Re: [PSUBS-MAILIST] Hatch design

["Dale" <heinzind@cadvision.com>]

-----Original Message-----
From: VBra676539@aol.com <VBra676539@aol.com>
To: personal_submersibles@psubs.org <personal_submersibles@psubs.org>
Date: Tuesday, July 18, 2000 1:14 PM
Subject: Re: [PSUBS-MAILIST] Hatch design


>Herman,
>
>The dome hatch on Captain Kittredge's K-250 design is rated for an
operating depth of 250 feet. It is plexiglas, which has much healthier
characteristics under pressure than lexan, and cost, the last I heard, about
$800 US. They can be ordered from a fabricator in Maryland, recommended by
the designer.
>
>One of the early K-250s was tested in a tank to destruction. Captain
Kittredge had calculated that the dome would be the first thing to go, and
it was. At 800-plus feet!!! Still, to be conservative, he has limited the
designed operating depth to 250 feet. If you want to go deeper, you will
need to redesign with thicker material (the K250 is made from one inch
material) or go Kittredge's K-350 design route, which gives you an all steel
conning tower with four viewports in the cylinder and one in the hatch. The
K-350 tests to 500 feet unmanned to verify strength and operability. I am
not sure what is called for to test the K-250.
>
>The dome builder could probably fabricate whatever you wanted, and if you
had someone on tap to redesign the retaining ring structure you could
probably go deeper with a heavy duty version on the K-250.
>
>Diving to 100 meters off Malta sounds very good indeed, although you might
think the same of my backyard on the Treasure Coast of Florida, or the Keys,
2 hours away. Or how about a psub rodeo in Hawaii? We've got a connection
out there. I wonder what the airlines would say about our excess luggage? I
can see it now. "Say, young feller, how much does that big box weigh?"
Psubber replies (sheepishly): "....er....2 tons, sir. Is that over the carry
on limit?"
>
>Best Regards,
>Vance Bradley
>

I bought the acrylic dome , and it was $800.00 US. ( you remembered
exactally Vance!!!)   The one I have is made from 1.25 inch thick material,
the plans call for 1 inch material...  as for testing the sub, George
recomended that I drop the K250 down to 500 feet, for 1 hr, ( unmanned) and
he said when I pull it up, to use it confidently to 250 feet..I also just
purchased the flat 16" viewport, and it was $275.00 US.  The one I got is
2.5 inches thick, instead of the 2inch one called for.  Interesting note
here is that the dome failed within 2% of where George figured it would..he
has done his homework on his subs..!!  The name and phone number of the
supplier is on the archives , if you are interested,and cannot find it,  I
still have it (somewhere), and can give them again.  He can make up just
about anything you want.  We have discussed domes as big as 36 inches.  As
for the retaining ring, I had mine machined out of a solid 2" thick piece of
material, both for stregnth, and because I could not get the other ones to
not warp when welding.. I have not inquired what the failure depth would be
on the ring, but if it is like everything else on this sub, it will be very
overbilt.


   dale..
by the way, does any one have an idea for an extendable toung on a trailer??

dale.