Re: [PSUBS-MAILIST] elliptical heads

In a message dated 10/23/2009 5:03:42 P.M. Pacific Daylight Time, vbra676539@aol.com writes:

Frank,

When you were looking for hull bits, did you find a fabricator who could and would do non-standard elliptic heads? I'm fiddlig with the old Diving Saucer shape, which was 1.5 meters by 2 meters, give or take an inch, and was 3/4" thick. I like the space and payload available with that shape. A 2:1 head gives you, what, four feet in height? I don't remember the thickness of your hull. What does the shell weigh and what depth are you figuring for test and operating?

Vance

Hi Vance. I didn't ask anyone about non-standard 2:1 eliptical heads but I bet you can order them that way if you supply specific dimensions. The spinning machines they use can be programmed to make just about any curvature you want.

The standard heads I ordered are 26 inches deep and 3/8 inch thick nominal.

The thinnest part is 3/8 and some gets a little thicker nearer the edge. Almost 1/2 inch.

The shells weigh about 900 pounds I think, I'll have to go back and check.

The finished hull holds about 800 gallons I think. Again, I can get more accurate numbers if you need them.

With no ribs, the hull buckle depth looks like about 320 feet, and once I add the ribs it should go to a little over 900 feet, depending on rib design.

I'm going to do shallow dives without ribs to apply some pressure cycles to the hull before I add the ribs.

The current rib design is 8 pieces, 4 inch by 1/2 inch ribs, arranged like the ribs on a pumpkin. There are extra pieces near the windows and two more across the floor where the drop weight, sliding weight, and seats mount to.

I hope to get an operating maximum depth of 600 feet so the rib design is still being tweaked.

It really is quite roomy inside there. If I was designing with a bigger check book, I'd still go with the two dome shape, but would replace the windows with a big curved front window, say about 36 inch. That would be plenty with the way the seating is.

Frank D.