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.