"Drink and dive"
Same goes for swimming, especially in natural waters that could be hiding obstacles. Or water that's too deep.
(Bought a new house last month and the pool goes to 10 feet. It's weird swimming in water over my head again that's not a natural lake with dirt/sand/mud bottom or steady wave action; haven't been in that situation since I was in high school. If I'm going to drink, I'll find a good floatie or stick to the shallow end, not just dive/jump in.)