WO2022201008A1 - A reversable jet powered watercraft and a reversable jet unit or of for such - Google Patents

A reversable jet powered watercraft and a reversable jet unit or of for such Download PDF

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Publication number
WO2022201008A1
WO2022201008A1 PCT/IB2022/052577 IB2022052577W WO2022201008A1 WO 2022201008 A1 WO2022201008 A1 WO 2022201008A1 IB 2022052577 W IB2022052577 W IB 2022052577W WO 2022201008 A1 WO2022201008 A1 WO 2022201008A1
Authority
WO
WIPO (PCT)
Prior art keywords
watercraft
water
fins
hull
intake opening
Prior art date
Application number
PCT/IB2022/052577
Other languages
French (fr)
Inventor
Ross Andrew WHITTAKER
Neil MANS
Original Assignee
Zerojet Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2021904020A external-priority patent/AU2021904020A0/en
Application filed by Zerojet Limited filed Critical Zerojet Limited
Publication of WO2022201008A1 publication Critical patent/WO2022201008A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H11/00—Marine propulsion by water jets
    • B63H11/02—Marine propulsion by water jets the propulsive medium being ambient water
    • B63H11/10—Marine propulsion by water jets the propulsive medium being ambient water having means for deflecting jet or influencing cross-section thereof
    • B63H11/101—Marine propulsion by water jets the propulsive medium being ambient water having means for deflecting jet or influencing cross-section thereof having means for deflecting jet into a propulsive direction substantially parallel to the plane of the pump outlet opening
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H11/00—Marine propulsion by water jets
    • B63H11/02—Marine propulsion by water jets the propulsive medium being ambient water
    • B63H11/10—Marine propulsion by water jets the propulsive medium being ambient water having means for deflecting jet or influencing cross-section thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H11/00—Marine propulsion by water jets
    • B63H11/02—Marine propulsion by water jets the propulsive medium being ambient water
    • B63H11/10—Marine propulsion by water jets the propulsive medium being ambient water having means for deflecting jet or influencing cross-section thereof
    • B63H11/107—Direction control of propulsive fluid
    • B63H11/113—Pivoted outlet
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H11/00—Marine propulsion by water jets
    • B63H11/02—Marine propulsion by water jets the propulsive medium being ambient water
    • B63H11/10—Marine propulsion by water jets the propulsive medium being ambient water having means for deflecting jet or influencing cross-section thereof
    • B63H11/107—Direction control of propulsive fluid
    • B63H11/117—Pivoted vane
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H23/00—Transmitting power from propulsion power plant to propulsive elements
    • B63H23/02—Transmitting power from propulsion power plant to propulsive elements with mechanical gearing
    • B63H23/08—Transmitting power from propulsion power plant to propulsive elements with mechanical gearing with provision for reversing drive
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H25/00—Steering; Slowing-down otherwise than by use of propulsive elements; Dynamic anchoring, i.e. positioning vessels by means of main or auxiliary propulsive elements
    • B63H25/46—Steering or dynamic anchoring by jets or by rudders carrying jets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H11/00—Marine propulsion by water jets
    • B63H11/02—Marine propulsion by water jets the propulsive medium being ambient water
    • B63H11/04—Marine propulsion by water jets the propulsive medium being ambient water by means of pumps
    • B63H2011/043—Marine propulsion by water jets the propulsive medium being ambient water by means of pumps with means for adjusting or varying pump inlets, e.g. means for varying inlet cross section area
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H11/00—Marine propulsion by water jets
    • B63H11/02—Marine propulsion by water jets the propulsive medium being ambient water
    • B63H11/04—Marine propulsion by water jets the propulsive medium being ambient water by means of pumps
    • B63H2011/046—Marine propulsion by water jets the propulsive medium being ambient water by means of pumps comprising means for varying pump characteristics, e.g. rotary pumps with variable pitch impellers, or adjustable stators
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H11/00—Marine propulsion by water jets
    • B63H11/02—Marine propulsion by water jets the propulsive medium being ambient water
    • B63H11/04—Marine propulsion by water jets the propulsive medium being ambient water by means of pumps
    • B63H11/08—Marine propulsion by water jets the propulsive medium being ambient water by means of pumps of rotary type
    • B63H2011/081—Marine propulsion by water jets the propulsive medium being ambient water by means of pumps of rotary type with axial flow, i.e. the axis of rotation being parallel to the flow direction

Definitions

  • the present invention relates to a reversable jet powered watercraft and a reversable jet unit or of for such.
  • jet powered watercraft Since the advent of jet powered watercraft in the 20 th century, water jet propulsion has become increasingly widespread on a variety of vessels.
  • Personal watercraft alternatively known as jet skis, have become a popular recreational vessel that is easily transportable. Jetboats of various sizes have also come into use and planing hulls allow high speeds even with larger boats.
  • the basic principle common to jet powered watercraft is an intake below the hull that draws water into a pump, which in turn generates a high velocity jet of water from the rear of the vessel.
  • Reversing a jet powered watercraft is somewhat different from reversing a conventional watercraft with an exposed propeller. It is common to use a reverse bucket mechanism which lowers over the nozzle when its desired to cause the vessel to reverse.
  • the jet pump is operated in the normal direction and the jet stream is deflected by the bucket to push water in the opposite direction and generate reverse thrust. Steering can then be achieved by vectoring the nozzle such that the jet stream is deflected in a different direction by the bucket.
  • Reverse buckets are bulky and can require complex mechanisms to raise and lower them which are prone to failure.
  • the present invention may be said to broadly consist in a reversable jet powered watercraft comprising: a hull; a jet pump unit secured to the hull and presenting a water intake opening on the underside of the hull and a water outlet opening at the rear of the hull, the intake opening and the outlet opening connected by a duct to define a passage for the water; an impeller in the passage, able to be powered for rotation by a motor to drive water through the duct; at least one fin, mounted in a rotatable manner relative to the intake opening to control and to change direction of the flow of water passing through the intake opening, the rotatable position of the fin(s) able to be controlled by a user of the watercraft; wherein the impeller can be rotated in a first direction to cause water to flow through the passage from intake opening to outlet opening corresponding to a forward direction of travel of the watercraft and in a second direction to cause water to flow out the intake opening corresponding to a reverse direction of travel of the watercraft and wherein
  • the present invention may be said to broadly consist in a reversable jet powered watercraft
  • a reversable jet powered watercraft comprising: a hull; a jet pump unit secured to the hull and presenting a water intake opening on the underside of the hull and a water outlet opening at the rear of the hull, the intake opening and the outlet opening connected by a duct to define a passage for the water; an impeller in the passage, able to be powered for rotation by a motor to drive water through the duct; at least one fin and preferably an array of a plurality of fins, mounted in a rotatable manner relative to the intake opening to control and to change direction of the flow of water passing through the intake opening, the rotatable position of the fin(s) able to be controlled preferably directly or indirectly by a user of the watercraft; wherein the impeller can be rotated in a first direction to cause water to flow through the passage from intake opening to outlet opening corresponding to a forward direction of travel of the watercraft and in a second
  • the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water is travelling towards the bow of the hull.
  • the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel towards the bow of the hull.
  • the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel that is downwards and a component of travel that is towards the bow of the hull. In one embodiment, the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel towards the bow of the hull.
  • the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel downwards and a component of travel towards the bow of the hull.
  • the motor is an electric motor.
  • the motor is an electric motor such that the direction of the impeller can be changed from the first direction to the second direction by reversing the polarity of the electric motor.
  • the mechanical fins are configured to vector the flow through the inlet opening, all in the same direction as each other.
  • a proximal end of the fin or each of the fins is rotatably mounted. In one embodiment, a proximal end of the fin or each of the fins is rotatably mounted by a mounting plate secured to the jet pump unit.
  • a mechanical linkage connects each of the plurality of fins such that they can be rotated in unison.
  • the mechanical linkage is a parallelogram linkage. In one embodiment, the mechanical linkage is a parallelogram linkage wherein each of the plurality of fins presents an orthogonally extending link at the proximal end, and a rod pivotally connects to each of the links such that motion of the rod causes unified rotation of the plurality of fins.
  • the position of the plurality of fins can be adjusted by at least one actuator controllable directly or indirectly by a user of the watercraft.
  • the actuator is secured to the jet pump unit.
  • the at least one actuator is a motor.
  • the at least one actuator is a stepper motor.
  • the at least one actuator is a hydraulic actuator.
  • the actuator rotatably drives a lever arm pivotally connected to the mechanical linkage thereby causing rotation of the plurality of fins.
  • the fin or fins are rotatable about respective rotational axis/axes that are parallel the centreline of the hull.
  • the fin or fins are rotatable about respective rotational axis/axes that allow the water exiting the intake opening to be directed to port and starboard as desired and as controlled.
  • the watercraft also comprises a tiller that is mechanically coupled to an outlet nozzle that is located adjacent the outlet opening.
  • the outlet nozzle is able to be rotated by the tiller to cause water leaving the outlet opening to be redirected to thereby steer the watercraft.
  • the tiller is also able to control the rotational position of the fin or fins.
  • the tiller is also able to control the rotational position of the fin or fins only when the impeller is rotating in its second direction. In one embodiment the tiller is also able to control the rotational position of the fin or fins to thereby steer the watercraft when travelling in reverse.
  • the tiller is also able to control the rotational position of the fin or fins by providing input to the actuator.
  • a tiller position sensor is provided that is able to sense the position of the tiller the signal from the position sensor providing input to the actuator.
