[Contract Diver]

My old rule of 1/3's about diving watches...a rated 30 meter or 100 ft watch should withstand maximum dynamic pressure at 10 meters...thats a 3 story building in depth..for "hard activities" like loosing a stuck anchor....at the 20 meter mark or a 6 story building deep..."careful activities" like hooking to a dropped tool box would be alright...at 30 meters or 100 feet... thats 10 stories deep.. "picking up a sea shell" would be alright...most non- divers don't realize just how deep 30 meters really is...When I was in the trade...I could "snorkel down" 20 meters or about 70 feet..the any weak link that I've noticed on my Mariner is the battery cover and gasket...if those two item or kept in good repair I can see no reason to have a deeper rating on a non-divers watch....and hottubs will destroy the sealing abilities of even a 600 meter instrument ..