non depth compensating poseidon 1st stage

curator

I've got a KISS valve I want to set up for a Dolphin KISS conversion. I've been thinking about buying an Apeks DS 1st stage and using a blanking plug, but I've also heard rumours about people modifying Poseidon 1st stages to be non depth compensating.

I've got several Poseidon Regs and can see that its very possible, so the question is, has anyone got a proven conversion thats available to buy?

Direct answers, offers, experiences and opinions welcome.

Cheers

Darren

EBT

you can do it, but the poseiden 1st tend to wobble a bit on their IP. Not a massive problem, but it does vary your flow rate.

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GKAM

This conversion has been done with sucess by a few homebulders. It involves i] soldering, ii] machining or iii] using epoxy resin to isolate the Poseidon 1st stage. I do not recall ever seeing a conversion kit ever being sold. Check http://www.therebreathersite.nl/ivan's_mccr_dolphin.htm for an example. I remember Kerry machined a plug for his Poseidon but his site is down. If you look around Jan's [www.therebreathersite.nl] site I am sure you will find more photos.

I suggest you purchase a DS4 [they go for 95 Euros] plus a derlin/SS plug. It's easy, it works and is very reliable. I have one on my mCCR and I am very happy with it.

curator

I agree the DS4 would be the easy route, but, I've already got Poseidons.

The other thought is that I'm designing my unit to run standard Dolphin SCR and KISS CCR depending on what gas is available at the time. I'm told that the Apeks can't be set to run an ISP as high as the Dolphin 1st stage. I'm wondering if the Poseidon can? This would allow me to have one universal 1st stage (Obviously I'd have to reset the ISP when I change from Dolphin dosage to KISS valve and back) plus a Dil 1st stage for mCCR/bailout for SCR.

Regarding the wobbly IP (thanks ETB) have you got any more detail?

Cheers

lizardland

The Draeger dosage unit has two feeds from the 1st stage. One goes to the orifice and the other runs the ADV. If it was me I'd use the Draeger 1st stage for diluent addition. Remove the hose to the orifice (and blank off the orifice itself) but leave the hose connected to the ADV. Have a different 1st stage for O2 addition. That way, converting back to SCR simply means removing the O2 system and replacing the hose to the appropriate orifice. I'd rather do that than start messing around with the IP each time I had to switch from CCR to SCR.

IIRC Oxycheq sold blanking plugs for the jets. If not then just get a spare and fill it with epoxy.

Also the Apeks conversion to non-depth compensated is much easier. It takes a couple of minutes, the Poseidon conversion takes much more work.

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curator

I like your thinking for simplicity. Changing IP would be a pain (tho somehow once on CCR I think I'd only go back to SC if I HAD to ).

However, if I used the Drager 1st stage for bypass and a DS for 02, wouldn't I need a third reg for Bailout (couldn't bailout on the 02, has anyone ever put a bailout on the drager ??).

Thanks for your thoughts everyone, I'm slowly getting resigned to the Idea of having a DS 1st stage for CC and a Drager 1st stage for SC. (Oh well, more baggage allowance).

Cheers

lizardland

Wouldn't you need the 3rd regulator regardless? One reg for oxygen, one reg for diluent, one reg for an independant bailout bottle. I suppose you could connect a 2nd stage to your diluent but to me having your bailout reg connected to your diluent is the same as carrying no bailout.

Using the same source of gas for both diluent and bailout... Personally, that's too much of a risk for me -- I carry an independant bailout bottle. No matter how many people say "stay on the loop at all costs" I'm still going to carry it.

Or have I misunderstood what you mean?

There is no reason you can't hook a 2nd stage to a Draeger 1st stage if the IP range of the 2nd stage matches. Failing that then a flow-stop valve on the 2nd stage would mean you could use any 2nd stage. With a fixed IP then the sure the pressure difference between 1st stage and ambient would drop. But for it to be a problem then you would be deeper than you should be if your bailout is your dil bottle. Another couple of things to consider: does the Draeger 1st stage have enough outlets and what are the connection threads (I don't know the reg well enough but I'm fairly certain they aren't standard 3/8-UNF).

Cheers,

Stuart

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Can you imagine drifting along in the sea with your mouth open and a load of f***ing plankton going in? You'd like it, would you?

www.westons-cider.co.uk

Azerbaijani Association of Technical Divers Publicity Officer and Goat Wrangler