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You aren't wrong, but there hasn't always bee a procedure covered in cave classes. I know for sure that it wasn't covered prior to 1984. After that, it was pretty much up to individual instructors what they taught.Quote:
Originally Posted by wallacm
I was taught that 1/3 is for going in, 1/3 for coming out, and the other 1/3 is to deal with problems, not for buddy's problems....not saying this is right, but if you have a gas problem, you will want that other 1/3 to deal with it. I've never heard of reevaluate thirds, or "new thirds." Cookie or arrow is a good idea, but not one I was taught.Quote:
Originally Posted by wallacm
If you do "start eating into his thirds," and find him and he has also been eating into "your" thirds, well, sounds like no one is going home.
So let me make this clear to everyone: You dive with me and we get separated, when I reach thirds, I'll be doing buddy search on the way out, not further in and not doing jumps into silt clouds. I will get out, get a stage or two and come back in though.
-skip
As I dive with my son, this is a tough question. But it would be a sad day for my wife if there were two caskets. Don and I have discussed this at leangth and before he got his full cave. You have to be willing to leave your buddy, even if it is your dad or son and exit the cave. At 2/3 rds, you leave your slate and one of your backup lights turned on, on the main line, and exit.
If both you and your buddy are not willing to do this, then don't get in the water with each other.
I pray neither my son or I have to do this. Ken
UFFDA is Minnesotan for OH MY !!!
or OH BOY etc ...
An expression of complete surprise... !!!
(something like that)
There are more colorful uses too , but I won't go into that...
Jeano Beano
Skip & I have played out this scenario several times.
We dive in silt filled caves & can be as close as 5 feet from each other & not know whether the other person is there or not.
We know this going in this type of cave & plan for it so, when we do the Fla. caves where you have great vis. (usually) we still dive the same way
( we keep a close eye on each other).
Like Skip said you have 1/3 in, 1/3 out & 1/3 for emergencies.
That emergency gas is to get you & your buddy out of the cave before you get to the last 1/3's. (IMO)
If you spend it looking & find him with a severe gas problem, neither of you is coming out alive.
Drills I was taught was to look at your gauge & decide how much gas you can afford to spend looking, decide then tie to the main line & search.
If you are getting close to 1/3's you need to have your buddy in close view to relate it's close to time to go.
In a silty situation you need to be right on your buddy like stink on you know what.
As far as the stage, if you don't have it with you, you can't count it as usable gas if you decide to search for your buddy on less than 1/3's.
My 2 centavos,
Mike M
If you do get caught solo due to misplaced buddy and have to search and/or exit solo, would you close your isolator valve to protect the gas supply in case the need for "emergency self rescue" were to arise? I split my time between backmount and sidemount. So I always have two pressure gauges so that I have a constant "kit" to reference on a dive.
If I were backmount and had to exit without a stage, solo. I would shut down my isolator and breath each tank equally knowing that both regs were working throughout the exit.
In answer to the original question, I agree that it should be part of the planning that you make prior to the dive. For me, I allow 1/2 to 2/3's of my emergency third to be used to look around depending on conditions and my stress level. This would allow me the rest of my second third to exit plus a little cushion to account for additional delays, problems, stress. I never want to leave a buddy, but I don't want to drown because I made an error in my gas management.
If in the senario that a lost diver is eventually found and then one of the team runs low on gas...most likely at least one diver dies in a two man team without stages or safety bottles. Depressing, but sobering.
Safe Diving,
Lee
Reference the line, shield your light and look for buddies light. If you don't see light, use your light to see if you can spot him. If not, drop an arrow on the line (pointing out), tie in a safety reel, re-evaluate thirds (add your gas used + your original usable third - this is your new turn pressure). Use your safety reel to conduct a search. If you leave the line without a reel, you are now the one that is "lost".
Bob
I'm confused on this "re-evaluate" your thirds idea. I'm pretty sure I was never taught this. Lost buddy drill was to check and "decide how much you are willing to use in the search," with no recalculation of thirds ever mentioned (unless I wasn't paying attention, or have forgotten).
From your post, I see something like this:
3000 total available before dive, thirds is then 1000, and turn pressure is at 2000. Assume buddy is same so team pressure is the same. You lose buddy "near thirds," so you now reference line, tie in if needed, cup light, search with light, and not seeing buddy check pressure to decide how much to use continuing search.... At this point you see you are at 2000, the turn pressure. So now you "recalcuate thirds" by taking the original thirds (1000) and adding gas used (1000), and you get 2000. This is not a "new thirds" but the same old turn pressure you started with!
Maybe it works better if you have half of your usuable gas left? So you lose buddy at 2500 psi, your original thirds was 1000 and the gas used is 500 psi, added they are 1500 psi, which is the new turn pressure. I see then that you are basically saying that as long as you are not already at thirds, you are now 500 psi in and only need 500 psi to get out again. and if buddy also only needs 500 psi from you, then you still have the "extra" third for emergencies. Hmmmmm, i like that. I especially like how it gives you your original thirds if you are already there!
-skip
Using the old adage of "An ounce of prevention is worth a pound of cure," maybe the lesson to be learned is - Don't dive with Bears.
(inside joke)
You are correct. In your first paragraph: Since you are at thirds, you don't have any gas left to search. You needed a thousand to get in, your gonna need at least a thousand to get out. The other thousand psi is your buddies. The idea, which you are correctly following in your second paragraph, is that you have to reserve the original one-third that you reserved for your buddy at the beginning of the dive. It's his gas, and you don't have a right to it - unless you are in an emergency yourself - which you're not because you have the line. What you need to get out is pretty much what you used to get in. Yes, this last sentence could be debated all day long, something I will not be participating in.Quote:
Originally Posted by skip
This is all based on the principles I was taught:
1) you are saving a third of your gas for the only one true emergency, ooa. Not for "contingencies" like I hear so many people say. It's your buddies gas, not yours. What contingencies? your lost? Well, that changes everything! (see #2 below)
2) How much gas do I use to find my way out of the cave? ALL OF IT!
3)You are not lost in a cave if you are on the line and using proper gas mgt protocols.
These principles fit the caves that I dive, the "popular" North Florida caves. For example, if you are diving one of Cindy's low, silty-no vis-possible no or very few line arrows- exploration-sidemount caves, do not reply to my post, it doesn't apply. If you are diving a cave that is a 10-minute swim from wall to wall and is 300 feet deep, again, a new plan is in order.
Bob