Increasing crush depth to a theoritical value

[Ducimus]

There is a basic premise that US subs could dive deeper then their test depth. Which is fact. What is often hotly debated is just when they actually crushed. Most people seem to agree that it was deeper then what we think. Getting research on this, is really hard. Ive looked on the internet time, and time again (since my book collection is lacking ), and finding accounts of deeper then test depth dives is really hard.

I think the primary reason for this, was because from all accounts ive found, submarine captains in the US Navy were admonished for taking their boat below the rated depth. They had to show a pretty good reason for doing so, or they were reprimanded. It could very well be that a number of captains simply didnt record a deeper dive in their logbooks because of this, so they're isnt much of a record of them today.

One thing ive wanted to do for awhile, was have a plausible excuse for increasing sub crush depths beyond 20 to 30 feet. So unless someone can come up with some hard evidence of a historical account of the deepest sustained depth, i got an idea.

Generally speaking, a subs crush depth was 1.5 times its saftey depth. At least, 1.5 was the number the navy used by accounts. So for example:

250 test depth * 1.5 = 375
300 test depth * 1.5 = 450
350 test depth * 1.5 = 525

(these numbers look familiar to ya? They should )

So, id like to increase the crush depth to a theortical one, based on the premise that subs could go a bit deeper then what was typically recorded. But to increase this depth conservatively.

So, i have two ideas.

Idea A.)
Take the old crush depth, and multiply it by 10%.
375 * 0.1 = 37.5. + 375 = 412.5

Idea B.)
Take the saftey depth, and multiplly it by 1.6 instead of 1.5
250 * 1.6 = 400


Key to this idea, is modding the deep depth gauge on the orders bar to read in increments of up to 600 feet or so instead of 450 feet, which i think is quite possible as its been done before. Also i think using a test depth of 400 feet instead of 350 feet for the balao is probably more desirable.

Thoughts?

[donut]

I like idea (B)

[hyperion2206]

I just read page 479 of Clair's "Silent victory" and there it says:

"Another of Fife's replacements was Balao, a new boat commanded by Richard Henry Crane. Balao, built at Portsmouth, had a new superthick pressure hull. Her test depth was 400 feet, in extremis, she might survive at 800 feet."

So I guess in theory at least some boats could go way deeper then 600 feet.

[Fincuan]

An interesting story related to the subject: http://www.usschopper.com/Chopper%20...e%20Report.htm

[Ducimus]

If i cant get a depth gauge to work at 600 feet i might not bother. I think the value range of the depth gauge is F'ing hard coded. I can get one to work at 450 meters... which is 1470 feet, which is silly. You'd only use less then half of the total gauge.

The value of the depth gauge seems like its hardcoded, and then translated on a 1 to 1 basis. For example, the depth gauge is 450 feet. A few tweaks, and all of a sudden it sees it as 450 meters, but reads it off as feet. This value is defined somewhere, and i can't find it to change it. I think its hardcoded.

hope you find a way to make it work, it sounds like your numbers are right on target.

[beartooth91]

Based on my experience (USS Pintado SSN-672) and my WW2 Submarine book collection; I believe "collapse depth" to be the minimum depth at which you're in danger of losing the submarine. Its historically been specified to be 1.5 x Test Depth. On Pintado, "collapse depth" was listed as 1.5x test depth in the boat's manual.
Based on some of my books regarding WW2 fleet boats, I believe a true crush depth to be around 1.9x to 2x of the test depth.
The Silent Victory account of the Balao is data point #1.
There is another account, also in Silent Victory, of the USS Salmon losing depth control in the midst of a depth charge attack and dropping down to 500 ft before the crew regained control of the boat. She obviously survived, but, was leaking heavily during the ordeal.
In "Find 'Em, Chase 'Em, Sink 'Em" (a newer book about the USS Gudgeon - and the best researched WW2 submarine book I've ever read); the boat went too deep while evading an attack by a Q-ship on her 2nd war patrol in the East China Sea. The patrol report listed the max depth as 350 ft. Some of the crew members interviewed said the boat went as deep as 513 ft during this episode. Her skipper, Joe Grenfell, admitted - after the war - she reached 425 ft during this event. Whether it was 425 or 513, she was still seaworthy after the event with no flooding reported.
The account of the USS Chopper (a Balao or Tench) surviving 1011 ft is another data point.
During Tang's sea trials, O'Kane took her to 612 ft.
I need to find some data on some of the Gatos with regard to the deepest recorded - or admitted - dives.
Its pretty clear the 1.5x number is on the conservative side.
However, I know of no submarine intentionally exceeding the 1.5x number. Many of the skippers were afraid to even go near the 1.5x number. Fluckey's normal evade depth in Barb (a Gato), was 375 ft. I believe once, he may have taken her to 415 or 425 ft. My impressions are that he was afraid to push her much deeper than 375.