Patent ID: 7581997

Claim:
A method for providing a hydrofoil comprising: (a) providing said hydrofoil with a foot attachment member having a heel portion end and a forward toe portion end in front of said heel portion end; (b) connecting an active portion in front of said foot attachment member, said active portion having opposing surfaces, outer side edges, a root portion near said foot attachment member and a free end portion spaced from said foot attachment member and said root portion, said active portion having a predetermined longitudinal dimension between said root portion and said free end portion, said active portion having a longitudinal midpoint between said root portion and said free end portion, said active portion having a first half portion between said predetermined body and said longitudinal midpoint and a second half portion between said midpoint and said free end portion; (c) providing said active portion with at least one substantially flexible elongated rib member, said rib member having a rib root portion near said foot attachment member and a rib forward portion that is forwardly spaced from said rib root portion and said foot attachment member, said rib member having a predetermined length between said foot attachment member and said free end portion, said rib member having a predetermined cross sectional shape having a cross sectional height and a cross sectional width along said predetermined length, said rib root portion having a predetermined rib root portion vertically oblong cross sectional shape that is substantially oblong in a substantially vertical direction in which said cross sectional height exceeds said cross sectional width, said rib forward portion having a predetermined rib forward portion cross sectional shape that is relatively less oblong in said vertical direction than said predetermined vertically oblong rib root portion cross sectional shape; and (d) providing said rib member with sufficient flexibility along said predetermined length to cause a significant portion of said second half portion to experience opposite movement that occurs in the opposite direction of said first half portion during at least one inversion phase of said reciprocating motion.