[PSUBS-MAILIST] Assistance needed, anyone please!

[Sean T. Stevenson via Personal_Submersibles]

Here is your hull using ASTM A516 Grade 70 steel, assuming that the 2 m dimension is the outer diameter of the sphere:

[image.png]

If I repeat the calculation, but use 2 m as the inside diameter (generally you design to ID, because that is typically how heads are manufactured), you get the following:

[image.png]

Hope that helps.

Sean

On Monday, November 3rd, 2025 at 23:42, via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

> Thank you Sean, It was so pleasing that several people unselfishly replied to my request.
>
> Thank you for the calc offer, no, the weight factor is for a completely different reason. If that is the weight then it is far too heavy I had considered 1/4” thickness sheet would be suitable, but did not know the framing required and safety margin requirements. To confirm this is for 100m (150psi) no opening no window, just the sphere! Again, thank you, Cheers Les 😉
>
>> From: Personal_Submersibles <personal_submersibles-bounces at psubs.org> On Behalf Of Sean T. Stevenson via Personal_Submersibles
>> Sent: Friday, 24 October 2025 2:10 AM
>> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
>> Subject: Re: [PSUBS-MAILIST] Assistance needed, anyone please!
>>
>> Les, I can happily run some test cases this weekend to figure the hull material weight of your proposed sphere, but if your concern is the ultimate handling / trailering weight, as a functional submersible that is going to be exactly the weight of an equivalent sphere of seawater, at ~ 1,025 kg/m^3. For your 2m sphere, that will be 4,293.5 kg or 9,465.5 lbs.
>>
>> Sean
>>
>> On Wednesday, October 22nd, 2025 at 19:00, 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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