[PSUBS-MAILIST] Assistance needed, anyone please!

[Jon Wallace via Personal_Submersibles]

You might be referring to the excel spreadsheet calculator which is available on the web site, no membership necessary.  You mentioned 150 meters or 160 psi, however 150 meters will put you at about 222 psi whereas 160 psi will put you at about 109 meters.

Using imperial units and A516g70 material, the spreadsheet is showing me that 1/4 inch thickness provides 175psi and 3/8 inch thickness provides 314 psi with a safety factor of about 1/3.  However keep in mind the calculator assumes perfect material, perfect sphere shape, perfect welding, and perfection for every other element of fabrication.  It's only a guide, not definitive.

Jon




On Wednesday, October 22, 2025 at 11:31:26 PM EDT, via Personal_Submersibles <personal_submersibles at psubs.org> wrote: 

After many years and many hospital holidays, 🙂 I am no longer a financial member.
However, I am hoping that someone may assist me in the spirit of  Psubs.
If memory serves, there was a calc formula on your site of which I no longer have access .
Any way, I have a project idea that to continue with, relies on the minimum weight achievable for the following ;
 
A 2 meter diameter sphere with appropriate bracing material and with safety margins 
To dive to sea-water safe depth of 150meter (160psi) No doors No windows 
Windows and doors will add much I know, however, are details to be considered later only if the basic weight indication makes the project viable.
So basically, I need to know the framing and sheeting steel sizes and thicknesses to calculate the overall weight in this basic form. If positive at such point I will apply for re- membership to follow through with my idea.
I know this sounds vague and I am asking much, but could someone assist me in this very basic task, which I know not how to do. 
Thanking any member who might be inclined to assist me. 
Cheers Les  
Safe diving 🙂
 
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