Abstract: An improved adjustable heel strap having an adjustable instep strap connected to the heel strap adjacent the heel portion of a swimmer' foot. Methods are provided for providing a highly adjustable strap system for preventing loss of swim fins in rough water conditions such as large surf and large open ocean waves. Methods are also provided for providing multi-dimensional heel strap adjustability around the ankle and instep to reduce ankle strain, increase ankle support, distribute load and stress points, reduce chaffing and blisters, increase leverage and power to the swim fin, reduce looseness and play between the foot and the swim fin, to increase comfort, to increase control, to improve positioning control, to improve sizing adjustment and to provide increased conformity to greater variations in foot and ankle sizes, shapes and contours.

Abstract: Designs and methods are disclosed for permitting permit scooped shaped swim fin blades (184) to flex around a transverse axis to a significantly reduced angle of attack while reducing or preventing the scooped blade portion (254) from collapsing or buckling under the longitudinal compression forces (222) exerted on the scooped portion during a large scale blade deflection (212) by strategically alleviating or controlling such compression forces (222). Method are also disclosed for increasing flow capacity, effective scoop length, scoop depth over a greater length of the blade, reducing blade resistance to large scale deflections, reducing bending resistance within scooped blade portions (254) that are experiencing high levels of blade deflection. Methods are also provided for reducing lost motion and increasing propulsion during the inversion phase of a reciprocating kicking stroke cycle while also increasing the formation of a scooped blade region (254) during the inversion phase of the stroke cycle.

Abstract: Methods are disclosed to design resilient hydrofoils (164) which are capable of having substantially similar large scale blade deflections under significantly varying loads. The methods permit the hydrofoil (164) to experience significantly large-scale deflections to a significantly reduced angle of attack under a relatively light load while avoiding excessive degrees of deflection under increased loading conditions. A predetermined compression range on the lee portion of said hydrofoil (164) permits the hydrofoil (164) to deflect to a predetermined reduced angle of attack with significantly low bending resistance.

Abstract: Methods are disclosed for increasing lift and decreasing drag on hydrofoils and swim fins. The methods include providing a hydrofoil with a highly swept back leading edge portion and orienting the hydrofoil at a significantly reduced angle of attack in which the reduced angle of attack occurs at an angle that is substantially transverse to the hydrofoil's direction of movement through a surrounding fluid medium. The lee surfaces of the hydrofoil are provided with a substantially unobstructed flow path as well as a separation reducing contour so as to permit lift generating attached flow conditions to form along such lee surfaces. Substantially rigid structural reinforcement is provided to prevent the hydrofoil from deforming significantly during use. Methods are disclosed for providing a hydrofoil with a substantially longitudinal recess or venting system located substantially along the center axis of the hydrofoil.

Abstract: Methods are disclosed to design resilient hydrofoils (164) which are capable of having substantially similar large scale blade deflections under significantly varying loads. The methods permit the hydrofoil (164) to experience significantly large-scale deflections to a significantly reduced angle of attack under a relatively light load while avoiding excessive degrees of deflection under increased loading conditions. A predetermined compression range on the lee portion of said hydrofoil (164) permits the hydrofoil (164) to deflect to a predetermined reduced angle of attack with significantly low bending resistance.

Abstract: Designs and methods are disclosed for permitting permit scooped shaped swim fin blades (184) to flex around a transverse axis to a significantly reduced angle of attack while reducing or preventing the scooped blade portion (254) from collapsing or buckling under the longitudinal compression forces (222) exerted on the scooped portion during a large scale blade deflection (212) by strategically alleviating or controlling such compression forces (222). Method are also disclosed for increasing flow capacity, effective scoop length, scoop depth over a greater length of the blade, reducing blade resistance to large scale deflections, reducing bending resistance within scooped blade portions (254) that are experiencing high levels of blade deflection. Methods are also provided for reducing lost motion and increasing propulsion during the inversion phase of a reciprocating kicking stroke cycle while also increasing the formation of a scooped blade region (254) during the inversion phase of the stroke cycle.

Abstract: A gas valve has housing and a barrier. The housing has a passageway with an upstream port and a downstream port. The barrier is disposed across the passageway and is formed from a material which is porous to compressed gas but which substantially prevents a low-pressure liquid from advancing through the passageway downstream of the barrier. The passageway may also contain a gas conditioner and/or a filter that is preferably disposed downstream of the barrier.

