Curious

[Diverlee]

I am new CCR/OPTIMA diver also Full Cave. Curious as to what size and type of tanks you are using and same for bail out. Talking about the easy dives like main line Little River or main line Peacock. Any input would be nice.

[Caver95]

if it was me, and I was told I was carrying too much gas. I would plan the cave dive I wanted to knowing I swim 50ft per minute find the ave depth take my SAC rate and carry enough gas to get me out from the furthest point *1.5 plus deco gas.
if I wanted to swim to the hinkle, 3000/50= 60 minutes to get there and not counting the flow 60 minutes out. so at the hinkle I have break thru and have to get off the loop. I would need enough gas to get out of the system and do the deco for 2hours of bottom time. say the ave depth is 99 for easy math and I have a sac rate of .5 thats 2ft3 of gas per minute, 2*60=120*1.5= 180 plus deco gas. Some break it up between the team, but I did not, and I sold my breather because I didn't get to dive it enough. Or you could just Aloine it.

[FW]

I *always* use sidemounted 85s, or 104s for bailout. I need the weight to hold my drysuit under water anyway, and would rather carry breathable gas than lead!

I have heard all the lame excusues for not carrying sufficient bailout, and I don't buy any of them. I don't buy the idea of the team spliting up bailout gas. I also don't calculate current into my exit plan. The current can get in the way more than help, especially if someone looses a main light, or there is a siltout. Most of the excuses amount to pure laziness.

FWIW, Caver95 isn't wrong, but it never hurts to have more than you will ever need :-)

[Randy Thornton]

I know the team bail out concept is very much in vogue rignt now, but I must admit that it makes me a little uncomfortable. If I am hour back in whatever cave, and I suffer breakthrough or have a serious CO2 hit for whatever reason, I am going go blow through tremendous amounts of bail out that far exceed anything that would even approach my normal SAC rate. This is a very tricky question, because at some point you are carrying so much bail out that it encumbers your movement. I'm not sure there is any black and white standard to this thing as of yet, because you hear so many variations. I think each person/team has to be comfortable with the individual concepts. Not easy decisions to make.

Regards,
Randy

[Gary]

My buddy and I are planning to each carry full bailout gas. For Little River type stuff that would be one 100cuft tank for bailout and the other as drive gas. For bigger stuff we plan to have both 100s for bailout and bouyancy and a smaller 20-40 cuft bottle for drive gas.

The team concept which we aren't planning to use I heard explained as each diver carries 75% of the gas needed for bailout. If bailout occurs you breath half and then switch with you buddy for the rest. So both team members still have some bailout availiable and the bailed out diver has what they need to get out on bailout. Another instructor talkied about carrying bailout broken up into smaller bottles so they can donate but still have some for themselves.

Even so we are going with ample bailout for both divers theory. Each diver carries 100%+ of each diver's needed bailout to swim out (even if we are scootering).

[Caver95]

But I have seen people at the hinkle with only a 40, Thats Not enough??? good point on the break thru I have seen a guy at 40ft deep go thru 2000psi on an al 40 in about 3 minutes

[Gary]

Here's my assumptions on bailout:



SAC 0.66
Swim rate 50 (+/- flow rate)
Flow Rate 15

Cuft/1000' Travel
Depth ATM RMV No flow Spring Siphon
0 1 0.66 13 10 19
33 2 1.32 26 20 38
67 3 1.98 40 30 57
100 4 2.64 53 41 75
133 5 3.3 66 51 94
167 6 3.96 79 61 113
200 7 4.62 92 71 132
233 8 5.28 106 81 151
267 9 5.94 119 91 170
300 10 6.6 132 102 189
333 11 7.26 145 112 207

[Gary]

But I have seen people at the hinkle with only a 40, Thats Not enough???


Ya, I'd say that's not enough at 100': 40 cuft per 1000' that'd be more like 120cuft for a safe swimout. I'm pretty sure I could swim out on an 80 though in ideal conditions from the Hinkel.

On a 40 they'd be depending on a fast scooter to get them out. (Though with their buddies 40 also they might make it - but that deprives the buddy of any bailout whatsoever.)

I know one person who dives past there with just his 14cuft drive bottle as his bailout. I don't think that is a good practice. I wouldn't even count drive gas as bailout since a free flowing reg could disable the RB and the drive gas at once.

