Wave-propelled vehicles

Abstract

A wave-propelled vehicle adapted to float at a surface of a body of fluid and having a hull, wherein the hull includes an upper hull portion and a lower hull portion, the lower hull portion having a hydrofoil structure defining an upward facing concavity, wherein the vehicle generates thrust in response to waves on the body of fluid.

1 - 26 . (canceled) 
     
     
         27 . A wave-propelled vehicle operable to float at a free surface of a body of fluid and having a hull, the hull comprising:
 an upper hull portion comprising at least one hydrofoil portion, the upper hull portion comprising that portion of the hull being defined by an upper extent and a lower extent of a dynamic immersion of the hull and therefore being arranged to periodically plunge through the free surface of the body of fluid under an action of surface waves of the body of fluid and being divided by a plane of the free surface of the body of fluid at equilibrium; and   a lower hull portion defined as that portion of the hull below the lower extent of a dynamic immersion comprising a hydrofoil structure comprising at least one hydrofoil portion, the hydrofoil structure being substantially non-planar, providing a vertically directed concavity when viewed from a front or rear of the vehicle,   wherein at least one, or both, of:
 a) the hydrofoil structure of the lower hull portion is substantially rigid; and 
 b) one or more than one hydrofoil portion of the at least one hydrofoil portion of the upper hull portion forms a majority of a volume of the upper hull portion. 
   
     
     
         28 . The vehicle of  claim 27 , wherein the hydrofoil structure of the lower hull portion is held in a substantially rigid arrangement relative to the vehicle, such that a gross motion of the vehicle and the motion of said hydrofoil structure are substantially directly coupled. 
     
     
         29 . The vehicle of  claim 27 , wherein at least one hydrofoil portion of the upper hull portion has at least a vertical extent. 
     
     
         30 . The vehicle of  claim 27 , wherein a longitudinal centre of gravity of the vehicle is closer to the front of the vehicle than to the rear of the vehicle. 
     
     
         31 . The vehicle of  claim 27 , wherein a centre of volume of the upper hull portion is positioned forwardly of a longitudinal centre of gravity of the vehicle. 
     
     
         32 . The vehicle of  claim 27 , wherein, when the vehicle is at rest in calm fluid, a centre of gravity is disposed above a centre of buoyancy. 
     
     
         33 . The vehicle of  claim 27 , wherein the hull is responsive to a power spectrum of waves comprising a component substantially at a natural heave or roll and pitch frequencies of the vehicle, taken jointly and severally in any and all permutations. 
     
     
         34 . The vehicle of  claim 27 , wherein, when the vehicle is at rest in calm fluid, the hull defines a longitudinally aligned upward-facing channel. 
     
     
         35 . The vehicle of  claim 34 , wherein the channel is formed substantially by one or more than one hydrofoil portion arranged to act as a boundary of the channel. 
     
     
         36 . The vehicle of  claim 35 , wherein at least one hydrofoil portion boundary of the channel extends above the free surface. 
     
     
         37 . The vehicle of  claim 27 , wherein the hull comprises a substantially rigid streamlined body comprising a longitudinally aligned conduit of closed shape when viewed from the front or rear of the vehicle. 
     
     
         38 . The vehicle of  claim 37 , wherein the closed shape of the conduit is partially or wholly of elliptical or circular. 
     
     
         39 . The vehicle of  claim 38 , wherein the closed shape of the conduit is partially or wholly polygonal. 
     
     
         40 . The vehicle of  claim 27 , further comprising a parameter-varying system to vary a parameter of the vehicle while the vehicle is in operation. 
     
     
         41 . The vehicle of  claim 40 , wherein the parameter-varying system comprises a buoyancy control system. 
     
     
         42 . The vehicle of  claim 41 , wherein the buoyancy control system is arranged to:
 change a ratio of a mass of the vehicle to a mass of fluid displaced by the vehicle, or   cause the vehicle to respectively descend or rise through a fluid column.   
     
     
         43 . The vehicle of  claim 42 , wherein a hydrofoil structure of the vehicle generates forward thrust in response to vertical movement of the vehicle through the fluid column due to operation of the buoyancy control system, causing the vehicle to glide forwards. 
     
     
         44 . The vehicle of  claim 27 , further comprising a control surface. 
     
     
         45 . The vehicle of  claim 27 , further comprising a thruster. 
     
     
         46 . The vehicle of  claim 27 , further comprising a solar energy harvesting device. 
     
     
         47 . The vehicle of  claim 27 , further comprising an empennage. 
     
     
         48 . The vehicle of  claim 27 , further comprising a steering system, responsive to a guidance system, operable to steer the vehicle. 
     
     
         49 . A method of operating the vehicle of  claim 27  in a wave-bearing body of fluid, the method comprising:
 propelling the vehicle forward by waves of the wave-bearing body of fluid. 
 
     
     
         50 . The method of  claim 49 , further comprising:
 steering the vehicle via a steering system while the vehicle is propelled forward by waves.   
     
     
         51 . The method of  claim 50 , wherein the steering system comprises:
 a) a control surface;   b) a thruster; or   c) a means of changing a parameter of the vehicle while the vehicle is in operation.   
     
     
         52 . A method of operating the vehicle of  claim 27 , comprising at different times wave-propelled locomotion on the surface of a body of fluid, and a further mode of locomotion selected from a group consisting of:
 a) above-surface gliding flight;   b) above-surface thruster-propelled flight;   c) on-surface thruster-propelled cruising;   d) subsurface gliding flight; and   e) subsurface thruster-propelled flight.