Surfcraft fin assembly

Abstract

A surfcraft fin assembly includes a generally rectangular open mounting box recessed into the underside of surfcraft and having lugs projecting internally at the front and rear of its open edge to retain a notch in the leading edge of the base of the fin and a flexible hook in the rear edge of the base of the fin which flexes allowing insertion into and removal from the mounting box.

1 . A surfcraft fin assembly comprising a generally rectangular open mounting box and
 a fin with a base;   the base having a notch in one end and a flexible portion at the other end,   the mounting box being adapted to be recessed into the underside of a surfcraft and having two long side edges and short front and rear edges, said front and rear edge having lugs projecting internally to retain the fin in the box by engaging the notch in the base and the flexible portion of the base which flexes to allow insertion into and removal from the mounting box.   
     
     
         2 . The surfcraft fin assembly of  claim 1  wherein the flexible portion is biased away from the fin such that during insertion it flexes towards the fin to allow insertion and once pressed past the lug springs away from the fin and under the lug to retain the fin in the mounting box. 
     
     
         3 . The surfcraft fin assembly of  claim 1  further comprising a lever which can be used to prise the flexible portion of the fin base away from the lug to remove the fin from the mounting box. 
     
     
         4 . The surfcraft fin assembly of  claim 1  wherein the fin base has a leading edge with a notch and a rear edge with a flexible portion. 
     
     
         5 . The surfcraft fin assembly of  claim 1  wherein the fin base has a leading edge with a flexible portion and a rear edge with a notch. 
     
     
         6 . The surfcraft fin assembly of  claim 1  wherein the flexible portion is a flexible hook. 
     
     
         7 . The surfcraft fin assembly of  claim 1  wherein the lugs are integrally formed with the box. 
     
     
         8 . The surfcraft fin assembly of  claim 1  in which the lugs are removably fastened to the box and are designed to snap off when the fin encounters an obstacle thus releasing the fin. 
     
     
         9 . The surfcraft fin assembly of  claim 1  in which the lugs are screwed into the box and are designed to snap off when the fin encounters an obstacle thus releasing the fin. 
     
     
         10 . The surfcraft fin assembly of  claim 1  wherein the flexible portion of the fin base is adapted to snap off when the fin encounters an obstacle thus releasing the fin.