  • a tiller position sensor is provided that is able to sense the position of the tiller the signal from the position sensor providing input to the actuator to control the position of the fin or fins based on the position of the tiller.
  • a tiller position sensor is provided that is able to sense the position of the tiller the signal from the position sensor providing input to the actuator to control the position of the fin or fins based on the position of the tiller only when the impeller is rotating in its second direction.
  • the present invention may be said to broadly consist in jet pump unit for a reversable jet powered watercraft that comprises a hull, the unit comprising: a duct secured to the hull to define a passage for the water and to present a water intake opening on the underside of the hull and a water outlet opening at the rear of the hull, an impeller in the passage, able to be powered for rotation by a motor to drive water through the duct; at least one fin and preferably an array of a plurality of fins, mounted in a rotatable manner relative to the intake opening to control and to change direction of the flow of water passing through the intake opening, the rotatable position of the fin(s) able to be controlled preferably directly or indirectly by a user of the watercraft; wherein the impeller can be rotated in a first direction to cause water to flow through the passage from intake opening to outlet opening corresponding to a forward direction of travel of the watercraft and in a second direction to cause water to flow through the passage from the outlet opening to intake
  • the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel towards the bow of the hull.
  • the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel that is downwards and a component of travel that is towards the bow of the hull.
  • the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel towards the bow of the hull.
  • the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel downwards and a component of travel towards the bow of the hull.
  • the motor is an electric motor.
  • the motor is an electric motor such that the direction of the impeller can be changed from the first direction to the second direction by reversing the polarity of the electric motor.
  • the mechanical fins are configured to vector the flow through the inlet opening, all in the same direction as each other.
  • a proximal end of the fin or each of the fins is rotatably mounted.
  • a proximal end of the fin or each of the fins is rotatably mounted by a mounting plate secured to the jet pump unit.
  • a mechanical linkage connects each of the plurality of fins such that they can be rotated in unison.
  • the mechanical linkage is a parallelogram linkage.
  • the mechanical linkage is a parallelogram linkage wherein each of the plurality of fins presents an orthogonally extending link at the proximal end, and a rod pivotally connects to each of the links such that motion of the rod causes unified rotation of the plurality of fins.
  • the position of the plurality of fins can be adjusted by at least one actuator controllable directly or indirectly by a user of the watercraft.
  • the actuator is secured to the jet pump unit.
  • the at least one actuator is a motor.
  • the at least one actuator is a stepper motor.
  • the at least one actuator is a hydraulic actuator.
  • the actuator rotatably drives a lever arm pivotally connected to the mechanical linkage thereby causing rotation of the plurality of fins.
  • the fin or fins are rotatable about respective rotational axis/axes that are parallel the centreline of the hull.
  • the fin or fins are rotatable about respective rotational axis/axes that allow the water exiting the intake opening to be directed to port and starboard as desired and as controlled.
  • the present invention may be said to broadly consist in a fin system to control direction of water flow from an inlet of a jet pump unit for a hull of a jet power watercraft, the fin system comprising: a plurality of fins rotatably mounted at the inlet opening; a mechanical linkage connecting each of the plurality of fins such that they can be rotated in unison; and an actuator that can adjust the control the rotational position of the plurality of fins.
  • the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water is travelling towards the bow of the hull.
  • the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel towards the bow of the hull.
  • the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel that is downwards and a component of travel that is towards the bow of the hull. In one embodiment, the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel towards the bow of the hull.
  • the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel downwards and a component of travel towards the bow of the hull.
  • the motor is an electric motor.
  • the motor is an electric motor such that the direction of the impeller can be changed from the first direction to the second direction by reversing the polarity of the electric motor.
  • the mechanical fins are configured to vector the flow through the inlet opening, all in the same direction as each other.
  • a proximal end of the fin or each of the fins is rotatably mounted.
  • a proximal end of the fin or each of the fins is rotatably mounted by a mounting plate secured to the jet pump unit.
  • a mechanical linkage connects each of the plurality of fins such that they can be rotated in unison.
  • the mechanical linkage is a parallelogram linkage.
  • the mechanical linkage is a parallelogram linkage wherein each of the plurality of fins presents an orthogonally extending link at the proximal end, and a rod pivotally connects to each of the links such that motion of the rod causes unified rotation of the plurality of fins.
  • the position of the plurality of fins can be adjusted by at least one actuator controllable directly or indirectly by a user of the watercraft.
  • the actuator is secured to the jet pump unit. In one embodiment, the at least one actuator is a motor.
  • the at least one actuator is a stepper motor.
  • the at least one actuator is a hydraulic actuator.
  • the actuator rotatably drives a lever arm pivotally connected to the mechanical linkage thereby causing rotation of the plurality of fins.
  • the fin or fins are rotatable about respective rotational axis/axes that are parallel the centreline of the hull.
  • the fin or fins are rotatable about respective rotational axis/axes that allow the water exiting the intake opening to be directed to port and starboard as desired and as controlled.
  • the present invention may be said to broadly consist in reverse vectoring mechanism for a jet pump unit with a reversable impeller in the passage between the intake opening and outlet opening for a reversable jet powered watercraft that comprises a hull, the mechanism comprising: at least one fin and preferably an array of a plurality of fins, mounted in a rotatable manner relative to the intake opening of the jet unit to control and to change direction of the flow of water passing through the intake opening of the jet unit, the rotatable position of the fin(s) able to be controlled preferably directly or indirectly by a user of the watercraft; wherein the impeller can be rotated in a first direction to cause water to flow through the passage from intake opening to outlet opening corresponding to a forward direction of travel of the watercraft and in a second direction to cause water to flow through
  • the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water is travelling towards the bow of the hull.
  • the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel towards the bow of the hull.
  • the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel that is downwards and a component of travel that is towards the bow of the hull. In one embodiment, the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel towards the bow of the hull.
  • the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel downwards and a component of travel towards the bow of the hull.
  • the motor is an electric motor.
  • the motor is an electric motor such that the direction of the impeller can be changed from the first direction to the second direction by reversing the polarity of the electric motor.
  • the mechanical fins are configured to vector the flow through the inlet opening, all in the same direction as each other.
  • a proximal end of the fin or each of the fins is rotatably mounted. In one embodiment, a proximal end of the fin or each of the fins is rotatably mounted by a mounting plate secured to the jet pump unit.
  • a mechanical linkage connects each of the plurality of fins such that they can be rotated in unison.
  • the mechanical linkage is a parallelogram linkage. In one embodiment, the mechanical linkage is a parallelogram linkage wherein each of the plurality of fins presents an orthogonally extending link at the proximal end, and a rod pivotally connects to each of the links such that motion of the rod causes unified rotation of the plurality of fins.
  • the position of the plurality of fins can be adjusted by at least one actuator controllable directly or indirectly by a user of the watercraft.
  • the actuator is secured to the jet pump unit.
  • the at least one actuator is a motor.
  • the at least one actuator is a stepper motor.
  • the at least one actuator is a hydraulic actuator.
  • the actuator rotatably drives a lever arm pivotally connected to the mechanical linkage thereby causing rotation of the plurality of fins.
  • the fin or fins are rotatable about respective rotational axis/axes that are parallel the centreline of the hull.
  • the fin or fins are rotatable about respective rotational axis/axes that allow the water exiting the intake opening to be directed to port and starboard as desired and as controlled.
  • the present invention may be said to be a jet powered watercraft with a jet unit having an ability to pass water through the jet unit in reverse to cause the watercraft to travel in reverse through the body of water there being at least one and preferably a plurality of fins at the intake opening of the jet unit that are able to cause the flow of water leaving the intake to project to both port and starboard sides of the watercraft.
  • the present invention may be said to broadly consist in a method of steerably reversing a jet powered watercraft having a hull with a jet pump unit attached, the method comprising the steps of: a. mounting to an inlet of the jet pump unit a fin system comprising a plurality of rotatable fins that can control and change direction of water flow through the inlet, the rotatable position of the fins able to be controlled by a user of the watercraft; b. reversing flow in the jet pump unit such that water is drawn in through the outlet and ejected through the intake; c. controlling the fin system such that water ejected from the intake can be directionally controlled.
  • the outlet nozzle can be moved between a first position and a second position where the outlet nozzle is in a position lower than in its first position.
  • the outlet nozzle can be moved between a first position and a second position where the outlet nozzle is more below the water line of the hull than in its first position.
  • the outlet nozzle is in the first position when the vessel is travelling forward.
  • outlet nozzle is in the second position when the vessel is travelling backward.
  • outlet nozzle and a bearing of the outlet nozzle have a seal therebetween.
  • the outlet nozzle can be tilted downwards.
  • the outlet opening of the outlet nozzle can be tilted downwards.
  • the outlet nozzle can be rotated about a horizontal axis such that it can be tilted downwards.
  • the outlet nozzle can be rotated about a horizontal axis such that it can be tilted downwards from a more upward condition.
  • the outlet nozzle can be rotated about a horizontal axis such that it can be tilted downwards to place the outlet opening in a position lower than its downward tilted position.
  • the outlet nozzle can be tilted downwards to reduce or cut off air flow into the outlet opening while travelling in the reverse direction.
  • a secondary opening for and downstream of the impeller is provided at a submerged position.
  • the impeller when being rotated in the second direction causes water to flow from a secondary opening, provided at the bottom of the hull, to the intake opening.
  • the impeller when being rotated in the second direction causes water to flow from a secondary opening, provided at the keel of the hull, to the intake opening.
  • a secondary opening for and downstream of the impeller is provided at a submerged position lower than the outlet opening.
