An apparatus for putting on flippers including means for retaining a user's foot inside a shoe of the flipper, the retaining means being mechanically connected to means for connection to the shoe of the flipper, the retaining means also being pivoted to the connection means by a hinge, the apparatus being characterised in that it comprises means for adjusting the mutual position between the retaining means and the connecting means for adapting the apparatus to the foot of the user.

An underwater recreation system for diving instruction and method of its use. The method includes providing a series of learning steps with diving techniques and instructions to practice at incrementally deeper depths and providing a surface floating depth limitation device that restricts the learning user to the particular maximum depth of their learning step. The apparatus for carrying out the method of diving instruction includes a surface floating depth limitation device with the means to connect to the breathing hose of a surface supplied air supply.

One embodiment of improved swim fins consists of a right foot attachment (101) with an outer right blade (111) and an inner right blade (112) which is arranged such that it does not mechanically interfere with an inner left blade (113). The blades may include a pivot mechanism (220) that allows the blades to maintain an optimal angle of attack as the swimmer moves their legs up and down. In another embodiment, a right blade (1011) and a left blade (1013) are attached to the feet of a person who is propelled by the blades above the surface of the water as they pump their feet up and down, forming a human-powered hydrofoil. Other embodiments are described and shown.

A method for providing a swim fin includes providing a foot attachment member and a blade member having a predetermined blade length. The blade member has a soft portion made with a relatively soft thermoplastic material. The method includes providing a relatively harder portion and the relatively soft thermoplastic portion that is molded to the relatively harder thermoplastic portion. The method includes providing an orthogonally spaced portion of the relatively harder portion that is arranged a predetermined orthogonal direction while said swim fin is in state of rest. The method includes providing the blade member with a predetermined biasing force portion that is arranged to urge the orthogonally spaced portion while the swim fin is in a state of rest. The method includes arranging a significant portion of the blade length to experience pivotal motion a lengthwise angle of attack during use.

A method for providing a swim fin includes providing a foot attachment member and a blade member having a predetermined blade length. The blade member has a soft portion made with a relatively soft thermoplastic material. The method includes providing a relatively harder portion and the relatively soft thermoplastic portion that is molded to the relatively harder thermoplastic portion. The method includes providing an orthogonally spaced portion of the relatively harder portion that is arranged a predetermined orthogonal direction while said swim fin is in state of rest. The method includes providing the blade member with a predetermined biasing force portion that is arranged to urge the orthogonally spaced portion while the swim fin is in a state of rest. The method includes arranging a significant portion of the blade length to experience pivotal motion a lengthwise angle of attack during use.

A method for providing a swim fin includes providing a foot attachment member and a blade member having a predetermined blade length. The blade member has a soft portion made with a relatively soft thermoplastic material. The method includes providing a relatively harder portion and the relatively soft thermoplastic portion that is molded to the relatively harder thermoplastic portion. The method includes providing an orthogonally spaced portion of the relatively harder portion that is arranged a predetermined orthogonal direction while said swim fin is in state of rest. The method includes providing the blade member with a predetermined biasing force portion that is arranged to urge the orthogonally spaced portion while the swim fin is in a state of rest. The method includes arranging a significant portion of the blade length to experience pivotal motion a lengthwise angle of attack during use.

A method for providing a swim fin includes providing a foot attachment member and a blade member having a predetermined blade length. The blade member has a soft portion made with a relatively soft thermoplastic material. The method includes providing a relatively harder portion and the relatively soft thermoplastic portion that is molded to the relatively harder thermoplastic portion. The method includes providing an orthogonally spaced portion of the relatively harder portion that is arranged a predetermined orthogonal direction while said swim fin is in state of rest. The method includes providing the blade member with a predetermined biasing force portion that is arranged to urge the orthogonally spaced portion while the swim fin is in a state of rest. The method includes arranging a significant portion of the blade length to experience pivotal motion a lengthwise angle of attack during use.

A method of coupling a boot toe body to a fin apparatus is disclosed. The fin apparatus includes a fin body coupled to a boot coupling body. The method involves connecting a first boot connector on a first end of the boot coupling body to a first complementary boot connector on a top side of the boot toe body, and connecting a second boot connector on a second end of the boot coupling body to a second complementary boot connector on a bottom side of the boot toe body. Boot toe bodies, fin apparatuses, and systems including the boot toe bodies and fin apparatuses are also disclosed.

A hand paddle (1) for a float (13) is described, having a grip part (6) and a paddle blade (2) which comprises a blade shoulder (3) and a blade edge (4) that is located opposite the blade shoulder (3) in the longitudinal direction of the paddle blade (2). In order to enable easy manufacture, flexible use possibilities, and use in a way that saves effort by the user, it is proposed that the paddle blade (2) forms the grip part (6) which is bounded by a grip cutout (5) that extends from the blade shoulder (3) in the longitudinal direction of the paddle blade (2).

A hand paddle (1) for a float (13) is described, having a grip part (6) and a paddle blade (2) which comprises a blade shoulder (3) and a blade edge (4) that is located opposite the blade shoulder (3) in the longitudinal direction of the paddle blade (2). In order to enable easy manufacture, flexible use possibilities, and use in a way that saves effort by the user, it is proposed that the paddle blade (2) forms the grip part (6) which is bounded by a grip cutout (5) that extends from the blade shoulder (3) in the longitudinal direction of the paddle blade (2).