What is your reason for not diving a rebreather while cave diving?

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Originally Posted by Kevin Carlisle

I would rather know why I need one? You have to carry as much oc gas as needed to safely exit from max penetration and im not doing 3-400ft dives so I find it totally unnecessary for me.

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Lets say my max penetration is 4000' from the entrance. I can do that on two AL80's. Now, as long as I go less than 4000' from the entrance of the cave, I can go wherever I want on a single dive. Take Ginnie for example. I can swim to the Henkel, swim back, do all the tunnels on the way back, check out double domes, check out hilliar tunnel, check out double lines, parallel lines and and bats or hill 400. Then I can go hit the Bone line. Check out the White Room, check out the Wonder Tunnel, Swim back down the rollercoaster, etc. etc. etc. I was never more than 4000' from the entrance, but I often do 4 or 5 OC dives on a single CCR cave dive like the one I just mentioned.

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Originally Posted by Kevin Carlisle

I would rather know why I need one? You have to carry as much oc gas as needed to safely exit from max penetration and im not doing 3-400ft dives so I find it totally unnecessary for me.

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Peter explained it quite nicely, but consider a typical JB dive for me on CCR: Scooter to stage rock in the trash room. Drop scooter and an AL80 stage. Jump to Middle Grounds, swim Crinoid Glory to the end. Go from there to the end of the line and poke around in the terminal room. Check out several leads on my way back, then follow Deloach's Delight to the Orange Bucket line. Do Source Nouveau from there, then back out to Gold Line following Mark's tunnel. Plenty of tees to explore along the way. From Gold, go back upstream a little bit then go down the Minnow Route. Back on Gold again, drift down to stage rock and retrieve my extra bottle and scooter, leisurely egress.

I'm never note than 2000 feet from my extra bottle and scooter (with 2 AL80's side mounted). Worst case I can swim to deco on one AL80 from stage rock (I've done it, I know). About a 4 1/2 hour or so dive.

The freedom is extraordinary. Not trying to convince you to change, that's not my place or intent. Just giving a familiar example of why I do it. And that's just just one small example.

Hell, we've done near 5 hour dives at the PC Jetties. Fun stuff.

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Originally Posted by Captain Bil

Peter explained it quite nicely, but consider a typical JB dive for me on CCR: Scooter to stage rock in the trash room. Drop scooter and an AL80 stage. Jump to Middle Grounds, swim Crinoid Glory to the end. Go from there to the end of the line and poke around in the terminal room. Check out several leads on my way back, then follow Deloach's Delight to the Orange Bucket line. Do Source Nouveau from there, then back out to Gold Line following Mark's tunnel. Plenty of tees to explore along the way. From Gold, go back upstream a little bit then go down the Minnow Route. Back on Gold again, drift down to stage rock and retrieve my extra bottle and scooter, leisurely egress.

I'm never note than 2000 feet from my extra bottle and scooter (with 2 AL80's side mounted). Worst case I can swim to deco on one AL80 from stage rock (I've done it, I know). About a 4 1/2 hour or so dive.

The freedom is extraordinary. Not trying to convince you to change, that's not my place or intent. Just giving a familiar example of why I do it. And that's just just one small example.

Hell, we've done near 5 hour dives at the PC Jetties. Fun stuff.

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indeed!!

Dive safe,

Celia

I know you can maintain a constant PO2, but still how much Deco do you have at five hours at 100ft?

Pete, Bill, while I think those examples are good examples for you, im not swimming that much :-P lol. I can get 4 hours of bt with my 100s and two stages and have tons of gas left. Until we have food service down there, I dont even like doing 4 hours. The only thing I really like about ccr is constant po2, and that's about it. I see them as taking a lot more work to prep, which I enjoy the freedom of turning a knob and going ok im ready.

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Originally Posted by Kevin Carlisle

Pete, Bill, while I think those examples are good examples for you, im not swimming that much :-P lol. I can get 4 hours of bt with my 100s and two stages and have tons of gas left. Until we have food service down there, I dont even like doing 4 hours. The only thing I really like about ccr is constant po2, and that's about it. I see them as taking a lot more work to prep, which I enjoy the freedom of turning a knob and going ok im ready.

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No doubt each has advantages and disadvantages. And while the dive I described costs me about $5.00 max for gas (as long as I don't have to use my bailout), there are still sorb costs to consider, as well as maintenance, prep, and sensor replacement. Anyone who thinks they can recoup the cost of CCR purchase and training via gas cost savings is seriously deluding himself. Trimix savings, while significant given the cost of helium, would still take many years and lots of diving to break even. Maybe others can swing it, but I have a wife, job, grand young'uns, etc that take up time too. If I can dive once a week, I'm doing well. More than that is a bonus. At that rate, I think old age will get me before I get back the investment.

Oh, and I still dive a lot of OC too. CCR makes no sense sometimes. All that being said, when I can use the CCR, I do - it's challenging and fun, for me. ;)

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Originally Posted by a64pilot

I know you can maintain a constant PO2, but still how much Deco do you have at five hours at 100ft?

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That's a total runtime. The deco portion is around an hour or less I think, but I don't have my log handy to be sure.

At the PC Jetties, we've done it with no deco at all, just a 3 minute safety stop.

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Originally Posted by a64pilot

I know you can maintain a constant PO2, but still how much Deco do you have at five hours at 100ft?

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I could explain it the way I heard a Poseidon rep explain it, but I don't want everyone spraying Coke on their screen.

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Originally Posted by Captain Bil

If I can dive once a week, I'm doing well. More than that is a bonus.

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You might want to keep a low profile after saying this - a lot of people will be wanting to whup up on you.

Pete, let me know the next time you want to swim to the Henkel. When was the last time (if ever) that you swam there? I did it earlier this month and never touched back gas.
I'm willing to do the dive you described OC. Lets get together and see who calls it first. I'll be in HS for most of Sept.

James

I have been diving a rebreathers for years on tech wreck dives and really like them. I prefer OC sidemount in caves. Easier to fine tune buoyancy in small silty tunnels etc. Also - It's really hard to plan bailout. The amount of bailout required can vary based on the reason for bailing. I bailed out in a cave once due to a moderate Co2 hit. I got about 1/2 the distance coming out on the bailout than I normally would have gotten without the C02 hit. Fortunately, I had not penetrated that far and had plenty of bailout to get out but it gave me something to think about. Bailing out due to a bad cocktail would really be difficult.