BACKGROUND OF THE INVENTION [0002] Trolling motors come in a variety of sizes, shapes and configurations and are generally used for commercial or recreational fishing boats. Fishing boats typically utilize a trolling motor for propelling the boat quickly for short distances and for maneuvering and precisely positioning the boat in the water. Trolling motors typically include a motor tube connecting a propulsion unit to a control head, a support assembly and a steering control. The steering control of a trolling motor typically includes steering arm extending from the trolling motor or a remote operated steering mechanism. The steering control of a trolling motor typically are configured to turn the propulsion unit and therefore the boat at a fixed, predetermined steering ratio in response to a steering control signal of the trolling motor user. Other steering control systems utilize complex electro-mechanical systems to adjust the steering control in a linear or non-linear manner.

[0003] Existing steering controls for trolling motors have a number of drawbacks.

First, the fixed uniform steering ratio inherent in a typical steering control for a trolling motor is incapable of optimizing motor steering control for high speed and low speed operation. Such fixed steering ratio trolling motor speed controls are limited to one of three typical settings. One typical steering control setting utilizes a high steering ratio which maximizes the user's ability to maneuver the boat at low speeds for precise positioning or to avoid obstacles, but the high steering ratio setting makes steering control difficult at increased speeds where sensitive steering control is desirable. A second common steering control setting utilizes a low steering ratio which optimizes steering control at increased speeds but decreases the boats maneuverability at low speeds (e. g. during fishing). A third common setting utilizes a mid-range steering ratio which provides a steering control with more sensitivity than a high steering ratio setting and more maneuverability than a low steering ratio setting. However, in the mid-range setting the steering ratio is not optimized for either mode of operation. In an effort to optimize steering control for both modes of operation, many boat owners utilize a trolling motor with a high steering ratio to optimize maneuverability at low speeds and then rely on an additional motor or engine driven propulsion unit with a low steering ratio for operation at higher speeds.

[0004] Second, trolling motors having adjustable steering ratios typically require manual readjustment of the steering control to accomplish the readjustment and may require additional tools to perform the readjustment. Finally, automatically adjustable steering controls typically require complex and expensive electronic circuits connected to the propulsion unit of the boat.

[0005] Thus, there is a continuing need for a steering control device for a trolling motor that provides a lower steering ratio, and increased steering sensitivity, for operation requiring relatively small angular adjustments of the steering control, and provides a higher steering ratio, for operations where precise positioning of the boat is desired and where large propulsion unit angular displacement is desired in response to a smaller angular displacement of the steering control. It would be advantageous to provide a steering control for a trolling motor that provides a high steering ratio when larger and quicker steering adjustments are desired, such as when it is desired to completely turn around a boat in a small turning radius, and a low steering ratio for when minor directional changes are desired, such as during high speed travel of the boat. What is needed is a steering control for a trolling motor that easily, automatically and inexpensively provides a non-uniform steering ratio between a propulsion unit and a steering control in response to angular displacement of the steering control. There is a need for a steering control device that provides greater steering sensitivity to small angular displacements when the propulsion unit is positioned substantially parallel to the boat and less steering sensitivity when a larger turn is required.

SUMMARY OF THE INVENTION [0006] The present invention provides a trolling motor for a boat. The trolling motor includes a motor tube, a steering control, a propulsion unit, a support assembly, and a coupling mechanism. The propulsion unit is coupled to a lower end of the motor tube. The support assembly is coupled to the motor tube and is configured to connect the trolling motor to the boat. The coupling mechanism is coupled to the support, the motor tube and the steering control. The coupling mechanism is configured to provide a non-uniform steering ratio between the steering control and the motor tube in response to angular displacement of the steering control.

[0007] The present invention also provides a steering control device for a trolling motor of a boat having a motor tube supporting a propulsion unit and a support coupled to the motor tube. The steering control device includes a tube extension, and a steering control extension. The tube extension has a tube opening configured to receive the motor tube of the trolling motor. The tube extension includes at least two projections.

The steering control extension is pivotally coupled to the support about the first axis.

The steering control extension has a main opening and at least two slots interconnected to the main opening. The main opening is sized to receive the motor tube and at least one projection of the tube extension. Each slot is configured to slidably and removably receive one of the projections, thereby providing a non-uniform steering ratio between the steering member and the motor tube in response to movement of the steering member.

