Outboard propulsion system

Abstract

To provide a steering device for an outboard propulsion system.SOLUTION: An outboard propulsion system includes a first portion for attaching to a boat and fixed around nearly vertical axis and a second portion connected to the first portion and composed to rotate around a steering shaft. The first portion includes a sealed housing 40 surrounding a member having a longitudinal axis as well as being capable of moving against the longitudinal axis, the second portion includes a gear 60 configured to engage with a member, such that movement of the member relative to its longitudinal axis generates rotational movement of the gear about its steering shaft 16, and the sealed housing includes a sensor 38 composed to determine the position of the member inside the sealed housing.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to improvements in or relating to outboard propulsion systems, and more particularly to steering arrangements for outboard propulsion systems. [Background technology]

[0002] A conventional outboard propulsion system is a self-contained unit that can be mounted on the transom of a boat; the system includes an engine, transmission, and propeller (or jet drive). The entire unit can rotate about a vertical steering axis relative to the transom to control the direction of thrust from the propeller and thus steer the boat. The entire unit can also rotate about a horizontal trim / tilt axis, a lateral axis relative to the transom, to trim the thrust angle of attack and / or to tilt the unit up, for example, when not in use.

[0003] These propulsion system configurations include one or more complex attachments to the boat's transom, including hydraulics, that allow the entire propulsion system to rotate about its steering axis and its trim / tilt axes. This complexity is due in part to the large number of rotational axes and in part to the need for the entire system to rotate about these axes. Rotating the powerhead requires significant force and requires ample space around the boat's transom for the powerhead to rotate about its steering axis. To accommodate these rotational movements, the powerhead is typically supported far behind the transom. As a result, many conventional outboard motors include a steering lever that extends into the boat's hull. This lever is attached to the powerhead and is used to rotate the outboard motor relative to the transom to steer the boat. The lever requires ample space to rotate, taking up valuable space within the boat's hull. Summary of the Invention [Problem to be solved by the invention]

[0004] It is against this background that the present invention arises. [Means for solving the problem]

[0005] According to the present invention, there is provided an outboard propulsion system comprising a first part for attachment to a boat, the first part being fixed about a substantially vertical axis, and a second part connected to the first part and configured to rotate about a steering axis, the first part comprising a sealed housing having a longitudinal axis and enclosing a member movable relative to the longitudinal axis, the second part comprising a gear configured to engage the member such that movement of the member relative to its longitudinal axis generates rotational movement of the gear about the steering axis, and the sealed housing comprising a sensor configured to determine the position of the member within the sealed housing.

[0006] The first portion may be adapted to be attached to the boat via a securing mechanism. The securing mechanism may include a transom bracket configured to connect to the boat and a cradle configured to connect to the first portion. The cradle may be connected to the transom bracket and configured to rotate about a substantially horizontal axis, such that the first portion can rotate about the substantially horizontal axis. The substantially horizontal axis may be substantially parallel to the transom of the boat. Alternatively or additionally, the substantially horizontal axis may be perpendicular to a longitudinal axis of the boat.

[0007] Enclosing the member in a sealed housing fixed about a substantially vertical axis allows the first portion to extend downwardly over the gear with which the member is mated. This allows for optimizing the positioning of the connection between the outboard propulsion system and the cradle. For example, the cradle can be connected to the first portion at a location closer to the water surface than the gear. This allows for a larger engine to be used for a given bracket and / or cradle size. Alternatively or additionally, the connection between the first portion and the cradle can be optimally positioned toward the bottom of the first portion. For example, the connection between the first portion and the cradle can optionally be optimally positioned less than 500 mm, less than 300 mm, less than 200 mm, or less than 100 mm from the bottom of the first portion.

[0008] Furthermore, enclosing the moving members in a sealed housing within the first portion of the outboard propulsion system allows the members to be protected from the external environment, such as seawater and marine life. Thus, the gears can be configured to engage the members within the protective confines of the first portion, thereby containing all of the moving parts of the steering system. Alternatively or additionally, the gears can be configured to engage the members within the protective confines of the sealed housing, thereby containing all of the moving parts of the steering system.

[0009] The sealed housing may be configured to surround the entire first section. For example, the sealed housing may surround each member and the engine in addition to other components within the first section. Thus, the sealed housing may be a cowling or part thereof. This reduces the number of seals between the internal components of the first section and the external environment, resulting in a more robust system. Thus, the sealed housing may be the first section and / or the cowling. The first section may be attached to the stern of the boat.

[0010] Alternatively, the sealed housing may be a separate element within the first portion, ensuring that the member remains enclosed when another element of the first portion, such as a cowling, is removed. For example, the sealed housing may be a steering gear housing.

[0011] Sensors allow steering direction to be precisely monitored and adjusted electronically via the helm. For example, an outboard propulsion system may become "steer-by-wire." This improves the responsiveness and packaging of the system.

[0012] The member may comprise a magnet, and the sensor may be configured to monitor changes in a magnetic field generated by the magnet to determine the position of the member within the sealed housing.

[0013] The magnet may be disposed within the member, for example, the magnet may be housed within the member, and disposing the magnet within the member does not alter the profile of the member, thus avoiding the need to modify the hermetic housing.

[0014] Alternatively, the magnet may be disposed on the outer surface of the member. The magnet may be embedded into the outer surface of the member. Alternatively or additionally, the magnet may be shaped to wrap around the member. For example, the magnet may be helical. Wrapping the magnet around the member causes a greater variation in the magnetic field when the member is moved, thus improving the accuracy and precision with which the sensor can determine the position of the member.

[0015] In some embodiments, the sensor may be a non-contact sensor. The sensor may be externally disposed relative to the hermetic housing. For example, the sensor may be configured to detect movement of a member from outside the hermetic housing. This ensures that no additional sealing of the housing is required, and ensures that sensor replacement and / or maintenance is simplified.

[0016] The first portion may comprise an engine and the second portion may comprise a propeller shaft, and the engine may be configured to provide power to the propeller shaft.

[0017] The gear may be connected to the second part such that rotation of the gear causes rotation of the second part relative to the first part. When the gear is fixed to the second part, the gear does not move relative to the second part. The second part may be configured to generate thrust. More specifically, the propeller shaft may be configured to generate thrust in use. Thus, rotating the second part relative to the first part via the gear changes the direction in which thrust is generated. Changing the direction in which thrust is generated can be used to steer the boat.

[0018] The first section may include a transmission assembly configured to control power provided to the propeller shaft. For example, the transmission assembly may be configured to control power provided to the propeller shaft via at least one drive shaft. Locating the transmission assembly within the first section, and thus above the steering device, allows the first section to extend downward closer to the water surface in use. This allows for optimal positioning of at least one additional connection between the first section and the cradle. This reduces vibrations to the boat and improves the stability of the outboard propulsion system in use.

[0019] The steering axis may be non-vertical, allowing the thrust generated by the system to have a vertical component, improving the dynamic behavior of the boat during turns and / or lowering the bow of the boat, reducing the likelihood of the boat skidding across the water during turns.

[0020] The member may be operably connected to a motor configured to generate movement of the member relative to its longitudinal axis. The motor may be connected to a control system, such as a boat helm, that is configured to control the movement of the member and thus the rotation of the gear, allowing a user to change the direction of thrust generated by the outboard propulsion system.