Of course I have like zero experience on a RB myself and the person is an expert so...

[Gary]

On a 40 they'd be depending on a fast scooter to get them out. (Though with their buddies 40 also they might make it - but that deprives the buddy of any bailout whatsoever.)

I believe Tom Mount said at the conference he dives with a 40cuft bailout. With his 40 and another 20cuft from his buddy's bottle (er... actually half of his and all of his buddy's was the rule), an excellent swim rate and SAC he might be able to swim out from the Hinkle but I don't know many people who could. I'm pretty sure I couldn't.

[Randy Thornton]

I believe Tom Mount said at the conference he dives with a 40cuft bailout. With his 40 and another 20cuft from his buddy's bottle (er... actually half of his and all of his buddy's was the rule), an excellent swim rate and SAC he might be able to swim out from the Hinkle but I don't know many people who could. I'm pretty sure I couldn't.

My point earlier is that once you suffer a major CO2 hit, all SAC/RMV rates go right out the window. Even once you are back on OC, your SAC rate will be right through the roof and will continue to be so for some time. So my point is, these guys that are basing their bail out calculations on a normal or even elevated SAC rate, really have absolutely no idea what it is really going to take to get themselves out of the cave, once they are in the midst of a CO2 hit. I don't think anyone can know. So the bottom line is, MORE bailout is better! (no disrespect to Mr. Tom Mount)

[FW]

My point earlier is that once you suffer a major CO2 hit, all SAC/RMV rates go right out the window. Even once you are back on OC, your SAC rate will be right through the roof and will continue to be so for some time. So my point is, these guys that are basing their bail out calculations on a normal or even elevated SAC rate, really have absolutely no idea what it is really going to take to get themselves out of the cave, once they are in the midst of a CO2 hit. I don't think anyone can know. So the bottom line is, MORE bailout is better! (no disrespect to Mr. Tom Mount)
They actually tried it, exiting from the Hinkle. However it wasn't a *real* emergency, and you are right, trying to expel CO2 buildup will take a lot of OC gas.

[fitnessdiver]

and you are right, trying to expel CO2 buildup will take a lot of OC gas.

Not to drag the thread way off topic but..... This is a good video of an CCR CO2 hit caught on film. It's broken up into a few segments so when the screen blanks keep watching. At the end you'll see the diver has increased the size of his bail out bottle. http://www.hse.gov.uk/diving/video/co2video.htm

[Diverlee]

Thanks for all the input. Got more than I was asking for but did learn alot from all the replies. I was just wondering like ST vs AL tanks and size, I wasnt planning a dive, I am no way ready for that.

[FW]

Thanks for all the input. Got more than I was asking for but did learn alot from all the replies. I was just wondering like ST vs AL tanks and size, I wasnt planning a dive, I am no way ready for that.
85s and 104s are steel. The 40s mentioned in other posts are AL, but the consensus seems to be they are too small.

I forgot to mention that I use an AL 14 for O2. It will last for several hours. I use one of my sidemount tanks for diluent.

[RAL]

I *always* use sidemounted 85s, or 104s for bailout. I need the weight to hold my drysuit under water anyway, and would rather carry breathable gas than lead!

I have heard all the lame excusues for not carrying sufficient bailout, and I don't buy any of them. I don't buy the idea of the team spliting up bailout gas. I also don't calculate current into my exit plan. The current can get in the way more than help, especially if someone looses a main light, or there is a siltout. Most of the excuses amount to pure laziness.

FWIW, Caver95 isn't wrong, but it never hurts to have more than you will ever need :-)
Thought I was the only chicken that dove like this. Give me a pair of Faber 50s, 85s or 108s side mounted & cave pumped.

Roger

[FW]

Thought I was the only chicken that dove like this. Give me a pair of Faber 50s, 85s or 108s side mounted & cave pumped.

Roger
The way I look at is, if tanks smaller that 85s are truely enough bailout, you didn't need a rebreather for that dive anyway :-)

[RAL]

The way I look at is, if tanks smaller that 85s are truely enough bailout, you didn't need a rebreather for that dive anyway :-)

True enough but if it is big enough to not need sidemount I like to use the breather. Makes me feel warm & fuzzy:smt004

RAL

[Caver95]

True enough but if it is big enough to not need sidemount I like to use the breather. Makes me feel warm & fuzzy:smt004

RAL

That sounds like me on air at 300ft

[Mike Edmonston]

There's nothing wrong with sidemounting a pair of 40's or even a single 40 for bailout. Your Bailout needs to be able to get you to either 1: the exit, or 2: your staged gas supply. It is entirely acceptable to sidemount a single 40 at the hinkle if you have a stage 80 tied off at 1000 or 1500 ft penetration.