  • the secondary opening is provided at the bottom of the hull.
  • the secondary opening is provided at the keel of the hull.
  • the secondary opening is provided to allow water from outside the hull to pass through the impeller, when operating the vessel in reverse.
  • a secondary opening feeding into the impeller is provided at a submerged position lower than the outlet opening.
  • the secondary opening is provided on the underside of a housing of the impeller.
  • the secondary opening can be closed.
  • the secondary opening can be closed by a closure.
  • a valve is provided that can at least partially cut off the outlet opening of the nozzle when the vessel is travelling in the reverse direction.
  • the outlet opening is fitted with a valve that can at least partially cut off the outlet opening of the nozzle when travelling in the reverse direction.
  • the impeller being rotated in the second direction causes water to flow through the passage from the outlet opening to intake opening.
  • the impeller being rotated in the second direction causes water to flow from a secondary opening that is intermediate of the outlet opening and the impeller.
  • the impeller being rotated in the second direction causes water to flow from a secondary opening, provided at a lower height of the hull than the outlet opening, to the intake opening.
  • This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.)
  • Figure 1 shows a side perspective view of the jet pump unit with the fin system attached
  • Figure 2 shows a bottom view of the jet pump unit including the array of fins
  • Figure 3 shows a top view of the jet pump unit including the array of fins
  • Figure 4 shows a side view of the jet pump unit including the array of fins and a downwardly tiltable outlet nozzle
  • Figure 4A shows a side view of the jet pump unit including the array of fins and a downwardly translatable outlet nozzle;
  • Figure 5 shows a rear view of the jet pump unit including the array of fins
  • Figure 6 shows a rear view of the array of fins and the mechanism for their positional control
  • Figure 7 shows a side perspective view of the array of fins and the mechanism for their positional control
  • Figure 8 shows an opposite side perspective view of the array of fins and the mechanism for their positional control
  • Figure 9 shows a side cutaway view of a jet powered watercraft with a jet pump unit and the array of fins, fitted within the hull.
  • a jet powered watercraft according to the invention is generally indicated by the numeral 1000 as seen in figure 9.
  • the jet powered watercraft 1000 may be a jetboat, or alternatively may be any other type of jet powered watercraft such as a personal watercraft.
  • the watercraft comprises of a hull 3 to float and travel through a body of water 1010.
  • the hull comprises a bow 600 and a stern 601.
  • the hull can travel through the body of water in a forward direction F and in a reverse direction R. Shown in a stationary condition in Figure 9 the hull 3 sits partially below the waterline WL.
  • a jet pump unit 4 which may be fixed in an internal space of the hull 3 as shown in Figure 9.
  • Jet pump unit 4 comprises an intake opening 20, an outlet opening 21 and a duct 22 that defines a water passage connecting the intake 20 and outlet 21.
  • the jet pump may be of an axial jet pump type.
  • the intake 20 is presented on the underside 602 of the hull 3 and near the stern 601.
  • the intake 20 is configured to draw in water from below the jet powered watercraft 1000. It is preferably submerged in water during operation.
  • the outlet 21 may be presented at the rear of the hull 3 and is preferably submerged in water during operation.
  • Within the duct 22 is an impeller 23 which may be driven by a motor 24 connected by a shaft 24A, to draw in water from the intake 20 and increase its pressure to create a high velocity water jet at the outlet.
  • Outlet 21 may be nozzled by a nozzle 21 A that increases the velocity of water driven out of it by the impeller 23.
  • At least one fin 10 and preferably a plurality of fins, in an array are presented at the intake 20.
  • the fin or fins are mounted to be rotatable relative the intake.
  • the fins are mounted in a rotational manner relative to the hull such as to the duct 22 at or adjacent the intake.
  • the fin or fins are provided to be controlled to allow the watercraft to be steered when travelling in reverse. Where a plurality of fins are provided they are able to act in concert to control the direction of travel of the watercraft when travelling in reverse.
  • the fin or fins 10 preferably span the intake opening 21 as shown in Figures 1 and 2.
  • the fins 10 may serve to block debris from entering the intake 20, and preferably allow the direction of the flow of water at the intake 20 to be controlled.
  • the fin or fins are preferably elongate and preferably extend parallel the centreline of the hull. They are preferably spaced apart from each other so that a gap exists between adjacent fins.
  • the axis of rotation of a fin is preferably at the same height as the axis of rotation of the other fins.
  • the fins have a chord that is shorter than their pan.
  • the fins include control surface or surfaces such as surface 10A and 10B that can control the direction of flow of water over them.
  • the fins are preferably rigid and at a first distal end 610 may each define an axle to be journaled to the duct for example.
  • the impeller 23 drives water from intake 20 to outlet 21 thereby generating forward thrust for the jet powered watercraft 4
  • the impeller 23 is preferably configured to be capable of operating in reverse such that water is instead driven from outlet 21 to intake 20 thereby generating reverse thrust with water flowing generally in direction RT as seen in figure 4.
  • the shape of the duct 22 and/or the intake may be such as to result in water flowing from the intake in direction RT, which has a component of flow in the direction of the bow of the watercraft. As such, when water is caused to flow out of the intake, the watercraft will travel in reverse.
  • the motor 24 In order to facilitate the operation of the impeller 23 in reverse, the motor 24 must either be capable of operating in reverse or there must be a system in place between the motor 24 and the impeller 23 to reverse the power provided such as a gearbox implementing a reverse gear.
  • the motor 24 is an electric motor such that reverse operation can be achieved by reversing the polarity of voltage supplied to the motor 24. Reversal of the polarity may be achieved by mechanical means such as a switch or switches, or alternatively by electronic means that may form part of a steering control system 40.
  • a gearbox may still be in place in embodiments where the motor 24 is an electric motor and may implement gears other than reverse.
  • the gearbox may implement a reverse gear and there may be no means in place of reversing the voltage polarity to the motor 24.
  • the motor 24 may be driven by internal combustion and a gearbox may be in place implementing at least a reverse gear.
  • the rotational position of fins 10 may be controlled directly or indirectly by a user of the jet powered watercraft 4, for example via input to a steering control system 40.
  • Rotatable mounting of the fins 10 relative to the duct 22 may be facilitated by a mounting plate 11 and/or a mounting shoe 12.
  • a proximal end 13 of each of the fins 10 may be shaped as a shaft that is received by a corresponding hole in mounting plate 11, within which each of the fins 10 can rotate.
  • a distal end 14 of each of the fins 10 may also be shaped as a shaft or axle 610 that is received by a corresponding hole of a mounting shoe 12, within which each of the fins 10 can rotate.
  • the fins span is the fore/aft direction of the hull.
  • the fins 10 are supported at both ends and the mounting plate 11 and mounting shoe 12 may be secured at opposite edges of intake 20.
  • the intake 20 may be modified to directly receive one or both ends of each of the fins 10.
  • the fins 10 may be connected by a mechanical linkage 15 such that they are controlled to move in concert.
  • the fins 10 are substantially parallel and are constrained by the linkage 15 such that they maintain the same rotational orientation. This helps the fins to cause the flow of water through the intake to be efficiently controlled in direction.
  • a movement of the linkage 15 may cause each of the fins 10 to rotate by the same degree, thus allowing all of the fins 10 to be rotationally adjusted by manipulating the linkage 15.
  • the linkage 15 has a rod 16 that pivotally connects to a plurality of links 17 rigidly connected to and extending orthogonally from the proximal ends 13 of the fins 10 as shown in Figure 8.
  • the linkage 15 may be a parallelogram type linkage formed by the rod 16, the links 17 and the mounting plate 11 of the fins 10, such that a translation of the rod 16 causes each of the fins 10 to rotate in unison by an equal degree.
  • the rod 16 may alternatively be a cable that is connected to the links, or in an alternative embodiment each of the fins 10 may be configured such that they can be adjusted independently.
  • At least one actuator 18 that facilitates adjustment of the fins 10 may be used. This may be controllable by a user of the jet powered watercraft 1000. Control of the actuator 18 may be achieved through a steering control system 40.
  • the steering control system may include a tiller 650.
  • the tiller may be used for controlling the direction of travel of the watercraft in the forward direction by changing the orientation of the nozzle 21 A.
  • the tiller may also be used to control the rotational orientation of the fins when the impeller is operating in reverse.
  • An electronic sensor may be used to detect the position of the tiller, the sensed signal used to control the rotational position of the fins. Such fin control may only be exercised when the motor is operating in reverse. When the impeller is operating in the forward direction the fins may be help in a stationary position by the actuator 18 and a change in the tiller position will not influence the fin rotation.
  • the actuator 18 is configured to drive movement of the linkage 15 in order to rotate each of the fins 10 in unison.
  • the actuator 18 is a rotary actuator, its output shaft may be fitted with a lever arm 19 pivotally connected to the rod 16 of the linkage 15 so as to translate the rod 16 and hence move the linkage 15.
  • the actuator 18 may spool or unspool a cable of the linkage 15.
  • the actuator 18 is a stepper motor, but alternatively it may be a servo motor, linear actuator or any other suitable means of moving the linkage 15. Wires may transmit electric power and/or control signals from a steering control system 40 to the actuator 18.
  • the actuator 18 may be replaced by a purely mechanical system configured to move the linkage 15 and that can be controlled by a user of the jet watercraft 4, for example by means of a lever or crank handle configured to pull a cable.
  • the fin or fins provide for improved control of the jet powered watercraft 4 when reversing by allowing the flow direction of water exiting the intake 20 to be directed.