[0021] Alternatively or additionally, the member may be operably connected to a hydraulic pump configured to generate movement of the member relative to its longitudinal axis. The hydraulic pump may be connected to a control system, such as a boat helm, that is configured to control the movement of the member and thus the rotation of the gear, allowing a user to change the direction of thrust generated by the outboard propulsion system.

[0022] The member may comprise at least one protrusion. The protrusion may be adapted to allow engagement with the gear. The protrusion may be a tooth. Alternatively, the protrusion may be a thread. Alternatively or additionally, the gear may comprise at least one protrusion configured to engage with the member. Thus, the gear can be configured to engage with the member.

[0023] The member may be elongated, which increases the length over which the member can engage with the gear, thus allowing for greater rotational movement of the gear.

[0024] The member may be adapted to move along its longitudinal axis. Moving the member along its longitudinal axis may result in a rack and pinion steering arrangement. For example, the member may be a rack and the gear may be a pinion gear. Rack and pinion steering arrangements are more compact and robust than some alternative steering arrangements.

[0025] The member may be adapted to move about its longitudinal axis. Alternatively or additionally, the member may be adapted to move about its longitudinal axis. Moving the member about its longitudinal axis may result in a worm drive steering device. For example, the member may be a screw and the gear may be a worm gear, resulting in a worm drive steering device.

[0026] Alternatively or additionally, the member may be directly connected to a motor. The motor may be configured to rotate the member in a first direction, thereby rotating the gear in a second direction. Reversing the motor may cause the member to rotate in a third direction opposite the first direction, thereby causing the gear to rotate in a fourth direction opposite the second direction.

[0027] The member may be adapted to move both along and about its longitudinal axis, for example, hydraulic fluid may be adapted to cause both rotational and axial movement of the member within the enclosed housing.

[0028] The sealed housing may include a cylinder having a chamber configured to receive hydraulic fluid. The chamber may be adjacent to the member. The cylinder may include an inlet in fluid communication with the chamber. The chamber may receive hydraulic fluid via the inlet.

[0029] A cylinder with a chamber configured to receive hydraulic fluid can be used to move each member relative to its longitudinal axis. The motor can be configured to pump hydraulic fluid into the chamber, thereby removing any vibrations caused by the engine from the vicinity of the motor. The hydraulic fluid in the chamber can exert pressure on the member, thereby moving the member relative to its longitudinal axis.

[0030] The chamber may include an outlet configured to control the flow of hydraulic fluid from within the chamber to the reservoir. The hydraulic fluid in the chamber may be in fluid communication with a reservoir. The outlet may include a valve configured to control the flow of hydraulic fluid from the chamber to the reservoir. When the valve is closed, the motor may pump hydraulic fluid from the reservoir into the chamber to pressurize the chamber and / or move the member in a first direction relative to its longitudinal axis. When the valve is open, the pressure in the chamber is reduced, resulting in the member being moved in a second direction relative to its longitudinal axis.

[0031] Alternatively, in some embodiments, the inlet is also the outlet. The motor may be configured to power a pump configured to pump fluid from the reservoir into the chamber, thereby pressurizing the chamber and / or moving the member in a first direction relative to its longitudinal axis. When the motor is reversed, this results in the chamber being depressurized and / or fluid flowing from the chamber back into the reservoir. Alternatively, when the motor is turned off, the fluid may flow from the chamber back into the reservoir under gravity.

[0032] The enclosed housing may include a cylinder having two chambers separated by a member, each chamber configured to receive hydraulic fluid, such that the enclosed housing includes a single double-acting member.

[0033] Each chamber may be configured to receive hydraulic fluid through at least one inlet. The member may include at least one seal configured to throttle fluid flow between the chambers in the cylinder. Each chamber may be configured to receive hydraulic fluid.

[0034] Alternatively or additionally, there is also provided an outboard propulsion system comprising: a first part for attachment to a boat, the first part being fixed about a generally vertical axis; and a second part connected to the first part and configured to rotate about a steering axis, the first part comprising a sealed housing enclosing two members, each having a longitudinal axis and movable relative to the longitudinal axis, and a gear configured to engage each member such that movement of at least one member relative to its longitudinal axis generates rotational movement of the gear about the steering axis.

[0035] The sealed housing may include a plurality of cylinders. More specifically, the sealed housing may include two cylinders. Each cylinder may include a chamber configured to receive hydraulic fluid.

[0036] The first and second members may be positioned such that rotational movement of the gear causes movement of the first member in a first direction and movement of the second member in a second direction, which may be opposite to the second direction.

[0037] Having two members move in opposite directions when the gears are rotated can reduce backlash in the system. In some embodiments, having two members move in opposite directions when the gears are rotated can eliminate backlash from the system. Having two members move in opposite directions when the gears are rotated can also reduce the amount of vibration generated in the system, potentially minimizing the risk of resonance. Therefore, vibrations transmitted through the entire system and into the boat hull are also reduced, resulting in reduced induced stress on all components in the system.

[0038] The first member may be moved in a first direction as a result of an increase in pressure in the first chamber. The first chamber may be adjacent to the first member. Movement of the first member may cause movement of the gear. Movement of the gear may cause movement of the second member in a second direction. Movement of the second member in the second direction may force fluid out of the second chamber. The second chamber may be adjacent to the second member. The first member may be disposed within a first cylinder. The first chamber may be disposed within the first cylinder. The second member may be disposed within a second cylinder. The second chamber may be disposed within the second cylinder.

[0039] Alternatively or additionally, the second member may be moved in the first direction as a result of an increase in pressure in the second chamber. Movement of the second member may cause movement of the gear. Movement of the gear may cause movement of the first member in the second direction. Movement of the first member in the second direction may force fluid out of the first chamber. As a result, the sealed housing comprises two single-acting members.

[0040] Alternatively or additionally, there is provided an outboard propulsion system comprising: a first part for attachment to a boat, the first part being fixed about a substantially vertical axis; and a second part connected to the first part and configured to rotate about a steering axis, wherein the first part comprises a sealed housing enclosing a first member and a second member, each having a longitudinal axis; and the second part comprises a gear including at least one protrusion configured to engage with each member, each protrusion configured to move along the longitudinal axis of the corresponding member to rotate the second part about the steering axis.

[0041] The gear may be generally circular. The at least one protrusion may be configured to move in a substantially curved or arc-like path. A chord of the curved or arc-like path may be parallel or generally parallel to the longitudinal axis of the member.

[0042] Rotational movement of the gear may cause movement of the first member in a first direction. Alternatively or additionally, rotational movement of the gear may cause movement of the second member in a second direction. The second direction may be opposite to the first direction. For example, the first member and second member may be located on opposite sides of the gear.

[0043] Alternatively, in some embodiments, the first member may be positioned adjacent to the second member, yet the first member may also be configured to move in an opposite direction relative to the second member.

[0044] Alternatively or additionally, the enclosed housing may include two cylinders each having two chambers separated by a member, and each chamber may be configured to receive hydraulic fluid, resulting in the enclosed housing having two double-acting members.

