Surfboard fin having a rearwardly offset bearing surface

Abstract

A fin for a surfboard, having a main body which comprises a first edge which is in contact with the board when the fin is secured to the board, a leading edge at the front and a trailing edge at the rear, a rear curve connecting the leading edge and the trailing edge, the trailing edge comprising a forwardmost front tip. The main body is extended rearwards by an arm which extends from a straight line which is perpendicular to the first edge and passes through the front tip of the trailing edge, as far as the rear curve, the arm having a length greater than approximately 8 cm.

1 - 15 . (canceled) 
     
     
         16 . A fin for a surfboard, configured to be secured, alone or along with other fins, to the underside of a board, comprising:
 a main body which comprises
 a first edge in contact with the board when said fin is secured to the board, 
 a leading edge at the front and a trailing edge at the rear, 
 a rear curve connecting the leading edge and the trailing edge, 
 the trailing edge comprising a forwardmost front tip, 
 an arm extending rearwards from the main body which arm extends from a straight line which is perpendicular to the first edge and passes through the front tip of the trailing edge, as far as the rear curve, said arm having a length greater than approximately 8 cm. 
   
     
     
         17 . The fin according to  claim 16 , wherein the arm comprises a height reduction, the arm comprising at the rear of the height reduction a bearing surface with a height greater than the height reduction. 
     
     
         18 . The fin according to  claim 17 , wherein the height reduction is between 2 and 4 cm. 
     
     
         19 . The fin according to  claim 17 , wherein the bearing surface has a height of between 3 and 5 cm. 
     
     
         20 . The fin according to  claim 17 , wherein the bearing surface is separated from the board by a distance greater than approximately 7 cm. 
     
     
         21 . The fin according to  claim 16 , wherein the arm has a total length of between approximately 10 and 20 cm. 
     
     
         22 . The fin according to  claim 16 , wherein the arm comprises at least one wing at the rear. 
     
     
         23 . The fin according to  claim 22 , further comprising a first angle of inclination formed between an axis of inclination passing through the center of the first edge and through a central point of a lower edge of the at least one wing, and an axis perpendicular to the first edge, which is greater than substantially 45°. 
     
     
         24 . The fin according to  claim 16 , further comprising a second angle of inclination formed between an axis of inclination passing through the center of the first edge and through a point of inflexion of the leading edge, and an axis perpendicular to the first edge, which is greater than substantially 26°. 
     
     
         25 . The fin according to  claim 16 , further comprising a third angle of inclination formed between an axis of inclination passing through the point where the trailing edge joins the first edge and the rearmost point of the rear curve, and an axis perpendicular to the first edge, which is greater than substantially 40°. 
     
     
         26 . The fin according to  claim 16 , further comprising a rectangle, one of the sides of which coincides with a straight line which is perpendicular to the first edge and passes through a point where the trailing edge joins the first edge, in which the arm and any wings are inscribed, said rectangle having a length to width ratio of greater than approximately 2. 
     
     
         27 . The fin according to  claim 16 , further comprising a wing which is inclined with respect to the plane of the main body. 
     
     
         28 . The fin according to  claim 16 , further comprising at least two wings arranged symmetrically with respect to the plane of the main body. 
     
     
         29 . The fin according to  claim 28 , further comprising a third wing arranged in the plane of the main body. 
     
     
         30 . A surfboard having at least one fin configured to be secured, alone or along with other fins, to the underside of a board, the at least one fin comprising:
 a main body which comprises
 a first edge in contact with the board when said fin is secured to the board, 
 a leading edge at the front and a trailing edge at the rear, 
 a rear curve connecting the leading edge and the trailing edge, 
 the trailing edge comprising a forwardmost front tip, 
 an arm extending rearwards from the main body which arm extends from a straight line which is perpendicular to the first edge and passes through the front tip of the trailing edge, as far as the rear curve, said arm having a length greater than approximately 8 cm.