Abstract: A fin and tag are formed from a unitary structure. The tag releasably secures to a tag engagement member embedded in a sportboard. A tag-pin extends through the tag about perpendicular to the longitudinal axis of the tag with first and second tag-pin ends extending outward from the tag. The engagement member has a longitudinal center slot for receiving the tag, and at least one bilateral slot intersecting the longitudinal center slot for allowing passage of the tag-pin as the tag is inserted in the center slot. The first and second tag-pin ends are respectively secured in first and second clamping engagements disposed on opposite sides of the center slot. Each clamping engagement is suspended by opposing flexible anti-torsion suspension members, and has elongated upper and lower clamping members between which a tag pin end is secured. Each clamping engagement is tightened and loosened by a cap screw and T-nut engagement.