Just to chip in, I subscribed to Scuba Diving Magazine and they sent me a little book with 200 tips for better diving. Yada, yada. Thumbing through the book, almost on the last page happens to be the FAQ section. I will type it in ver batim and let you all make your own assumptions. And please don't respond by telling me that Scuba Diving Magazine isn't a sanctioned scuba instructor organization. I think I figured that one out myself.
FAQ #7
It's been drummed into my head since my open-water class that I should never dive deeper thatn 130 feet. Other than decompression condierations, is there some reason that the diving community set an absolute limit on depth?
Response by Magazine:
In the 1950's, the U.S. Navy set the depth limit for its divers at 130 feet primarily for the reason of human performance with the regulators of that era. At around 130 feet, the performance of regulators of that era would diminish significantly and the work of breathing would increase to the point that it became unsafe for divers to routinely go deeper.
The recreational diving community adopted the 130-foot limit established by the Navey as gospel, and it has since become as deeply ingrained in redreational diving as the commandment that prohibits holding your breath. But regulators have come a long way in the last 50 years, and there are now models that perform as well at 260 feet as they do at 130 feet. The original rationale behind the depth limit no longer applies. But does that mean you should head straight for 140 on your next dive? Not necessarily.
There are plenty of reasons to stay shallower. Very limited no-deompression times are a significant consideration for recreational divers, as is limited air supply. The deeper you go, the faster you get into decompression. The deeper you go, the faster you use your air. The deeper you go, the harder it becomes to make an emeregency ascent. The deeper you go, the greather the chance of nitrogen narcosis. And the deeper you go, the more problems are magnified.
The face is that for most recreational divers, including all those without advanced training, the depth limit should be less than 130 feet. For some divers with advanced skills, the 130-foot limit is appropriate. But for others, who have the skills, the equipment and the confidence, 130 feet shouldn't be the absolute barrier just because they've always been taught that it is.
End.
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So, that kind of opens up a new can of worms for people who like to hardline accepted guidlines. I mean, the magazine does a good job of explaining both sides of the deeper diving equation, but people who live in absolutes probably had to wire their jaws shut after they hit the floor.
Maybe that will help this topic along as I really haven't seen a post on the subject that was quite as informative as the Scuba Diving Mag. excerpt.
