What is the crush depth of modern Navy submarines?

Answer 1

The Test and Crush depth of any modern U.S. Navy Submarine is Classified Secret/NOFORN and cannot be disclosed publicly. Published public sources are merely estimates only; I can say that it varies with the type of submarine class, and that the official U.S. Navy statement on any submarine depth capability is that they can exceed 400 feet. But you probably already know that.

Such information is classified at a high level because with such knowledge, an enemy could calibrate torpedoes or any deep depth weapon to the known limits of an enemy submarine. A real-life example occurred in WW2, when the Allies captured a German U-Boat and recommissioned her a Royal Navy vessel. It was used as a training and research platform to determine the limits of her depth capabilities.

Having said that, you can always check the unverifiable information in Jane's Fighting Ships. Anyone like myself who is a current or Veteran Submariner is prohibited by Federal Law from releasing such information. Whether Jane's is accurate, I cannot confirm either way. You might be able to discern the information in Blind Man's Bluff, a 1990's book about Submarine Warfare during the Cold War, in which some of my old buddies are mentioned. However, as with Jane's, no one can confirm or deny the information. All crew members sign a 30 year non-disclosure agreement when they muster out of the Navy or leave their vessel. I've still got 8 years or so, but even with the details that have come out, I don't believe in making such information public for any reason anyway. A submarine's greatest asset is its secrecy.

There is a common misconception in the public that Submarines need to have extreme depth capability. For example, some Russian attack submarines have a listed capability of 3,000 feet (e.g., the titanium hulled Alfa class). However, we don't need a submarine that can go that deep - all we need is a TORPEDO that can go that deep. At that depth, any significant hull damage caused by even a near miss explosion will cause massive flooding, pushing the vessel toward crush depth quickly. At that depth, pressure on the submarine's hull per square inch in incredibly high, and it doesn't take much damage to make small hole big. Think of the little boy with the finger in the dike suddenly getting hit by a huge storm surge - there's no way to contain the damage once done.