Shallow water Rebreather diving

denka

Hello
I am new at the game and I am considering a SCR or CCR. The dives I normaly do are in the range of 5 to 25 meters in fresh water. I thougt about going SCR but after looking at the dolfin and the Azimuth I still am not sure. this is because i would like to be total silance underwater and the SCR would not give me that. So I did my research on theKISS, pelagian and R-evo (at boot in Germany) and talk to Paul and his friend. The units all looks nice and seem to fit the bill. But for my dives is it wise to go CCR because i heard off shallow water black-out .

What should the best unit be and what are the criteria of choice

Greatings Dennis (Holland)

divetheworld

My first thoughts are open circuit.
you've got to have a very good reason to want to go rebreather at those very shallow depths.
CCR is no bubbles, SCR is a leaky box so only CCR could give you the reason of no bubbles.

A rebreather is a very efficient tool when used correctly, it has numerous risks that could and has caused fatalities. there is no point increasing your risks unless there is a good reason.

The only good reason that keeps me CCR is the high cost of bulk helium.


Brent

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onetime

A lot of my diving is shallow very often in the ranges that you're looking to do. I've been using a KISS for the last couple of years. The main reason I went CCR was logistics, relative silence was a secondary but oh so rewarding offshoot of it. It's just far easier to have my KISS with me for a weekend of diving than it is to bring a bunch of bottles and need to get them refilled.

Sure I could spend a couple of hours u/w on an aluminum 80 @ 20 ft but to do it 4 times means bringing 4 bottles or refilling a couple of them. Lugging them back and forth from the truck to the boat, then securing them on the boat, switching out bottles between dives, then lugging them all off the boat to the truck to get them refilled is just inconvenient.

IMO, it's not always about cost. Most of us have very limited free time, I want to use mine as efficiently as possible.

And the silence is awesome.

Outlaw

hello,

i think your best option would be the mini meg. it would be lite, small and very efficient. within time you shall become very cool with it and you shall be enjoying your dives. about the shallow water blackouts, i think this is the term people have given to the phenomenon of ccr divers fainting or having issues due to O2? i am not quite sure but i know that most of ccr divers, when at shallow water, usually raise their setpoint in order to get less deco, and that is giving them the risk of convulsions etc etc.....i hope i am right about this. correct me guys?

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Maui Nobubbles

I do almost 100% of my diving in shallow water 15-50 FSW and have been using a Dolphin running 60% EAN and a bubble silencer (yes, they work) -but I can also tell you after doing this for 4 years I'm now looking at CCR for the same reasons you see posted above. If you are looking for longer durations underwater you have to use bigger tanks than the 29 CF drager, so another plus for CCR.

I think most folks start with Dolphins due to the cost difference and most of the non tech dive shops teach Dolphins.

Just my 2 cents.

Gilles

Amen.

But if

• you want to turbo-charge your interest in diving
• don't want bubbles
• can tolerate more risk than what is really necessary for a shallow dive

you may not regret the mCCR choices you mentioned. There is very much to learn, and it goes on and on and on...

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Andy Del

Hi Dennis

You raise an interesting point of view. While most of my diving is on wrecks past 40m, I still do shallow dives on my KISS. In fact, when I do OC dives, I get all nervy about not having redundancy, needing to rely on buddies, etc. etc.

If ussing a rebreather is what you feel is necessay, then go CCR. SCR is just too complex for little ole me to fathom!

The question of which unit comes next. Considering that in shallowdepths, your PO2 changes a lot more than at depth, an eCCR is going to potentially pumpin lots of O2 and give you a degree of grief as far as buoyancy goes.

Using a mCCR, you can, ESPECIALLY shallow, just pick a setpoint and dive, forgetting to hold a setpoint with a death grip, a littel change here and there isn't going to effect you decompression obligation - it won't exist!

KISS, rEVO, Copismeg, they are all good options.

cheers

Andy

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lizardland

Another vote for OC. I really can't be bothered with the hassle of diving a rebreather in shallow water. It's a good way of making simple diving more complicated, more expensive, more equipment reliant and more open to screw ups.

Cheers,

Stuart

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marekm

For long shallow dives, I'd say a Rebreather is good. For short shallow dive, better off going OC.

Marc T

About this one, the solution is to use the right dil for ex NX 40 or even 50, see previous discussions about that!!

Ayway Im very surprise that nobody proposed the Ray, great tool for that depth an way more silent than OC, far less expensive than CCR ( think less 1000 Euros no sensors prob... etc ).

Yes the Ray is not sexy, but easy to sale because cheep.

Oh and easy to turn CCR ( see tecme part ) but thats an other story.

Cheers

Marc