Abstract: A fin for a watersport board, such as a surfboard, includes a substantially rigid core covered by a flexible core covering. The core may include one or more positioning members located on either side surface of the core. The core covering may be formed over the core without covering the positioning members. The fin may include a board coupling assembly that includes a plurality of plugs that each have a lumen lined with material of the flexible core covering. The board coupling assembly may secure the fin to the board by compression forces between a screw and the lining of the plug lumens. Methods of making and using such a fin are also disclosed.

Abstract: In mounting of a fin on a surfboard, there is formed a through hole within the surfboard with the fin to be mounted within the through hole and extend from the underside of the surfboard. The through hole is normally open the top side of the surfboard. A cover, comprising a thin flexible base, is adhesively secured onto the top side of the surfboard surrounding the through hole. The cover includes a nametag which is removably mounted in conjunction with the base. Removing of the nametag permits access into the surfboard fin mounting box.

Abstract: A fin mounting system for a surfboard which utilizes a box embedded within the surfboard with the mounting being achieved by producing a through cavity within the surfboard, placing the box within the through cavity and then pouring a hardenable resin between the box and the sidewall of the cavity completely filling such. The box is constructed of a glass filled polyurethane plastic. After the resin is hardened, any portion of the box that protrudes exteriorly of the surface of the surfboard is removed. The fin has a mounting end which is to be transversely snugly received within the box. The fin is adjustable longitudinally within the box. A fastener is employed to fix in position the fin when the desired adjusted position is achieved. The fin is constructed of a glass-filled, nylon material. The fastener comprises a conventional bolt and nut with the nut being embedded within the fin.