[0008] The present invention also provides a steering control device for a trolling motor having a support coupled to a motor tube and configured to couple to a boat.

The steering control device includes a steering control and a coupling mechanism. The coupling mechanism is coupled to the steering control about a first axis, and to the support and the motor tube of the trolling motor. The coupling mechanism forms a variable steering control mechanism having a first steering range in which the coupling mechanism has lesser steering sensitivity and a second steering range in which the coupling mechanism has greater steering sensitivity.

[0009] The present invention also provides a steering control device for a trolling motor having a support, a propulsion unit, and a motor tube that is coupled to the propulsion unit and the support. The steering control device includes a steering control and a coupling mechanism. The steering control has an angular displacement operating range about a first axis. The coupling mechanism includes a steering control extension coupled to the steering control and to the support of the trolling motor, and a motor tube extension coupled to the motor tube. The steering control extension has at least one slot and the motor tube extension has at least one pin. The at least one pin is configured to slidably engage the steering control extension such that the differential between the angular translation of the steering control about the first axis and the resultant angular translation of the propulsion unit about a motor tube axis non- uniformly varies over the angular operating range of the steering control.

[0010] The present invention also provides a steering control device for a boat motor having a support, a propulsion unit, and a motor tube that is coupled to the propulsion unit and the support. The steering control device includes a steering control, a steering control extension, and a motor tube extension. The steering control extension is coupled to the steering control about a first axis and to the support of the motor. The motor tube extension is coupled to the motor tube. The steering control device is configured such that the inter-engagement of the steering control extension and the motor tube extension non-uniformly rotates the tube in response to angular displacement of the steering control about the first axis.

[0011] The present invention also provides a trolling motor for a boat including a lower propulsion unit, a motor support coupled to the propulsion unit and configured to rotate about a first axis, a steering control member coupled to the motor support and pivotable about a second axis between a first position and a second position, and means for rotating the steering control member about the second axis between the first and second positions. The control member is coupled to the motor support at a first radial distance from the first axis when in the first position. The control member is coupled to the motor support at a second radial distance from the first axis when in the second position.

BRIEF DESCRIPTION OF THE DRAWINGS [0012] Figure 1 is side view of one exemplary embodiment of a trolling motor of the present invention.

[0013] Figure 2 is an exploded sectional view a steering control device of the trolling motor of Figure 1.

[0014] Figure 3 is a cross-sectional view of the steering control device of the trolling motor of Figure 1.

[0015] Figure 4 is a top sectional view of the trolling motor of Figure 1 with the steering control and the propulsion unit aligned along the same longitudinal plane.

[0016] Figure 5 is a top sectional view of the trolling motor of Figure 1 illustrating angular translation of the steering control and the propulsion unit.

[0017] Figure 6 is a top sectional view of the trolling motor of Figure 1 illustrating angular translation of the steering control and the propulsion unit.

[0018] Figure 7 is a top sectional view of the trolling motor of Figure 1 illustrating angular translation of the steering control and the propulsion unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0019] Figure 1 illustrates a trolling motor 10, having a variable trolling motor steering control according to an exemplary embodiment of the present invention.

Trolling motor 10 includes a propulsion unit 12, a motor tube 14, a support assembly 16, a control head 18, a steering control 20, and a coupling mechanism 22. Propulsion unit 12 is a motor of conventional design. Propulsion unit 12 is connected to a lower end 28 of motor tube 14. Propulsion unit 12 converts electrical energy, preferably from a battery (not shown), into rotational mechanical energy. In an alternative exemplary embodiment, propulsion unit 12 transfers rotational mechanical energy from a shaft (not shown), downwardly extending from control head 18, to a propeller 24 that is coupled to propulsion unit 12. In an exemplary embodiment, propulsion unit 12, produces minimal turbulence when operating at trolling speed. Additionally, propulsion unit 12 can be sized to accommodate motors of varying horse power ratings to match the horse power requirements of a specific boat or user.