[0045] The motor may be configured to pump hydraulic fluid from the reservoir into a first chamber in each cylinder to pressurize the first chamber in each cylinder. Pressurizing the first chamber in each cylinder causes each member to move relative to its longitudinal axis. The first member may move in a first direction and the second member may move in a second direction. The first direction may be opposite to the second direction. Simultaneously, fluid in the second chamber in each cylinder flows back into the reservoir.

[0046] The pump is then reversed, pumping hydraulic fluid from the reservoir into the second chamber in each cylinder. Pumping hydraulic fluid into the second chamber in each cylinder pressurizes the second chamber, causing the first and second members to move in the second and first directions, respectively, relative to their longitudinal axes. Simultaneously, fluid in the first chamber in each cylinder flows into the reservoir.

[0047] Alternatively or additionally, at least one hydraulic control valve may be configured to direct hydraulic fluid pumped from the reservoir into the first reservoir and / or the second reservoir in each cylinder.

[0048] The two double-acting members provide a level of redundancy to the system, allowing the gears to rotate even if one member disengages from the gear or if the user's ability to move one of the members is impaired or limited. The members are located on opposite sides of the gear, resulting in parallel, offset longitudinal axes. As a result, rotation of the gears moves the members in opposite directions relative to their respective axes.

[0049] In some embodiments, each member may initially operate as a single-acting member, preventing hydraulic fluid from entering the second chamber in the cylinder. This may reduce backlash in the system. Alternatively, or additionally, backlash in the system may be completely eliminated. During use, the cylinder may be configured to switch to double-acting, allowing hydraulic fluid to enter the second chamber in the cylinder only when needed. Fluid flow into the second chamber in the cylinder may be controlled via a second pump and / or at least one valve. The valve may be a custom valve. In some embodiments, the member may be configured to be single-acting when the gear is positioned near the neutral steering position.

[0050] Thus, there may be multiple members, each of which may be single acting, or alternatively or additionally, each of which may be double acting.

[0051] Alternatively or additionally, the outboard propulsion system may include a conduit providing fluid communication between the first and second sections. Thus, there is also provided an outboard propulsion system including a first section for mounting to a boat, the first section being fixed about a generally vertical axis, and a second section connected to the first section and configured to rotate about a steering axis, the first section including a sealed housing having a longitudinal axis and enclosing a member movable relative to the longitudinal axis, the second section including a gear configured to engage the member such that movement of the member relative to the longitudinal axis generates rotational movement of the gear about the steering axis, and a conduit providing fluid communication between the first and second sections. The conduit providing fluid communication between the first and second sections allows a fluid, such as exhaust gas or water, to be transported throughout the system. The fluid may be a liquid and / or a gas.

[0052] The conduit may pass directly from the first portion into the second portion. Alternatively or additionally, the conduit may pass directly from the second portion into the first portion. Passing the conduit directly from the first portion into the second portion minimizes the length of the conduit, thus improving the efficiency of the system. Passing the conduit directly from the first portion into the second portion further reduces the overall packaging size of the system.

[0053] The conduit between the first and second portions may be substantially straight, further improving the efficiency of the system and further reducing the overall packaging size of the system.

[0054] The conduit may pass through an opening in the gear. Passing the conduit through an opening in the gear further shortens the length of the conduit. Furthermore, passing the conduit through an opening in the gear allows the conduit to be positioned about a center of rotation. For example, the center of gravity of the conduit near the gear may be aligned with the steering axis.

[0055] The outboard propulsion system may include a drive shaft configured to transfer power between the first portion and the second portion, a portion of the drive shaft may be disposed within the conduit.

[0056] The outboard propulsion system may include a sleeve disposed within the conduit, the sleeve being configured to surround a portion of the drive shaft.

[0057] Locating the drive shaft within the conduit reduces the overall packaging size of the system, thereby reducing the overall weight. The sleeve can protect the drive shaft from fluids within the conduit. The sleeve therefore increases the robustness of the system and prevents the drive shaft from deteriorating beyond its optimum state.

[0058] The outboard propulsion system may include a second conduit. The second conduit may be configured to surround the first conduit. The second conduit may be configured to provide fluid communication between the first and second sections. The conduits may be concentric. Enclosing the first conduit within the second conduit allows both water and exhaust gases to be transported separately and efficiently throughout the system. The first conduit may be configured to receive water. The second conduit may be configured to receive exhaust gases. Alternatively, the first conduit may be configured to receive exhaust gases. The second conduit may be configured to receive water.

[0059] Alternatively or additionally, there is provided an outboard propulsion system comprising: a first part for attachment to a boat, the first part being fixed about a generally vertical axis; and a second part connected to the first part and configured to rotate about a steering axis, the first part comprising a member having a longitudinal axis and movable relative to the longitudinal axis; the second part comprising a gear configured to engage with the member, such that movement of the member relative to its longitudinal axis generates rotational movement of the gear about the steering axis; and the first part comprising an engageable element having an axis and movable relative to the axis, the engageable element being operably engaged with the gear such that movement of the engageable element relative to its axis generates rotational movement of the gear about the steering axis.

[0060] An engageable component configured to operably engage with the gear such that movement of the engageable element relative to its axis generates rotational movement of the gear about the steering axis provides redundancy to the outboard propulsion system. For example, in some embodiments, even when the member becomes immobile, the second part can be rotated via the engageable component. The engageable component can be used to rotate the second part in an emergency.

[0061] The engageable component may be a toothed disc configured to rotate about an axis passing through its center, such that rotation of the toothed disc about its axis generates rotational movement of the gear about the steering axis.

[0062] The toothed disc allows engagement with the gear, thus allowing rotational force to be transmitted therebetween. The toothed disc may be a gear. The system may include a plurality of toothed discs operatively connected to the gear. A first toothed disc may have a larger diameter than a second toothed disc. The first toothed disc and the second toothed disc may be configured to create a gear ratio. As a result, the first toothed disc and the second toothed disc may be configured to increase and / or decrease the power output of the rotational force provided to the engageable member.

[0063] Alternatively or additionally, the engageable member may be a toothed bar having a longitudinal axis and movable along the longitudinal axis, such that movement of the toothed bar along its longitudinal axis produces rotational movement of the gear about the steering axis.

[0064] A toothed bar may be used in place of a toothed disc. The toothed bar may be a member having a plurality of protrusions. The plurality of protrusions may be teeth. A bar may reduce the overall packaging size compared to a disc. In some embodiments, the toothed bar may be operably connected to a toothed disc. The toothed bar may be operably connected to a plurality of toothed discs. The plurality of toothed discs may be configured to create a gear ratio as described above.

[0065] Alternatively or additionally, the engageable member may be a threaded bar having a longitudinal axis and movable about the longitudinal axis, such that movement of the threaded bar about its longitudinal axis produces rotational movement of the gear about the steering axis.

[0066] A threaded burr may be used in place of the toothed disc and / or toothed burr. The threaded burr may comprise a single elongated projection. In some embodiments, the threaded burr may be operably connected to the toothed disc. The threaded burr may be operably connected to multiple toothed discs. The multiple toothed discs may be configured to create a gear ratio as described above.

[0067] Furthermore, the threaded bar may provide a steering lock configured to ensure that movement of the gear can only be achieved via the engageable member, allowing a user to lock the steering position via the engageable member in scenarios where the member is free to move, which may occur if fluid leaks from the hydraulic system.

