Rebreathing the wing???

[Mark Chase]

First many thanks to Andy (Wet lettuce) for getting me a look at the DIR3 vid it was very interesting. Mind you GI3 should be kept well away from my regs after the abuse he gave those sets he was playing with. I actually winced as the reg hit the concrete for the third or fourth time.

OK a couple of issues on the use of the flat wing, which got me sitting up and listening.

1: What’s all this about re breathing the wing?? Is it really possible to extend gas time if trapped by re-breathing every breath 4 times through the wing? I thought that was a guaranteed CO2 hit but it sounds an interesting concept.

Does it only work on high He mixes?

2: The bit about the gas in the wing equalising pressure with the water at all depths allowing you to dump fully. How does this work? Surely if that were the case you have to fin down at the beginning of the dive.

Obviously you will have to have seen it to understand the second bit but I assume all the dir boys have.

ATB

Mark Chase

[And]

<font color='#000080'>Hi Mark

1. Don't recall that bit but it makes sense I guess. It would have to be an absolute last resort! If you think about it with backgas in the wing then the ppO2 would be around 1 ish as per DIR standard gasses. As you only use 4% of the O2 in a breath then I guess you could rebreath it for a limited time. I thought the main advice was NOT to rebreath the wing, but if you are trapped and that is the last resort then anything goes I suppose! It would only work for those 4 breaths though as you wouldn't want to dump all gas out of the wing and fill it again if you were so low on supplies.

2. Never understood this myself but it does seem to work but only when using the bottom dump on my 40lb wing and my 36lb wing. With twin twelves the 55lb wing wraps around the tanks too much. I can just pull the dump whenever I want and it seems to only dump enough to stay neutral. Needless to say it only seems to work when horizontal. Probably because the dump isn't the highest part of the wing and so only the expanded gas escapes. If you were overweighted or vertical I don't think this would apply. Bungies would force the gas out.

Kindest Regards

Andy

[Tibbs]

Quick point, short of it being a total life/death situation NEVER EVER EVER rebreathe the gas in the wing. Your wing is a damp, warm environment which will grow a large amount of bugs. Unless you disinfect your wing with the regularity rebreather divers do their counterlungs, there is a pretty good chance of getting a very nasty infection.

If you push both inflate and deflate buttons at the same time you can use your inflator as a Heath-Robinson regulator, though it is quite difficult to either not breathe out of the bag, or not breathe enough and ruin your buoyancy.

And the chanse of a CO2 hit is pretty good as well if you keep doing it.

Chris