O2 Injection Question

Smudgegs

Ok, an idle question while the weather excludes diving here!

I've been offered some kit which would allow me to inject O2 into the dolphin, now presumably, (with appropriate O2 monitoring of course), this would allow me to run a mix which would otherwise be hypoxic near the surface and top up the O2 as required, thereby extending my maximum depth.

Soooo my questions are,
Does anyone on here run a similar setup?
What would people think might be a maximum depth with this arrangement?
What minor detail have I forgotten about which will undoubtedly see Mrs Smudge collecting the insurance!? (assuming I have)

Over to the experts...

divetheworld

Do a KISS course and convert your dolphin accordingly. Make sure you have training fro hypoxic Diluents.
Otherwise, in all seriousness, the best you can hope for and not run the risk of a serious incedent is accelorated deco by adding O2 into your loop when decompressing at 6m.
You are adding another tank, O2 inject and staying semi closed? and a Hypoxic Dil? Homebuild hell here Im afraid.

I make the above statement with a complete lack of knowledge as to your training and expertise, but in the full knowledge that hypoxic dil can kill in less than two minutes.


Brent

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bletso

Yeh, since back in 2000. www.airheadsscuba.com/rbrsprt.html

A lot of people have done it. It is my preferred kit.

Dale

Smudgegs

Thanks for the replies gents. It is in the plan to do a KISS course sometime but of course the problem in the UK is you have to own a KISS to do the course as it's not CE approved so no-one is allowed to rent you one.

A bl**dy stupid way to allegedly protect our safety imho but hey, that's a different argument.

So yes... I think now, having had a cuppa and reflected on it for a bit, the way forward for me is to continue experience building on the set and *if* I use the O2 injection then use it for rich deco mixes as suggested.

Closing it properly would undoubtedly work... but then if I sell my Dolphin and my twinset I'm probably more than two thirds of the way to a decent used CK... and that has recognised support, no dramas using it at commercial sites/boats and an *excellent* safety record.

Hmmm, must stop thinking as I type and try thinking first, keep answering my own questions!

Ta for the brainstorming gents

narked at 90

you still have options, you can do a generic ccr course, there are a few inscructors around now that will do this for you on a converted unit.
i dived a ccr dreager for many years and never had problems on boats or dive sites, but it will teach you alot about rebreathers, infact i can point to most of the newer manufactures on the market now that started off converting dreagers, there was many of us that started off at the same time and used the same list to post to long before Rebreather World came about.
The Dolphin is a fantastic gas extender, I can see no reasonable argument why you shouldnt have an O2 feed for deco with the right knowledge and experience. It makes a very efficient way to deco without having to carry vast amounts of gas. It's also a great stepping stone to full CCR.
If you fit a very small O2 bottle with some adaptors form Martin at Tecme to plumb in the O2 into a second small orifice and tee into the ADV feed. when your ready for pure O2, just turn off your main tank and open your O2. This will require experience and discipline to be safe.
If your advancing to the point of needing accelorated deco, then the 60% jet is probably becoming obsolete, you could use this as your O2 jet. The 60 jet flows about 5.5ltr/min if I remeber correctly, it has two jets inside that split the flow between them. If you cant find a 100% jet then you could use one of the 60% orifices to flow 2.5ltr min.
There are significant risks in running a pure o2 rebreather, many military personel have found out to their misfortune and died. Better to get some expert tuition to get the most out of this mode.
Undoubtably there is a reasoned argument that you are increasing the risks without the advatages of CCR but I just wanted to pass on some thoughts.
kind regards john routley

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divetheworld

Dave Cooper on Rebreather World here does a generic course. I cant recommend him highly enough.

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