Equipment Assisted Swim Races

A fellow master swimmer recently posed the question of whether or not there have been any swim races in the past (I think open water races is what he had in mind) where the participants can use any equipment they want as long as it is not motorized equipment in any way....i.e. fins, paddles, wetsuits, ...etc...as long as the human body provides all of the energy (i.e. no motors of any kind)? Does anyone know the answer? I thought that it was an interesting question......I wonder how fast a group of swimmers could swim in an open water race of say 2 or 3 miles if the participants were all allowed to use fins, paddles, and wetsuits? Newmastersswimmer