[PSUBS-MAILIST] onboard gear

Mon Apr 22 18:26:29 EDT 2019

Sorry you are right as I just found the email I had from him and it is as below.  Hugh

Most of the question you pose are answered (in theory) in the 2009 paper I sent, and they would advocate the use of air; even from that depth.

However, that work was done with mass escapees in mind where air is probably the only option. You may have others. For example, if you could flush your hood with oxygen-helium 16:84 that would completely circumvent the narcosis problem and 16% oxygen would still sustain consciousness at the surface. However, you might make DCS more likely or worse. Maybe a trimix with some helium to ameliorate narcosis would be better, but the oxygen fraction must NOT be less than 16% and I repeat that by using helium you may increase the possibility of severe DCS. No easy answers I’m afraid and for simplicity, you may be best sticking with air (and hope its never necessary).

Simon M

Associate Professor Simon J. Mitchell

MB ChB, PhD, DipDHM. DipOccMed, FUHM, FANZCA

Consultant Anaesthesiologist and Diving Physician

From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of Rick Patton via Personal_Submersibles
Sent: Tuesday, 23 April 2019 10:13 AM
To: Personal Submersibles General Discussion
Subject: Re: [PSUBS-MAILIST] onboard gear

I believe our body needs at least 16% ppo2 at any given depth before feeling drowsy and passing out?

Rick

On Mon, Apr 22, 2019 at 12:08 PM Hugh Fulton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

I started with two inch and a half valves but was concerned about the rate of pressurisation.  To half fill the sub it means you are only at 33 ft equivalent. The next stop at ¾ full is supposedly around 100 ft equivalent.  That is where it needs to slow down as the same flowrate would mean 300 ft of increase in only a few seconds..  So I have changed to two one inch valves for approx. 1.5 – 2.0 m3 of cabin space.  3” valve IMHO is too big. 

 I asked a bloke at the local university what mix it should be for 400 ft and I think he said about 12% O2 with helium to get out of the sub without narcosis but if you fill the Steinke with air then as it escapes and you breathe the mix in the hood it will deplete the mix in your lungs.  i.e. escape mix reg is only used to exit the sub.    The reason I chased that scenario is that evidently many sunken subs in the war had escape hatch open and the submariners lying outside around the hatch.  Deduction was that they were narc’d.  Chs Hugh 

From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of Alec Smyth via Personal_Submersibles
Sent: Tuesday, 23 April 2019 7:36 AM
To: Personal Submersibles General Discussion
Subject: Re: [PSUBS-MAILIST] onboard gear

Greg Cottrell once pointed out something that had been non-obvious to me in connection with bailouts from shallow-diving subs like ours - just how big the seacock needs to be to flood the sub quickly enough. Imagine you had a little ball valve of about the diameter of a garden hose. Now lets say you are hung up at 140 feet and need to bail. The ambient pressure is 60 psi, which happens to be the normal pressure for household plumbing. Therefore, your sub would take as long to fill up as it would if you opened the hatch while it was parked on your driveway and stuck the garden hose in. I'm not sure how long that is, and it will depend on the volume of your cabin, but surely it's way past the 10 minute no-decompression time for 140 feet. The bottom line is PSUB seacocks need to be very generously sized because we dive shallow. Shackleton's is 3". 

Best,

Alec  

On Mon, Apr 22, 2019 at 2:39 PM Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Shanee

Depending on the depth that you have to flood the sub and make a free accent to the surface, it really depends on how fast you need to equalize to try and get to the surface before exceeding the nitrogen uptake limits for getting bent on course. Only the air cavity's are affected in a rapid pressurization I believe but my sub has a rated working depth of 350' and as I remember from the old navy tables, you only have about 5 minutes at 165' before you have to make a stop at 10' so due to that fact, I would have to flood the sub as fast as I can to minimize the nitrogen uptake to make it to the surface before getting bent and the negatives to that are that most people can't clear their ears that fast so you are looking at possibly blowing your ear drums which in turn is really painful and screws up you equilibrium which is going to hamper your safe accent to the surface in a timely manner. I am going to have mixed gas in my bailouts to buy me time for getting to the surface and keeping the nitrogen uptake as minimal as possible.

Rick

On Mon, Apr 22, 2019 at 7:15 AM Shanee Stopnitzky via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Doesn't feel like it compared to Hank! Also, forgetting food, water, blankets and a first aid kit. Forgetting those has been my specialty for my whole life!

Steinke hoods are probably a good idea, although I'm terrified of them myself. Does anyone have any information on what pressure change effects happen physiologically during an emergency escape? I'm a diver so I'm very familiar with what happens when you descend and ascend on scuba, but I'm not sure what happens with a sudden and extreme pressure increase. Other than all your organs getting squished, of course. 

Thanks for your input everybody!

On Sun, Apr 21, 2019 at 6:58 PM Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Hi Shanee,

That's a pretty comprehensive list you have, and I couldn't fit all that. But how about a pair of Steinke hoods? Oh, and one very simple thing... a flashlight.

Best,

Alec

On Sun, Apr 21, 2019 at 4:35 PM Shanee Stopnitzky via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Hi all,

I'm wondering what everyone's onboard safety/repair kits contain, or what 'loose' gear you carry on dives with you. Ours are (so far): 

CG requirements

air horn

whistle

life jackets

fire extinguisher

safety

fire blanket

2x scuba masks

2x spare air

primary gas analyzer

backup gas analyzer

spare CO2 scrubber - battery powered

handheld radios

uw radio system

repair kit

gorilla tape

electrical tape

butyl tape

zip tie assortment

spare battery terminals

spare wire connectors

spare wire

splash zone

JB weld

steel tie wire

steel strap

e6000 glue 

hose clamp assortment

screwdriver set

adjustable wrench

multi-tool

hammer

scissors

What's in your kits?

Best,

Shanee

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Institute for Emergence//Community Submersibles Project

:::::

'The fact remains that political frontiers are impervious to our verbal cultures, while the substantially nonverbal civilization of playfulness crosses them with the happy freedom of the wind and the clouds.' ~ Primo Levi 

:::::

'Caught up in a mass of abstractions, our attention hypnotized by a host of human-made technologies that only reflect us back to ourselves, it is all too easy for us to forget our carnal inherence in a more-than-human matrix of sensations and sensibilities. Our bodies have formed themselves in delicate reciprocity with the manifold textures, sounds, and shapes of an animate earth. Our eyes have evolved in subtle interaction with other eyes, as our ears are attuned by their very structure to the howling of wolves and the honking of geese. To shut ourselves off from these other voices, to continue by our lifestyles to condemn these other sensibilities to the oblivion of extinction, is to rob our own senses of their integrity, and to rob our minds of their coherence. ' ~David Abrams

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