[0020] Propulsion unit 12 includes a body 23, propeller 24 and a fin 26. Body 23 is a generally tubular housing having a conical front end 25 and a rear end 27. Body 23 is connected to lower end 28 of motor tube 14. Body 23 supports and encloses internal components of propulsion unit 12. Body 23 is made of metal. Body can be made of alternative materials such as plastic, etc. Propeller 24 is a multi-blade impeller coupled to rear end 27 of body 23. In operation, the rotation of propeller 24 in one direction propels propulsion unit 12 forward and rotation of propeller 24 in an opposite direction propels propulsion unit 12 rearward. Propeller 24 is made of metal. Propeller 24 can be made of alternative materials such as molded plastic, etc. Fin 26 is a substantially planar extension downwardly extending from propulsion unit 12 and is positioned substantially parallel to a longitudinal axis of propulsion unit 12. Fin 26 functions as a rudder to facilitate steering of trolling motor 10 and a boat 48 in water.

[0021] Motor tube 14 is a tubular member connected to and upwardly extending from propulsion unit 12 at a lower end 28 and connected to a control head 18 at an upper end 30 of motor tube 14. Motor tube 14 also extends through and is rotatably coupled to support assembly 16, steering control 20, and coupling mechanism 22.

Motor tube 14 provides a pathway for the routing of control and power lines (not shown) to propulsion unit 12 and to steering control 20. In an alternative exemplary embodiment, motor tube provides a pathway for a gear operated shaft (not shown) extending from control head 18 to propulsion unit 12. Motor tube 14 supports and separates propulsion unit 12 from control head 18, allowing control head 18 to be positioned above the water surface and propulsion unit 12 to be positioned below the water surface. Motor tube 14 is made of plastic. Motor tube 14 can also be made of alternative materials, such as steel, aluminum, etc. In an exemplary embodiment, motor tube 14 can be axially adjusted relative to support assembly 16 in order to obtain the optimum depth of propulsion unit 12 below the water surface. Motor tube 14 allows for those components with reduced water resistance to be disposed above the water surface. Alternatively, motor tube 14 can be a solid cylindrical member having externally mounted propulsion unit control cables.

[0022] Support assembly 16 is a structure that includes a base 31 and at least one support bracket 32. Base 31 includes an upper portion 34 and a lower portion 36.

Base 31 is coupled to coupling mechanism 22 and steering control 20 at upper portion 34. Base 31 provides a support structure for coupling mechanism 22, steering control 20, motor tube 14 and support bracket 32. Base 31 is configured to allow for axial and rotational movement of motor tube 14 relative to support assembly 16. Base 31 of support assembly is made of molded plastic. Alternatively, base 31 can be made of steel, aluminum, etc. Base 31 includes at least one opening 38 (shown in Figure 2) for receiving motor tube 14, and a hole positioned transverse to the longitudinal axis of motor tube 14 and extending through base 31. The hole is configured for receiving a bracket pin 42. Bracket pin 42 pivotally couples base 31 to support bracket 32.

[0023] Support bracket 32 is an elongated structure having an outwardly extending arm 40 with a downwardly extending distal end 41. Pin 42 transversely extends through and pivotally connects support bracket 32 and base 31. Two apertures 43 extend through distal end 41 of arm 40 substantially parallel to the longitudinal axis of arm 40. Two fasteners 44 (one shown) extend through arm apertures 43. In an exemplary embodiment, each fastener 44 is a threaded rod having a manually-operated knob 44 at one end and a bracing support 46 at the opposing end. Support bracket 32 is configured for adjustably and removably connecting trolling motor 10 to boat 48 without the use of tools. Support bracket 32 is made out of molded plastic.

Alternatively, support bracket 32 can be made out of steel, aluminum, etc. The rotational and axial coupling of base 31 to motor tube 14, the pivotal coupling of support bracket 32 to base 31, and the adjustability of support bracket 32 and fastener 44 maximizes the range of adjustment and the connectability of trolling motor 10 to boat 48.

[0024] Steering control 20 is coupled to coupling mechanism 22 and is pivotally coupled to upper portion 34 of base 31. Steering control 20 includes a housing 52 and a control arm 54. Housing 52 substantially covers an upper side of coupling mechanism 22. Control arm 54 is an elongated bar pivotally coupled to housing 52.