[0068] The outboard propulsion system may further include a handle configured to engage the engageable member with the gear. Alternatively, the handle may be a button. For example, in some embodiments, the engageable member may be engaged and disengaged from the gear via the handle. However, in some embodiments, the engageable member is always operably coupled to the gear.

[0069] The handle may be configured to create an engagement between the engageable member and the gear in use. The engagement of the engageable member and the gear may be such that movement of both the gear and the member is permitted via the engageable member. Furthermore, in some embodiments, the engagement of the engageable member may be such that movement of the member is prevented. The engageable member would then need to be disengaged from the gear to allow the member to rotate the gear during normal use.

[0070] Movement of the engageable member may produce rotational movement of the gear about the steering axis and movement of the member relative to its longitudinal axis, allowing the user to override any input provided to the member, thus giving the user complete control over the rotation of the second part.

[0071] The gear may include a plurality of protrusions configured to engage with an engageable member. The protrusions may be positioned around at least 30% of the circumference of the gear. The plurality of protrusions may be teeth. A gear including a plurality of protrusions positioned around at least 30% of the circumference and configured to engage with an engageable member may allow the gear to be rotated through at least 108 degrees via movement of the engageable member.

[0072] In some embodiments, the member may include at least one protrusion, as described in more detail above. A plurality of protrusions on the gear may also be configured to engage with at least one protrusion on the member. Protrusions positioned around at least 30% of the circumference of the gear may allow movement of the member and the engageable member without disengaging either from the gear.

[0073] In some embodiments, the outboard propulsion system may include two members, and thus the plurality of protrusions may be positioned around at least 60% of the circumference of the gear and configured to engage with at least one protrusion on each member and the engageable member.

[0074] In some embodiments, the gear may have protrusions positioned around at least 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100% of its circumference.

[0075] The engageable members may be directly connected to the gears. Connecting the engageable members directly to the gears can reduce the overall package size of the system. Furthermore, connecting the engageable members directly to the gears can simplify the system to reduce the number of components that can fail, wear out, or require replacement.

[0076] Alternatively, the engageable member may be connected to the gear via at least one intermediate gear. The engageable member may be connected to the gear via multiple intermediate gears. The intermediate gear may be configured to increase the torque, moment, and / or rotational force applied to the gear during use. Accordingly, the intermediate gear may have a smaller diameter than the gear. Alternatively or additionally, the intermediate gear may have a larger diameter than the engageable member. The multiple intermediate gears may have multiple different diameters.

[0077] The engageable member may be operably connected to a motor configured to move the engageable member relative to its axis. The motor may be controllable in use via the helm of the boat. Alternatively or additionally, the motor may be controllable via a button on or attached to the outboard propulsion system. The motor may be configured to receive power from a battery. Alternatively or additionally, the motor may be configured to receive power from the outboard propulsion system.

[0078] The engageable member may be operably connected to an actuator. The actuator may be configured to be manually rotated by a user. Furthermore, the actuator may be configured to receive a lever adapted to assist a user in rotating the actuator. The lever may be a wrench. A manually operated actuator configured to rotate the engageable member may be used to ensure that the second portion of the outboard propulsion system can be rotated mechanically and not rely on electronic signals and / or hydraulic fluid. This reduces the likelihood of a complete failure of the steering system. Alternatively or additionally, the actuator may be configured to be rotated by an outboard motor. Furthermore, in some embodiments, the actuator may be configured to be rotated by a separate motor. The motor may be battery-operated and / or controlled from the boat's helm.

[0079] As a result, the engageable member can be configured to receive energy from at least one of the user, the outboard motor, and the battery, thereby providing redundancy within the system. Furthermore, the user can operate the engageable member using the energy source most convenient for them and / or from the location on the boat that is most desirable for a given situation.

[0080] The engageable member may be operably connected to the actuator via a flexible shaft. The flexible shaft may be used to improve packaging of the system. The flexible shaft may be configured to connect the engageable member to the actuator via a tortuous path. Alternatively, the engageable member may be operably connected to the actuator via multiple rigid shafts, each connected to an adjacent rigid shaft via a rotatable joint, such as a universal joint. Alternatively, the engageable member may be operably connected to the actuator via at least one rigid shaft. The engageable member may be operably connected to the actuator via a single rigid shaft.

[0081] The actuator may be accessible by a user inside the boat during use. Allowing a user to access the actuator from inside the boat allows the user to rotate the second part and thus steer the boat from within the boat. This is particularly convenient for the user in the unlikely event that control of the outboard propulsion system via the boat's helm is lost during use.

[0082] As previously disclosed, the first portion can include a hermetic housing configured to surround the member. Alternatively or additionally, the hermetic housing can be configured to surround the engageable member.

[0083] Enclosing the engageable member in a sealed housing protects the engageable member from the external environment, such as seawater, marine life, etc. Thus, the gear can be configured to engage the engageable member within the protective confines of the first part, thereby allowing all moving parts of the steering system to be contained.

[0084] Alternatively, the hermetic housing may include an additional chamber configured to surround the engageable member. The additional chamber may be attached to the body of the hermetic housing. The connection between the body of the hermetic housing and the additional chamber may be substantially liquid-tight.

[0085] Also as described above, the sealed housing may include a cylinder having a chamber configured to receive hydraulic fluid from a reservoir via an inlet. The cylinder may include a first chamber and a second chamber separated by a member. Each chamber may be configured to receive hydraulic fluid from the reservoir via an inlet. The first chamber may be in fluid communication with the second chamber via the reservoir.

[0086] Alternatively or additionally, the sealed housing may enclose two members, each having a longitudinal axis and movable relative to the longitudinal axis. The gear may be configured to engage each member such that movement of at least one member relative to its longitudinal axis produces rotational movement of the gear about the steering axis. Thus, the sealed housing may include a first cylinder having a first chamber and a second cylinder having a second chamber. Each chamber may be configured to receive hydraulic fluid from a reservoir via an inlet. The first chamber may be in fluid communication with the second chamber via the reservoir.

[0087] The outboard propulsion system may further include a switch configured to create direct fluid communication between the first chamber and the second chamber, the switch configured to create direct fluid communication between the first chamber and the second chamber allowing the gear to rotate even when hydraulic fluid is unable to return to the reservoir.

[0088] In some embodiments, the switch is configured to operate an override valve. Alternatively or additionally, the override valve may be manually operated by a user. Thus, the override valve may be referred to as a manual override valve. In a first position, the manual override valve allows hydraulic fluid in the system to flow between the first chamber and the second chamber via the reservoir, while in a second position, the manual override valve allows hydraulic fluid to flow directly from the first chamber to the second chamber.

[0089] The outboard propulsion system may include a locking mechanism operable between a first position configured to permit movement of the engageable member relative to its axis and a second position configured to prevent rotation of the engageable member relative to its axis. The locking mechanism may be a shuttle valve configured to control flow of hydraulic fluid into and out of the reservoir. The shuttle valve may be electronically controlled.

