Depth limit of mCCR Dolphin?

montyg · 3rd December 2007, 12:34

Hi all

I never took my mCCR Dolphin very deep, and I am now diving an IDA-71 which I intend to dive in the normoxic range - no more than 60 meters or so (with both scrubbers in parallel)

Some friends of mine have been diving their mCCR Dolphins to 60 meters regularly for the last 3 years and now they want to go deeper.

How deep have divers on this forum taken mCCR Dolphins?

Besides the modifications to get oxygen addition working, the ability to carry adequate bail-out and the small water trap/ inability to recover from loop flood, what limitations are there?

The scrubber on of the better ones IMHP, but at 100m?

My gut feeling is that it is not a suitable machine for this endeavour, but at the same time they are not looking at doing many 100 meter dives and it's hard to justify a new machine for dives which they will do a handfull of times in their lives.

Their diving ability, knowledge, attitude, discipline, skill and planning does not concern me at all, it's just the limitations of the equipment.

rgds
monty

***caveseeker7*** · 3rd December 2007, 13:09

For what it's worth, Dräger had originally planned an 80 meter version of the Dolphin, and IIRC ANDI actually trained a couple of the Dräger guys that were to develop and test the unit.

I also vaguely remember them helping out someone modifying Dolphins for some deeper diving, reviewing the changes and pitching in a few parts in the process. There was an article in a German dive mag some time back about it, I believe the units were still SC but had gas switching hardware.

Personally I don't like the idea of diving RBs without reasonable draining ability into overhead environs (I include substancial deco here), but that's me.

OceanOpportunity · 3rd December 2007, 17:48

I'm pretty sure there's a thread on here listing peoples deepest dives with various units adn someone took an mCCR Dolphin sub 120meters.

I've been working on a conversion for some time,a dn trying to address the many limitations you menitioned. There are viable solutions, and I plan to share them on Rebreather World shortly this winter.

generally speaking, I dont see any physical limitations of the equipment with depth. Hose bores are comparable to other units, scrubber volume is comparable, etc. In fact, a look at the LARV units will bear a striking resemblance to the Dolphin scrubber. I know of a few former military guys that said experimental dives were made from saturation sub-150meters with a mixed-gas version of the LARV. So, with some creative engineering, it can be done

My only concern would be planning deep dives requireing lengthy decompression. With a scrubber duration around 3-4 hours, that may present a limitation

ML

seppu · 3rd December 2007, 17:57

hi
friends used the the mccr dolphin for 120m+.
gruss sepp

**jmurba** · 3rd December 2007, 20:17

Hi

I've dived mine down to 80m scr and mccr.
I'm not really competent in canister évaluation, but I tend to think that 2,2kilos of sorb is not worst then many ccr's
of course you have to know that I had a big double 45lt dive rite wing and back plate tied up to a thick fiberglass shell...not he original dolphin shell/wing set...
at 80m it breathed well on trimix 10/60.
after almost 9 years on the machine... I can't make up my mind to change ...
I've even started to builta nw shell, able to tand up.
but I am not a deep diver.
regards
jean mi

montyg · 4th December 2007, 16:30

Thanks very much for the replies, gents.

May I ask who went for a smaller orifice and who elected to add a compensated first stage, and who added a manual bypass for the really deep section - and maybe the reasons why you chose to do what you did?

rgds
monty

OceanOpportunity · 4th December 2007, 16:42

I use a .0025 orifice with a normal 'compensated' first stage. When the flow gets too high, I plumbed the unit to isolate the orifice, leaving manual addition capabilities. works well.

tauchertom · 11th January 2008, 01:12

I did som 50m+ dives with a EAN 32% mix and the 50% orfice. My Buddy used a EAN 50% mix and the 100% orfice and had the bypass valve connected to the bailout (air). In the deep part of the dive he closed the EAN tank and used the bypass.

there are different mixes/orfices that work for deep dives.

now I want to use trimix on one orfice and O2 on an other orfice (2 x 4 L tanks with 2 fist stages.
Sure I take a 10l air for bailout with me and have a close look on the Oxygauge!

Wich mix seems to be the best to minimize the nitrogen-narcosis effect?
Thinking about a Tmx 15/70.
Anyone have experiences with that mix deeper than 60m?

mortenkjerulff · 11th January 2008, 07:36

Hi.

I dived my converted Dolphin to 75 meters in cold water, using the KISS valve with standard orifice.

