Re: Wet Navy in the future was Re: Questions regarding NAC ground units, was SG IF morale

Roger Burton West wrote:

> On Sat, Dec 01, 2001 at 08:28:14AM -0800, John Atkinson wrote:
> >As a side note, what's the difference between a
> >starship and a submarine?  Both have to be
> >water/vacuum proof--what's to stop a streamlined ship
> >from splashing into an ocean and hiding on the bottom
> >of the sea for a while, then flying out to launch
> >hit-and-run strikes on the enemy?
>
> The spaceship needs to resist up to one atmosphere of negative
pressure
> (1 atm inside, vacuum outside), and should rarely if ever encounter
> positive pressure. A submarine doesn't need to resist negative
pressure,
> but does need to resist 40+ atmospheres of positive pressure (450m is
> the official maximum depth for the Los Angeles class, which is over 44
> atmospheres above surface pressure). While a streamlined ship may well
> be capable of shallow-water lurking, I suspect that the internal
bracing
> is entirely different. (There'll be more overlap than I've mentioned
> here, since one of the effects of a nearby warhead explosion is
> overpressure, but the basic design goals are distinct.)

To deal with the overpressure of an explosion, the starship must resist
a
short pressure spike, and it can get away with damped, elastic
deformation,
or sacrificial plastic deformations for really big blasts (ship
collapses in
on itself, sacrificing some hull volume to preserve overall integrity).
Niether of these methods is useful for the high static pressure on a
submarine.[useless trivia: the pressure vessel of TMI was designed for a