Dissimilar Tank Matching

[twaldo]

If you're bad at math just print this, laminate it, put it in your wet-notes, done. If you need to add another size tanks, feel free to copy the contents into a spreadsheet, add your new tanks, and print it out.

my dive buddy dives same tanks... pretty much everyone else I've dove with either also had LP85's or turned when I hit 3rds since I was the smaller volume tank. It will be interesting to see how Chris's request influences the turn volumes.

The intent is to get a collection of scripts that meet the tek diver needs and build them all into a single Android application. And who doesn't have their cellphone at the dive site now days??

[kensuf]

I don't bring my phone in the water, I don't calculate gas reserves until I'm in the water, and my cell phone looks like this:

[Draker]

With sidemount I don't bother gas matching now, it is every man for himself. I always keep enough reserve for me in my left bottle to get out, but if you need it, you get to figure out how to get out on the right bottle. It's rather rude I guess, but in sidemount if you can't get out on your own gas then you did something really bad....

Welcome to the Jungle.

Boys and girls, please choose your dive buddies wisely.

This sort of attitude can help contribute to your death.

As evidenced a few weeks ago.

[tbone1004]

this is a mutual decision between myself and my dive buddies btw. We will always offer the gas in our right tank which is why we have a long hose on there if needed, but #### better have hit the fan real bad before that ever happens... If you're in sidemount you screwed up royally *note, you not your equipment* if you actually have to use your buddies gas. In backmount it is different and if I'm diving mixed teams we do proper gas matching, but in sidemount you shouldn't have to. What happened a few weeks ago had little to do with buddy issues, the dive team was stupid and didn't bring enough gas for that dive, they screwed up. Again, the ONLY time you should EVER have to share air in sidemount, is if something happens to the valve or you have a catastrophic first stage failure, in conjunction with something happening to the other valve. I.e. when my Hog first stage literally exploded in Peacock, if I had a valve failure on the other side, then yes you would likely share air out of convenience, but the odds of that happening are essentially 0, so why worry about it? You can feather valves, any good sidemount instructor should have taught that to you in your cave class or sidemount class, and with two fully redundant systems, each containing a full third of your gas supply for exit, you shouldn't ever have to share air in a full sidemount team.

[cavekrazi]

this is a mutual decision between myself and my dive buddies btw. We will always offer the gas in our right tank which is why we have a long hose on there if needed, but #### better have hit the fan real bad before that ever happens... If you're in sidemount you screwed up royally *note, you not your equipment* if you actually have to use your buddies gas. In backmount it is different and if I'm diving mixed teams we do proper gas matching, but in sidemount you shouldn't have to. What happened a few weeks ago had little to do with buddy issues, the dive team was stupid and didn't bring enough gas for that dive, they screwed up. Again, the ONLY time you should EVER have to share air in sidemount, is if something happens to the valve or you have a catastrophic first stage failure, in conjunction with something happening to the other valve. I.e. when my Hog first stage literally exploded in Peacock, if I had a valve failure on the other side, then yes you would likely share air out of convenience, but the odds of that happening are essentially 0, so why worry about it? You can feather valves, any good sidemount instructor should have taught that to you in your cave class or sidemount class, and with two fully redundant systems, each containing a full third of your gas supply for exit, you shouldn't ever have to share air in a full sidemount team.

Problems often multiply in failure situations. People do screw up royally when stressed. The##### does hit the fan. You would feel pretty helpless if those "0 odds" hit one of your friends and he was staring you in the face waiting for help. It happens. I think you have thought this in a reasonable fashion...but maybe you could take it to the next level with a mental tweek...might make you a better buddy...or not. Just thinkin out loud. t

[kensuf]

What happened a few weeks ago had little to do with buddy issues, the dive team was stupid and didn't bring enough gas for that dive, they screwed up.

What do you base this statement on? I would think anytime you leave your buddy to swim out from 3000' back in a cave, and are on the surface with 1500 psi in your tanks when he has run out of air 300' from the exit, there are buddy issues.

[cmint]

I use a similar cheat sheet. I have this chart in wet notes written big enough that I don't need my glasses on. Mine has pressure, thirds and cubic feet to be used on entry. My buddy dives double 108's and I dive LP 85's sidemount. It takes about 3 seconds to match with this.

