Re: Air Use Calculations

["Scott L" <diver@chilli.net.au>]

This is ridiculous. Do people actually do this? I mean dive with no gas
recirculating system? It is the equivilent to walking around breathing off
a paper bag. 

The CO2 will give you a headache before you pass out but the low o2 will
just put you quietly to sleep. A very soft and silly way to die.

Scott

----------
> From: Carsten Standfuß <MerlinSub@t-online.de>
> To: personal_submersibles@psubs.org
> Subject: Re: Air Use Calculations
> Date: Saturday, October 30, 1999 8:02 PM
> 
> Hi Chris, 
> 
> I use this way in Sgt.Peppers during test work in my garage. 
> My girlfriend was outside with a clock and I shut the hutch. 
> After 40 Minutes the headedges started because of the CO2 level which 
> gives earlier a problem (and is a good indicator) than loss of O2. 
> 
> The internal displacement of the cabin is 480 liter minus 80 liters
> of my body = 400 Liter, so you can say 400/40 = 
> estimate 10 Liter free volume of the cabin is 1 minutes livetime. 
> I use this sometimes for short test dives to save the 02 and the
> absorber of the rebrather system - but never longer than 20 Minutes
> and ever with the rebrather ready as second security system. 
> 
> One problem is to clean the cabin after using this way. My cabin is so 
> small that I go in / go out 3 times a the displacment of my body remove
> parts of the dirty air. But a bigger ventilator with a mobile pipe
> to the hutch will be work better (I think). 
> 
> If you have no rebreather system in your boat and your boat catch a net
> on the bottom you need a very big flooding vale to flood your boat
> and get quick way out. 
> 
> Its a cheap way to dive with the internal air - but you need a 
> rebreather system to give you the time to make some repairs underwater,
> or to leave the boat, or give your friends the time to look for a crane,
> lifting ballone, your boat..
> 
> The both people which died in the two person sub Tigerhai in the 60ies
> died because of the C02 level after some hours on the bottom in the
> damaged boat. The died a very hard way - the police found
> destroyed/damaged finger nails on the dead bodys and scratches all over
> inside the sub, the shoes of the unlucky persons also damaged ...
> 
> The normal security time for a certified sub is 72 hour. 
> 
> Be happy, Carsten 
> 
> 
> Chris Nugent schrieb:
> > 
> >      Hey all,
> > 
> >      There having been a lot of discussion about
> > rebreathers and other various environmental systems
> > lately, I came up with a question.
> >      The design of my sub being as economical and
> > simple as possible, I have only allowed for a
> > submerged endurance of say one or two hours.  Mostly
> > the idea is to avoid building a scrubber and just use
> > cabin air.  As long as I have a good monitoring system
> > in place, I plan to come up every hour or so and just
> > ventilate the cabin w/fresh air.  Opinions on this?
> >      So my question is, does anyone know where to find
> > how to calculate volume of breathable air used by the
> > human body per minute?  Can one extrapolate an
> > estimate of submerged endurance  based on the volume
> > of air in the cabin versus volume of air used by the
> > human body?  Let me know what you guys think.
> > 
> >                                   Thanks,
> > 
> >                                     Chris
> > 
> >  P.S.  Thanks to all who sounded off on the "Tour of
> > The Boat"  thing....nice to meet ya
> > 
> > =====
> > "Noisy outside, empty inside." - Confucius
> > __________________________________________________
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