ALVIN submersible construction - Is it even possible for the regular guy?

[kowalski]

I see in the news that the navy is investing 21 million dollars in a new Alvin deep sea submersible. I actually like the original one.
I wonder how hard it would be for a hobbyist to build his own 1/1 scale Alvin. Considering how much of the equipment was made in the 60s you'd think all that would be a lot cheaper now. So I did some daydreaming...
Still, that same pressure sphere in the Alvin would cost $600,000 to fabricate in titanium, and only a fraction of that if in steel. I think it was like under $10,000 in steel. Let's see...
The external diameter of the pressure sphere is 82 inches
Internal diameter is 78 inches, so it's a 4" thick thing.
The volume of the sphere is 40221 cubic inches (rounded up from 40220.76354636157).
Titanium density]http://www.subcommittee.com/forum/icon_razz.gif[/img]

K.

[Guest]

I didn't check all your

I didn't check all your calculations, but it appears that the walls would be 2" thick, not 4" thick, according to your diameter measurements. That would change most of your conclusions, if I am correct. Just trying to be helpful.

[bob the builder]

Yup, Art's right. A differential

Yup, Art's right. A differential in diameter of 4" will yield up a wall thickness of 2", not 4".

If you're dead set on trying to find out the feasibility of this project, be sure to visit www.psubs.org. The people there specialize in building their own personal submersibles. There are tons of 150'+ sub projects documented there, and there are a few deep divers as well.

Well worth the visit, even if just for your own enjoyment.


Bob

[kowalski]

That oughta teach me to

That oughta teach me to "daydream" at 3AM
Thanks for the posts, guys! I'll check out that post.
Still, I'm just paranoid enough that if 2" is safe, 4" is even safer!

"Special K"

[tsenecal]

if i remember correctly, from

if i remember correctly, from the book "WaterBaby", the original steel sphere was 3" thick in the main, and thickened to 5" around the portholes and the hatch. for purposes of being capable of handling the pressure exerted on it (8000 feet), the walls had to be milled to an accuracy of +- 3 thousands of an inch....

if i am also remembering correctly, the titanium sphere is also 3" thick, allowing the sub to achieve its greater (current) diving depth of 14,500 feet.

last but not least, and this is all third party hearsay on my part, I recall a press release stating that there are only 2 or 3 manufacturers in the world that would be capable of making a titanium sphere of the required size, and with the required tolerances for the new Alvin...

[kowalski]

I started this site for

I started this site for fun]http://www.arislan.net/~kowalski/index.html[/url]
It talks about building an Alvin in the garage, and it's probably going to generate some interesting e-mails in the long run.