Re: PRESSURE HULLS

[VBra676539@aol.com]

In a message dated 5/5/99 8:52:48 AM, t-knapp@home.com writes:

<< I'm
interested in building a two person, dry, submersible, that can safely
dive to 300ft (give or take). >>

Tom--
	Congratulations!  Now that you have said it out loud EVERYBODY will 
know you're crazy!  Jon Shawl is playing a trick on you.  He thought you 
meant submarine SANDWICHES, and figured a 300-footer would make a nice profit 
for somebody.  Way to go Jon!

	Just in case you were really serious, I must tell you that I doubt 
you could do any better than contacting George Kitteredge 
(Kittredg@midcoast.com) for a set of plans to one of his submarines. All the 
information is there, and George will be an invaluable resource. He has 
already answered most of those pesky questions that have been driving you 
crazy, and will be there to answer the thousand or so more that pop up during 
construction. Otherwise, nothing to it. All you have to do is fab this, weld 
that, glue over here and paint this and those two things over there and then 
you go diving.  More or less.  Unless you are bound and determined to go the 
whole torturous way on your own, a K-350 is the way to go.  The hulls are 
incredibly tough and are easily built by small shop(s).  If you want to carry 
two people, order his 2-man.  If you want to do it different, order the 1-man 
and stretch the hull.  
	I would suggest that you talk some with the psubbers about the 
thinner material wall thickness in LP tanks--it looks like a sub hull, and 
has been used as one by members of this group with success--but may be a 
little light for your proposed application.  Most of the guys running thin 
walled boats are diving shallow in fresh water lakes and such, so don't put 
too heavy a structural demand on their hulls (although these things build up 
very quickly indeed as the pressure builds). Don't know where you plan to 
operate, but if there is any sort of water column in the area that lends 
itself to the deeper end of your plan, I'd opt for 1/4" material.
	Truth be told, I'd build the K-600 if I had it to do over again, just 
because it does more and doesn't really cost much more to fabricate. The boat 
I have in sketch form is for 1200 feet or so with a 42" OD hull and a 150 
degree arc segment full diameter main viewport. What fun!  Hull material: 
George recommends A516 Grade 70,  which is a good medium carbon steel and 
readily available.  Some of the Hyco boats (the shallower ones) and most of 
the Perry boats used this or A537 for the hulls. Don't be intimidated by the 
tank guy.  Sure, he's cautious. Can't blame him for that these days.  Just 
remind him that he will not be building a submarine, but rather a custom 
tailored tank with a bunch of holes in it.  And if he can build a plain old 
tank, he can damn sure roll 1/4" stuff and special order thicker elliptical 
heads with your material.
	Reinforcements?  Got some, you bet.  On my K the conning tower 
penetration is a ring of 1/2" material welded to a saddle of 1/2" material in 
turn welded into the hull.  The conn itself is 1/4" welded to the 1/2" ring.  
Internal t-bar ribs are welded on 12" centers.  Viewports are heavily framed, 
as you might expect.
	As an illustration of just how tough these little boats are, check 
this out. One of George's K-350s was chained down on deck of a ship that sank 
in the Sea of Japan in a typhoon.  The ship was 100' long and was salvaged 
after a couple of months from 900' of water.  The sub was intact.  No 
leakage, no failed seals, and no visible hull distortions!  The thing is 
built like an anvil!
Hope this helps your ruminations some.
Regards,
Vance