Tater,
I apologize if my previous post seemed a little harsh. That was not my intention. Subtlety of expression in these forums can be difficult at times.
Norman Friedman's book,
U.S. Submarines through 1945 has a table on page 311 which lists the characteristics of several classes of submarines. The test depth for the Tench class is listed as 400 feet. Schemes 2 and 3 are listed next. These were proposals for follow on classes that were never built. The figure of 1000 is listed in the test depth column. However, the 1000 has an asterisk next to it. Checking the preface for the data tables, it clearly states that any depth figure listed with an asterisk denotes
collapse depth.
Test depth: The depth at which a submarine can routinely operate without damage to the hull or associated piping systems.
Collapse (or crush) depth: The
theoretical depth at which the submarine hull will fail due to water pressure.
In Table 12-3 on page 250, Friedman lists the operating (test) depth of the SS-475 (USS Argonaut) as 450 feet and the collapse depth of 750 feet. Proposed Design A and B had a test depth of 500 feet and a collapse depth of 800 feet.
Norman Friedman is a very reliable author. However, his writing style is very choppy and academic and is sometimes hard to follow.
Interesting fact: The internal watertight bulkheads of these boats were built to a different standard. Their thickness was reduced to reduce the overall weight of the boat. They would give way at 450 feet. This means that if a boat suffered battle damage and had a compartment completely flooded, the bulkhead separating it from the rest of the interior of the boat would collapse at 450 feet causing the loss of the boat.
The devil is in the details!
Dave
www.pigboats.com