Safety fin over mold system and safety fin sleeve for surfboard and other recreational vehicles

A fin for an recreational device including: a rigid fin core having opposite sides, at least one edge and a base; at least one registration post on each of the opposite sides of the core, and a flexible material at least partially covering the core, wherein the flexible material include leading and trailing fin edges extending outward from the edge of the core and the flexible material is flush with an end surface of each of the at least one registration post.