[PSUBS-MAILIST] concept query

["Dan J. Rice" <dan.j.rice@sherwin.com>]

- a hull within a hull within a hull, etc., each one being pressure tight and
each interhull space being pressure controlled thus acheiving a step down series
of pressure differences.  As the sub descends hull interspaces are pressurized
so that the difference between the inside and outside of each hull is a fraction
of the total pressure difference from the sub interior to the sub exterior.
Hatches and ports would of course have to withstand the total pressure and
bridge all the other spaces. The interhull spaces should be as small as possible
to minimize the amount of equipment needed to control the various pressures.

Possible advantages:

- Less structural bracing - more room inside.

- Using a non corrosive gas to pressurize the spaces, no oxygen, no rust.

- insulation by dead air space, stay nice and warm.

- greater depth possibilities.

Disadvantages;

- greater cost,

- not as practical for smaller subs, weight vs displacement.

- more difficult construction and maintenance.

your thoughts?
Dan