Re: [PSUBS-MAILIST] Re: Fabricating "T" Bars

[Carsten Standfuss <Merlinsub@t-online.de>]

> PSUBS schrieb:
> 
> Anyone care to comment further on "I" beam vs "T" bar for the internal
> rings?
> 
> 1) Why does a "T" bar have to be welded to the hull, but not an "I"
> beam?

A T-beam need the hull as upper chord or he will went to the side under
pressure. A I-beam comes with his own upper chord and needs not the hull
to stay stable in both directions. For the reason that that the T-beam
needs the hull - it needs a full weld all over the material. 
 
> 2) When I think of "I" beams I tend to think of big bridge
> structures.  How does the price of a
> rolled "I" beam compare to rolling a "T" bar?  What is the
> availability of small "I" beams in the
> US that can be used for internal rings in a psub?

For a small 1-2 person sub a I-Bema is maybe overshoot. Here the welds
are in both cases the same small welds. For the reason that a T-beam is
not so easy to roll on a standard plate roll machine over the "hard end"
(eceppt you have a profile rolling machine) I think on a sub with a
diameter of less than 1 meter (3 feet) I would use U-Profiles. 

You can use this U-beams in two ways : As U-beam with the open end
connect by step welds to the hull - or cut the U-beam after the rolling
process longitudinal to two L-beams - and you have two L-beams with one
rolling process.. 

With the full U-Beam connect full weld around both sides to the hull you
create a nice small tank for gas or fluid.  Such a closed frame is
easier to paint. If full closed inside the U-beam/shell the oxygen wil
be gone after some time to rust - and than the corossion inside stops
complete. 

best regards Carsten

> Jon
>




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