The pivotal mounting of steering control 20 to support assembly 16 allows for steering control 20 to rotate in a generally horizontal plane. The pivotal coupling of control arm 54 to housing 52 of. steering control 20 allows for rotation of control arm 54 in a generally vertical plane. In an exemplary embodiment, control arm 54 further includes a hand grip 56 coupled to an extendable, rotatable arm extension 58 co-axially positioned within control arm 54. Control arm 54 provides a rotatable, extendable and manually-operable steering lever for the user of boat 48. The pivotal movement of control arm 54 in horizontal and vertical directions and the extendable length of control arm 54 allows trolling motor 10 to readily adapt to each user's size and position on the boat. Steering control 20 is made of plastic. Alternatively, steering control 20 can be made of other materials, such as aluminum, steel, etc. In an exemplary embodiment, arm extension 58 and hand grip 56 comprise a throttle for varying the speed of propulsion unit 12 in both a forward direction and a rearward direction. Therefore, in an exemplary embodiment control arm 54 is used to control the steering and the speed of boat 48 and trolling motor 10. In an exemplary embodiment, arm extension 58 is operably coupled to propulsion unit 12 through control arm 54 and motor tube 14.

[0025] Control head 18 is coupled to upper end 30 of motor tube 14. Control head 18 can be used to hold equipment for controlling the speed and power of trolling motor and can include one or more of the following components: suitable circuitry, a gear assembly, a servo-motor, a power supply and a governor. In an exemplary embodiment, control head 18 includes control circuitry (not shown) and a power cable 60 for coupling to the power supply (not shown).

[0026] Figures 2 and 3 illustrate support assembly 16, coupling mechanism 22, steering control 20, and motor tube 14 in greater detail. As shown by Figures 2 and 3, upper portion 34 of support assembly 16 has an aperture 62 and a recess 78. Aperture 62 extends into upper portion 34 of support assembly 16 substantially parallel to motor tube 14. Aperture 62 is outwardly positioned in support assembly 16 with respect to motor tube 14 and is positioned opposite of support bracket 32 (shown in Figure 1).

Aperture 62 is configured to receive pin fastener 64. Recess 78 accommodates rotational movement of a tube extension 66 of coupling mechanism 22.

[0027] As best shown on Figure 2, coupling mechanism 22 includes tube extension 66 and a steering control extension 68. Tube extension 66 preferably comprises a triangular-shaped member encircling motor tube 14. Tube extension 66 is disposed between upper portion 34 of support assembly 16 and steering control extension 66.

Tube extension 66 is configured to couple to motor tube 14 and rotatably, slidably and removably engage steering control extension 68. Tube extension 66 is made of plastic.

Alternatively, tube extension 66 can be made of other materials such as steel, aluminum, etc. Tube extension 66 includes first, second and third pins 72,74 and 76 and has a pair of opposing notches 70. First, second and third pins, 72,74 and 76, respectively, upwardly extend in a direction substantially parallel to a longitudinal axis 80 of motor tube 14 and are positioned near each corner of triangular tube extension.

Second pin 74 of tube extension 66 is radially spaced a greater distance from longitudinal axis 80 than each of first and third pins 72,76, respectively.

[0028] Notches 70 of tube extension 66 are configured for slidable, axial and removable engagement with a sleeve 82 of motor tube 14. Notches 70 function to couple extension 66 to tube 14 such that extension 66 rotates with the rotation of tube 14 brought about by movement of steering control 20.

[0029] Sleeve 82 is a tubular member configured to slide over, to co-axially align with, and to couple to motor tube 14. Sleeve 82 is made of plastic. Alternatively, sleeve 82 can be made of other materials such as metal, aluminum, etc. Sleeve 82 includes an upper fastener portion 84 and lower portion 86. Fastener portion 84 outwardly extends from sleeve 82 and includes a fastener 88 for axially and removably repositioning sleeve 82 at any point along the length of motor tube 14 to accommodate various height adjustments of propulsion unit 12 with respect to boat 48. Fastener 88 includes a manually adjustable knob (not shown) for tightening and loosening fastener 88 without the use of tools. Lower portion 86 of sleeve 82 includes opposing outwardly extending projections 89 configured to removably engage notches 70 within tube extension 66 of coupling mechanism 22. The engagement of notches 70 with projections 89 causes extension 66 to rotate with the rotation of tube 14. When sleeve 82 is fixedly secured by fastener 88 to motor tube 14, motor tube 14 can be raised, disengaging sleeve 82 from notches 70. In the raised position, motor tube 14 and propulsion unit 12 can be rotated approximately 180 degrees and then lowered to reengage projections 89 of sleeve 82 to notches 70 of tube extension 66. The removal, lifting, and rotation and reengagement of motor tube 14 and sleeve 82 to tube extension 66 allows for the easy readjustment of propulsion unit 12 to accommodate forward and backward trolling. Alternatively, extension 66 can be press fit or integrally formed to tube. Additionally, extension 66 can be coupled to tube 14 through the use of alternative means such as alternative male-female connectors, releasable connectors, adhesives, fasteners, biasing devices or a combination thereof.

