I was a lifeguard at Barton Springs for years. When we would clean the pool, instead of schlepping the water hoses from the storage room all the way around the pool to the other side, we would just swim them across.
After hosing off the decks, we would roll the hoses back up without draining them and tell the new guy (whoever that was) to swim them back across. New guy would jump in with 30 or 40 feet of water hose curled up, and the hose would promptly sink to the bottom of the pool.
Turns out water hose float pretty well when they are empty, but sink like very long, tangly rocks when full of water.
edit to add more lifeguard shenanigans:
When we would train with the backboard, if any new guy was the victim, once he was secured to the backboard, lifted out of the water, and placed on the deck, we would all stand over them and wring out our wet bathing suits onto their face.