[PSUBS-MAILIST] publicity

Fri Jun 19 09:37:27 EDT 2020

 Rick, your reference to 600 feet is the first I've heard of a standard test depth for the 350.  Deep water is difficult to find in lakes within the continental US with only 15 of them being 600 feet or deeper.  Kittredge lived on the coast and had direct access to deep water, plus being a manufacturer and having a need to promote his products as safe vessels would have wanted to test near the limits of the vessel.
Let me see if I can clarify the numbers.
525 feet is 1.5x the nominal max operating depth of 350 feet.  I believe most certifying agencies want 1.4 or 1.5 safety margins...I could be wrong about that, but it's what I think they want.
576 feet is the maximum "theoretical" operating depth of the K350 based upon nominal usage factors as defined within ASME/ABS design calculations.  This represents a 1.64 safety margin.
Both those numbers are close to 600 feet which is likely why Kittredge tested to that depth, or close to it.  
As a side reference, the K600 was tested to 380 psi or 842 feet of seawater, and certified by ABS, which is a 1.42 safety factor.

Jon

    On Friday, June 19, 2020, 12:35:19 AM EDT, Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

 Thanks Jon, that's what I thought you were referring too  but just wanted to clarify it as you had said 525 feet and I could have sworn that the captain had said to test it unmanned at 600 feet for one hour so I am confused as that's more than the ABS calcs of 1.5? Dan Hycroft built a 350 and tested his to 550' as that's the deepest hole he could find in the lake he tested in. James, you just built one, what did you test your's at?
Rick
On Thu, Jun 18, 2020 at 6:18 PM Jon Wallace via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

  Theoretical crush depth. 

  On 6/18/2020 7:20 PM, Rick Patton via Personal_Submersibles wrote:

 Jon, Are you talking about test or crush depth on the 350?  Rick  
  On Thu, Jun 18, 2020 at 2:50 AM Jon Wallace via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

  I ran the numbers again in the calculator and got the same numbers.  If I change the usage factor to 1.0 then I get 884 feet.  I suppose when trying to ascertain a theoretical crush depth a usage factor of 1.0 would be acceptable in the calculator.  It's been my understanding that ABS, Lloyds, etc, look for a safety factor of about 1.5 which would put the 350 at 525 feet.  That may explain the 600 foot test depth you mentioned, but even so, my opinion is that's overkill. 
  Jon

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