Re: [PSUBS-MAILIST] Ambient running on nitrox

Subject: Re: [PSUBS-MAILIST] Ambient running on nitrox

From: simon blackburn <siblack10000@googlemail.com>

Date: Tue, 11 Aug 2009 12:36:34 +0100

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Reply-to: personal_submersibles@psubs.org

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Hi Alan

From the sound of things I take it you are already Nitrox certified for scuba. How are you proposing to deal with CO2 build up as you sound like you're looking at long submersion. How much of your space needs setting aside for scrubber system? Just my first thoughts

Regards Simon

On 8/11/09, Alan James <alanjames@xtra.co.nz> wrote:

Hi psub experts,

What do you guys think of the idea of running an ambient subs life support on nitrox?

I'm building a very small fiberglass sub, almost canoe like. Eventually I want to build it 1 atm but

thought it would be smart to try the design out as an ambient first.

There might be close to 200 liters of air space in the hull. I have 2 x 80cubic ft tanks. If I filled them with

40% O2 it would take 2hrs 40min for the air to get down to 21% O2. This is in the worst case scenario of traveling just

under the surface. At 33ft I'd have 5hrs 20min etc. I could open a valve & flush the system any time & in the normal

course of a dive this would happen as the air expanded on ascent & filled on descent.

There is a dive limit of round 90ft with nitrox but longer no decompression times. However I guess I would need

to stay inside this depth limit & keep to the air decompression tables to stay safe.

On the plus side, I won't have to get anything 02 cleaned, & its pretty simple.

Alan

References:

[PSUBS-MAILIST] Ambient running on nitrox
- From: "Alan James" <alanjames@xtra.co.nz>