RE: [PSUBS-MAILIST] I survived an escape from a sunken Psub this weekend!

[MerlinSub@t-online.de]

Hi Hugh, on the Nemo100 they have had original a 1/2 inch vale and make test filling with that in 1m - 5m and 8 meter depth. 
It cames out that it takes 7,6 minutes in 1 meter, 17,3 minutes in 5 meter and 16,1 Minutes in 8 meter depth. 

We come to the conclusion that it is way to long. Exit must be possible in less than 10 minutes otherwise in cold water in the depth the crew cool down to fast. Faster ist better.

We install in all our 1-4 person subs now 2 Inch vales. On the test on the weekend we open on the first dives this ballvale only half way or less. Some dives later with more expierence we open it full and the exit time was very fast.

I think in general you are right. The flood rate should be first fast as possible and later with th last 25% cabin volume the rush of water into the boat has to be may to reduce. Maybe a diver depth gauge INSIDE the boat would be very helpful for the pilot to control the process.  

One intressting result on that test was that the secured domes comes untight with the air overpressure in the sub. 

I for example dive down during the test to the sunken sub. Attemp to rasie the sub. Dive in with a divers bottle and close both domes and lock them. Make the flood vale fully open and open the scuba bottle to empty the sub. The domes empty and about 10 % of the sub compartment but than the domes seal lift off just a little and the o-ring comes untight because of the overpresure in the cabin and I was not able to lift the boat. I have to flood and escape again. The conclusion on this was that it is nessesary that the dome locking device should be able to look against an internal over pressure of 0,2-0,3 of an atmosphere!