[0030] Steering control extension 68 is a substantially planar member having a main opening 90, a pin fastener opening 92, and first, second and third slots 92,94 and 96, respectively. Main opening 90 is sized to receive motor tube 14 and at least one of the first, second or third pins 72,74 or 76. Fastener pin opening 92 is sized to receive and rotatably couple to fastener pin 64. First, second and third slots 92,94 and 96 are interconnected to main opening 90 and are configured to slidably and removably engage with first, second and third pins 72,74 and 76, respectively. Steering control extension 68 is rotatably coupled to steering control 20 and support assembly 16 at pin fastener 64 for rotation of steering control extension 68 with respect to support assembly 16 about an axis 100 longitudinally extending through pin fastener 64.

Steering control extension 68 is configured to slidably and removably engage tube extension 66. Steering control extension 68 is made of plastic. Alternatively, steering control extension 68 can be made of steel, aluminum, etc.

[0031] Figures 2 and 3 illustrate steering control 20 in greater detail. Referring to Figure 3, arm 40 is pivotally coupled to housing 52 through a steering control pin 102, allowing for rotation of control arm 54 about pin 102 in a generally vertical plane.

Steering control pin 102 transversely extends with respect to the longitudinal axis of arm 40 through arm 40 and into housing 52.

[0032] As best shown in Figure 2, housing 52 further includes a housing opening 106 and an elongated arcuate groove 104. Housing opening 106 extends through housing 52 and is configured to receive pin fastener 64 along a pin fastener axis 100. Pin fastener 64 extends through housing 52, steering control extension 68 and connects to support assembly 16 allowing for pivotal movement of housing 52 and steering control extension 68 with respect to support assembly 16 and about fastener pin axis 100.

Groove 104 of housing 52 is superimposed to the front portion of main opening 90 of steering control extension 68. Groove 104 is configured to receive motor tube 14 and to allow for rotational and axial movement of motor tube 14 about and along longitudinal axis 80 of motor tube 14 during the angular translation of steering control 20 about fastener pin axis 100.

[0033] Figures 4 through 7 illustrate the non-uniform and non-linear angular translation of propulsion unit 12 about axis 80 in response to the angular translation of steering control 20 about axis 100. Figures 4 through 7 further illustrate the operation and movement of the variable steering control mechanism created by the engagement of tube extension 66 with steering control extension 68 in response to the angular translation of steering control 20 about axis 100. During the angular translation of steering control 20, propulsion unit 12, motor tube 14 and tube extension 66 rotate with respect to support assembly 16, and motor tube 14 rotates along and within groove 104 of housing 52 and within main opening 90 of steering control extension 68.

[0034] Figure 4 is a top sectional view of coupling mechanism 22, steering control 20 and propulsion unit 12. In Figure 4, arm 40 and propulsion unit 12 are aligned along a longitudinal plane 110 of trolling motor 10. In an exemplary embodiment, plane 110 is parallel to the longitudinal plane of boat 48. In Figure 4, the trolling motor 10 is positioned for forward trolling with no angular translation of arm 40 of steering control 20 about axis. 100 and no angular translation of propulsion unit 12 about axis 80. Second pin 74 of tube extension 66 is fully engaged within second slot 96 of steering control extension 68, and first pin 72 and third pin 76 of tube extension 66 are positioned within main opening 90 of steering control extension 68. The steering ratio, also known as the turning ratio, referring to the angular translation of propulsion unit 12 about axis 80 with respect to the angular translation of steering control 20 about axis 100 is initially, as shown in Figure 4, governed by the distance of pin 74 to axis 80 due to the contact of pin 74 with steering control extension 68 at second slot 96 and the distance between axes 80 and 100. The steering ratio of trolling motor 10 when arm 40 is initially angularly translated from the longitudinal position of Figure 4 is approximately 1.0.