[0090] The locking mechanism may be used to fix the position of the second portion relative to the first portion. This can provide a consistent steering direction that can be used to maintain the boat's heading in use. The locking mechanism may also be configured to allow movement of the member about its axis when in the first position and to prevent movement of the member about its axis when positioned in the second position. The locking mechanism may be adapted to control the flow of hydraulic fluid within the system. For example, the first position may allow the flow of hydraulic fluid within the system, while the second position may prevent the flow of hydraulic fluid within the system.

[0091] Alternatively or additionally, the outboard propulsion system may include a lockable collar configured to prevent movement of the first portion relative to the second portion. The lockable collar may be operably connected to the actuator. Alternatively or additionally, the lockable collar may be operably connected to the engageable member. The lockable collar may be operably connected to the engageable member via a shaft.

[0092] More specifically, the lockable collar may have a first position configured to permit rotation of the second portion relative to the first portion. Furthermore, the lockable collar may have a second position configured to prevent rotation of the second portion relative to the first portion. The lockable collar may be manually moved between the first and second positions. As a result, in the second position, the lockable collar can maintain the direction and / or orientation of the second portion relative to the first portion. This is particularly advantageous in situations where the system has an insufficient amount of hydraulic fluid, which may occur, for example, if the hydraulic system has a leak.

[0093] Furthermore, the lockable collar may be adapted to be secured in either the first position or the second position. More specifically, the lockable collar may include a lock configured to prevent movement of the lockable collar between the first position and the second position.

[0094] The lockable collar may be configured to engage with the actuator such that the lockable collar can prevent rotation of the actuator, which in turn prevents rotation of the engageable member and gear.

[0095] The invention will now be further and more particularly described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0096] [Figure 1] 1 illustrates an outboard propulsion system according to some embodiments of the present invention. [Figure 2] 1 illustrates a sealed housing according to some embodiments of the present invention. [Figure 3] 1 illustrates an embodiment of the present invention with a rack and pinion steering system. [Figure 4] 1 illustrates an embodiment of the present invention with a worm drive steering system. [Figure 5] 1 illustrates an embodiment of the present invention with two concentric conduits providing fluid communication between a first portion and a second portion. [Figure 6] 6 shows a cross section through the outboard propulsion system shown in FIG. 5. [Figure 7] 6 illustrates a schematic diagram of a plurality of valve arrangements configured to control the flow of hydraulic fluid through the outboard propulsion system shown in FIG. 5. [Figure 8] 1 illustrates an embodiment of the present invention with engageable members. [Figure 9] The actuator is shown. [Figure 10A] 13 shows a cross section through the actuator when the lockable collar is disengaged. [Figure 10B] 10 shows a cross section through the actuator when the lockable collar is engaged. DETAILED DESCRIPTION OF THE INVENTION

[0097] 1 shows an outboard propulsion system 10 including a first section 20 for mounting to a boat. More specifically, the first section 20 is mounted to the stern of the boat via a cradle or bracket, although any suitable means for connecting the outboard propulsion system to a boat may be used.

[0098] The first portion 20 is fixed about a generally vertical axis 14. Alternatively or additionally, in some embodiments not shown, the first portion 20 may be fixed about a generally vertical plane.

[0099] First section 20 includes an engine 22 and a transmission assembly 24. Engine 22 is a conventional four-stroke compression ignition diesel engine, although any internal combustion engine may be used. In some embodiments, the engine is diesel fueled, while in other embodiments, the engine is gasoline fueled. Furthermore, in some embodiments, the engine is hybrid and includes at least one battery, at least one electric motor, and an internal combustion engine. In some embodiments not shown, the outboard propulsion system is fully electric and includes one or more electric motors and corresponding batteries. Transmission assembly 24 is configured to control the power output from engine 22.

[0100] The outboard propulsion system 10 further includes a second section 50 connected to the first section and configured to rotate about the steering axis 16. The second section 50 includes a propeller shaft 52 configured to generate thrust. The engine 22 is configured to provide power to the propeller shaft 52, thereby generating thrust. The transmission assembly 24 is configured to control the power provided to the propeller shaft 52.

[0101] The steering shaft 16 is non-vertical. In some embodiments, the steering shaft 16 may intersect the longitudinal axis of the at least one propeller shaft 52 at an angle between 100 and 140 degrees. Alternatively or additionally, the steering shaft 16 may intersect the longitudinal axis of the at least one propeller shaft 52 at an angle of approximately 120 degrees. However, in some embodiments not shown, the steering shaft 16 may intersect the longitudinal axis of the at least one propeller shaft 52 at an angle between 90 and 180 degrees, between 95 and 160 degrees, between 100 and 140 degrees, between 110 and 130 degrees, between 115 and 125 degrees, or at an angle of approximately 120 degrees.

[0102] In some embodiments, the steering axis 16 may intersect the generally vertical axis 14 at an angle between 40 and 80 degrees. Alternatively or additionally, the steering axis 16 may intersect the generally vertical axis 14 at an angle of approximately 60 degrees. However, in some embodiments not shown, the steering axis 16 may intersect the generally vertical axis 14 at an angle between 0 and 90 degrees, between 20 and 85 degrees, between 40 and 80 degrees, between 50 and 70 degrees, between 55 and 65 degrees, or at an angle of approximately 60 degrees.

[0103] As shown in Figures 3 and 4, the first section 20 includes an enclosed housing 40 having a first cylinder 41A and a second cylinder 41B. The cylinder 41A surrounds the first member 30A, and the second cylinder 41B surrounds the second member 30B. Each member 30A, 30B has a longitudinal axis 32A, 32B along which the member 30A, 30B moves. The second section 50 includes a gear 60 configured to engage the members 30A, 30B such that movement of each member relative to its longitudinal axis 32A, 32B produces rotational movement of the gear about the steering axis 16.

[0104] The gear 60 is connected to the second portion 50 such that rotation of the gear 60 causes the second portion 50 to rotate relative to the first portion 20. When the gear 60 is fixed to the second portion 50, the gear 60 does not move relative to the second portion 50. The second portion 50 is configured to rotate up to 180 degrees relative to the first portion 20. However, in some embodiments, the second portion 50 is configured to rotate up to 40 degrees, 60 degrees, 80 degrees, 90 degrees, 100 degrees, 120 degrees, 140 degrees, or 160 degrees relative to the first portion 20. The second portion 50 can rotate clockwise and / or counterclockwise.

[0105] In some embodiments not shown, the sealed housing 40 is configured to surround the entire first portion 20. Alternatively or additionally, the first portion 20 may include separate sealed housings 40 configured to surround the first member 30A, the second member 30B, and the gear 60, as shown in Figures 2-4.

[0106] 3 illustrates an embodiment of the present invention comprising two members 30A, 30B, each configured to engage a gear 60. A sealed housing 40 comprises two cylinders 41A, 41B, each comprising a chamber 42A, 42B, respectively. Each chamber 42A, 42B is configured to receive hydraulic fluid 44 via an inlet (not shown). Each chamber further comprises an outlet (not shown) configured to control the flow of hydraulic fluid out of the chamber and back to a reservoir 49. The hydraulic fluid in each chamber is in fluid communication with the reservoir 49 via a respective conduit 45A, 45B. Each conduit provides a fluid path between the reservoir 49 and the inlet and / or outlet.

