Wave Power

Abstract

A wave-powered water vehicle includes a surface float, a submerged swimmer, and a tether which connects the float and the swimmer, so that the swimmer moves up and down as a result of wave motion. The swimmer includes one or more fins which interact with the water as the swimmer moves up and down, and generate forces which propel the vehicle forward. The vehicle, which need not be manned, can carry communication and control equipment so that it can follow a course directed by signals sent to it, and so that it can record or transmit data from sensors on the vehicle.

What is claimed is: 
     
         1 . A wave-powered water vehicle which comprises
 (1) a float,   (2) a swimmer, and   (3) a tether connecting the float and the swimmer;   
       the float, swimmer and tether being such that, when the vehicle is in still water,
 (i) the float is on or near the surface of the water, 
 (ii) the swimmer is submerged below the float, and 
 (iii) the tether is under tension; 
 
       the swimmer comprising
 (2a) a swimmer body having a longitudinal axis, and 
 (2b) a fin system which
 (a) is secured to the body, 
 (b) comprises a fin, and 
 (c) when the device is in wave-bearing water,
 (i) has a configuration which changes as a result of the wave motion, and 
 (ii) interacts with the water to generate forces which tend to move the swimmer in a horizontal direction; 
 
 
 
       the device having one or more of the following characteristics:
 (A) the fin system comprises a fin which rotates about an axis of rotation, the axis of rotation having a spatial relationship to the swimmer body which changes when the vehicle is in wave-bearing water; 
 (B) the fin system comprises (i) a fin which rotates about an axis of rotation, and (ii) an elastic component which is not part of the fin, and which deforms elastically and thus influences changes in the configuration of the fin system when the vehicle is in wave-bearing water; 
 (C) the fin system comprises a fin having a leading edge which comprises (i) a relatively rigid central section which has a fixed spatial relationship with the swimmer body, and (ii) relatively deformable outboard sections; 
 (D) the fin system comprises two generally laminar fins, each of which rotates about an axis of rotation generally aligned with the longitudinal axis of the swimmer body; 
 (E) the tether comprises an elastically deformable member; 
 (F) the tether comprises a component which transmits data and/or electrical power; 
 (G) the swimmer body has a substantially rigid fore section, a midsection which is relatively flexible in the vertical plane, and a substantially rigid aft section; 
 (H) the swimmer body comprises one or more components selected from electrical equipment, communications equipment, recording equipment, control electronics, steering equipment, and sensors; 
 (I) the swimmer comprises a fin which influences the orientation of the swimmer body in the horizontal plane when the device is in the water-bearing water; 
 (J) the device is a water vehicle which moves in a horizontal direction when the device is in wave-bearing water; 
 (K) the swimmer comprises a swimmer body comprising a central tubular housing and wave-actuated fins which extend either side of the housing; and 
 (L) the swimmer body comprises a generally tubular housing and vertical fin surfaces respectively adjacent to the leading end and the trailing end of the swimmer body. 
 
     
     
         2 . A water vehicle according to  claim 1  which has characteristic (A), and wherein the fin is a generally laminar fin and the axis of rotation is generally transverse to the longitudinal axis of the swimmer body. 
     
     
         3 . A water vehicle according to  claim 1  which has characteristic (B), and wherein the fin is a generally laminar fin and the axis of rotation is generally transverse and longitudinal axis of the swimmer body, and the elastic component is a spring or torsion bar. 
     
     
         4 . A water vehicle according to  claim 3  wherein the generally laminar fin is elastically deformable and the elastic component is a torsion bar mounted to the leading edge of the generally laminar fin. 
     
     
         5 . A water vehicle according to  claim 1  wherein the fin is generally laminar and elastically deformable, and the rigid central section rotates about an axis of rotation having a fixed spatial relationship with the swimmer body. 
     
     
         6 . A water vehicle according to  claim 5  wherein the fin is the sole elastic component of the fin system 
     
     
         7 . A wave-powered water vehicle which comprises
 (1) a float,   (2) a swimmer,   (3) a tether connecting the float and the swimmer, and   (4) a computer system;   
       the float, swimmer and tether being such that, when the vehicle is in still water,
 (i) the float is on or near the surface of the water, 
 (ii) the swimmer is submerged below the float, and 
 (iii) the tether is under tension; 
 
       the swimmer, when the vehicle is in wave-bearing water, interacting with the water to generate forces which tend to move the float horizontally; 
       the float comprising a satellite-based position sensor; 
       the swimmer comprising (a) a horizontal sensor which senses direction in a horizontal plane, and (b) a steering actuator; and 
       the computer system (a) being linked to the position sensor, the horizontal sensor and the rudder, (b) containing, or being programmable to contain, instructions to control the steering actuator in response to signals received from the position sensor and the horizontal sensor, or in response to signals received from a sensor on the vehicle. 
     
     
         8 . A water vehicle according to  claim 7  wherein the horizontal sensor is a magnetic compass and the steering actuator is a rudder. 
     
     
         9 . A water vehicle according to  claim 7  wherein the swimmer has a center of gravity, and the tether is attached to the swimmer substantially vertically above the center of gravity. 
     
     
         10 . A water vehicle according to  claim 7  wherein the float has a center of buoyancy, and tether is attached to the float substantially vertically below the center of buoyancy. 
     
     
         11 . A water vehicle according to  claim 7  of wherein the float has a center of drag, and the tether is attached to the float in front of the center of drag. 
     
     
         12 . A method of utilizing wave power which comprises placing a device according to  claim 1  in a body of water which has or which is expected to have water waves traveling across its surface. 
     
     
         13 . A method of utilizing wave power which comprises placing a device according to  claim 7  in a body of water which has or which is expected to have water waves traveling across its surface. 
     
     
         14 . A novel component, for example a float, a swimmer, a swimmer body, or a fin system substantially as described herein. 
     
     
         15 . A method of obtaining information which comprises analyzing information obtained from or recorded by a water vehicle according to  claim 1 . 
     
     
         16 . A method of obtaining information which comprises analyzing information obtained from or recorded by a water vehicle according to  claim 7 . 
     
     
         17 . A method for controlling a function of a water vehicle according to  claim 1  which comprises sending signals to the water vehicle. 
     
     
         18 . A method for controlling a function of a water vehicle according to  claim 7  which comprises sending signals to the water vehicle.