  • the fins allow the water existing the intake to be directed to port and starboard sides.
  • a user input to the steering system of the jet powered watercraft may be translated to rotation of the fins 10 by the steering control system 40 when a user engages the reverse gear or otherwise initiates travel in reverse.
  • the steering control system 40 may make a corresponding rotation of the fins 10 such that the flow out of the intake 20 is directed towards the appropriate side of the hull for achieving the desired turning of the watercraft. Reverse thrust is thereby provided by the pulling of water into the outlet 21, while turning torque is provided by the directed flow of water exiting the intake 20.
  • the steering control system 40 may return the fins 10 to the neutral position in order to reduce drag as water is drawn into the intake 20, leaving them in that position regardless of forward steering inputs by the user.
  • Reverse thrust levels may be lowered undesirably if too much air is drawn into the outlet 21 compared to the rate of water drawn in, which may occur for example if the outlet 21 is at least sometimes partially above the waterline.
  • the outlet nozzle 21 A may be moveable to a lower position than its normal position.
  • the outlet nozzle 21 A is rotatable on a horizontal axis 210 in addition to the vertical axis used for forward direction steering, which may be achieved via a mechanism similar to those sometimes used for trim control. Rotation on the horizontal axis can allow the outlet nozzle 21 A to be tilted downwards while in reverse to submerge it more fully, thereby preventing air from being drawn in through the outlet 21.
  • the steering control system 40 may perform this rotation automatically via an actuator when the user engages reverse.
  • the outlet nozzle 21 A could be downwardly moveable by translating as shown in figure 4A, for example by a sliding mechanism.
  • a seal may also be provided between the outlet nozzle 21 A and the bearing that mounts it on outlet 21 in order to reduce the amount of air that can enter through any gap between them.
  • a secondary opening 25 could be provided at a lower height than the outlet 21 such that the secondary opening 25 is further submerged below the waterline during operation.
  • the secondary opening 25 can feed water from outside the hull 3 into the impeller 23 in the reverse direction without any air being drawn into it.
  • One or more valves or closures 125 may be used to open the secondary opening and/or at least partially cut off outlet 21 while in reverse, such that while in reverse most or all of the water is drawn in through the secondary opening 25 without as much air being drawn in. These could include passive one-way valves, manually actuated closures, or could be valves or closures actuated automatically by the steering control system 40 for example.
  • a closure 125 or valve may be used to close the secondary opening 25 when travelling in the forward direction.
  • the secondary opening could be provided on the underside of the housing of impeller 23, at the bottom of the hull 3, at the keel of the hull 3, or it could be provided at some other point intermediate the outlet 21 and the impeller 23.
  • An example position for the secondary opening 25 and an associated closure 125 is indicated on figures 4-4A.
  • the system should take the steering signal which the user delivers, in one example the angle which the tiller is pushed/pulled, this signal is then applied to the intake fins through the rotation of the actuator and con- rod.
  • the intake fins then in a pivoted position deflect the reversed jet of water to achieve sideways and reverse movement of the vessel.
  • the intake fins then are pivoted back to an upright position so as to create the least amount of drag in the intake.
  • Control may also be provided through a manually operated lever and a push/pull cable controlled by the pilot
  • the fin or fins and their control mechanism may be retrofittable as a system onto existing jet pump units 2 so as to provide an improved means of control when reversing the jet powered watercraft 4. Retrofitting of the fin system may involve the replacement of any existing system present for control when reversing such as a reversing bucket. Retrofitting may require some modifications to the jet pump unit 2, for example drilling holes to mount the mounting plate 11 or mounting shoe 12 or for accommodating one or both ends of the fins 10.
  • the outlet 21 must be located beneath the waterline during operation such that it can pull in water when operated in reverse. The ability for the impeller to operate in reverse and for watercraft to be steered in reverse negates the need for a reverse bucket to be used on a jet powered watercraft that incorporates the present invention.

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Abstract

The invention relates to a reversable jet powered watercraft (1000) comprising a hull (3) and a jet pump unit (4) secured to the hull (3). The jet pump unit (4) presents a water intake opening (20) on the underside of the hull (3) and a water outlet opening (21) at the rear of the hull (3), the openings connected by a duct (22) to define a passage for water. An impeller (23) in the passage drives water through the duct (22). At least one fin (10) is mounted in a rotatable manner relative to the intake opening (20) to control and to change direction of the flow of water passing through the intake opening (20), the rotatable position of the fin(s) (10) able to be controlled by a user of the watercraft (1000). The impeller (23) can be rotated in a first direction to cause water to flow through the passage from intake opening (20) to outlet opening (21) corresponding to a forward direction of travel of the watercraft (1000) and in a second direction to cause water to flow out the intake opening (20) corresponding to a reverse direction of travel of the watercraft (1000). Water leaving the intake (20) can be changed in direction by the fin(s) (10) to cause the watercraft (1000) to be directionally controlled.

Description

A REVERSABLE JET POWERED WATERCRAFT AND A REVERSABLE JET UNIT
OR OF FOR SUCH
The present invention relates to a reversable jet powered watercraft and a reversable jet unit or of for such.
BACKGROUND
Since the advent of jet powered watercraft in the 20th century, water jet propulsion has become increasingly widespread on a variety of vessels. Personal watercraft, alternatively known as jet skis, have become a popular recreational vessel that is easily transportable. Jetboats of various sizes have also come into use and planing hulls allow high speeds even with larger boats. The basic principle common to jet powered watercraft is an intake below the hull that draws water into a pump, which in turn generates a high velocity jet of water from the rear of the vessel.
Reversing a jet powered watercraft is somewhat different from reversing a conventional watercraft with an exposed propeller. It is common to use a reverse bucket mechanism which lowers over the nozzle when its desired to cause the vessel to reverse. The jet pump is operated in the normal direction and the jet stream is deflected by the bucket to push water in the opposite direction and generate reverse thrust. Steering can then be achieved by vectoring the nozzle such that the jet stream is deflected in a different direction by the bucket. Reverse buckets are bulky and can require complex mechanisms to raise and lower them which are prone to failure.
Due to the limitations of reverse bucket mechanisms for reversing jet powered watercraft, it is desirable to find alternative solutions that are less bulky while still allowing for good steering control when reversing.
In this specification, where reference has been made to external sources of information, including patent specifications and other documents, this is generally for the purpose of providing a context for discussing the features of the present invention.
Unless stated otherwise, reference to such sources of information is not to be construed, in any jurisdiction, as an admission that such sources of information are prior art or form part of the common general knowledge in the art.
It is an object of the present invention to provide a reversable jet powered marine vessel and a reversable jet unit or of for such which overcomes or at least partially ameliorates some of the abovementioned disadvantages or which at least provides the public with a useful choice.
BRIEF DESCRIPTION OF THE INVENTION
In a first aspect the present invention may be said to broadly consist in a reversable jet powered watercraft comprising: a hull; a jet pump unit secured to the hull and presenting a water intake opening on the underside of the hull and a water outlet opening at the rear of the hull, the intake opening and the outlet opening connected by a duct to define a passage for the water; an impeller in the passage, able to be powered for rotation by a motor to drive water through the duct; at least one fin, mounted in a rotatable manner relative to the intake opening to control and to change direction of the flow of water passing through the intake opening, the rotatable position of the fin(s) able to be controlled by a user of the watercraft; wherein the impeller can be rotated in a first direction to cause water to flow through the passage from intake opening to outlet opening corresponding to a forward direction of travel of the watercraft and in a second direction to cause water to flow out the intake opening corresponding to a reverse direction of travel of the watercraft and wherein water leaving the intake can be changed in direction by the fin(s) to cause the watercraft to be directionally controlled.
In a second aspect the present invention may be said to broadly consist in a reversable jet powered watercraft comprising: a hull; a jet pump unit secured to the hull and presenting a water intake opening on the underside of the hull and a water outlet opening at the rear of the hull, the intake opening and the outlet opening connected by a duct to define a passage for the water; an impeller in the passage, able to be powered for rotation by a motor to drive water through the duct; at least one fin and preferably an array of a plurality of fins, mounted in a rotatable manner relative to the intake opening to control and to change direction of the flow of water passing through the intake opening, the rotatable position of the fin(s) able to be controlled preferably directly or indirectly by a user of the watercraft; wherein the impeller can be rotated in a first direction to cause water to flow through the passage from intake opening to outlet opening corresponding to a forward direction of travel of the watercraft and in a second direction to cause water to flow through the passage from the outlet opening to intake opening corresponding to a reverse direction of travel of the watercraft and wherein water leaving the intake can be changed in direction by the fin(s) to cause the watercraft to be directionally controlled, travelling in the reverse direction.
In one embodiment, the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water is travelling towards the bow of the hull.
In one embodiment, the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel towards the bow of the hull.
In one embodiment, the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel that is downwards and a component of travel that is towards the bow of the hull. In one embodiment, the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel towards the bow of the hull.
In one embodiment, the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel downwards and a component of travel towards the bow of the hull.
In one embodiment, the motor is an electric motor.
In one embodiment, the motor is an electric motor such that the direction of the impeller can be changed from the first direction to the second direction by reversing the polarity of the electric motor.
In one embodiment, the mechanical fins are configured to vector the flow through the inlet opening, all in the same direction as each other.
In one embodiment, a proximal end of the fin or each of the fins is rotatably mounted. In one embodiment, a proximal end of the fin or each of the fins is rotatably mounted by a mounting plate secured to the jet pump unit.
In one embodiment, a mechanical linkage connects each of the plurality of fins such that they can be rotated in unison.