[0107] Each member 30A, 30B is elongated and includes at least one protrusion 34A, 34B configured to engage gear 60. Additionally, each member 30A, 30B includes a magnet 36A, 36B. Hermetically sealed housing 40 further includes at least one sensor 38A, 38B per member, configured to determine the position of the magnet within the hermetically sealed housing and, therefore, the position of each member 30A, 30B and, ultimately, the steering direction. Sensors 38A, 38B are configured to monitor the position of the magnet based on changes in a magnetic field.

[0108] However, any suitable magnet and / or sensor may be used. The sensor may be analog or digital. For example, in some embodiments, a Hall effect sensor may be used. Alternatively or additionally, in some embodiments, a magnetic pickup sensor may be used.

[0109] In use, the motor 70 powers the pump 72 to pump hydraulic fluid 44 from the reservoir 49, along the first conduit 45A, and into the first chamber 42A via the first inlet. The hydraulic fluid 44 in the chamber 42A exerts pressure on the member 30A. The pressure from the hydraulic fluid 44 in the chamber 42A moves the member 30A in a first direction away from the first position. The movement of the first member 30A in the first direction rotates the gear 60 in a counterclockwise direction. The resulting rotation of the gear 60 moves the second member 30B in a second direction away from the first position. The movement of the second member 30B in the second direction forces the hydraulic fluid 44 in the second chamber 42B out of the second chamber 42B, through the outlet, along the second conduit 45B, and back into the reservoir 49. As a result, the second part 50 is rotated in a counterclockwise direction about the steering axis 16 relative to the first part 20. This process is reversed to rotate the second portion 50 relative to the first portion 20 in the opposite direction about the steering axis 16 .

[0110] For example, in use, motor 70 powers pump 72 to pump hydraulic fluid 44 from reservoir 49, along second conduit 45B, and into second chamber 42B via the first inlet. Hydraulic fluid 44 in chamber 42B exerts pressure on member 30B. Pressure from hydraulic fluid 44 in chamber 42B moves member 30B in a first direction away from the second position. Movement of second member 30B in the first direction rotates gear 60 in a clockwise direction. As a result, rotation of gear 60 moves first member 30A in a second direction away from the second position. Movement of first member 30A in the second direction forces hydraulic fluid 44 in second chamber 42A out of first chamber 42A, along first conduit 45A, via the outlet, and back into reservoir 49. As a result, second portion 50 is rotated in a clockwise direction about steering axis 16 relative to first portion 20.

[0111] In some embodiments not shown, at least one outlet includes a valve configured to control the flow of hydraulic fluid 44 from the chamber 42 to the reservoir 49. The outlet may include multiple valves. Alternatively or additionally, the reservoir 49 may include at least one valve configured to control the flow of hydraulic fluid 44 from the reservoir 49 to the chamber 42. When the valve is closed, the pump 72 pumps hydraulic fluid from the reservoir 49 into the first chamber 42A, 42B through the inlet, pressurizing the chamber and / or moving the members 30A, 30B in a first direction relative to their longitudinal axes 32A, 32B. When the valve is open, hydraulic fluid flows from the chamber 42A, 42B into the reservoir 49 through the outlet. As a result, the pressure in the chamber 42A, 42B decreases, thus allowing the members 30A, 30B to move in a second direction relative to their longitudinal axes 32A, 32B.

[0112] FIG. 7 illustrates a schematic of a multiple valve arrangement configured to control the flow of hydraulic fluid 44 between reservoir 49 and at least one chamber 42 in the outboard propulsion system 10 described above.

[0113] 7, pump 72 is a bi-directional pump configured to receive power from motor 70. Pump 72 is configured to pump hydraulic fluid from reservoir 49 into first chamber 42A through first user-operated check valve 141A and first restriction 142A. Simultaneously, hydraulic fluid is directed to flow from second chamber 42B into reservoir 49 through second restriction 142B and second user-operated check valve 141B. When pump 72 is turned off, user-operated check valves 141A, 141B remain in a closed or "locked" position, thus preventing the flow of hydraulic fluid through the system.

[0114] Each user-operated check valve 141A, 141B may be operated between an open and a closed position as a result of an electronic signal. Alternatively or additionally, each user-operated check valve 141A, 141B may be operated between an open and a closed position as a result of hydraulic fluid pressure within the system.

[0115] Each restriction 142A, 142B is configured to throttle the flow of hydraulic fluid between chambers 42A, 42B and reservoir 49, thereby maintaining a predetermined hydraulic fluid pressure within the system. Furthermore, the system includes a first relief valve 143A and a second relief valve 143B disposed in parallel with first restriction 142A and second restriction 142B, respectively. The relief valves 143A, 143B are configured to limit the maximum hydraulic fluid pressure within the system. Alternatively or additionally, the relief valves 143A, 143B are configured to control the flow and / or pressure of hydraulic fluid flowing back into reservoir 49.

[0116] There are also third and fourth relief valves 144A and 144B that are configured to return fluid to reservoir 49 in the event of a large pressure spike in the system.

[0117] The system further includes a manual override valve 145 disposed between the restrictors 142A, 142B and the chambers 42A, 42B. When positioned in a first position, the manual override valve 145 enables the system to function as described above. However, when positioned in a second position, the manual override valve is configured to allow fluid to flow directly between the first chamber 42A and the second chamber 42B. This may allow the outboard propulsion system to be manually steered, for example, in an emergency. In some embodiments, the manual override valve 145 is operable between a first position and a second position via a switch (not shown). The switch may be an electronic switch. The switch may be located on the helm of the boat in use and / or on the outboard propulsion system. The switch is thus configured to create direct fluid communication between the first chamber 42A and the second chamber 42B.

[0118] Furthermore, the system includes a shuttle valve 146 configured to control the flow of hydraulic fluid back into the reservoir 49. The shuttle valve 146 is electronically controlled. As a result, the shuttle valve can act as a locking mechanism. For example, the shuttle valve can block the flow of hydraulic fluid into or out of the reservoir 49, thereby immobilizing the member 32 and gear 60 relative to their respective axes.

[0119] In some embodiments not shown, each cylinder includes two chambers separated by a member, resulting in each cylinder being a double-acting hydraulic cylinder with member 30. Alternatively, the enclosed housing may include two double-acting hydraulic cylinders with members configured to move in opposite directions. Each chamber may include an inlet and an outlet in fluid communication with a reservoir via separate conduits.

[0120] Alternatively or additionally, a first chamber in the first cylinder may be in fluid communication with a first chamber in the second cylinder, and further, a second chamber in the first cylinder may be in fluid communication with a second chamber in the second cylinder, such that hydraulic fluid can flow between each pair of chambers in the opposing cylinders to move the member relative to its longitudinal axis.

[0121] In some embodiments, each member 30 includes a plurality of projections 34. For example, Figure 3 illustrates an embodiment of the present invention including a rack and pinion steering system. Each member 30A, 30B includes a plurality of projections 34A, 34B in the form of teeth shaped to engage with gear 60. Each member 30A, 30B moves along its longitudinal axis 32A, 32B as indicated by arrow X, thus rotating gear 60.

