Submarine crush depth?

Question

In atmospheres; How much pressure can a modern submarine take before its hull is crushed.

Answer 1

It completely depends on which class submarine you are talking about. Current submarines in service cover a wide range of depth capabilities. This information, of course, is classified.

- US Navy Submariner

Answer 2

The pressure on a submarine's hull increases with depth, limiting the depth below the ocean surface at which it can operate. The water pressure increases by 44.45 pounds per square inch for every 100 feet of additional depth in salt water.

Submarine designers normally intend their creations to operate well away from the hull's physical limits, imposing a safety margin that varies from country to country [1.5 in the USA, 1.75 in the UK, and 2.0 in Germany]. Typically a submarine will have three diving depths:

a normal operating or "test" depth

a safe excursion depth

a crush or collapse depth

A submarine's hull is normally constructed of steel, or exceptionally of titanium. Special High Yield [HY] steel alloys have been developed to increase the diving depth of submarines, although the improved depth performance of these alloys imposes a price of increased fabrication challenges. These special steels are denominated by their yield stress in thousands of pounds per square inch -- thus HY-80 steel has a yield stress of 80,000 pounds per square inch [corresponding to a depth of 1,800 feet], HY-100 a a yield stress of 100,000 pounds per square inch [corresponding to a depth of 2,250 feet], and so on.

During World War II, American fleet submarines normally operated at a depth of 200 feet, though in emergencies they would dive to a depth of 400 feet.

Post-War American submarines, both conventional and nuclear, had improved designs and were constructed of improved materials [the equivalent of "HY-42"]. These boats had normal operating depths of some 700 feet, and a crush depth of 1100 feet.

The Thresher, the first American submarine constructed of HY-80 steel, reportedly had a normal operating depth of 1,300 feet, roughly two-thirds the crush depth limit imposed by the HY-80 steel.

The Seawolf, the first American submarine constructed of HY-100 steel, is officially claimed by the Navy to have a normal operating depth of "greater than 800 feet," but based on the reported operating depth of the Thresher, it may be assumed that the normaly operating depth of the Seawolf is roughly double the official figure.

The Soviet Alfa submarines, constructed of titanium, reportedly had an operating depth of nearly 4,000 feet.

Answer 3

Depends on the size and design but it's greater than 800 feet or 24 atmospheres.

Answer 4

Depends on the sub. Submersibles have made it to the deepest parts of the ocean.

If you are asking about military subs, I believe that this info is classified.