Abstract: A pair of laterally spaced generally cylindrical hollow bodies are provided and connected by a thin connecting flange assembly extending there between and lying along a plane containing the longitudinal center axis of said bodies. One pair of corresponding end walls of the bodies include ingress and egress ports formed therein having removable fluid tight closures engaged therewith whereby the interiors of the bodies may be partially or completely filled with liquid to vary the buoyancy of the bodies. Adjacent portions of the bodies, on opposite sides of the connecting flange assembly, defined outwardly opening channels in which the adjacent portions of the thighs of a swimmer may be seated with the swimmer's thighs seated primarily against the bodies rather than being primarily seated against the connecting flange assembly.