The Casio F-91W is probably the most popular ... and it looks like he may have succeeded. This classic watch is now waterproof, down to 700 meters of depth. If you’re ever 700 meters underwater ...

It's waterproof, and also has a battery that Casio says will last for around two years, but is replaceable to keep this watch ticking over (okay, digitally cycling) a lot longer than that.