" U " Bootes !

You are Right !

 Now couple that with even smaller pipes for the ballast tanks and you would be good to go . On one I did for a friend of my Dad's ( He wanted only the control room) .( in the main hull )  I used a two and one - half inch pipe  .I used the next size down to create the ribs and frames .Worked perfectly ! Good Thinking !   T.B.

Once my headaches faded 9and getting over could be unter the Plowman, Böotes, other than Virgo), an answer for pipe clutter occurred to me.

Those inenner pressure hulls from that era are of round section, typically.  This could allow a body with an inclination to economy to seek out some PVC or ABS pipe of the right diameter for the pressure hull.  The circular section would make for simpler bulkheads, too.  If a body were supremely luck, the next size smaller pipe would make a form for building between-bulkhead ribs eas(ier), especially with pipe, duct, & conduits fished through.

Aw C'mon ;

  I know Spreken ze englich .Okay ,I'll do that ! He. He.

Yeah, CapnMac82;

I know my German sucks ! that's alright though I do have fun . You are right about the clutter and piping in a Sub . If you don't make it look " Busy " it won't look right .     T.B.

oh ye!

Was fuer katzenjammer!

aber habt Ihr spass damit.

Ach du Lieber, iIhre schreckliche Deutsch mein Kopf schmerzte aufmachen.

But, it sounds like a cool build.  Tough part may be in controlling how much pipe & plumbing "clutter" you include.