Waterjet control systems

Abstract

A dual axis joystick control system is used intuitively for manoeuvring a waterborne vessel having two or more waterjets with steering deflectors ( 13 ) and reverse ducts ( 14 ) mounted independently of the steering deflectors. The joystick ( 21 ) is operated to actuate the reverse ducts of the port and starboard waterjets for either common or differential deflections of thrust, and to actuate the steering deflectors of the port and starboard waterjets for common deflections of thrust.

1 . A waterjet propulsion system for a water-borne vessel, including: 
 port and starboard waterjet propulsion units,    thrust steering means associated with the port waterjet propulsion unit(s) and thrust steering means associated with the starboard waterjet propulsion unit(s) for deflecting the waterjet from the propulsion(s) unit for steering the vessel, which thrust steering means are linked for common steering movement together,    thrust reverse means associated with the waterjet propulsion units for reverse deflecting the waterjets from the propulsion units and which thrust reverse means are mounted independently of the thrust steering means, and control means operable to actuate the thrust reverse means to cause either common or differential deflections of thrust from the propulsion units and to control the thrust steering means.    
   
   
       2 . A system according to  claim 1  further including: 
 third control means for controlling the power levels of the propulsion units.    
   
   
       3 . A system according to  claim 1  or  claim 2  wherein a control means is responsive within a first degree of freedom to determine a common deflection of reverse thrust for the port and starboard propulsion units, and within a second degree of freedom to determine different deflections of reverse thrust for the port and starboard units.  
   
   
       4 . A system accordingly to  claim 3  wherein the first control means actuates the thrust steering means while actuating the thrust reverse means to cause port or starboard translational movement.  
   
   
       5 . A system according to anyone of  claims 1  to  4  wherein the thrust steering means maintains a common deflection of thrust for the propulsion units during translational movements transverse to the vessel.  
   
   
       6 . A system according to anyone of  claims 1  to  4  wherein the thrust steering means maintains a common deflection of thrust for the propulsion units during all movements of the vessel.  
   
   
       7 . A system according to anyone of  claims 1  to  6  wherein the control means includes a multiple axis joystick.  
   
   
       8 . A system according to any one of  claims 1  to  7  wherein the thrust reverse means includes deflector buckets which are lowerable into the waterjets from the propulsion units for reverse deflecting the waterjets.  
   
   
       9 . A system according to any one of  claims 1  to  7  wherein the thrust reverse means includes deflector buckets which are lowerable into the waterjets from the propulsion units for reverse deflecting the waterjets and wherein the deflector buckets are split or double cavity deflector buckets.  
   
   
       10 . A system according to any one of  claims 1  to  9  wherein the thrust steering means include a deflector nozzle associated with the waterjet propulsion units.  
   
   
       11 . A system according to anyone of  claims 1  to  9  wherein the thrust steering means include deflector nozzle associated with the waterjet propulsion units, which deflector nozzles are mechanically linked for said common steering movement together.