[tbone1004]

we have made a conscious decision to adopt solo diving with the same general proximity. It is a mental change that involves bringing higher levels of safety. An extra buddy bottle comes in for all dives more than one stage *Granted that is for the "team"*, we are all prepared for multiple failures. No level of team mentality could have fixed what happened in Ginnie, only better diver preparation would have all but guaranteed success. One buddy bottle dropped when they had hit sixths while scootering would have been more reliable than the buddy waiting. There is no reason you can't plan solo dives in the same cave, and with a fully redundant dive system, no reason we can't safely dive like that.

That all being said, our tanks are matched fairly close, PST 120's vs 104's, and that is my buddies decision not to gas match just as much as it is mine. Plan well, treat every dive like a solo dive, that is what I don't like about the "team mentality", and have never liked. They rely on other people and their actions far too much. I rely on me, if I screw up, then I screw up, I shouldn't ever have to rely on my buddy to get me out of a situation. If I have to rely on a buddy then I had no business doing that dive in the first place. My buddy is there to help make situations slightly less stressful or a bit easier, never to the point where I have to rely on him, if you are relying on your buddy it is no better than a trust me dive.


Ken, no guarantee the buddy would have been able to find said diver, the diver was clearly on the line, would it not have been better if there was a full AL80 1500ft back for him to grab and use? I don't know the whole situation, I try my best to avoid discussing accidents until the reports are published, but if that diver was found OOA 300' from the entrance, he would be alive today if they had taken a buddy bottle in and dropped it even 500ft back in the cave. That was poor dive planning, compounded by an unfortunate situation, sure if diver1 had stayed or gone back in the cave *which I would have btw, alert the surface and head back in until you hit thirds in that situation, or whatever* but if the divers had planned that dive as a solo dive, there would have been at least one safety bottle back there and we wouldn't be having this discussion.

[cmint]

What do you base this statement on? I would think anytime you leave your buddy to swim out from 3000' back in a cave, and are on the surface with 1500 psi in your tanks when he has run out of air 300' from the exit, there are buddy issues.

She might have just suddenly looked around, realized her buddy was nowhere to be seen, then had no clue whether he'd left her and headed out or was further in and having trouble. It's possible, to her, he just *poof* vanished and she assumed he might have left.

I have a friend that I don't dive with any more because I've had to swim out of a cave twice not knowing if he was dead or back at the steps. I feel bad because he's a really good diver otherwise but flaky as hell. Once he was the diver on the tail end, I was the lead diver and my regular buddy was in the middle. Apparently he told the middle diver he was leaving for us to continue. The middle diver didn't tell me. When we turned I was like "Where is he?" the reply was "he left" ... so the whole swim out, I'm looking around on the ceiling to make sure he didn't have problems on the way out and was dead. The second time we were a team of three diving with a team of two. He decided to swim off with the other team in the middle of the dive. After that I decided enough was enough. I never said anything to him, but he doesn't get a text when I go diving now.

I don't do dives like they did, I don't scooter. From everything I read the protocol is to drop stages along the route. It sounds to me like the mistake was not to leave emergency bailout gas along the route.

FWIW, from everything I've read, I don't fault her for not searching every inch of cave back there if she truly didn't know whether he was in trouble or already gone.

[cavekrazi]

She might have just suddenly looked around, realized her buddy was nowhere to be seen, then had no clue whether he'd left her and headed out or was further in and having trouble. It's possible, to her, he just *poof* vanished and she assumed he might have left.

I have a friend that I don't dive with any more because I've had to swim out of a cave twice not knowing if he was dead or back at the steps. I feel bad because he's a really good diver otherwise but flaky as hell. Once he was the diver on the tail end, I was the lead diver and my regular buddy was in the middle. Apparently he told the middle diver he was leaving for us to continue. The middle diver didn't tell me. When we turned I was like "Where is he?" the reply was "he left" ... so the whole swim out, I'm looking around on the ceiling to make sure he didn't have problems on the way out and was dead. The second time we were a team of three diving with a team of two. He decided to swim off with the other team in the middle of the dive. After that I decided enough was enough. I never said anything to him, but he doesn't get a text when I go diving now.

I don't do dives like they did, I don't scooter. From everything I read the protocol is to drop stages along the route. It sounds to me like the mistake was not to leave emergency bailout gas along the route.

FWIW, from everything I've read, I don't fault her for not searching every inch of cave back there if she truly didn't know whether he was in trouble or already gone.

I like your assessment and I like your gas match table. What happened to staying with your team or leaving a light or a note on the line if you got separated????