Watercraft manoeuvring device and a surface watercraft including the manoeuvring device

Abstract

A watercraft manoeuvring device for mounting on a watercraft is disclosed comprising an elongate member having a mounting end and an opposed fin end that is spaced from the mounting end. The device includes a mounting formation on the mounting end for mounting on the watercraft and a fin mounted on the fin end. The fin has a bearing surface for interacting with water and the elongate member is capable of flexing when the fin is subjected to hydrodynamic water forces when travelling through water. The device may be integrally formed from a polymeric material. A watercraft such as a surfboard having the watercraft manoeuvring device is also disclosed.

What is claimed is: 
     
         1 . A watercraft manoeuvring device for mounting on a watercraft, the watercraft manoeuvring device comprising:
 an elongate member having a mounting end and a fin end that is opposed to said mounting end, wherein the elongate member is capable of flexing;   a mounting formation on the mounting end of the elongate member for mounting on the watercraft; and   a fin at the fin end of the elongate member having a bearing surface for interacting with water through which the fin travels.   
     
     
         2 . The watercraft manoeuvring device of  claim 1 , wherein the elongate member has a length of 1 mm to 1200 mm. 
     
     
         3 . The watercraft manoeuvring device of  claim 1 , wherein the fin on the elongate member is capable of an angular deflection of 15 to 30 degrees from its resting position due to flexing of the elongate member during use. 
     
     
         4 . The watercraft manoeuvring device of  claim 1 , wherein the elongate member has a cross-sectional configuration that curves around its full circumferential extent, and the elongate member has a maximum cross-sectional dimensional extent that does not exceed 30 mm. 
     
     
         5 . A watercraft manoeuvring device of  claim 1 , wherein the elongate member, the mounting formation and the fin are integrally formed of a resiliently flexible material, and the mounting formation is detachably mountable to the watercraft. 
     
     
         6 . The watercraft manoeuvring device of  claim 5 , wherein the mounting formation has a leading end at a forward end of the device and a rear end at a rearmost point of attachment to the watercraft, and the mounting formation includes a mounting projection for inserting in a complementary socket in the watercraft to detachably mount the device to the watercraft. 
     
     
         7 . A watercraft for travelling across the surface of water, the watercraft comprising:
 an elongate body having an operatively upper surface for a user and an operatively lower surface for facing down into water, and   a watercraft manoeuvring device mounted on the elongate body, comprising an elongate member having a mounting end and a fin end that is opposed to said mounting end, the elongate member being capable of flexing when the device is travelling through water, a mounting formation on the mounting end of the elongate member mounted on the elongate body, and a fin on the fin end of the elongate member.   
     
     
         8 . The watercraft for travelling across the surface of water of  claim 7 , wherein the elongate body has a front end and a rear end, and the watercraft manoeuvring device is mounted on the operatively lower surface of the elongate body towards the rear end thereof. 
     
     
         9 . The watercraft for travelling across the surface of water of  claim 7 , wherein the elongate member extends substantially parallel to the operatively lower surface of the elongate body, and the elongate member is positioned a vertical distance of not more than 100 mm beneath the operatively lower surface of the body. 
     
     
         10 . The watercraft for travelling across the surface of water of  claim 7 , wherein the elongate body has a center line extending along a length of the elongate body and the watercraft manoeuvring device is mounted on the center line of the elongate body. 
     
     
         11 . The watercraft for travelling across the surface of water of  claim 10 , wherein the watercraft is a surfboard and further includes at least one fixed fin rigidly mounted on the operatively lower surface of the elongate body. 
     
     
         12 . The watercraft for travelling across the surface of water of  claim 11 , including two said fixed fins mounted respectively on left and rights sides of the center line of the board. 
     
     
         13 . The watercraft for travelling across the surface of water of  claim 12 , wherein the fixed fins on the left and right sides of the body are laterally aligned with each other and the fixed fins are positioned forward of the fin of the water manoeuvring device. 
     
     
         14 . The watercraft for travelling across the surface of water of  claim 7 , wherein the mounting formation is detachably mounted to the elongate body, and the elongate body has a plurality of fin boxes in the operatively lower surface, and each fin box is configured to releasably clamp the mounting formation of the water craft manoeuvring device to the elongate body. 
     
     
         15 . A surfboard comprising:
 an elongate board having a nose and a tail and two rails extending between the nose and the tail, an operatively upper surface forming a deck on which a user stands and an operatively lower surface facing down; and   a watercraft manoeuvring device mounted on the elongate board comprising, an elongate member having a mounting end and a fin end that is opposed to said mounting end, wherein the elongate member is capable of flexing when the board is travelling through water, a mounting formation on the mounting end of the elongate member that is mounted on the lower surface, and a fin on the fin end of the elongate member.   
     
     
         16 . The surfboard of  claim 15 , wherein the elongate member has a length of 1 mm to 500 mm, and the elongate member extends substantially parallel to the operatively lower surface of the board. 
     
     
         17 . The surfboard of  claim 16 , wherein the elongate member has a length of 30 to 150 mm, and the elongate member is positioned a vertical distance of not more than 50 mm beneath the operatively lower surface. 
     
     
         18 . The surfboard of  claim 15 , wherein the elongate member has a cross-sectional configuration that curves around its full circumferential extent, and the elongate member has a maximum diameter of 15 to 30 mm. 
     
     
         19 . The surfboard of  claim 15 , wherein the watercraft manoeuvring device is integrally formed from a polymeric material, and wherein the mounting formation is detachably mounted on the board whereby to enable the device to be detached from the board and replaced with another device. 
     
     
         20 . The surfboard of  claim 15 , wherein the watercraft manoeuvring device is mounted on a center line of the board, and the board further includes left and right fixed fins on left and right sides of the center line that are directly mounted to the board, and wherein the watercraft manoeuvring device and the left and right fixed fins are mounted on the board such that the longitudinal and lateral positions of the fin of the device and the fixed fins resemble a tri fin thruster configuration.