An arm extension apparatus comprising a propulsion blade comprising a top half and a bottom half, wherein the top half is generally straight and wherein the bottom half comprises a curve, and wherein the bottom half comprises a proximal end and a distal end, and wherein the distal end comprises a foot, and wherein the foot comprises two split toes.

An arm extension apparatus comprising a propulsion blade comprising a top half and a bottom half, wherein the top half is generally straight and wherein the bottom half comprises a curve, and wherein the bottom half comprises a proximal end and a distal end, and wherein the distal end comprises a foot, and wherein the foot comprises two split toes.

Provided is a functional shoe comprising a shoe body, a flipper member extended in a plate shape from an end of the shoe body to be used as a flipper function and deformed upward to be folded so as to cover an upper surface of the shoe body, a fixing part fixing the flipper member, and a strap closely adhering the shoe body to a rear part of a user's foot, wherein the strap is selectively folded or unfolded to adjust a contact area with the user's foot. Accordingly, a shoe function and a flipper function are applied to one shoe to be conveniently used, a contact area with the user's foot may be increased to prevent the shoe from coming off when used in the water, and the strap may be folded to increase convenience outside the water.

Provided is a functional shoe comprising a shoe body, a flipper member extended in a plate shape from an end of the shoe body to be used as a flipper function and deformed upward to be folded so as to cover an upper surface of the shoe body, a fixing part fixing the flipper member, and a strap closely adhering the shoe body to a rear part of a user's foot, wherein the strap is selectively folded or unfolded to adjust a contact area with the user's foot. Accordingly, a shoe function and a flipper function are applied to one shoe to be conveniently used, a contact area with the user's foot may be increased to prevent the shoe from coming off when used in the water, and the strap may be folded to increase convenience outside the water.

An underwater propulsion system is disclosed comprising a foot board with one or more battery-powered propulsion units. A throttle control system may be enabled in the foot board such that a movement of the user’s foot controls the throttle. Flattened Lithium batteries allow thin lightweight construction of the foot board. Use of trolling motors as propulsion units provides thrust advantages over pre-existing underwater scooters.

An underwater propulsion system is disclosed comprising a foot board with one or more battery-powered propulsion units. A throttle control system may be enabled in the foot board such that a movement of the user’s foot controls the throttle. Flattened Lithium batteries allow thin lightweight construction of the foot board. Use of trolling motors as propulsion units provides thrust advantages over pre-existing underwater scooters.

A swim or scuba diving fin includes an open-back shoe portion having a pocket for receiving the foot of the user and no heel portion, a blade portion forming a forward extension of the shoe portion, and an element holding the foot in the open-back shoe portion, includes an elongate element in the form of a strap, belt or the like and a length sufficient to surround the heel portion, the sidewalls of the pocket of the shoe, and at least part of the tip of the shoe. Such elongate element is at least partially separated from the open-back shoe portion, and is or may be connected to the open-back shoe portion (3) in length-adjustable and/or at least partially removable fashion through first coupling members, which engage corresponding second coupling members located at the front tip of the open-back shoe.

A swim or scuba diving fin includes an open-back shoe portion having a pocket for receiving the foot of the user and no heel portion, a blade portion forming a forward extension of the shoe portion, and an element holding the foot in the open-back shoe portion, includes an elongate element in the form of a strap, belt or the like and a length sufficient to surround the heel portion, the sidewalls of the pocket of the shoe, and at least part of the tip of the shoe. Such elongate element is at least partially separated from the open-back shoe portion, and is or may be connected to the open-back shoe portion (3) in length-adjustable and/or at least partially removable fashion through first coupling members, which engage corresponding second coupling members located at the front tip of the open-back shoe.

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 β 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).

A fin blade for free diving or swimming or scuba diving is described, which has a cross section at one end angled about a yaw, or longitudinal, axis relative to the cross section at the other end. The arrangement is such that a lateral line at a proximal end is disposed at an angle relative to a lateral line at a portion spaced from the proximal end. The fin blade is more closely aligned with the ergonomic complexities of the human body, such that during finning the fin blade provides greater comfort and/or propulsion. A fin blade is also described which includes a reinforced zone in one portion of the fin blade, such that one portion of the blade at the distal end is relatively increased in flexibility to provide a catch zone at one portion of the distal end of the fin blade.