In one embodiment, the mechanical linkage is a parallelogram linkage. In one embodiment, the mechanical linkage is a parallelogram linkage wherein each of the plurality of fins presents an orthogonally extending link at the proximal end, and a rod pivotally connects to each of the links such that motion of the rod causes unified rotation of the plurality of fins.
In one embodiment, the position of the plurality of fins can be adjusted by at least one actuator controllable directly or indirectly by a user of the watercraft. In one embodiment, the actuator is secured to the jet pump unit.
In one embodiment, the at least one actuator is a motor.
In one embodiment, the at least one actuator is a stepper motor.
In one embodiment, the at least one actuator is a hydraulic actuator. In one embodiment, the actuator rotatably drives a lever arm pivotally connected to the mechanical linkage thereby causing rotation of the plurality of fins.
In one embodiment, the fin or fins are rotatable about respective rotational axis/axes that are parallel the centreline of the hull.
In one embodiment, the fin or fins are rotatable about respective rotational axis/axes that allow the water exiting the intake opening to be directed to port and starboard as desired and as controlled.
In one embodiment the watercraft also comprises a tiller that is mechanically coupled to an outlet nozzle that is located adjacent the outlet opening.
In one embodiment the outlet nozzle is able to be rotated by the tiller to cause water leaving the outlet opening to be redirected to thereby steer the watercraft.
In one embodiment the tiller is also able to control the rotational position of the fin or fins.
In one embodiment the tiller is also able to control the rotational position of the fin or fins only when the impeller is rotating in its second direction. In one embodiment the tiller is also able to control the rotational position of the fin or fins to thereby steer the watercraft when travelling in reverse.
In one embodiment the tiller is also able to control the rotational position of the fin or fins by providing input to the actuator. In one embodiment a tiller position sensor is provided that is able to sense the position of the tiller the signal from the position sensor providing input to the actuator.
In one embodiment a tiller position sensor is provided that is able to sense the position of the tiller the signal from the position sensor providing input to the actuator to control the position of the fin or fins based on the position of the tiller.
In one embodiment a tiller position sensor is provided that is able to sense the position of the tiller the signal from the position sensor providing input to the actuator to control the position of the fin or fins based on the position of the tiller only when the impeller is rotating in its second direction.
In a third aspect the present invention may be said to broadly consist in jet pump unit for a reversable jet powered watercraft that comprises a hull, the unit comprising: a duct secured to the hull to define a passage for the water and to present a water intake opening on the underside of the hull and a water outlet opening at the rear of the hull, an impeller in the passage, able to be powered for rotation by a motor to drive water through the duct; at least one fin and preferably an array of a plurality of fins, mounted in a rotatable manner relative to the intake opening to control and to change direction of the flow of water passing through the intake opening, the rotatable position of the fin(s) able to be controlled preferably directly or indirectly by a user of the watercraft; wherein the impeller can be rotated in a first direction to cause water to flow through the passage from intake opening to outlet opening corresponding to a forward direction of travel of the watercraft and in a second direction to cause water to flow through the passage from the outlet opening to intake opening corresponding to a reverse direction of travel of the watercraft and wherein water leaving the intake can be changed in direction by the fin(s) to cause the watercraft to be directionally controlled, travelling in the reverse direction. In one embodiment, the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water is travelling towards the bow of the hull.
In one embodiment, the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel towards the bow of the hull.
In one embodiment, the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel that is downwards and a component of travel that is towards the bow of the hull.
In one embodiment, the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel towards the bow of the hull.
In one embodiment, the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel downwards and a component of travel towards the bow of the hull.
In one embodiment, the motor is an electric motor.
In one embodiment, the motor is an electric motor such that the direction of the impeller can be changed from the first direction to the second direction by reversing the polarity of the electric motor.
In one embodiment, the mechanical fins are configured to vector the flow through the inlet opening, all in the same direction as each other.
In one embodiment, a proximal end of the fin or each of the fins is rotatably mounted.
In one embodiment, a proximal end of the fin or each of the fins is rotatably mounted by a mounting plate secured to the jet pump unit. In one embodiment, a mechanical linkage connects each of the plurality of fins such that they can be rotated in unison.
In one embodiment, the mechanical linkage is a parallelogram linkage.
In one embodiment, the mechanical linkage is a parallelogram linkage wherein each of the plurality of fins presents an orthogonally extending link at the proximal end, and a rod pivotally connects to each of the links such that motion of the rod causes unified rotation of the plurality of fins.
In one embodiment, the position of the plurality of fins can be adjusted by at least one actuator controllable directly or indirectly by a user of the watercraft. In one embodiment, the actuator is secured to the jet pump unit.
In one embodiment, the at least one actuator is a motor.
In one embodiment, the at least one actuator is a stepper motor.
In one embodiment, the at least one actuator is a hydraulic actuator.
In one embodiment, the actuator rotatably drives a lever arm pivotally connected to the mechanical linkage thereby causing rotation of the plurality of fins.
In one embodiment, the fin or fins are rotatable about respective rotational axis/axes that are parallel the centreline of the hull.
In one embodiment, the fin or fins are rotatable about respective rotational axis/axes that allow the water exiting the intake opening to be directed to port and starboard as desired and as controlled.
In a fourth aspect the present invention may be said to broadly consist in a fin system to control direction of water flow from an inlet of a jet pump unit for a hull of a jet power watercraft, the fin system comprising: a plurality of fins rotatably mounted at the inlet opening; a mechanical linkage connecting each of the plurality of fins such that they can be rotated in unison; and an actuator that can adjust the control the rotational position of the plurality of fins. In one embodiment, the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water is travelling towards the bow of the hull.
In one embodiment, the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel towards the bow of the hull.
In one embodiment, the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel that is downwards and a component of travel that is towards the bow of the hull. In one embodiment, the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel towards the bow of the hull.
In one embodiment, the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel downwards and a component of travel towards the bow of the hull.
In one embodiment, the motor is an electric motor.
In one embodiment, the motor is an electric motor such that the direction of the impeller can be changed from the first direction to the second direction by reversing the polarity of the electric motor. In one embodiment, the mechanical fins are configured to vector the flow through the inlet opening, all in the same direction as each other. In one embodiment, a proximal end of the fin or each of the fins is rotatably mounted.
In one embodiment, a proximal end of the fin or each of the fins is rotatably mounted by a mounting plate secured to the jet pump unit. In one embodiment, a mechanical linkage connects each of the plurality of fins such that they can be rotated in unison.
In one embodiment, the mechanical linkage is a parallelogram linkage.
In one embodiment, the mechanical linkage is a parallelogram linkage wherein each of the plurality of fins presents an orthogonally extending link at the proximal end, and a rod pivotally connects to each of the links such that motion of the rod causes unified rotation of the plurality of fins.
In one embodiment, the position of the plurality of fins can be adjusted by at least one actuator controllable directly or indirectly by a user of the watercraft.
In one embodiment, the actuator is secured to the jet pump unit. In one embodiment, the at least one actuator is a motor.
In one embodiment, the at least one actuator is a stepper motor.
In one embodiment, the at least one actuator is a hydraulic actuator.
In one embodiment, the actuator rotatably drives a lever arm pivotally connected to the mechanical linkage thereby causing rotation of the plurality of fins. In one embodiment, the fin or fins are rotatable about respective rotational axis/axes that are parallel the centreline of the hull.
In one embodiment, the fin or fins are rotatable about respective rotational axis/axes that allow the water exiting the intake opening to be directed to port and starboard as desired and as controlled. In a further aspect the present invention may be said to broadly consist in reverse vectoring mechanism for a jet pump unit with a reversable impeller in the passage between the intake opening and outlet opening for a reversable jet powered watercraft that comprises a hull, the mechanism comprising: at least one fin and preferably an array of a plurality of fins, mounted in a rotatable manner relative to the intake opening of the jet unit to control and to change direction of the flow of water passing through the intake opening of the jet unit, the rotatable position of the fin(s) able to be controlled preferably directly or indirectly by a user of the watercraft; wherein the impeller can be rotated in a first direction to cause water to flow through the passage from intake opening to outlet opening corresponding to a forward direction of travel of the watercraft and in a second direction to cause water to flow through the passage from the outlet opening to intake opening corresponding to a reverse direction of travel of the watercraft and wherein water leaving the intake can be changed in direction by the fin(s) to cause the watercraft to be directionally controlled, travelling in the reverse direction.
In one embodiment, the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water is travelling towards the bow of the hull.
In one embodiment, the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel towards the bow of the hull.
In one embodiment, the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel that is downwards and a component of travel that is towards the bow of the hull. In one embodiment, the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel towards the bow of the hull.
In one embodiment, the water exiting the intake opening when the impeller is rotating in the second direction has a component of direction of travel downwards and a component of travel towards the bow of the hull.
In one embodiment, the motor is an electric motor.
In one embodiment, the motor is an electric motor such that the direction of the impeller can be changed from the first direction to the second direction by reversing the polarity of the electric motor.
In one embodiment, the mechanical fins are configured to vector the flow through the inlet opening, all in the same direction as each other.
In one embodiment, a proximal end of the fin or each of the fins is rotatably mounted. In one embodiment, a proximal end of the fin or each of the fins is rotatably mounted by a mounting plate secured to the jet pump unit.
In one embodiment, a mechanical linkage connects each of the plurality of fins such that they can be rotated in unison.
