[PSUBS-MAILIST] Hull construction concept: pipes

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

Look at Stan Zimmerman's "Submarine Technology for the 21st Century."
He recalls, on page 84, how subs were called "sewer pipes."  That's
the lead-in to the torodoial hull: a hull made of HY 80 pipe bent
into a ring. 

The rings are welded together.  They can be used to contain ballast
or other fluids, of course.   In the first attempt at using it, an
Italian company built a 29-ton boat called "3GST9."  That first 
number is the diameter in inches of the pipe used to make the 
hull.  It's insured to 430 meters, but the builder thinks it could
go to 600 meters with no trouble.  No date was given, but from the
context it must have been built before 1990.  

Has anyone else heard of this?  The designer was G. G. Santi, who
worked for Maritalia S.p.A., Milan.  Maritalia is bankrupt, it
seems.

(I wondered if perhaps the idea might be adapted to create the
slab-sided hull of a sub from the American Civil War, with
more security than would be available if flat sheets of steel
were used.)

One question I have is about rust.  If the pipes aren't used to contain
something that would exclude water, would not the submarine be faced 
with a pressure hull that was rusting invisibly?






Mike