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

[MerlinSub@t-online.de]

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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