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Re: [PSUBS-MAILIST] Request for pressure factors difference GL/ABS



Oh - thats a good question - and a simple answer - 

For example in a submarine designed 

for 	Pn 		= 30 ft 
with 	Pz = 3,2 x 30 	= 96 ft

with a sinking rate ("Houston - we have a problem") 
of - for example - 33 ft/minute the crew (or Houston..)
has just (96-30)/33 = 2 minutes (searching for the drop weight key) 
to make the right reaction from Pn to Pz before the sub collapse. 

A simillar sister ship with a stronger hull 
designed 

for  Pn			= 300 ft
with Pz = 2,4 x 300	= 720 ft

and with the same sinking rate of 33 ft a minutes
the crew has (720-300)/33 = 12,7 minutes.  

for Pn = 		= 3000 ft
with Pz = 1,73 x 3000 	= 5190 ft

it figures out : (5190-3000)/33 = 66 Minutes 
(building a new drop weight key..) reaction time !!

One reason I don't like subs designed for 5 feet 
waterdeep.. 5 x 3,2 = 16 feet destroy deep.
with (16-5)/33 = 0,33 minutes = 20 seconds..  

Conclusion I : The relative saftey factor is smaller within greater 
deeps - but the absolut saftey distance is greater.. 

Another think : Most subs are designed to work near the bottom. 
For a 10 ft sub near the bottom it is easy to find a deeper bottom 
area of say 30 ft deep. For a 3000 ft sub near the bottom it is really 
difficult to find a 5000 ft deep hole.. 

Conclusion II: The bottom is a really good dive stop automatic.. 

see you Carsten

Lew Clayman schrieb:
> 
> --- Carsten Standfuß <MerlinSub@t-online.de> wrote:
> > I have here a table witch gives the factors you have to calculate
> > the pressure hull according to GL (Germanischer Lloyd) classification.
> 
> Please help me understand.  The "test" and "destroy" pressure seems to decrease as the depth
> increases.  Why?
> 
> <snip>
> > Pn            Pp/Pn           Pz/Pn
> > Workdive      Test            Destroy
> > pressure      pressure        pressure
> > (bar)                  S1             S2
> >
> > 05  (164 ft)  1,70            3,20
> > 10  (328 ft)  1,40            2,40
> <snip>
> > 50  (1640ft)  1,20            1,76
> > >60 (1968ft)  1,20            1,73
> 
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