ok, that is a hell of a lot more human!! On my swim team (I always get crap because i'm a diver), there's what's called the "hourglass", and if someone does it, practice ends. It's starting in the corner of the pool, swimming underwater to the opposite corner, continuing along the shorter end to the corner along the long end that they started, then swimming to that opposite corner, then back to where they started, there's only been one person I can recall who has done it. and that was in a 4 lane pool so that has to be close to 75 meters, that's just plain crazy. 75 feet on the other hand, will probably be easy for most swimmers to do once they can mostly acclimate to the altitude.