A friend of mine added a needle valve instead, and have taken the Dolphin to 100 meters in the Red Sea, with no problems at all.

Cheers

**jmurba** · 20th March 2008, 20:06

Quote: (Originally Posted by mortenkjerulff)

Hi.

I dived my converted Dolphin to 75 meters in cold water, using the KISS valve with standard orifice.

A friend of mine added a needle valve instead, and have taken the Dolphin to 100 meters in the Red Sea, with no problems at all.

Cheers

the thing is we are speaking of dolphins that are not dolphins anymore

is it still a dolphin ?
/Users/urbani/Desktop/Recycleur 28 light-1.JPG
/Users/urbani/Desktop/Recycleur 31 light.JPG

the cannister, the lungs, the dsv and hoses are the same, I made the shell (with denis my buddy) the electronics etc etc...

the good question would be is the dolphin loop and cannister can support life deep ?

regards

jean mi

3rd December 2007, 12:34	#1 (permalink)
montyg Custom Title Allowed! Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Feb 2007 Location: Cape Town, South Africa Posts: 224	Depth limit of mCCR Dolphin? Hi all I never took my mCCR Dolphin very deep, and I am now diving an IDA-71 which I intend to dive in the normoxic range - no more than 60 meters or so (with both scrubbers in parallel) Some friends of mine have been diving their mCCR Dolphins to 60 meters regularly for the last 3 years and now they want to go deeper. How deep have divers on this forum taken mCCR Dolphins? Besides the modifications to get oxygen addition working, the ability to carry adequate bail-out and the small water trap/ inability to recover from loop flood, what limitations are there? The scrubber on of the better ones IMHP, but at 100m? My gut feeling is that it is not a suitable machine for this endeavour, but at the same time they are not looking at doing many 100 meter dives and it's hard to justify a new machine for dives which they will do a handfull of times in their lives. Their diving ability, knowledge, attitude, discipline, skill and planning does not concern me at all, it's just the limitations of the equipment. rgds monty
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3rd December 2007, 13:09	#2 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,435	Re: Depth limit of mCCR Dolphin? For what it's worth, Dräger had originally planned an 80 meter version of the Dolphin, and IIRC ANDI actually trained a couple of the Dräger guys that were to develop and test the unit. I also vaguely remember them helping out someone modifying Dolphins for some deeper diving, reviewing the changes and pitching in a few parts in the process. There was an article in a German dive mag some time back about it, I believe the units were still SC but had gas switching hardware. Personally I don't like the idea of diving RBs without reasonable draining ability into overhead environs (I include substancial deco here), but that's me. __________________ Cheers Stefan "Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.'!"
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3rd December 2007, 17:48	#3 (permalink)
OceanOpportunity for a world of water Current Rebreather/s: Other CCR Dolphin Home Build Other Rebreather/s: Not Bought Yet Inspiration Classic Other CCR Dolphin Home Build Join Date: Nov 2006 Location: Providence, RI USA Posts: 527	Re: Depth limit of mCCR Dolphin? I'm pretty sure there's a thread on here listing peoples deepest dives with various units adn someone took an mCCR Dolphin sub 120meters. I've been working on a conversion for some time,a dn trying to address the many limitations you menitioned. There are viable solutions, and I plan to share them on Rebreather World shortly this winter. generally speaking, I dont see any physical limitations of the equipment with depth. Hose bores are comparable to other units, scrubber volume is comparable, etc. In fact, a look at the LARV units will bear a striking resemblance to the Dolphin scrubber. I know of a few former military guys that said experimental dives were made from saturation sub-150meters with a mixed-gas version of the LARV. So, with some creative engineering, it can be done My only concern would be planning deep dives requireing lengthy decompression. With a scrubber duration around 3-4 hours, that may present a limitation ML __________________ Michael Lombardi Oceans of Opportunity www.oceanopportunity.com Elected Director, Society for Human Performance in Extreme Environments MN'07, The Explorers Club Project Manager, Diving a Dream Last edited by OceanOpportunity : 3rd December 2007 at 17:52.
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3rd December 2007, 17:57	#4 (permalink)
seppu i ko nix dafüa Current Rebreather/s: Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2006 Location: bayern Posts: 192	Re: Depth limit of mCCR Dolphin? hi friends used the the mccr dolphin for 120m+. gruss sepp
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3rd December 2007, 20:17	#5 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 718	Re: Depth limit of mCCR Dolphin? Hi I've dived mine down to 80m scr and mccr. I'm not really competent in canister évaluation, but I tend to think that 2,2kilos of sorb is not worst then many ccr's of course you have to know that I had a big double 45lt dive rite wing and back plate tied up to a thick fiberglass shell...not he original dolphin shell/wing set... at 80m it breathed well on trimix 10/60. after almost 9 years on the machine... I can't make up my mind to change ... I've even started to builta nw shell, able to tand up. but I am not a deep diver. regards jean mi __________________ when will I be able to think about something else then spending hours underwater, when will I be normal ? http://web.mac.com/jmurba/Site_2/home.html http://web.mac.com/jmurba/Site_3/home.html
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4th December 2007, 16:30	#6 (permalink)
montyg Custom Title Allowed! Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Feb 2007 Location: Cape Town, South Africa Posts: 224	Re: Depth limit of mCCR Dolphin? Thanks very much for the replies, gents. May I ask who went for a smaller orifice and who elected to add a compensated first stage, and who added a manual bypass for the really deep section - and maybe the reasons why you chose to do what you did? rgds monty
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4th December 2007, 16:42	#7 (permalink)
OceanOpportunity for a world of water Current Rebreather/s: Other CCR Dolphin Home Build Other Rebreather/s: Not Bought Yet Inspiration Classic Other CCR Dolphin Home Build Join Date: Nov 2006 Location: Providence, RI USA Posts: 527	Re: Depth limit of mCCR Dolphin? I use a .0025 orifice with a normal 'compensated' first stage. When the flow gets too high, I plumbed the unit to isolate the orifice, leaving manual addition capabilities. works well. __________________ Michael Lombardi Oceans of Opportunity www.oceanopportunity.com Elected Director, Society for Human Performance in Extreme Environments MN'07, The Explorers Club Project Manager, Diving a Dream
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11th January 2008, 01:12	#8 (permalink)
tauchertom New Member Current Rebreather/s: Dolphin Other Rebreather/s: Not Bought Yet Dolphin Join Date: Dec 2007 Location: Germany Posts: 5	Re: Depth limit of mCCR Dolphin? I did som 50m+ dives with a EAN 32% mix and the 50% orfice. My Buddy used a EAN 50% mix and the 100% orfice and had the bypass valve connected to the bailout (air). In the deep part of the dive he closed the EAN tank and used the bypass. there are different mixes/orfices that work for deep dives. now I want to use trimix on one orfice and O2 on an other orfice (2 x 4 L tanks with 2 fist stages. Sure I take a 10l air for bailout with me and have a close look on the Oxygauge! Wich mix seems to be the best to minimize the nitrogen-narcosis effect? Thinking about a Tmx 15/70. Anyone have experiences with that mix deeper than 60m?
(Offline)

