spacemanspiff1974
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I find 20 feet much more manageable for deco stops/safety stops in the ocean. I suppose 10 feet would be fine in a lake.
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I was just wondering - it seems a little arbitrary. Does that mean that a safety stop at 20 feet is less safe? Or one that begins at 20 ft and ends at 10 ft 3 minutes later won't allow proper off-gasing? Or, what if there is a very convenient place to stop at 25 or 10 feet, but not at 15? Should I try to hover at 15 anyway?
Here are the givens, from the theoretical scientific laws of the physical universe, as least for here on this Earth (the planet Jupiter would have different laws of physics):
It makes sense, but is not at all correct.OK - so if DCI doesn't begin to occur until 33 ft or more, then that means that at 33 ft the human body can off-gas at the same rate at which the nitrogen would collect, meaning that no additional nitrogen will develop.
Does that make sense?
It makes very little difference to your deco. Do what's convenient, what's pretty, whatever. quote]
Absolutely... unless it's mandatory deco, you can do your safety stop where ever you want, within reason of course.
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Other thoughts...
Remember, the primary reason for a safety stop is to compenstate because most divers ascend too quickly. If you don't ascend too quickly then you don't need to insert an artificial shallow stop to compensate. However, most divers now do both ascend slowly and do a safety stop, which adds extra conservatism. It's good practice, but it also makes the mechanics of the SS less important, allowing more freedom and flexibility. As long as you're not in deco, your computer shouldn't care either.
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Other than creating difficulty holding your position, wave action doesn't affect deco. No one ever got bent because a wave passed over while they were doing deco.
OK - so if DCI doesn't begin to occur until 33 ft or more, then that means that at 33 ft the human body can off-gas at the same rate at which the nitrogen would collect, meaning that no additional nitrogen will develop. Therefore, it can be assumed that at anything less than 33 ft the human body is able to off-gas faster than the nitrogen is building up.
Obviously every human body is different. However, assuming the above, 15 ft. is pretty arbitrary, and in fact any time that you spend at less than 33 ft. allows off-gas time. Therefore, it would seem to me that a stop at 30 ft followed by another at 20 or 15 would make more sense, or even better would be to slow your descent so gradually at the 30 ft mark that it takes 4-5 minutes to surface from 30 ft. That would allow for the most gradual return to normal as possible, and it is safe because as long as you are less than 30 feet you aren't taking on any more nitrogen.
Does that make sense?