Abstract: Methods are disclosed for increasing lift and decreasing turbulence and drag on hydrofoils and swim fins. Fins are disclosed having at least one pivoting blade region connected to the swim fin with a pivotal connection made from reduced blade thickness, blade cutout regions, and injection molding of the flexible material of the foot pocket. Methods are also provided for limiting the deflections of at least one pivoting blade region with a expandable blade limiting member connected to both the pivoting blade region and a less flexible region with a chemical bond created during injection molding. Methods are disclosed for orienting at least one pivoting blade region at a reduced angle of attack sufficient for increased efficiency and reduced effort. Injection molding assembly methods with chemical bonds and mechanical bonds are provided. Fins having transverse flexible elements, transverse recesses, longitudinal flexible portions and venting systems are also disclosed.

Abstract: Methods are disclosed for increasing the performance of a foil (100) by using tip droop (102) having an inward directed camber capable of generating an inward directed lifting force on the tip droop (102) in order to control spanwise flow conditions adjacent the tip (112) of a foil (100). Methods for varying the inward lifting shape of a tip droop (102) are provided along with methods for varying the angle of attack and camber of the tip droop (102) as the angle of attack of the foil (100) is changed and as spanwise flow conditions vary.

Abstract: Methods are disclosed to design resilient hydrofoils (164) which are capable of having substantially similar large scale blade deflections under significantly varying loads. The methods permit the hydrofoil (164) to experience significantly large-scale deflections to a significantly reduced angle of attack under a relatively light load while avoiding excessive degrees of deflection under increased loading conditions. A predetermined compression range on the lee portion of said hydrofoil (164) permits the hydrofoil (164) to deflect to a predetermined reduced angle of attack with significantly low bending resistance.

Abstract: Methods are disclosed for increasing lift and decreasing turbulence and drag on hydrofoils and swim fins. Fins are disclosed having at least one pivoting blade region connected to the swim fin with a flexible joint element made from reduced blade thickness, blade cutout regions, and injection molding of the flexible material of the foot pocket. Methods are also provided for limiting the deflections of at least one pivoting blade region with a movable blade limiting member connected to both the pivoting blade region and a blade limiting load bearing member with a chemical bond created during molding. Methods are disclosed for orienting at least one pivoting blade region at a reduced angle of attack sufficient for increased efficiency and reduced effort. Injection molding assembly methods with chemical bonds and mechanical bonds are provided. Fins having transverse flexible elements, transverse recesses, longitudinal recesses and venting systems are also disclosed.

Abstract: Methods are disclosed for increasing lift and decreasing turbulence and drag on hydrofoils and swim fins. Fins are disclosed having at least one pivoting blade region connected to the swim fin with a pivotal connection made from reduced blade thickness, blade cutout regions, and injection molding of the flexible material of the foot pocket. Methods are also provided for limiting the deflections of at least one pivoting blade region with a expandable blade limiting member connected to both the pivoting blade region and a less flexible region with a chemical bond created during injection molding. Methods are disclosed for orienting at least one pivoting blade region at a reduced angle of attack sufficient for increased efficiency and reduced effort. Injection molding assembly methods with chemical bonds and mechanical bonds are provided. Fins having transverse flexible elements, transverse recesses, longitudinal flexible portions and venting systems are also disclosed.

Abstract: Methods are disclosed for increasing lift and decreasing turbulence and drag on hydrofoils and swim fins. Fins are disclosed having at least one pivoting blade region connected to the swim fin with a flexible joint element made from reduced blade thickness, blade cutout regions, and injection molding of the flexible material of the foot pocket. Methods are also provided for limiting the deflections of at least one pivoting blade region with a movable blade limiting member connected to both the pivoting blade region and a blade limiting load bearing member with a chemical bond created during molding. Methods are disclosed for orienting at least one pivoting blade region at a reduced angle of attack sufficient for increased efficiency and reduced effort. Injection molding assembly methods with chemical bonds and mechanical bonds are provided. Fins having transverse flexible elements, transverse recesses, longitudinal recesses and venting systems are also disclosed.