[0035] Figure 5 illustrates the angular translation of propulsion unit 12 about axis 80 in response to a relatively small angular translation of steering control 20. A first angle defined by a plane 116 extending through the longitudinal axis of arm 40 and plane 110 is generally indicated by 112 and a second angle defined by a plane 118 extending through the longitudinal axis of propulsion unit 12 and plane 110 is generally indicated at 114. In an exemplary embodiment, as illustrated in Figure 5, first angle 112 is approximately 18 degrees offset from longitudinal plane 110 and second angle 114 is approximately 45 degrees offset from longitudinal plane 110, resulting in a steering ratio of approximately 2.5.

[0036] Due to the angular translation of steering control 20, second pin 74 is positioned within slot 96 closer to main opening 90, and first pin 72 begins to slidably engage first slot 94 of steering control extension 68. The engagement of pin 72 with slot 94 and the progressive disengagement of second pin 74 from second slot 96 results in an increased rotation of motor tube 14 and propulsion unit 12 about axis 80, and an increase in the steering ratio of motor 10, due to the contact of pin 72 with steering control extension 68 and the reduced radial distance between pin 72 and axis 80 versus the radial distance between pin 96 and axis 80. The reduced radial distance between pin 72 and axis 80 as pin 72 contacts steering control extension 68, causes an increase in rate of rotation of the propulsion unit 12 with respect to rotation of steering control 20. The variation in this radial distance of pins 72,74 and 76, and contact with steering control extension 68, along with the distance between rotational axis 80 and rotational axis 100 results in the non-uniform steering ratio of the trolling motor 10.

[0037] The non-uniform steering ratio of trolling motor 10 enables a fisherman to achieve increased steering sensitivity when traveling for short distances at high speeds and an increased steering ratio for when abrupt, sharp turns are desired such as when the fisherman positions the boat over a specific fishing spot. The fisherman obtains the benefit of increased steering sensitivity, or a low steering ratio (less than 2.0) in response to a slight angular translation of control arm 54. Yet, the fisherman also obtains the benefit of an increased steering ratio when a larger angular translation of control arm 54 is required, such as when the fisherman desires to turn the boat around or substantially re-direct the boat. Therefore, trolling motor 10 optimally satisfies the varying boat steering control needs of a fisherman.

[0038] Referring to Figure 6, steering control 20 is shown in a position of greater angular translation with respect to longitudinal plane 110 than Figure 5. First pin 74 is positioned at the edge of slot 96 where slot 96 inter-connects with main opening 90 of steering control extension 68 and pin 72 is fully engaged within slot 94 of steering control extension 68 such that rotation of motor tube 14 and propulsion unit 12 occurs about the contact point of pin 72 with slot 94 for continued angular translation of steering control 20. In an exemplary embodiment as illustrated in Figure 6, the steering ratio over the complete angular translation of control arm 54 and propulsion unit 12 from the original position of Figure 4 is approximately 2.65 with first angle 112 being approximately 32 degrees and second angle 114 being approximately 86 degrees. Therefore, a user of the trolling motor simply deflects or angularly translates steering control 20 by approximately 32 degrees and achieves a 114 degrees angular translation of propulsion unit 12. In an exemplary embodiment, as shown in Figures 6 and 7, slot 94 can be angled resulting in an increased angular translation of propulsion unit 12 about axis 80 relative to the angular translation of control arm 54 of steering control 20 when pin 72 reaches the angled portion of slot 94.

[0039] Figure 7 illustrates continued non-uniform and non-linear angular displacement of steering control 20 about axis 100 and the resultant continued angular displacement of propulsion unit 12 about axis 80. Angular translation of propulsion unit 12 occurs as a result of rotation of motor tube 14 and tube extension 66 about steering control extension 68 at pin 72 within slot 94. Due to the closer radial distance between pin 72 and axis 80, rotation of motor tube 14 and propulsion unit 12 increases with continued angular translation of steering control 20. Additionally, curved slot 94 allows for the increased and continued rotation of tube extension 66 relative to steering control extension 68. Therefore, in an exemplary embodiment as illustrated in Figure 7, first angle 112 is approximately 43 degrees beyond longitudinal plane 110 and second angle 114 is approximately 124 degrees beyond longitudinal plane 110. The steering ratio at this position for the complete angular translation of control arm 54 by 43 degrees and the complete angular translation of propulsion unit 12 by 124 degrees is approximately 2.88. Therefore, the user displaces steering control mechanism by approximately 43 degrees and obtains a propulsion unit displacement of approximately 124 degrees. More specifically, the steering ratio of trolling motor 10 over the travel of control arm 54 and propulsion unit 12 from the position of Figure 6 to the position of Figure 7 is approximately 3.45. This variation in steering ratio demonstrates the non-linear progression of the steering ratio in response to further angular translation of control arm 54.