VBR Carsten


"Hugh Fulton" <hc.fulton@gmail.com> schrieb:
> Hi Carsten,  What a great experience, thanks for sharing.  The 2" valve is
> fine for shallow water escape but for deep water escape the rate of
> pressurization is too great for a normal person.  (Divers Eustachian tubes
> are much bigger than normal person's.) 
> 
> My study, which is only theoretical, says that for filling the sub to half
> full ( 2 bar abs) can be done with a 2 inch valve in less than 1 minute but
> to continue filling  to final escape volume means that the last
> pressurization would be the equivalent of diving from 20 meters to 120
> meters in less than 10 seconds.
> 
> If the last filling the Valve rate is reduced to less than that of a 1"
> valve the rate of pressurisation  is reduced to say 50 meters a minute.  I
> am interested in your comments on this as I have changed from having 2 x 2"
> valves to 2 x 1" valves.  Regards,  Hugh
> 
>  
> 
>  
> 
> From: owner-personal_submersibles@psubs.org
> [mailto:owner-personal_submersibles@psubs.org] On Behalf Of
> MerlinSub@t-online.de
> Sent: Monday, 5 September 2011 8:13 a.m.
> To: personal_submersibles@psubs.org
> Subject: Re: [PSUBS-MAILIST] I survived an escape from a sunken Psub this
> weekend!
> 
>  
> 
> Hi Alan, 
> 
> you can not open a dome hatch even in relative shallow water without
> equliaze the pressure. 
> The water pressure on the dome will prevent this. 
> 
> The boat was flooded. But because of the shallow water just with a relative
> small amount of water. 
> 
> The first test we make we flooded the boat complete with the 2 inch flooded
> vale open to let the water in and the 3/4 inch overpressure vale open to let
> the water out. Only in the domes was air. The escape was relative soft
> because it was not so much air anymore in the boat. But it takes 8-9 minutes
> to flood the complete boat. And teh crew is relative dived in the sub. 
> 
> Than we figure out that you have allways to unlook the dome hatch before you
> try to flooded the boat. The simple reason is that you can not open the dome
> latches with the boat allready flooded for to reasons: First you have 30
> Liters air in the dome create a lot of lift. And if you flood the boat you
> have a overpressure in the sub (distance of the compressed air  from the
> inside water level to the hatch seal) which create also a hell of lift to
> the dome latches - about a quader of a ton..
> At the end you can not open the dome. 
> 
> Rule : ALLWAYS unlock the dome you want to exit before you flood the sub.. 
> 
> If you do that way the dome open automaticly if the pressure on the o-ring
> is equilazied by the pressure and the 
> lift force op the dome itself. In our case it was just seconds after you
> open the vale. For this reason we bild out the dome springs to get less
> opening force and more time. The normal time than was 1-2 minutes from
> opening flood vale a both crew get out. 
> 
> We make a lot of test: But allways sunk the sub to the ground, than unlook
> the dome, than flood. 
> 
> One dome unlook, one looked, water rush in an air out on the unlooked dome.
> Pilot goes out there. 
> After this the second mate open his dome with not so much lift (only the
> lift of the air in the dome). 
> 
> One dome unlook, one looked, water rush in an air out on the unlooked dome.
> Pilot goes out there. 
> Second mate dive under and leave the sub via the open pilot hatch.  
> 
> Both dome unlooked, both open simoutanisly both leave the sub via there own
> domes, one first the other after sonme seconds. 
> 
> My conclusion is that on a double dome sub it is the best that only the
> pilot dome is unlooked. Than flood the sub. Pilot dome opens and the pilots
> get all the heavy shower, air rush out, violent sound and out of vissiblity
> effect and than he goes out and wait. The guest stays in his dome -bubble
> until eyerthuing is silence after some seconds. Than he follow by the open
> dome of the pilot or the pilot open his dome from outside to help him to
> escape.
> 
> We escape without any gear, with diver mask only, with diver mask and diver
> bouancy aid, with scuba gear and with Steinke hoods. We learn a lot of which
> unit is the best for what purpose.
> 
> 01) For a Psub the best unit ios a diver mask with a old fashion divers
> bouancy aid. the tyo with a breathing hose and a small spare air bottle. 
> 
> 02) The Steinke hood works only during a acent to the surface. If you seat a
> minutes in a sunken, flooded submarine and without a bypass air line to the
> hood - you can not breaze anymore. We feel than 01) is the better solution.
> The Steinke hood is may the better solution on really long escapes. 
> 
> 03) The concluion for large submarines like Euronaut is than we will rebuild
> or dry diversuits. In that way that we install a breathing hose to the
> suits. In that way we can breath out of the suits during the way on the
> surface. And need no dive gear at all. We conect the inflator hose to the
> ships emergency breahting hose line systzen short before we leave the sub. 
> 
> We learn a lot more from the exercise but anyhow this letter is allready
> long. 
> 
> vbr Carsten 
> 
> 
> "Alan James" <alanjames@xtra.co.nz> schrieb:
> > Can you explain what was happening Carsten?
> > It looks like you didn't flood the sub at all prior to opening the hatch.
> > I guess that because you were so shallow there was no pressure on the
> hatch & it
> > could be opened easily.
> > Can you please do it again at 100 ft
> > Regards Alan
> > 
> > ----- Original Message ----- 
> > From: <MerlinSub@t-online.de>
> > To: <personal_submersibles@psubs.org>
> > Sent: Monday, September 05, 2011 6:49 AM
> > Subject: [PSUBS-MAILIST] I survived an escape from a sunken Psub this
> weekend!
> > 
> > 
> > Hi submadmans, some of us a little more crazy than others,
> > or more serious - depents may on the view of the observer. 
> > 
> > http://www.youtube.com/user/CarstenStandfuss#p/a/u/2/jsBCnWZCj7E
> > 
> > http://www.youtube.com/user/CarstenStandfuss#p/a/u/1/mKe76HRVPSQ
> > 
> > http://www.youtube.com/user/CarstenStandfuss#p/a/u/0/gtQ3HNuxcGA
> > 
> > We learn a lot on this weekend. 
> > And the is now some serious experience we can share. 
> > 
> > vbr Carsten
> > 
> > 
> > 
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