[PSUBS-MAILIST] Re: Hull construction concept: pipes

["Michael B. Holt" <mholt@richmond.edu>]

MerlinSub@t-online.de wrote:
> 
> Hi Mike -
> 
> "GST" stands for "gaseous oxygen stored in the toroidal pressure hull"
> and is also the explantion for this hull design. I have here
> the main data of the project from 1988 the
> gst Midget 100MK1 LWT 27-4 :
> 
> Length overall          27,10 m
> Outside diameter         3,14 m
> Standard Displacement   100 ts
> Submerged displ.        136 ts
> Underwater speed max    18 kn
> Underwater sp.transit    8 kn
> Underwater range        1600 nautical miles
> Crew space              12 + 4

What does "12 + 4" mean?

> Underwater endurance    14 Days

They stay submerged for 14 days?

> Operation deep  >       200 m
> Armament                4 LW Torpedos
> 
> The sub has an two Anerobic diesel engine generators
> and a electric main drive.

Was this built?  Zimmerman's book indicated that a full sized
boat -- the one you describe -- was never built.
 
> I think about this kind of hull :
> 
> 1.) Most problem on this design (for a psuber) is the
> amazing quantity of welding each 3 inch of the hull length
> - a full both side turn around welding in this example.

That was the first problem I could see. 
 
> 2.) Its nice because you can create any kind of (full axis symetrical)
> hull shape with just a pipeprofil-roller machine and a full
> automatic cylinder welder. Rocket style, teardrop style,
> coca-cola bottle style etc.. all the same process..

Who has a machine to bend pipe?  I can get small ones to
bend conduit for electrical stuff, but to bend anything
stronger and larger ... I need a bigger machine.

> 3.) Any kind of hull penetration is more difficult than
> in normal hull design.

I wondered about that.  It seemed to me that it might be a 
good idea to place all the penetrators at one end.  Of
course, that has drawbacks.
 
> 4.) Could be very intresting for a deep diving sandwich
> GRP design..  .. you have not to weld..

Please explain.

I may have been thinking about something similar.  Start
with the pipes, but do not weld them: encase them in
GRP.

> 5.) Maybe better : a pipe ring - than a short cylinder
> make from flat steel profil - than pipe ring etc.

Isn't that using the rings as stiffeners?

> Double hull subs has always problem with rust.. so I have
> no tanks, rooms or even pipes in Sgt.Peppers or in CSSX
> which I can not go in or inspect by hatches.
> In CSSX I can go into the soft tanks and also into the
> Regulator tanks.

Good idea.  I suppose this idea might be lost during 
construction.
 



Mike