[0040] Figures 4 through 7 illustrate the variable steering ratio inherent in the variable steering control of coupling mechanism 22. In this configuration, motor tube 14 and steering control extension 68 act in a similar fashion to a ring gear assembly with the tube being equivalent to a pinion gear and steering control extension being the equivalent of the ring gear. In an exemplary embodiment, the distance between axis 80 and axis 100 is set so as to achieve an approximate three to one turning or steering ratio. In an alternative exemplary embodiment, motor tube 14, tube extension 66 and steering control extension 68 can be configured to achieve a five or six to one turning or steering ratio. For example, pins 72 and 76 may alternatively be supported in closer proximity to axis 80 as compared to pin 74, with slots 94,96 and 98 correspondingly repositioned, to provide for greater turning or steering ratios as propulsion unit 12 is rotated and offset from the longitudinal center line of the boat by steering control 20.

This is advantageous when larger and quicker steering adjustments of trolling motor 10 are desired, such as when the boat 48 is being completely turned around or when precise positioning and relocation of the boat 48 is required.

[0041] The variable steering control of coupling mechanism 22 provides a first steering position in which coupling mechanism 22 has low steering sensitivity (and a high steering ratio) and a second steering position in which coupling mechanism 22 has high steering sensitivity (and a low steering ratio). In an exemplary embodiment, the angular translation of steering control 20 and the angular translation of propulsion unit 12 non-uniformly vary over the angular operating range of steering control 20. The inter-engagement of steering control extension 68 and tube extension 66 non-uniformly rotates motor tube 14 in response to angular displacement of steering control 20.

[0042] Various alternatives of the exemplary coupling mechanism 22 are also contemplated. These alternatives include additional pins on tube extension 66 and additional, variously configured slots on steering control extension 68. The number and configuration of the slots and pins may be selected to provide different steering ratios during the steering of trolling motor 10.

[0043] Although coupling mechanism 22 is illustrated in conjunction with a manually steered trolling motor in which manual rotation of steering control 20 results in angular rotation of propulsion unit 12, coupling mechanism 22 may alternatively be employed with other means for rotating extension 68 such as foot-operated steering systems. In such alternative systems, conventionally known foot pedals would be coupled to steering control extension 68 by cables, hydraulics, pneumatics or conventionally known electronics, wherein depressment or pivoting of the foot pedal or pedals results in rotation of extension 68 which, as described above, engages pins 72,74 or 76 to rotate propulsion unit 12.

[0044] Although less desirable, in lieu of providing a smaller turning ratio and greater steering sensitivity when propulsion unit 12 generally extends along the longitudinal center line of a boat or larger turning ratios and lower steering sensitivity as propulsion unit 12 is rotated further away from the longitudinal center line of the boat, coupling mechanism 22 may alternatively be configured in an opposite fashion such that coupling mechanism 22 provides a larger turning ratio and lower sensitivity when propulsion unit 12 extends generally along or close to the longitudinal center line of the boat and such that coupling mechanism 22 provides a smaller turning ratio and greater sensitivity as propulsion unit 12 is turned or rotated away from or further out of alignment with the longitudinal center line of the boat. In such an alternative embodiment, pin 74 would be positioned closer to axis 80 as compared to pins 72 and 76, with slots 94,96 and 98 correspondingly reconfigured.

[0045] Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. The present invention described, with reference to the preferred embodiments, and set forth in the following clams, is manifestly intended to be as broad as possible. For example, unless otherwise noted, the claims reciting a single particular element also encompass a plurality of such elements. This invention is not limited to the methods of implementation that have been explicitly described, but it includes various variants and generalizations contained in the following claims.