I was recently buddied up with someone I had never met on a 2-tank dive on a wreck at the limits of recreational diving. We chatted briefly before the first dive, and he indicated that he was an experienced diver. He also said he was very conservative in his diving. I noted that he was using nitrox, but I did not look at his MOD sticker. I saw that he was using a Shearwater Petrel, an advanced computer used primarily by tech divers. I was using 27% nitrox for the first dive, and I was using Shearwater computers myself.
The first dive took us to 130 feet, and I saw that his skills were very good--he did indeed look to be quite experienced. When I got to NDL, I indicated that and moved to the ascent line. He indicated that he was going to stay for a while longer. I was puzzled--how did he have more NDL than I did? Maybe he had 30% in his tank. Oh well, I was not his keeper. I started up the line, and he followed about 5 minutes later.
On the boat, I asked him about his computer settings. He said he had his computer set to GFs of 30/85, which he said was "very conservative." I realize that I am writing in the Basic Scuba forum and most people will not know what that means, but I will summarize: he had his computer on technical diving settings that would have ended his dive for NDLs sooner than mine. By saying it was "conservative," he meant that when he went into decompression, the computer would make the first stop deeper than a recreational computer would. I mentioned that although most people do indeed use the word that way, I personally do not agree with that usage--I think staying deeper longer on such a dive is not conservative.
Most importantly, in that conversation, I realized he did not understand what I was talking about. Even though we had just met, I resolved to pay closer attention to him on the next dive. On that dive, we did not go nearly as deep. As I approached NDL, we were on the far end of the wreck as I approached NDL. This time, instead of signalling him, I went over to him and looked at his computer. He was already well into deco, with the computer indicated he had to do a 5 minute stop at 20 feet. I very forcefully signalled and headed the length of the 350 foot wreck to get to the ascent line. By the time we had ascended, his computer was requiring 10 minutes at 20 feet. I stayed with him all the way so that he could share air with me in case of a problem.
Back on the boat, I had a brief and polite, but still firm, discussion about doing so much deco with no redundant gas supply. He indicated that he did 5-10 minutes of decompression on every dive. He had had no technical diving training, and it had never occurred to him that if he had a loss of gas, he would have to surface with a deco obligation. He obviously did not understand the theory behind that kind of diving. He was just adding time at depth, the way his computer was telling him to do it.
This is just a friendly reminder to all recreational divers that carrying a technical diving computer and keeping it in tech mode does not make you a technical diver. There is a reason technical divers go through all that training and carry that extra gear--if something goes wrong at depth, you cannot go to the surface without a significant risk of DCS. You have to be able to solve your problems at depth.
Most of all, setting your computer on decompression settings that some people call "conservative" does not make you a conservative diver.
The first dive took us to 130 feet, and I saw that his skills were very good--he did indeed look to be quite experienced. When I got to NDL, I indicated that and moved to the ascent line. He indicated that he was going to stay for a while longer. I was puzzled--how did he have more NDL than I did? Maybe he had 30% in his tank. Oh well, I was not his keeper. I started up the line, and he followed about 5 minutes later.
On the boat, I asked him about his computer settings. He said he had his computer set to GFs of 30/85, which he said was "very conservative." I realize that I am writing in the Basic Scuba forum and most people will not know what that means, but I will summarize: he had his computer on technical diving settings that would have ended his dive for NDLs sooner than mine. By saying it was "conservative," he meant that when he went into decompression, the computer would make the first stop deeper than a recreational computer would. I mentioned that although most people do indeed use the word that way, I personally do not agree with that usage--I think staying deeper longer on such a dive is not conservative.
Most importantly, in that conversation, I realized he did not understand what I was talking about. Even though we had just met, I resolved to pay closer attention to him on the next dive. On that dive, we did not go nearly as deep. As I approached NDL, we were on the far end of the wreck as I approached NDL. This time, instead of signalling him, I went over to him and looked at his computer. He was already well into deco, with the computer indicated he had to do a 5 minute stop at 20 feet. I very forcefully signalled and headed the length of the 350 foot wreck to get to the ascent line. By the time we had ascended, his computer was requiring 10 minutes at 20 feet. I stayed with him all the way so that he could share air with me in case of a problem.
Back on the boat, I had a brief and polite, but still firm, discussion about doing so much deco with no redundant gas supply. He indicated that he did 5-10 minutes of decompression on every dive. He had had no technical diving training, and it had never occurred to him that if he had a loss of gas, he would have to surface with a deco obligation. He obviously did not understand the theory behind that kind of diving. He was just adding time at depth, the way his computer was telling him to do it.
This is just a friendly reminder to all recreational divers that carrying a technical diving computer and keeping it in tech mode does not make you a technical diver. There is a reason technical divers go through all that training and carry that extra gear--if something goes wrong at depth, you cannot go to the surface without a significant risk of DCS. You have to be able to solve your problems at depth.
Most of all, setting your computer on decompression settings that some people call "conservative" does not make you a conservative diver.