[0122] In some embodiments, each member 30 includes a single protrusion 34. The single protrusion may be a continuous thread. For example, FIG. 4 illustrates an embodiment of the present invention including a worm drive steering system. Each member 30A, 30B includes a single protrusion 34A, 34B in the form of a thread shaped to engage with gear 60. Each member 30A, 30B moves about and / or around its longitudinal axis 32A, 32B, as indicated by arrow Y, thereby rotating gear 60. In FIG. 4, the members may be rotated about their axes via pressure generated by hydraulic fluid, as previously described. However, in some embodiments not shown, each member 30A, 30B is directly connected to a motor 70. The motor is configured to rotate the member in a first or second direction, thereby generating rotation of the gear and second portion in a third or fourth direction.

[0123] 5 illustrates an embodiment of the present invention comprising two concentric conduits 80, 81, each providing fluid communication between first portion 20 and second portion 50. First conduit 80 is configured to receive water. Second conduit 81 is configured to receive exhaust gases from engine 22. Each conduit 80, 81 provides fluid communication between first portion 20 and second portion 50.

[0124] More specifically, each conduit 80, 81 passes directly from first portion 20 into second portion 50. Thus, each conduit 80, 81 provides a direct fluid path between first portion 20 and second portion 50. Conduits 80, 81 pass through opening 62 in gear 60. As a result, the centers of gravity of conduits 80, 81 are aligned with steering shaft 16.

[0125] The outboard propulsion system 10 further includes a drive shaft 84 configured to transfer power from the engine 22 in the first section 20 to the propeller shaft 52 in the second section 50. In some embodiments, a plurality of intermediate shafts, gears, and / or connections are operably coupled to the drive shaft 84. At least one of the intermediate shafts, gears, and / or connections is disposed between the engine 22 and the propeller shaft 52. Thus, "coupled to XX" includes both "directly coupled to XX" and "indirectly coupled to XX." For example, in some embodiments, the transmission 24 is disposed between the engine 22 and the drive shaft 84. Thus, at least one additional drive shaft, not shown, may be disposed between the engine 22 and the transmission 24.

[0126] A portion of the drive shaft 84 is disposed within the first conduit 80, as shown in FIG. 5. The drive shaft 84 is surrounded by a sleeve 82 configured to prevent fluid within the conduits 80, 81 from contacting the drive shaft 84. The second conduit 81 surrounds the first conduit 80 and provides additional fluid communication between the first portion 20 and the second portion 50. Each conduit is configured to prevent fluid associated with the first conduit from mixing with fluid within the second conduit. In some embodiments, the first conduit 80 is configured to receive water, and the second conduit 81 is configured to receive exhaust gases.

[0127] Figure 6 shows a cross section through the outboard propulsion system 10 shown in Figure 5. More specifically, Figure 6 shows conduits 80, 81 passing from the first portion 20 directly into the second portion 50. Alternatively or additionally, Figure 6 shows conduits 80, 81 passing from the second portion 50 directly into the first portion 20.

[0128] Figure 8 illustrates an embodiment of an outboard propulsion system 10 that includes an engageable member 90. The engageable member 90 has an axis 91 about which the engageable member 91 is configured to move. In some embodiments, the engageable member is a toothed disk, such as a gear, configured to rotate about or about its own axis 91, as shown in Figure 8. Alternatively, in some embodiments not shown, the engageable member is a toothed bar, such as a rack, that moves along its own axis, or a threaded bar, such as a screw thread, that rotates about or about its own axis.

[0129] 8, the engageable member 90 is operably coupled to the gear 60 via an intermediate gear 92. However, in some embodiments not shown, the engageable member 90 is directly coupled to the gear 60. Alternatively or additionally, in some embodiments not shown, the outboard propulsion system includes a handle configured to effect engagement of the engageable member 90 with the gear 60 and / or the intermediate gear 92.

[0130] Intermediate gears 92 are configured to increase the rotational force provided by engageable members 90 to gear 60. Any number of intermediate gears 92 may be used. For example, some embodiments include 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more than 10 intermediate gears 92.

[0131] Gear 60 includes a plurality of protrusions 96 configured to engage engageable member 90 and / or intermediate gear 92. As shown in Figure 8, protrusions 96 are positioned around at least 30%, more specifically 50%, and most specifically 75% of the circumference of gear 60.

[0132] The engageable member 90 shown in FIG. 8 is enclosed within the sealed housing 40. However, in some embodiments not depicted in the accompanying drawings, the sealed housing includes an additional chamber configured to attach to the main body of the sealed housing 40 and configured to enclose the engageable member 90. Each of the foregoing configurations protects the engageable member from the external environment. Alternatively, in some embodiments, the engageable member 90 is external to the sealed housing 40. This configuration can provide easy access for maintenance, for example.

[0133] The engageable members are operatively coupled to actuators 97 via one or more shafts 94. Shafts 94 may be flexible or rigid. The actuators are manually operated via a user to rotate shafts 94, thereby rotating engageable members 90, which rotates intermediate gear 92, which rotates gear 60 about its axis 16.

[0134] In some embodiments, the engageable member 90 is operably coupled to a motor operable via buttons and / or a control panel, the motor configured to use energy from the engine 22 or a battery (not shown) to rotate the engageable member.

[0135] Figure 9 shows an actuator 97. The actuator 97 is operably coupled to the engageable member 90 via a shaft 94. The engageable member 90 is operably coupled to the gear 60. Thus, during normal use of the outboard motor, the actuator 97 rotates as the gear 60 rotates. Therefore, in some embodiments, the actuator 97 is covered by a cap 99, as shown in Figure 8.

[0136] In the event of a failure of the normal steering system, actuator 97 may be used to rotate gear 60, and thus steer the outboard motor. For example, if members 30A, 30B become unresponsive or disengaged from gear 60, gear 60 may be locked in place by the presence of hydraulic fluid 44 in cylinders 41A, 41B. In this scenario, a user moves override valve 145 to the second position, allowing hydraulic fluid movement between cylinders 41A, 41B. The user then manually rotates actuator 97, which rotates gear 60. The user then returns override valve 145 to the first position, locking gear 60 in its new position.

[0137] However, if sufficient hydraulic fluid is lost from the system, gear 60 will move freely. Again, this will result in a loss of control over members 30A, 30B, resulting in a steering failure. In this scenario, moving override valve 145 between the first and second positions is redundant. However, the user can still control the rotation of gear 60 via actuator 97.

[0138] In some embodiments, the outboard propulsion system includes a lockable collar 98, as shown in Figures 9, 10A, and 10B. The lockable collar 98 is configured to prevent movement of the second portion 50 relative to the first portion 20 when activated. The lockable collar 98 thus allows a user to lock the steering direction of the outboard propulsion system in the event of insufficient hydraulic fluid in the system. Thus, the lockable collar 98 provides additional redundancy within the system.

[0139] The lockable collar 98 is secured to the transom of the boat and is configured to engage and prevent rotation of the actuator 97. More specifically, the lockable collar 98 is movable between a first position and a second position, the first position permitting rotation of the actuator 97 and the second position preventing rotation of the actuator 97.

