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[PSUBS-MAILIST] Buoyancy Options During Escape





If one is not using a Steike hood for buoyancy, one thing comes to mind, perhaps syntactic foam inserts for a vest might be a option. The other option I was asking a SCUBA instructor about, was the use of the carbon fiber or Kevlar high pressure tanks that firemen some times use, and are used for a variety of other applications that require very high pressures in a light tank. This tank could be the one you leave the sub with, and hang onto for dear life.  The other use I had for them is to mount them under my stern deck, which will give me some more interior room, and not be heavy higher up on the sub.

Do you guys think those ideas will sink or float?  ;}
   

I think that's a bit Letterman does.


Szybowski





From: alanjames@xtra.co.nz
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] escape from sub
Date: Wed, 5 Aug 2009 15:56:19 +1200

Thanks Jay,
I'll save my wine bag for rock fishing & have a look for a suitable snorkeling vest with an over expantion valve.
Alan
----- Original Message -----
Sent: Wednesday, August 05, 2009 2:13 PM
Subject: RE: [PSUBS-MAILIST] escape from sub

The Brits used buoyant thermal suits and you will need some controlled buoyancy to get up to the surface during an emergency ascent.  Being slightly negative and with lots of drag added from clothing it will probably be impossible to get to the surface without added buoyancy….you are going nowhere (and sometimes even sinking) without buoyancy.  You want to make this as simple as you can.  You are going to find trying to deal with a plastic bag impossible in the most stressful emergency situation you will ever deal with.  You want to get to the surface as fast as you can…submariners practicing escapes shoot out of the water up to their knees.  You will flare your body out on the ascent by outstretching your arms and bending your head back, this opens your airway and allows you to HO-HO-HO.

 

Keep the solution simple using as little equipment possible otherwise you are task overloaded and will screw up.  You are correct in noting that if you feel the pressure in your lungs, it is probably too late.  You will have a pneumothorax which can lead to an embolism.

Respectfully,

Jay

 

From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Alan James
Sent: Tuesday, August 04, 2009 9:23 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] escape from sub

 

Thanks for the comments guys,

No Frank, I don't buy the stuff in cartons. ( Note that the email was addressed to the psub wine-os)

 At 300ft an average full lung volume of 6 liters will expand to 60 liters by the time you hit the surface but only to 8.5

at the 200ft mark & then by another 6.5 liters to the 100ft mark. Maybe if you ho-ho-hoed too much in the first 200ft

you could run yourself low on air. If you were concerned about this & held back you risk an embolism,  they say that

when you can feel your lungs expanding too much its too late.

If you had a small air supply to rely on as back up it may encourage more exhailing & make the trip safer.

With regard to floatation; Most people are pretty well neutrally bouyant, some are negative. If you were comming up

from 300ft totally frozen & without bouyancy or fins wouldn't it require the same effort as to swim horizontally underwater

for that distance fully clothed? Did the "Brits" mentioned have floatation? If 3 liters was an overkill & took you up too fast,

maybe 1 liter would have some benefit. With a plasticbag & the valve open you could always squeeze air out or let it go.

It wouldn't be any more complex than operating a BCD.

When you hit the surface you'd have floatation. Nice if you came up successfully from 300ft & there was no boat about

& you drowned.

Am a scuba diver of 20+ years but have never done an emergency accent from any great depth so I'm only hypothesising.

Thanks Dean thats encouraging will have a go.

Regards Alan