Re: [PSUBS-MAILIST] Test and questions

[MerlinSub@t-online.de (Carsten Standfuß)]

Gregc02@ibm.net schrieb:
> 
> >    A friend told me that U.S. Navy subs use carbon dioxide in
> > their ballast systems.  I am skeptical.  Is this true?  The only
> > reasons I could think of were maybe for quieting or
> > firefighting, and even then, wouldn't it be impractical and more
> > expensive to use than just the good old regular air?  This is a
> > question for you ex-bubbleheads out there.
> 
> As an ex bubblehead, the only systems I've ever seen (or heard of) in US Submarines are plain
> old air. On WWII fleet boats the high pressure air system was a nominal 3,000 psi, reduced to
> 225 psi for ship service air used for tools and blowing sanitary tanks and engine starting. Ballast
> tank blow was 3,000 psi air reduced through expansion to 600 psi nominal and introduced to the
> tanks by manual valves on the high pressure air manifold. There were six banks of high pressure
> air bottles outside the pressure hull in the ballast tanks.
> The nukes of my time (1960s) used much the same systems except that they used remote,
> electrically actuated valves.
> 
> >    Another one recently posed to me is how much air pressure you
> > need to have available to blow your ballast tanks.  I assumed it
> > was equal to or greater than the ambient pressure of the water
> > at the depth you are working at.  Yes?  No?
> 
> True, although the more blow pressure you have the faster you can get the water out of the
> tanks. Fleet boats used the high pressure air for initial blow (usually from periscope depth) and
> then when on the surface and with the main induction valve and/or the conning tower hatch open,
> start up the low pressure blower to finish up the blowing of water from the tanks without using up
> high pressure air. I believe that at least some of the WWII German boats used engine exhaust to
> finish the blow instead of a low pressure blower.

Yes ,thats right -I think they use the trick also today - and I will use
them also -
there is a report thats exhaust diesel gas prevents the ballast tanks
better from rust..

Some of the driver of the small midget of the Seehund class reported
that the drive
to snorckel deep and blow the tanks directly with the Diesel exhaust
without useing any air. 
And thats save much compressor run time. 

Another emergency trick is to blow the tanks with hydrazin emergency
(only) 
gas generators - if the compress air fails to run - there is in each of
the both 
main ballast tanks a hydrazin generator set in. The force of quick
bouancy is so heavy
that the sub will raise also to the surface (for a short time) with a
bad leak. 

But note: If you blow your 100 liter with 10 liters compress air at 100
meter deep - 
the sub surface quickly and the tank will be completly empty on the
surface without
any more blowing..

Im have here a fornular to quick calculate the vertical speed of the
submarine
during raising or sinking. Ask if you want a quick calculation, its
needs beam 
of the pressure hull, middle length of the sub (square area length) and
the over/under weight.   

Carsten
 
> 
> Hope this helps,
> 
> Greg Cotton
> 
> ex-USS Torsk (SS-423)