A related lol
Back in college during a maths session (not a euphemism) one lad was bragging about how awesome his watch was.

Bragger: "... And it's waterproof to 200 metres, which is really important when I go diving."
Other boy: "Where do you go diving?"
Bragger: "At the swimming pool."
Other boy: "Do you often get to 200 metres in a swimming pool?"

Chortles ensued.
(ThatNiceMan thought he was being funny, Fri 30 Sep 2011, 11:37, 1 reply)

Surely it's a good idea to have your watch be waterproof
to a depth beyond that which you'd normally do down to? Or do you have a different watch for each dive?
( monster munch person, man, woman... camera... TV?, Fri 30 Sep 2011, 13:15, closed)

General rule amongst actual divers
is that devices which are waterproof only as a secondary feature are only reliable up to about 10-20% of the stated depth. So a 200m normal watch might be useful for a normal 30m dive or might implode, while a 50m divers watch will probably work to 50m.
( Fronds are waving gently on, Fri 30 Sep 2011, 13:54, closed)

Divers watches are the dog's because they're tested doing what they're designed for. Watches which say 200m would probably be ok sitting in a static tank at 200m equivalent, but when you're swimming about and knocking it off your diving tank the actual pressure your watch sees varies quite a bit. I've got a Tag which has 200m on it and I wouldn't take that deeper than snorkeling.
( AWPS, Fri 30 Sep 2011, 15:55, closed)

Mmm
I have a watch which is water resistant to 30m. Apparently, that translates to "Don't submerge it in water"

en.wikipedia.org/wiki/Water_Resistant_mark
( le brian, Sat 1 Oct 2011, 10:51, closed)