[PSUBS-MAILIST] New submarine

[Alan James]

I'm a bit confused Jon,
Scott was asking for the thickness for a crush depth of  5709 feet (2543 psi).
You are saying 2.5 for a maximum working pressure of 2578 psi. The working pressure
I thought was the design depth or maximum operating depth.
Alan


________________________________
 From: Jon Wallace <jonw at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
Sent: Thursday, April 10, 2014 1:16 PM
Subject: Re: [PSUBS-MAILIST] New submarine
 


Wow, big difference here...ABS calculator shows 2.5 inch thickness for 72inch sphere with maximum working pressure of 2578 psi utilizing the ABS/ASME recommended usage factor of .67 which takes into account material fatigue.

I don't think the UnderPressure program considers usage factor. 
      If you discount the usage factor then the ABS calculator comes up
      with 1.75 inch thickness with max working pressure of 2679 psi.  A
      thickness of 1.5 inches provides 2303 psi, below your 2543 psi
      requirement.

Jon


On 4/9/2014 6:53 PM, Alan James wrote:

Scott,
>I make 1.23" thick for a 72" ID sphere 516-70 to that depth, sea water. 
>That was on the "free" Under Pressure program. It should be somewhere in the ball park.
>Alan
>
>
>
>________________________________
> From: "swaters at waters-ks.com" <swaters at waters-ks.com>
>To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
>Sent: Thursday, April 10, 2014 10:29 AM
>Subject: Re: [PSUBS-MAILIST] New submarine
> 
>
>
> 
>Would anyone on psubs who knows how to use CAD run a pressure test on a simple 6' sphere with ASME 516 grade 70 steel, then again with HY-80? What are required wall thicknesses to meet crush depth of 5709 feet (2543 psi). If you have time maybe even a 48" cylinder with ribs. 
>On a lighter note, Alec and I have been talking about hard to find things that I can make for psub members with my plasma robot. I am going to attempt making a manipulator arm kit that will be inexpensive and very functionable for our subs. I'll post progress as it comes.
> 
>Thanks,
>Scott Waters
> 
>

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