11th January 2008, 07:36	#9 (permalink)
mortenkjerulff Customise Me! Current Rebreather/s: Megalodon Other Rebreather/s: Not Bought Yet Join Date: Mar 2005 Location: Denmark Posts: 137	Re: Depth limit of mCCR Dolphin? Hi. I dived my converted Dolphin to 75 meters in cold water, using the KISS valve with standard orifice. A friend of mine added a needle valve instead, and have taken the Dolphin to 100 meters in the Red Sea, with no problems at all. Cheers
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20th March 2008, 20:06	#10 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 718	Re: Depth limit of mCCR Dolphin? Quote: (Originally Posted by mortenkjerulff) Hi. I dived my converted Dolphin to 75 meters in cold water, using the KISS valve with standard orifice. A friend of mine added a needle valve instead, and have taken the Dolphin to 100 meters in the Red Sea, with no problems at all. Cheers the thing is we are speaking of dolphins that are not dolphins anymore is it still a dolphin ? /Users/urbani/Desktop/Recycleur 28 light-1.JPG /Users/urbani/Desktop/Recycleur 31 light.JPG the cannister, the lungs, the dsv and hoses are the same, I made the shell (with denis my buddy) the electronics etc etc... the good question would be is the dolphin loop and cannister can support life deep ? regards jean mi __________________ when will I be able to think about something else then spending hours underwater, when will I be normal ? http://web.mac.com/jmurba/Site_2/home.html http://web.mac.com/jmurba/Site_3/home.html
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