. . .The other way to get it [DCS] is to do a dive and then to do another quick dive down and come back up again. In other words, you've done a dive, you're getting out of the water and you are bubbling. Now you remember, "Oh, I left my oxygen bottle at 20ft." So you jump down with your mask on, grab the oxygen bottle and come right back up. Well, as you go down you compress the bubbles that are coming on the venous side enough to get by the heart, by the lungs. It just takes you a couple seconds to go down, a few seconds to go back up. Now they're expanding on the arterial side, and lodging in tissue. That's how we bent a bunch of support divers. That's how we found out about it. These guys didn't even do a dive, they'd be in a chamber. All he'd done is get oxygen bottles and be bent like a pretzel from that bouncing. Free diving after a dive, that's a classic one. . .
. . .You don't really have all this residual stuff during the surface interval. It doesn't really count. It doesn't really work that way.
You can go back in the water and do it again as long as you're not bouncing. Remember what happens when you bounce. Once you get out of the water you're still cascading bubbles. You've started that process. You get back in the water, go down and come back up. When you relieve the pressure that process is going to resume and you're going to cause yourself problems.
It's actually better to do deeper dives. But it's especially important if you're doing a second or third or whatever dive is that you stay down and ascend properly. You don't bounce it. You stay down and when you do come up that you do it meticulously. You really don't have to do a whole lot more deco on the second or third dive because you [should have] pretty much taken care of it by the first dive. And if you're in real good shape, you're going to be fairly clear after 30 minutes or so out of the water. And even if you're not in really good shape you're going to be, for the most part, clear. And you're not going to do any better if you're not in good shape. You get into that four-hour bit. If you go back in the water and recompress you're probably better off than if you're just sitting out of the water not diving. So you're not really going to have to, let's say, do twice as much or three times as much deco. I've done that for years, repeated dives and back-to-back dives, and it's never been an issue. But I also ascend real carefully. I think the bigger issue is tox. . .
http://www.frogkick.nl/files/george_irvine_lecture_to_baue.pdf
