Methods and devices for personal water craft

Abstract

Jet-powered water craft have become popular recreational pleasure craft for people worldwide as well as providing rapid response in a water environment for life savers, police, customs, etc. However, once the throttle has been cut there is no braking or steering mechanism for such craft. Equally such braking or steering is limited at low speeds. Accordingly it would be beneficial to provide means for braking and/or steering such jet-powered water craft under low speed operation and/or when the throttle is cut. According to embodiments of the invention such mechanisms are provided whilst providing for ease of use during operation as well as beaching/launching/storage.

1 . A structure comprising:
 a hull forming a predetermined portion of a water craft;   a first channel disposed within the hull; and   at least one flap of a first plurality of flaps disposed within the first channel, each flap comprising at least a first surface and being positionable between a first position and a second position wherein the flaps position between the first and second positions is determined in dependence upon the pressure applied by water impinging upon the first surface resulting from motion of the hull through the water.   
     
     
         2 . The structure according to  claim 1  wherein,
 the first channel is disposed in the bow of the water craft; and 
 the at least one flap is disposed so as to cover the channel in the first position and expose the channel in the second position. 
 
     
     
         3 . The structure according to  claim 1  wherein,
 the plurality of flaps automatically return to the first position when the pressure applied to the first surface is below a predetermined value. 
 
     
     
         4 . The structure according to  claim 1  further comprising;
 a second channel disposed within the hull; and 
 at least one flap of a second plurality of flaps, each flap comprising at least a first surface and being positionable between a first position and a second position wherein the flaps position between the first and second positions is determined in dependence upon the pressure applied by water impinging upon the first surface resulting from motion of the hull through the water. 
 
     
     
         5 . The structure according to  claim 1  wherein,
 the first position of the plurality of flaps is substantially perpendicular to the hull; and 
 the second position of the plurality of flaps is substantially parallel to the hull. 
 
     
     
         6 . The structure according to  claim 1  wherein;
 the first position of the plurality of flaps is such that they are inclined in a manner that a first end of the flaps closer to the hull surface is further from the bow of the water craft than a second end of the flaps that are further from the hull surface. 
 
     
     
         7 . The structure according to  claim 1  wherein;
 the plurality of flaps are associated with at least two flap groups of a plurality of flap groups, each flap group characterised by a predetermined flap profile defining a position of the flap ss as a function of water pressure. 
 
     
     
         8 . A device comprising:
 a nozzle mounted in a predetermined location on a hull of a water craft, the nozzle receiving water from a channel forming a predetermined portion of the hull and exhausting said water to provide variable thrust for the water craft between zero and a maximum thrust in dependence upon a control setting provided by a user of the water craft;   a first flap comprising at least a first plate and a first mounting, the first mounting for attaching the first plate to the hull in a predetermined location relative to the nozzle and being impinged upon by water during motion of the water craft and allowing the first plate to pivotably displace between a first predetermined position and a second predetermined position.   
     
     
         9 . The device according to  claim 8  wherein,
 the predetermined location of the first flap is such that a predetermined portion of the water exiting the nozzle impinges upon the first flap; and 
 the position of the first flap varies between the first position and second position in dependence upon at least the thrust provided by the nozzle. 
 
     
     
         10 . The device according to  claim 8  wherein,
 the predetermined location of the first flap is such that the water impinging on the first flap is not primarily from the nozzle; and 
 the position of the first flap varies between the first position and second position in dependence upon the velocity of the water craft. 
 
     
     
         11 . The device according to  claim 8  further comprising;
 a second flap comprising at least a second plate and a second mounting, the second mounting for attaching the second plate to the hull in a predetermined location relative to the nozzle and being impinged upon by water during motion of the water craft and allowing the second plate to pivotably displace between a third predetermined position and a fourth position. 
 
     
     
         12 . The device according to  claim 11  wherein,
 the first and second flaps are symmetrically disposed with respect to at least one of an axis of the nozzle and an axis of the water craft. 
 
     
     
         13 . The device according to  claim 11  wherein,
 the first and second mountings are at least one of always in the nozzle exhaust and displaced laterally with respect to the nozzle exhaust. 
 
     
     
         14 . The device according to  claim 8  wherein,
 the first plate comprises a base plate and a bladder, the bladder comprising a shell surrounding a chamber filled with a predetermined gas at a predetermined pressure such that the bladder presents a variable profile to the water in dependence upon the pressure exerted by water flowing past the bladder as a result of at least one of the nozzle water exhaust and motion of the water craft. 
 
     
     
         15 . The device according to  claim 14  wherein,
 the base plate comprises at least a chamber of a plurality of chambers, each chamber linked to the bladder via a pressure valve such that gas movement between a chamber and the bladder was determined in dependence upon the pressure applied to the bladder by water impinging upon the bladder. 
 
     
     
         16 . A device comprising:
 an engine comprising at least a drive shaft and operating in dependence upon an engine control signal;   a first coupling selectably engageable with a drive shaft of the engine and comprising a first impeller shaft;   a first exhaust providing thrust to a water craft through the exhausting of water under pressure from the first exhaust, the pressure generated by a first impeller coupled to the first impeller shaft;   a second coupling selectably engageable with another drive shaft and comprising a second impeller shaft;   a second exhaust providing thrust to a water craft through the exhausting of water under pressure from the second exhaust, the pressure generated by a second impeller coupled to the second impeller shaft, wherein   the first and second exhausts exhaust in opposite directions thereby allowing one of the first and second exhausts to provide driving thrust and the other of the first and second exhausts to provide braking thrust.   
     
     
         17 . The device according to  claim 16  wherein;
 the selective engagement of the first and second couplings are each controlled in dependence upon at least the throttle control signal. 
 
     
     
         18 . The device according to  claim 16  further comprising:
 a third coupling selectably engageable with the another drive shaft and comprising a third impeller shaft; 
 a third exhaust providing thrust to a water craft through the exhausting of water under pressure from the third exhaust, the pressure generated by a third impeller coupled to the third impeller shaft; wherein 
 the principle axis of thrust of the second and third exhausts are disposed at approximately equal but opposite angles with respect to the principle axis of thrust of the first exhaust thereby allowing each of the second and third exhausts to selectively provide at least one of braking thrust and steering thrust to the water craft whilst the first exhaust selectively providing driving thrust to the water craft. 
 
     
     
         19 . The device according to  claim 18  wherein,
 the first exhaust provides driving thrust in dependence upon at least a throttle control signal; and 
 the second and third exhausts provide at least one of braking thrust and steering thrust in dependence upon at least the throttle control signal and a steering control signal generated in dependence upon an aspect of the steering of the water craft.