text: can you help...i need to know how deep a submarine can dive before it implodes? submarines there is a factor called "crush depth".  crush depth is the depth at which the submarine's structure could collapse due to extensive water pressure of the surrounding.  wwii u-boats reportedly had a crush depth of 200-250 meters.  modern nuclear propulsion submarines (although not tested) could have crush depths of just above 700 meters.  to get the "feel" of it i suggest you watch the movies "u-571" starring matthew mcconnaughey, and "crimson tides" starring gene hackman and denzel washington