Flipper for underwater swimming - has trapezoidal cross=section reinforced rib which connects foot portion to flat, flexible, propulsive area

摘要

The flipper is used for underwater swimming and comprises a portion at one end provided with a suitably shaped recess for holding the swimmer's foot (1,2). At the other end is the area used for propulsion. This has a flat surface which is flexible and has its side edges (8, 9) stiffened by means of ribbing. Another single rib (10) is positioned centrally and this is continued and extended to join onto the foot portion. This extended connecting rib (3) has a lozenge shaped cross section and is reinforced by a metal or synthetic resin stiffening core to prevent twisting or sideways movement.