic discs, optical discs, flash memory, virtual memory, and non-virtual memory, magnetic storage devices, or any other medium which can be used to store information and be accessed by an instruction execution system, for example. 
     The functional block diagrams, operational sequences, and flow diagrams provided in the Figures are representative of exemplary architectures, environments, and methodologies for performing novel aspects of the disclosure. While, for purposes of simplicity of explanation, the methodologies included herein may be in the form of a functional diagram, operational sequence, or flow diagram, and may be described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts may, in accordance therewith, occur in a different order and/or concurrently with other acts from that shown and described herein. For example, those skilled in the art will understand and appreciate that a methodology can alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all acts illustrated in a methodology may be required for a novel implementation. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. Certain terms have been used for brevity, clarity, and understanding. No unnecessary limitations are to be inferred therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes only and are intended to be broadly construed. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have features or structural elements that do not differ from the literal language of the claims, or if they include equivalent features or structural elements with insubstantial differences from the literal languages of the claims.