Abstract: Methods are disclosed to design resilient hydrofoils (164) which are capable of having substantially similar large scale blade deflections under significantly varying loads. The methods permit the hydrofoil (164) to experience significantly large-scale deflections to a significantly reduced angle of attack under a relatively light load while avoiding excessive degrees of deflection under increased loading conditions. A predetermined compression range on the lee portion of said hydrofoil (164) permits the hydrofoil (164) to deflect to a predetermined reduced angle of attack with significantly low bending resistance.

Abstract: Disclosed herein is a swim fin comprising a foot attachment member, a blade region connected to the foot attachment member and forming a forward extension of the foot attachment member. The blade region has at least one side edge that may twist, and at least one longitudinal rib member secured to the blade region. The longitudinal rib member is laterally spaced from the side edge that may twist. At least one stiffening member is disposed within the blade region between the longitudinal rib member and the side edge that may twist. The stiffening member is made with a thermoplastic material secured to the blade region with a thermal-chemical bond.

Abstract: Methods are disclosed for increasing lift and decreasing turbulence and drag on hydrofoils and swim fins. Fins are disclosed having at least one pivoting blade region connected to the swim fin with a flexible joint element made from reduced blade thickness, blade cutout regions, and injection molding of the flexible material of the foot pocket. Methods are also provided for limiting the deflections of at least one pivoting blade region with a movable blade limiting member connected to both the pivoting blade region and a blade limiting load bearing member with a chemical bond created during molding. Methods are disclosed for orienting at least one pivoting blade region at a reduced angle of attack sufficient for increased efficiency and reduced effort. Injection molding assembly methods with chemical bonds and mechanical bonds are provided. Fins having transverse flexible elements, transverse recesses, longitudinal recesses and venting systems are also disclosed.

Abstract: Methods are disclosed for increasing lift and decreasing turbulence and drag on hydrofoils and swim fins. Fins are disclosed having at least one pivoting blade region connected to the swim fin with a flexible joint element made from reduced blade thickness, blade cutout regions, and injection molding of the flexible material of the foot pocket. Methods are also provided for limiting the deflections of at least one pivoting blade region with a movable blade limiting member connected to both the pivoting blade region and a blade limiting load bearing member with a chemical bond created during molding. Methods are disclosed for orienting at least one pivoting blade region at a reduced angle of attack sufficient for increased efficiency and reduced effort. Injection molding assembly methods with chemical bonds and mechanical bonds are provided. Fins having transverse flexible elements, transverse recesses, longitudinal recesses and venting systems are also disclosed.

Abstract: Disclosed herein is a swim fin comprising a foot attachment member, a blade region connected to the foot attachment member and forming a forward extension of the foot attachment member. The blade region has at least one side edge that may twist, and at least one longitudinal rib member secured to the blade region. The longitudinal rib member is laterally spaced from the side edge that may twist. At least one stiffening member is disposed within the blade region between the longitudinal rib member and the side edge that may twist. The stiffening member is made with a thermoplastic material secured to the blade region with a thermal-chemical bond.

Abstract: Methods are disclosed to design resilient hydrofoils (164) which are capable of having substantially similar large scale blade deflections under significantly varying loads. The methods permit the hydrofoil (164) to experience significantly large-scale deflections to a significantly reduced angle of attack under a relatively light load while avoiding excessive degrees of deflection under increased loading conditions. A predetermined compression range on the lee portion of said hydrofoil (164) permits the hydrofoil (164) to deflect to a predetermined reduced angle of attack with significantly low bending resistance.

Abstract: Methods are disclosed for increasing lift and decreasing drag on hydrofoils and swim fins. These methods include providing a hydrofoil with a highly swept back leading edge portion and orienting the hydrofoil at a significantly reduced angle of attack in which the reduced angle of attack occurs at an angle that is substantially transverse to the hydrofoil's direction of movement through a surrounding fluid medium. The lee surfaces of the hydrofoil is provided with a substantially unobstructed flow path as well as a separation reducing contour so as to permit lift generating attached flow conditions to form along such lee surfaces. Substantially rigid structural reinforcement is provided to prevent the hydrofoil from deforming significantly during use. Methods are disclosed for providing a hydrofoil with a substantially longitudinal recess or venting system located substantially along the center axis of the hydrofoil.