In one embodiment, the mechanical linkage is a parallelogram linkage. In one embodiment, the mechanical linkage is a parallelogram linkage wherein each of the plurality of fins presents an orthogonally extending link at the proximal end, and a rod pivotally connects to each of the links such that motion of the rod causes unified rotation of the plurality of fins.
In one embodiment, the position of the plurality of fins can be adjusted by at least one actuator controllable directly or indirectly by a user of the watercraft. In one embodiment, the actuator is secured to the jet pump unit.
In one embodiment, the at least one actuator is a motor.
In one embodiment, the at least one actuator is a stepper motor.
In one embodiment, the at least one actuator is a hydraulic actuator.
In one embodiment, the actuator rotatably drives a lever arm pivotally connected to the mechanical linkage thereby causing rotation of the plurality of fins.
In one embodiment, the fin or fins are rotatable about respective rotational axis/axes that are parallel the centreline of the hull.
In one embodiment, the fin or fins are rotatable about respective rotational axis/axes that allow the water exiting the intake opening to be directed to port and starboard as desired and as controlled.
In a further aspect the present invention may be said to be a jet powered watercraft with a jet unit having an ability to pass water through the jet unit in reverse to cause the watercraft to travel in reverse through the body of water there being at least one and preferably a plurality of fins at the intake opening of the jet unit that are able to cause the flow of water leaving the intake to project to both port and starboard sides of the watercraft.
In a further aspect the present invention may be said to broadly consist in a method of steerably reversing a jet powered watercraft having a hull with a jet pump unit attached, the method comprising the steps of: a. mounting to an inlet of the jet pump unit a fin system comprising a plurality of rotatable fins that can control and change direction of water flow through the inlet, the rotatable position of the fins able to be controlled by a user of the watercraft; b. reversing flow in the jet pump unit such that water is drawn in through the outlet and ejected through the intake; c. controlling the fin system such that water ejected from the intake can be directionally controlled.
In one embodiment the outlet nozzle can be moved between a first position and a second position where the outlet nozzle is in a position lower than in its first position.
In one embodiment the outlet nozzle can be moved between a first position and a second position where the outlet nozzle is more below the water line of the hull than in its first position.
In one embodiment the outlet nozzle is in the first position when the vessel is travelling forward.
In one embodiment the outlet nozzle is in the second position when the vessel is travelling backward.
In one embodiment the outlet nozzle and a bearing of the outlet nozzle have a seal therebetween.
In one embodiment the outlet nozzle can be tilted downwards.
In one embodiment the outlet opening of the outlet nozzle can be tilted downwards.
In one embodiment the outlet nozzle can be rotated about a horizontal axis such that it can be tilted downwards.
In one embodiment the outlet nozzle can be rotated about a horizontal axis such that it can be tilted downwards from a more upward condition.
In one embodiment the outlet nozzle can be rotated about a horizontal axis such that it can be tilted downwards to place the outlet opening in a position lower than its downward tilted position.
In one embodiment the outlet nozzle can be tilted downwards to reduce or cut off air flow into the outlet opening while travelling in the reverse direction. In one embodiment a secondary opening for and downstream of the impeller is provided at a submerged position.
Preferably the impeller when being rotated in the second direction causes water to flow from a secondary opening, provided at the bottom of the hull, to the intake opening.
Preferably the impeller when being rotated in the second direction causes water to flow from a secondary opening, provided at the keel of the hull, to the intake opening.
In one embodiment a secondary opening for and downstream of the impeller is provided at a submerged position lower than the outlet opening. Preferably the secondary opening is provided at the bottom of the hull.
Preferably the secondary opening is provided at the keel of the hull.
In one embodiment the secondary opening is provided to allow water from outside the hull to pass through the impeller, when operating the vessel in reverse.
In one embodiment a secondary opening feeding into the impeller is provided at a submerged position lower than the outlet opening.
In one embodiment the secondary opening is provided on the underside of a housing of the impeller.
In one embodiment the secondary opening can be closed.
In one embodiment the secondary opening can be closed by a closure. In one embodiment a valve is provided that can at least partially cut off the outlet opening of the nozzle when the vessel is travelling in the reverse direction.
In one embodiment the outlet opening is fitted with a valve that can at least partially cut off the outlet opening of the nozzle when travelling in the reverse direction. In one embodiment the impeller being rotated in the second direction causes water to flow through the passage from the outlet opening to intake opening.
In one embodiment the impeller being rotated in the second direction causes water to flow from a secondary opening that is intermediate of the outlet opening and the impeller.
In one embodiment the impeller being rotated in the second direction causes water to flow from a secondary opening, provided at a lower height of the hull than the outlet opening, to the intake opening.
Other aspects of the invention may become apparent from the following description which is given by way of example only and with reference to the accompanying drawings.
As used herein the term "and/or" means "and" or "or", or both.
As used herein "(s)" following a noun means the plural and/or singular forms of the noun.
The term "comprising" as used in this specification means "consisting at least in part of". When interpreting statements in this specification which include that term, the features, prefaced by that term in each statement, all need to be present but other features can also be present. Related terms such as "comprise" and "comprised" are to be interpreted in the same manner.
The entire disclosures of all applications, patents and publications, cited above and below, if any, are hereby incorporated by reference.
This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.)
The invention will now be described by way of example only and with reference to the drawings in which:
Figure 1 : shows a side perspective view of the jet pump unit with the fin system attached;
Figure 2: shows a bottom view of the jet pump unit including the array of fins;
Figure 3: shows a top view of the jet pump unit including the array of fins;
Figure 4: shows a side view of the jet pump unit including the array of fins and a downwardly tiltable outlet nozzle;
Figure 4A: shows a side view of the jet pump unit including the array of fins and a downwardly translatable outlet nozzle;
Figure 5: shows a rear view of the jet pump unit including the array of fins;
Figure 6: shows a rear view of the array of fins and the mechanism for their positional control;
Figure 7: shows a side perspective view of the array of fins and the mechanism for their positional control;
Figure 8: shows an opposite side perspective view of the array of fins and the mechanism for their positional control; and
Figure 9: shows a side cutaway view of a jet powered watercraft with a jet pump unit and the array of fins, fitted within the hull.
DETAILED DESCRIPTION
With reference to the above drawings, in which similar features are generally indicated by similar numerals, a jet powered watercraft according to the invention is generally indicated by the numeral 1000 as seen in figure 9.
The jet powered watercraft 1000 may be a jetboat, or alternatively may be any other type of jet powered watercraft such as a personal watercraft. The watercraft comprises of a hull 3 to float and travel through a body of water 1010. The hull comprises a bow 600 and a stern 601. The hull can travel through the body of water in a forward direction F and in a reverse direction R. Shown in a stationary condition in Figure 9 the hull 3 sits partially below the waterline WL.
Preferably incorporated with and mount to the hull 3 is a jet pump unit 4, which may be fixed in an internal space of the hull 3 as shown in Figure 9.
Jet pump unit 4 comprises an intake opening 20, an outlet opening 21 and a duct 22 that defines a water passage connecting the intake 20 and outlet 21. The jet pump may be of an axial jet pump type. In a preferred embodiment the intake 20 is presented on the underside 602 of the hull 3 and near the stern 601. The intake 20 is configured to draw in water from below the jet powered watercraft 1000. It is preferably submerged in water during operation. The outlet 21 may be presented at the rear of the hull 3 and is preferably submerged in water during operation. Within the duct 22 is an impeller 23 which may be driven by a motor 24 connected by a shaft 24A, to draw in water from the intake 20 and increase its pressure to create a high velocity water jet at the outlet. Outlet 21 may be nozzled by a nozzle 21 A that increases the velocity of water driven out of it by the impeller 23.
At least one fin 10 and preferably a plurality of fins, in an array are presented at the intake 20. The fin or fins are mounted to be rotatable relative the intake. The fins are mounted in a rotational manner relative to the hull such as to the duct 22 at or adjacent the intake. The fin or fins are provided to be controlled to allow the watercraft to be steered when travelling in reverse. Where a plurality of fins are provided they are able to act in concert to control the direction of travel of the watercraft when travelling in reverse.
The fin or fins 10 preferably span the intake opening 21 as shown in Figures 1 and 2. The fins 10 may serve to block debris from entering the intake 20, and preferably allow the direction of the flow of water at the intake 20 to be controlled.
The fin or fins are preferably elongate and preferably extend parallel the centreline of the hull. They are preferably spaced apart from each other so that a gap exists between adjacent fins. The axis of rotation of a fin is preferably at the same height as the axis of rotation of the other fins.
Preferably the fins have a chord that is shorter than their pan.
Preferably the fins include control surface or surfaces such as surface 10A and 10B that can control the direction of flow of water over them.
The fins are preferably rigid and at a first distal end 610 may each define an axle to be journaled to the duct for example.
Although in normal operation the impeller 23 drives water from intake 20 to outlet 21 thereby generating forward thrust for the jet powered watercraft 4, the impeller 23 is preferably configured to be capable of operating in reverse such that water is instead driven from outlet 21 to intake 20 thereby generating reverse thrust with water flowing generally in direction RT as seen in figure 4. The shape of the duct 22 and/or the intake may be such as to result in water flowing from the intake in direction RT, which has a component of flow in the direction of the bow of the watercraft. As such, when water is caused to flow out of the intake, the watercraft will travel in reverse.
