Canuk:
A friend of mine went for his first cave dive in Hawaii. He was part of a charter of 4 and they visited an underwater volcano and swam though maze of lava tubes into a large room. I asked him if they strung or followed lines etc, he said no because one of charter guys "knew the way". I'm pretty much a newbie diver -but this struck me as pretty unsafe thing to do..follow someone in..what if you lost the only diver who knew the way out?
Even if you know the way...I can't see this being a wise thing to do...comments?
Canuk
I agree with you, it is NOT a wise thing to do.
I just finished my full cave certification last week and through the training I was exposed to the risks and instructed in ways to mitigate those risks to what are generally acceptable levels.
Think about it, if YOU were in this lava tube and YOU became separated from the other divers in what you have described as a "maze" would you be able to absolutely guarantee that you could get out before you run out of air? If there is no line run and you loose your light, could you get out? What if that was the moment that your mask was kicked off by the diver in front of you and you could not find it, do you have a spare? Was the passage restricted to prevent side by side diving? If it was, could you share air with another diver who through poor planning or bad luck was unfortunate enough to run out of air at just the wrong time? These scenarios may seem remote, and thankfully are not that common. If they happen on a regular open water dive they will inconvienience you, and will probably cut short your dive. They might even scare you a little in the process. If these things happen to you in a cave or cavern you could quite easily end up dead.
I may get slammed for my reply here, many people consider "little" or "managed" exposures to caverns or caves as OK. Some people have the opinion that if you are with a guide you will be OK. I am not familiar with the specific lava tubes you are talking about, it is possible that these are no more complex systems than a couple of 10' swim thrus. I do not know. If they are simple little swim thrus then my message most likely does not apply. If however they are real overhead caverns or caves that have considerable horizontal penetrations and possibly currents that push you into the cave making a swim out a difficult workout, then my message here is worth considering. Remember, THERE IS NOTHING IN THAT CAVE WORTH DIEING FOR! This may sound harsh, but pause and think about it.
Your reaction is correct, it does not seem like a good idea to enter the lava tube with that group. But if I were you I would not enter it even if a line was run. A line is only one of the things needed to safely exit a cavern or cave, there is a lot more to it than just the line.
Mark Vlahos