This was settles centuries ago. Riding on the water in a boat is called "sailing" and using your body to move through the water is called "swimming". The nature

This was settles centuries ago. Riding on the water in a boat is called "sailing" and using your body to move through the water is called "swimming". The nature of "swimming" is defined as the verb "to swim". Which curtails that one is not "sailing". So no boats involved. There is some to be said about "drifting" (e.g floating on ones' back) being a form of "swimming" but I think that's the only grey line and as for a competition I don't think "drifting" would ever win in a race. If one wishes to "drift" as their method of "swimming" they will lose the race.