In order to facilitate the operation of the impeller 23 in reverse, the motor 24 must either be capable of operating in reverse or there must be a system in place between the motor 24 and the impeller 23 to reverse the power provided such as a gearbox implementing a reverse gear. In a preferred embodiment, the motor 24 is an electric motor such that reverse operation can be achieved by reversing the polarity of voltage supplied to the motor 24. Reversal of the polarity may be achieved by mechanical means such as a switch or switches, or alternatively by electronic means that may form part of a steering control system 40. A gearbox may still be in place in embodiments where the motor 24 is an electric motor and may implement gears other than reverse. Alternatively, the gearbox may implement a reverse gear and there may be no means in place of reversing the voltage polarity to the motor 24. In an alternative embodiment the motor 24 may be driven by internal combustion and a gearbox may be in place implementing at least a reverse gear. The rotational position of fins 10 may be controlled directly or indirectly by a user of the jet powered watercraft 4, for example via input to a steering control system 40.
Rotatable mounting of the fins 10 relative to the duct 22 may be facilitated by a mounting plate 11 and/or a mounting shoe 12. A proximal end 13 of each of the fins 10 may be shaped as a shaft that is received by a corresponding hole in mounting plate 11, within which each of the fins 10 can rotate. A distal end 14 of each of the fins 10 may also be shaped as a shaft or axle 610 that is received by a corresponding hole of a mounting shoe 12, within which each of the fins 10 can rotate. The fins span is the fore/aft direction of the hull. In embodiments with both a mounting plate 11 and a mounting shoe 12, the fins 10 are supported at both ends and the mounting plate 11 and mounting shoe 12 may be secured at opposite edges of intake 20. In an alternative embodiment, the intake 20 may be modified to directly receive one or both ends of each of the fins 10.
The fins 10 may be connected by a mechanical linkage 15 such that they are controlled to move in concert. Preferably the fins 10 are substantially parallel and are constrained by the linkage 15 such that they maintain the same rotational orientation. This helps the fins to cause the flow of water through the intake to be efficiently controlled in direction. A movement of the linkage 15 may cause each of the fins 10 to rotate by the same degree, thus allowing all of the fins 10 to be rotationally adjusted by manipulating the linkage 15. In a preferred embodiment the linkage 15 has a rod 16 that pivotally connects to a plurality of links 17 rigidly connected to and extending orthogonally from the proximal ends 13 of the fins 10 as shown in Figure 8. The linkage 15 may be a parallelogram type linkage formed by the rod 16, the links 17 and the mounting plate 11 of the fins 10, such that a translation of the rod 16 causes each of the fins 10 to rotate in unison by an equal degree. The rod 16 may alternatively be a cable that is connected to the links, or in an alternative embodiment each of the fins 10 may be configured such that they can be adjusted independently.
At least one actuator 18 that facilitates adjustment of the fins 10 may be used. This may be controllable by a user of the jet powered watercraft 1000. Control of the actuator 18 may be achieved through a steering control system 40. The steering control system may include a tiller 650. The tiller may be used for controlling the direction of travel of the watercraft in the forward direction by changing the orientation of the nozzle 21 A. The tiller may also be used to control the rotational orientation of the fins when the impeller is operating in reverse. An electronic sensor may be used to detect the position of the tiller, the sensed signal used to control the rotational position of the fins. Such fin control may only be exercised when the motor is operating in reverse. When the impeller is operating in the forward direction the fins may be help in a stationary position by the actuator 18 and a change in the tiller position will not influence the fin rotation.
Preferably the actuator 18 is configured to drive movement of the linkage 15 in order to rotate each of the fins 10 in unison. If the actuator 18 is a rotary actuator, its output shaft may be fitted with a lever arm 19 pivotally connected to the rod 16 of the linkage 15 so as to translate the rod 16 and hence move the linkage 15. Alternatively, the actuator 18 may spool or unspool a cable of the linkage 15. In a preferred embodiment the actuator 18 is a stepper motor, but alternatively it may be a servo motor, linear actuator or any other suitable means of moving the linkage 15. Wires may transmit electric power and/or control signals from a steering control system 40 to the actuator 18. In an alternative embodiment, the actuator 18 may be replaced by a purely mechanical system configured to move the linkage 15 and that can be controlled by a user of the jet watercraft 4, for example by means of a lever or crank handle configured to pull a cable.
The fin or fins provide for improved control of the jet powered watercraft 4 when reversing by allowing the flow direction of water exiting the intake 20 to be directed. The fins allow the water existing the intake to be directed to port and starboard sides.
A user input to the steering system of the jet powered watercraft may be translated to rotation of the fins 10 by the steering control system 40 when a user engages the reverse gear or otherwise initiates travel in reverse. For example, when a watercraft is in reverse and the user turns the steering wheel or tiller, the steering control system 40 may make a corresponding rotation of the fins 10 such that the flow out of the intake 20 is directed towards the appropriate side of the hull for achieving the desired turning of the watercraft. Reverse thrust is thereby provided by the pulling of water into the outlet 21, while turning torque is provided by the directed flow of water exiting the intake 20. When the jet powered watercraft 4 is operated in the forward direction, the steering control system 40 may return the fins 10 to the neutral position in order to reduce drag as water is drawn into the intake 20, leaving them in that position regardless of forward steering inputs by the user.
Reverse thrust levels may be lowered undesirably if too much air is drawn into the outlet 21 compared to the rate of water drawn in, which may occur for example if the outlet 21 is at least sometimes partially above the waterline. To reduce the fraction of air pulled into outlet 21 while in reverse, the outlet nozzle 21 A may be moveable to a lower position than its normal position.
As shown in figure 4, preferably the outlet nozzle 21 A is rotatable on a horizontal axis 210 in addition to the vertical axis used for forward direction steering, which may be achieved via a mechanism similar to those sometimes used for trim control. Rotation on the horizontal axis can allow the outlet nozzle 21 A to be tilted downwards while in reverse to submerge it more fully, thereby preventing air from being drawn in through the outlet 21. The steering control system 40 may perform this rotation automatically via an actuator when the user engages reverse. Alternatively the outlet nozzle 21 A could be downwardly moveable by translating as shown in figure 4A, for example by a sliding mechanism.
A seal may also be provided between the outlet nozzle 21 A and the bearing that mounts it on outlet 21 in order to reduce the amount of air that can enter through any gap between them.
In an alternative embodiment, a secondary opening 25 could be provided at a lower height than the outlet 21 such that the secondary opening 25 is further submerged below the waterline during operation. The secondary opening 25 can feed water from outside the hull 3 into the impeller 23 in the reverse direction without any air being drawn into it.
One or more valves or closures 125 may be used to open the secondary opening and/or at least partially cut off outlet 21 while in reverse, such that while in reverse most or all of the water is drawn in through the secondary opening 25 without as much air being drawn in. These could include passive one-way valves, manually actuated closures, or could be valves or closures actuated automatically by the steering control system 40 for example. A closure 125 or valve may be used to close the secondary opening 25 when travelling in the forward direction.
The secondary opening could be provided on the underside of the housing of impeller 23, at the bottom of the hull 3, at the keel of the hull 3, or it could be provided at some other point intermediate the outlet 21 and the impeller 23. An example position for the secondary opening 25 and an associated closure 125 is indicated on figures 4-4A.
Once the user of the vessel engages reverse, the system should take the steering signal which the user delivers, in one example the angle which the tiller is pushed/pulled, this signal is then applied to the intake fins through the rotation of the actuator and con- rod. The intake fins, then in a pivoted position deflect the reversed jet of water to achieve sideways and reverse movement of the vessel. Once the user has finished reversing the vessel the intake fins then are pivoted back to an upright position so as to create the least amount of drag in the intake.
The synchronous relationship between the steering of the vessel and the electronically controlled angle of intake fins is not essential. Control may also be provided through a manually operated lever and a push/pull cable controlled by the pilot
The fin or fins and their control mechanism may be retrofittable as a system onto existing jet pump units 2 so as to provide an improved means of control when reversing the jet powered watercraft 4. Retrofitting of the fin system may involve the replacement of any existing system present for control when reversing such as a reversing bucket. Retrofitting may require some modifications to the jet pump unit 2, for example drilling holes to mount the mounting plate 11 or mounting shoe 12 or for accommodating one or both ends of the fins 10. For the fin system 1 to function when retrofitted onto an existing jet pump unit 2, the outlet 21 must be located beneath the waterline during operation such that it can pull in water when operated in reverse. The ability for the impeller to operate in reverse and for watercraft to be steered in reverse negates the need for a reverse bucket to be used on a jet powered watercraft that incorporates the present invention.
Where in the foregoing description reference has been made to elements or integers having known equivalents, then such equivalents are included as if they were individually set forth.
Although the invention has been described by way of example and with reference to particular embodiments, it is to be understood that modifications and/or improvements may be made without departing from the scope or spirit of the invention. In addition, where features or aspects of the invention are described in terms of
Markush groups, those skilled in the art will recognise that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group.

Claims

1. A reversable jet powered watercraft comprising: a hull; a jet pump unit secured to the hull and presenting a water intake opening on the underside of the hull and a water outlet opening at the rear of the hull, the intake opening and the outlet opening connected by a duct to define a passage for the water; an impeller in the passage, able to be powered for rotation by a motor to drive water through the duct; at least one fin, mounted in a rotatable manner relative to the intake opening to control and to change direction of the flow of water passing through the intake opening, the rotatable position of the fin(s) able to be controlled by a user of the watercraft; wherein the impeller can be rotated in a first direction to cause water to flow through the passage from intake opening to outlet opening corresponding to a forward direction of travel of the watercraft and in a second direction to cause water to flow through the passage from the outlet opening to intake opening corresponding to a reverse direction of travel of the watercraft and wherein water leaving the intake can be changed in direction by the fin(s) to cause the watercraft to be directionally controlled.
