Abstract: Aquatic activity fin (1) comprising a foot support portion (2) configured for fixing to a person's foot, and a fin portion (3) extending from the foot support portion substantially along a base plane (P). The fin portion (3) comprises a support frame (4), a plurality of hydrofoil blades (5) mounted pivotally to the support frame (4) via pivot couplings (6), and a mechanism for limiting the maximum blade pivot angle ? of each hydrofoil blade. The mechanism for limiting the maximum blade pivot angle comprises bidirectional angle stops (7) configured to allow pivoting of the hydrofoil blade from the a thrust position where a trailing edge (9b) of the hydrofoil blade is above said base plane (P), to a return position where the trailing edge (9b) is below said base plane (P).

Abstract: Aquatic activity fin (1) comprising a foot support portion (2) configured for fixing to a person’s foot, and a fin portion (3) extending from the foot support portion substantially along a base plane (P). The fin portion (3) comprises a support frame (4), a plurality of hydrofoil blades (5) mounted pivotally to the support frame (4) via pivot couplings (6), and a mechanism for limiting the maximum blade pivot angle ? of each hydrofoil blade. The mechanism for limiting the maximum blade pivot angle comprises bidirectional angle stops (7) configured to allow pivoting of the hydrofoil blade from the a thrust position where a trailing edge (9b) of the hydrofoil blade is above said base plane (P), to a return position where the trailing edge (9b) is below said base plane (P).