[0140] FIG. 10A shows a cross section through actuator 97 in a first position in which lockable collar 98 is disengaged. In this position, actuator 97 can rotate freely as gear 60 rotates. Conversely, FIG. 10B shows a cross section through actuator 97 in a second position in which lockable collar 98 is engaged, thereby preventing rotation of gear 60. More specifically, lockable collar 98 includes a plurality of protrusions 101. Actuator 97 also includes a plurality of protrusions 102. Protrusions 101 on lockable collar 98 are configured to engage and disengage with protrusions 102 on actuator 97, as shown in FIGS. 10A and 10B.

[0141] Shaft 94 has a threaded bore 104 at its distal end. Threaded bore 104 has a longitudinal axis 106. Actuator 97 is attached to shaft 94 via a threaded bar 103 positioned within threaded bore 104. In use, actuator 97 can be rotated relative to shaft 94 via bolt 105 by winding and unwinding threaded bar 103 within threaded bore 104 along the bore's axis 106. Actuator 97 can therefore move along the bore's axis 106 relative to lockable collar 98. At a certain point, protrusion 102 on actuator 97 engages protrusion 101 on lockable collar 98. In this configuration, actuator 97 is locked in place, and as a result, shaft 94, engageable member 90, and gear 60 are prevented from rotating. The actuator can then be released by rotating the nut 105 in the opposite direction until the projections 102 on the actuator 97 disengage from the projections 101 on the lockable collar 98 .

[0142] Alternatively, in some embodiments not shown, the lockable collar may be a mechanical fastener. The lockable collar may be configured to engage with the actuator, shaft 94, and / or engageable member 90. Alternatively or additionally, the lockable collar may be configured to directly engage with second portion 50.

[0143] Various further aspects and embodiments of the present invention will be apparent to those skilled in the art in view of the present disclosure.

[0144] As used herein, "and / or" should be construed as disclosing each of the two specified features or components with or without the other. For example, "A and / or B" should be construed as specifically disclosing each of (i) A, (ii) B, and (iii) A and B, as if each were individually set forth herein.

[0145] Unless the context dictates otherwise, the feature descriptions and definitions set forth above are not limited to any particular aspect or embodiment of the invention, but apply equally to all aspects and embodiments described.

[0146] While the invention has been described by way of example with reference to certain embodiments, those skilled in the art will further appreciate that the invention is not limited to the disclosed embodiments and that alternative embodiments may be constructed without departing from the scope of the invention as defined by the appended claims. [Explanation of symbols]

[0147] 10 Outboard Propulsion System 14 Approximately vertical axis 16 Steering shaft 20 Part 1 22 Engine 24 Transmission Assembly 30A First member 30B Second member 32, 32A, 32B longitudinal axis 34, 34A, 34B protrusion 36A, 36B magnets 38A, 38B Sensors 40 Sealed Housing 41A No. 1 cylinder 41B No. 2 cylinder 42A First Chamber 42B Second Chamber 44 Hydraulic Fluids 45A, 45B conduit 49 Reservoir 50 Part 2 52 Roper shaft 60 gears 62 Aperture 70 Motor 72 Pump 80 1st conduit 81 Second conduit 82 Sleeve 84 Drive shaft 90 Engageable member 91 Axis of engageable member 92 Intermediate shaft 94 Shaft 97 Actuator 98 Lockable Collars 99 Cap 101 Protrusion 102 Protrusion 103 Threaded Bar 104 Threaded Hole 105 Bolts and nuts 106 Longitudinal axis of hole 141A First User-Operated Check Valve 141B Second User-Operated Check Valve 142A First Aperture 142B 2nd aperture 143A First relief valve 143B Second relief valve 144A Third relief valve 144B 4th relief valve 145 Manual override valve 146 Shuttle valve X, Y: Direction of movement of member 30

Claims

1. a first portion for attachment to a boat, the first portion being secured about a substantially vertical axis; a second portion connected to the first portion and configured to rotate about a steering axis; An outboard propulsion system comprising: the first portion comprises a sealed housing having a longitudinal axis and enclosing a member movable relative to the longitudinal axis, and the second portion comprises a gear configured to engage the member such that movement of the member relative to its longitudinal axis produces rotational movement of the gear about the steering axis; The enclosed housing includes a sensor configured to determine a position of the member within the enclosed housing.

2. 2. The outboard propulsion system according to claim 1, the member comprises a magnet, and the sensor is configured to monitor changes in a magnetic field generated by the magnet to determine the position of the member within the enclosed housing.

3. 3. The outboard propulsion system according to claim 1, 1. An outboard propulsion system, wherein the first portion comprises an engine and transmission assembly, and the second portion comprises a propeller shaft, the engine configured to provide power to the propeller shaft via the transmission assembly.

4. 4. The outboard propulsion system according to claim 1, the gear is connected to the second portion such that rotation of the gear causes rotation of the second portion relative to the first portion.

5. 5. The outboard propulsion system according to claim 1, 1. An outboard propulsion system, wherein the steering axis is non-vertical.

6. 6. The outboard propulsion system according to claim 1, The member is operably connected to a motor configured to generate motion of the member relative to its longitudinal axis.

7. 7. The outboard propulsion system according to claim 1, The member moves along its longitudinal axis.

8. 7. The outboard propulsion system according to claim 1, The member moves about its longitudinal axis.

9. 9. An outboard propulsion system according to claim 1, the sealed housing comprises a cylinder having two chambers separated by the member, each chamber configured to receive hydraulic fluid.

10. 10. The outboard propulsion system according to claim 1, the sealed housing encloses two members each having a longitudinal axis and movable relative to the longitudinal axis; 1. An outboard propulsion system, wherein the gears are configured to engage each member such that movement of at least one member relative to its longitudinal axis produces rotational movement of that gear about the steering axis.

11. 11. The outboard propulsion system according to claim 10, the first member and the second member are positioned such that rotational movement of the gear causes movement of the first member in a first direction and movement of the second member in a second direction.

12. 12. The outboard propulsion system according to claim 11, the first direction is opposite to the second direction.

13. 13. An outboard propulsion system according to any one of claims 1 to 12, comprising:

1. An outboard propulsion system, further comprising a conduit providing fluid communication between said first portion and said second portion, said conduit passing from said first portion directly into said second portion.

14. 14. An outboard propulsion system according to claim 12 or 13, the conduit between the first portion and the second portion is substantially straight.

15. 15. An outboard propulsion system according to any one of claims 12 to 14, the conduit passes through an opening in the gear.

16. 16. An outboard propulsion system according to any one of claims 12 to 15, comprising:

1. An outboard propulsion system, further comprising a drive shaft configured to transmit power between the first portion and the second portion, a portion of the drive shaft disposed within the conduit.

17. 17. An outboard propulsion system as defined in claim 16, comprising: a sleeve disposed within the conduit and configured to surround a portion of the drive shaft.

18. 18. An outboard propulsion system according to any one of claims 12 to 17, comprising: a second conduit configured to surround the first conduit and to provide fluid communication between the first portion and the second portion.

19. 20. The outboard propulsion system of claim 18, the first conduit is configured to receive water and the second conduit is configured to receive exhaust gases.

20. 20. An outboard propulsion system according to any one of claims 1 to 19, the first portion having an axis and including an engageable component movable relative to the axis, the engageable component operatively engaged with the gear such that movement of the engageable component relative to its axis produces rotational movement of the gear about the steering axis.

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