To each his own.

[Randy Thornton]

There's nothing wrong with sidemounting a pair of 40's or even a single 40 for bailout. Your Bailout needs to be able to get you to either 1: the exit, or 2: your staged gas supply. It is entirely acceptable to sidemount a single 40 at the hinkle if you have a stage 80 tied off at 1000 or 1500 ft penetration.

To each his own.

Absolutely! I guess the bigger issue is those alpinists or semi alpinists that either don't have sufficient bailout on their person, team or staged. I see them quite often, and I just shake my head thinking, "Dude, it is just a matter of time!" It's not a matter of if someone is going to have an issue with CCR, it's a matter of when. If you have been following the thread on RBW lately about CCR deaths, you will notice a huge amount of deaths due to insufficient bailout. It's sad, because a lot of these deaths really don't need to happen.

[RAL]

There's nothing wrong with sidemounting a pair of 40's or even a single 40 for bailout. Your Bailout needs to be able to get you to either 1: the exit, or 2: your staged gas supply. It is entirely acceptable to sidemount a single 40 at the hinkle if you have a stage 80 tied off at 1000 or 1500 ft penetration.

To each his own.

How long will 40cf last a diver at 80' who is dealing with a major CO2 hit?

To each his own.

RAL

[Mike Edmonston]

How long will 40cf last a diver at 80' who is dealing with a major CO2 hit?

To each his own.

RAL

My last post indicated a solo RB diver, and a total SNAFU of the entire breathing loop. Therefore, caution suggests that he go no further past his stage than 1/2 of his bailout will allow. Assuming the diver is sidemounting 2 40's, once the stage is dropped, he SHOULD go no further than 40cf worth of gas to get back to his stage.

There are a zillion different scenarios,and you can't account for them all. Just like an OC diver, you assume some risks. I don't judge what another RB diver or team chooses to do.

To each his own....

[RAL]

My last post indicated a solo RB diver, and a total SNAFU of the entire breathing loop. Therefore, caution suggests that he go no further past his stage than 1/2 of his bailout will allow. Assuming the diver is sidemounting 2 40's, once the stage is dropped, he SHOULD go no further than 40cf worth of gas to get back to his stage.

There are a zillion different scenarios,and you can't account for them all. Just like an OC diver, you assume some risks. I don't judge what another RB diver or team chooses to do.

To each his own....

I am not sitting in judgment. I simply asked a question. How long will 40 cf last a diver dealing with a major CO2 hit at 80'. I believe it is relevant, you stated that a 40 is fine at the Hinkle if an 80 was stashed between 1000' & 1500' penetration. It would not be unrealistic to blow through the first half of that 40 just getting back to square from a CO2 hit. Now you have 20cf left to get back to your bottle....... do not kid yourself you might find your breathing rate is a bit higher than on a drill.
You're right there are risks & we must decide how close to the edge we wish walk. Myself I would rather have too much gas than almost enough, but thats just me:-D

RAL

[Mike Edmonston]

I am not sitting in judgment. I simply asked a question. How long will 40 cf last a diver dealing with a major CO2 hit at 80'.
IMHO about even to 18cf of gas.


I believe it is relevant, you stated that a 40 is fine at the Hinkle if an 80 was stashed between 1000' & 1500' penetration. It would not be unrealistic to blow through the first half of that 40 just getting back to square from a CO2 hit.
Yes I agree, you could blow through more than half. In a team environment a 40 should be fine. Solo diving, I would personally use twin 40al or 51cf steels sidemounted.



Do not kid yourself you might find your breathing rate is a bit higher than on a drill.
No dissagreement there



You're right there are risks & we must decide how close to the edge we wish walk. Myself I would rather have too much gas than almost enough, but thats just me
Again we agree. I do believe that more is better when it comes to gas supplies on a dive.

I would feel confident with staged cylinders in a team environment while sidemounting twin 40's.:-D

YMMV