2. A watercraft as claimed in claim 1 wherein the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water is travelling towards the bow of the hull.
3. A watercraft as claimed in claim 1 or 2 wherein the passage adjacent the intake opening is shaped and configured so that when water exits the intake opening the water has a component of direction of travel towards the bow of the hull.
4. A watercraft as claimed in claim 1 or 2 wherein the passage, adjacent the intake opening, is shaped and configured so that when water exits the intake opening the water has a component of direction of travel that is downwards and a component of travel that is towards the bow of the hull.
5. A watercraft as claimed in any one of claims 1 to 4 wherein the water exiting the intake opening, when the impeller is rotating in the second direction, has a component of direction of travel towards the bow of the hull.
6. A watercraft as claimed in any one of claims 1 to 4 wherein the water exiting the intake opening, when the impeller is rotating in the second direction, has a component of direction of travel downwards and a component of travel towards the bow of the hull.
7. A watercraft as claimed in any one of the preceding claims wherein the motor is an electric motor.
8. A watercraft as claimed in claim 7 wherein the motor is an electric motor such that the direction of the impeller can be changed from the first direction to the second direction by reversing the polarity of the electric motor.
9. A watercraft as claimed in any one of the preceding claims wherein there are a plurality of parallel spaced apart adjacent fins all configured to vector the flow through the inlet opening, all in the same direction as each other.
10. A watercraft as claimed in any one of the preceding claims wherein a proximal end of the fin or each of the fins is rotatably mounted.
11. A watercraft as claimed in any one of the preceding claims wherein a proximal end of the fin or each of the fins is rotatably mounted by a mounting plate secured to the jet pump unit.
12. A watercraft as claimed in any one of the preceding claims wherein a mechanical linkage connects each of the plurality of fins such that they can be rotated in unison.
13. A watercraft as claimed in claim 12 wherein the mechanical linkage is a parallelogram linkage.
14. A watercraft as claimed in claim 12 wherein the mechanical linkage is a parallelogram linkage wherein each of the plurality of fins presents an orthogonally extending link at the proximal end, and a rod pivotally connects to each of the links such that motion of the rod causes unified rotation of the plurality of fins.
15. A watercraft as claimed in any one of the preceding claims wherein the position of the plurality of fins can be adjusted by at least one actuator controllable directly or indirectly by a user of the watercraft.
16. A watercraft as claimed in claim 15 wherein the actuator is secured to the jet pump unit.
17. A watercraft as claimed in claim 15 or 16 wherein the at least one actuator is a motor.
18. A watercraft as claimed in any one of claims 15 to 17 wherein the actuator rotatably drives a lever arm pivotally connected to the mechanical linkage thereby causing rotation of the plurality of fins.
19. A watercraft as claimed in any one of the preceding claims wherein the fin or fins are rotatable about respective rotational axis/axes that are parallel the centreline of the hull.
20. A watercraft as claimed in any one of the preceding claims wherein the fin or fins are rotatable about respective rotational axis/axes that allow the water exiting the intake opening to be directed to port and starboard as desired and as controlled.
21. A watercraft as claimed in any one of the preceding claims wherein the watercraft also comprises a tiller that is mechanically coupled to an outlet nozzle that is located adjacent the outlet opening.
22. A watercraft as claimed in claim 21 wherein the outlet nozzle is able to be rotated by the tiller to cause water leaving the outlet opening to be redirected to thereby steer the watercraft.
23. A watercraft as claimed in claim 21 or 22 wherein the tiller is also able to control the rotational position of the fin or fins.
24. A watercraft as claimed in claim 23 wherein the tiller is also able to control the rotational position of the fin or fins only when the impeller is rotating in its second direction.
25. A watercraft as claimed in any one of claims 21 to 24 wherein a tiller position sensor is provided that is able to sense the position of the tiller, the signal from the position sensor providing input to the actuator to control the position of the fin or fins based on the position of the tiller.
26. A watercraft as claimed in any one of claims 21 to 24 wherein a tiller position sensor is provided that is able to sense the position of the tiller the signal from the position sensor providing input to the actuator to control the position of the fin or fins based on the position of the tiller only when the impeller is rotating in its second direction.
27. A jet pump unit for a reversable jet powered watercraft that comprises a hull, the unit comprising: a duct secured to the hull to define a passage for the water and to present a water intake opening on the underside of the hull and a water outlet opening at the rear of the hull, an impeller in the passage, able to be powered for rotation by a motor to drive water through the duct; at least one fin and preferably an array of a plurality of fins, mounted in a rotatable manner relative to the intake opening to control and to change direction of the flow of water passing through the intake opening, the rotatable position of the fin(s) able to be controlled preferably directly or indirectly by a user of the watercraft; wherein the impeller can be rotated in a first direction to cause water to flow through the passage from intake opening to outlet opening corresponding to a forward direction of travel of the watercraft and in a second direction to cause water to flow through the passage from the outlet opening to intake opening corresponding to a reverse direction of travel of the watercraft and wherein water leaving the intake can be changed in direction by the fin(s) to cause the watercraft to be directionally controlled, travelling in the reverse direction.
28. A fin system to control direction of water flow from an inlet of a jet pump unit for a hull of a jet power watercraft, the fin system comprising: a plurality of fins rotatably mounted at the inlet opening; a mechanical linkage connecting each of the plurality of fins such that they can be rotated in unison; and an actuator that can adjust the control the rotational position of the plurality of fins.
29. A jet powered watercraft with a jet unit having an ability to pass water through the jet unit in reverse to cause the watercraft to travel in reverse through the body of water there being at least one and preferably a plurality of fins at the intake opening of the jet unit that are able to cause the flow of water leaving the intake to project to both port and starboard sides of the watercraft.
30. A reversable jet powered watercraft comprising: a hull; a jet pump unit secured to the hull and presenting a water intake opening on the underside of the hull and a water outlet opening at the rear of the hull, the intake opening and the outlet opening connected by a duct to define a passage for the water; an impeller in the passage, able to be powered for rotation by a motor to drive water through the duct; at least one fin, mounted in a rotatable manner relative to the intake opening to control and to change direction of the flow of water passing through the intake opening, the rotatable position of the fin(s) able to be controlled by a user of the watercraft; wherein the impeller can be rotated in a first direction to cause water to flow through the passage from intake opening to outlet opening corresponding to a forward direction of travel of the watercraft and in a second direction to cause water to flow out the intake opening corresponding to a reverse direction of travel of the watercraft and wherein water leaving the intake can be changed in direction by the fin(s) to cause the watercraft to be directionally controlled.
31. A watercraft as claimed in claim 30 wherein the impeller being rotated in the second direction causes water to flow through the passage from the outlet opening to intake opening.
32. A watercraft as claimed in claim 30 wherein the impeller being rotated in the second direction causes water to flow from a secondary opening that is intermediate of the outlet opening and the impeller.
33. A watercraft as claimed in claim 30 wherein the impeller being rotated in the second direction causes water to flow from a secondary opening, provided at a lower height of the hull than the outlet opening, to the intake opening.
PCT/IB2022/052577 2021-03-22 2022-03-22 A reversable jet powered watercraft and a reversable jet unit or of for such WO2022201008A1 (en)

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AU2021904020A AU2021904020A0 (en) 2021-12-13 A reversable jet powered watercraft and a reversable jet unit or of for such
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Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB739315A (en) * 1952-11-13 1955-10-26 Cem Comp Electro Mec Central arrangements for jet propelled marine craft
US3040696A (en) * 1960-04-08 1962-06-26 Charles J Dahle Propulsion and steering unit for boats
US3071102A (en) * 1960-08-08 1963-01-01 Buchler Corp Tiller for jet boat
US4015556A (en) * 1973-06-04 1977-04-05 Bordiga Alejandro Lorenzo Carl Device for propelling boats
EP0037865A1 (en) * 1980-04-09 1981-10-21 Weir Pumps Limited Valve system for controlling the direction of fluid discharge from a nozzle in a thruster system
GB2075452B (en) * 1980-05-02 1984-04-18 Schottel Werft Watercraft having a thruster
US5505640A (en) * 1994-05-16 1996-04-09 Angulo; Francisco M. Propulsion system for ships
US20030056704A1 (en) * 2000-10-04 2003-03-27 Eiichi Ishigaki Boat propulsion device
US20090042464A1 (en) * 2005-04-11 2009-02-12 Ocor Corporation Water jet propulsion system

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB739315A (en) * 1952-11-13 1955-10-26 Cem Comp Electro Mec Central arrangements for jet propelled marine craft
US3040696A (en) * 1960-04-08 1962-06-26 Charles J Dahle Propulsion and steering unit for boats
US3071102A (en) * 1960-08-08 1963-01-01 Buchler Corp Tiller for jet boat
US4015556A (en) * 1973-06-04 1977-04-05 Bordiga Alejandro Lorenzo Carl Device for propelling boats
EP0037865A1 (en) * 1980-04-09 1981-10-21 Weir Pumps Limited Valve system for controlling the direction of fluid discharge from a nozzle in a thruster system
GB2075452B (en) * 1980-05-02 1984-04-18 Schottel Werft Watercraft having a thruster
US5505640A (en) * 1994-05-16 1996-04-09 Angulo; Francisco M. Propulsion system for ships
US20030056704A1 (en) * 2000-10-04 2003-03-27 Eiichi Ishigaki Boat propulsion device
US20090042464A1 (en) * 2005-04-11 2009-02-12 Ocor Corporation Water jet propulsion system

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