Patent Publication Number: US-6983710-B1

Title: High speed braking of submerged propelled sea craft

Description:
STATEMENT OF GOVERNMENT INTEREST 
   The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefore. 

   The present invention relates to deceleration and stopping of submerged propelled sea craft. 
   BACKGROUND OF THE INVENTION 
   The maneuvering and stopping of submerged sea craft including waterjet propelled and conventional propeller driven submarines heretofore involved diversion of jet outflow from its propulsion unit or reversal of propeller rotation. It is therefore an important object of the present invention to improve travel stoppage of such sea craft without adverse impact on its propulsion unit. 
   SUMMARY OF THE INVENTION 
   In accordance with the present invention, when propulsion of a fully submerged sea craft at a high speed is terminated, forward movement of the sea craft may then be decelerated and stopped by projection of drag plates from retracted positions within the sea craft hull or the steering rudders on the stern end portion of the hull. In such retracted positions, outer surfaces on the drag plates are flush with the outer surface of the hull or the steering rudders. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     A more complete appreciation of the invention and many of its attendant advantages will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein: 
       FIG. 1  is a side elevation view of a jet propelled sea craft with braking devices pursuant to one embodiment the present invention; 
       FIG. 2  is a partial section view taken substantially through a plane indicated by section line  2 — 2  in  FIG. 1 ; 
       FIG. 2A  is a partial section view corresponding to that of  FIG. 2 , showing projection of a braking device from the retracted position shown in  FIG. 2 ; 
       FIG. 3  is a partial section view taken substantially through a plane indicated by section line  3 — 3  in  FIG. 2A ; 
       FIG. 4  is a partial section view taken substantially through a plane indicted by section line  4 — 4  in  FIG. 2 ; 
       FIG. 5  is a block diagram illustrating operational controls associated with the braking devices shown in  FIGS. 1 ,  2 ,  2 A,  3  and  4 ; 
       FIG. 6  is a partial top plan view of a stern end portion of a sea craft having a rudder from which braking devices are projected according to another embodiment of the present invention; and 
       FIG. 7  is a partial top plan view corresponding to that of  FIG. 6 , showing a braking device projected from the rudder according to yet another embodiment. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
   Referring now to the drawing in detail,  FIG. 1  illustrates an underwater submerged sea craft  10  having an axis-symmetric shaped hull  12  according to one embodiment. The sea craft  10  is propelled in a forward direction by emergence of propelling water jets  14  from a conical stern end portion  16  of the hull  12  as generally known in the art. The propelling jets  14  emerge from any number of main water outflow nozzles  18  such as four. Accordingly to one embodiment, conventional rudders  20  are mounted on and project from the hull  12  at locations thereon along a hull centerline  22 , closer to the stern end portion  16  than a forward bow end portion  24  onto which seawater flow  26  impinges during propelled travel of the sea craft  10 . 
   Pursuant to the embodiment of the present invention as shown in  FIG. 1 , four (4) high speed flow drag braking devices  28  are positioned on the bow end portion  24  of the hull  12  in angularly spaced relation to each other. Each of the braking devices  28  as illustrated in  FIGS. 2 ,  3  and  4  includes an elongated arcuate drag plate  34  that is projected from the hull  12 . An end cap  36  at the radially outer end of the drag plate  34  is positioned with its outer surface flush with the outer surface of the hull  12  at the bow end portion  24  in a retracted position of the braking device  28  as shown in  FIGS. 1 and 2 . Each of the braking devices  28  is projected from its retracted position to an extended position as shown in  FIGS. 2A and 3  by an actuator  38  connected thereto inside of a ballast tank chamber  40  enclosed within the hull  12 . 
   Projection of the drag plates  34  from the hull  12  is effected for emergency deceleration and stopping of the craft  10  by flow drag during forward travel under high speed conditions. Toward that end an electric power supply  42  within the sea craft  10 , as diagramed in  FIG. 5 , is connected to a maneuvering control system  44  through which the drag plate actuators  38  are operated in response to input of signals from a craft operator  45  and a craft speed sensor  46 . Accordingly, pursuant to one embodiment of the present invention the sea craft  10  under travel propulsion is decelerated and then stopped by the extension of the drag devices  28  from their retracted positions under selective control after termination of propulsion. 
   According to other embodiments of the present invention, the braking devices  28  as hereinbefore described are replaced by braking devices  28 ′ that are projected laterally from the rudders  20  as shown in  FIG. 6  or some other type of directional controls. Such braking devices  28 ′ extended from the rudders  20  are plates pivoted to the lateral sides of the rudders  20 , with outer plate surfaces  48  flush with the rudder sides in their retracted positioned within slots  50  formed in the rudders  20 . In  FIG. 7 , yet another embodiment is shown wherein braking devices  28 ″ extended laterally from the rudders  20  are arcuate shaped plates slidably retracted into arcuate slots  50 ′ within the rudders  20 . 
   Obviously, other modifications and variations of the present invention may be possible in light of the foregoing teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.