How is the best way to go about understanding algorithms?
Step one is ignoring the INCESSANT SALES PITCH of a dive gear salesman in response to a very pertinent question.
Step two is to start reading about the concepts of multiple 'tissue compartments' and 'fast vs slow' compartments. There's a pretty good explanation in the PADI encyclopedia of recreational diving, then you can expand your reading.
Here's a thumbnail sketch of the concept. Human physiology is such that the most accurate way of predicting the body's reaction to breathing compressed gas while diving at various depths involves the formation of theoretical-not actual- 'tissue compartments.' Each of these compartments is thought to both absorb and release dissolved N2 at different rates. It's important to understand that while the whole concept is based on our bodies, it's not like each 'compartment' represents an actual part of the body. The compartments are really just mathematical models. The different algorithms assign somewhat different time limits for each compartment, and some are based on a higher number of compartments, and some add in other factors. But what's in common is that depending on how you dive, one or more of these compartments will eventually load up with N2 to the point at which you can not surface safely. That's when your NDL is zero and you must do decompression stops. How you get to that point, and how quickly you can off-gas enough to surface safely, is somewhat dependent on the particular mathematical model.
One very useful bit of information you'll acquire when you start to study this stuff (and I'm hardly an expert) is that within recreational limits, it's thought that a 10 minute shallow stop, like 10-15 feet, is particularly efficient at removing excess N2 from our tissues. Part of the reason for this is that in recreational diving, it's the 'faster' compartments that often load up first, and those are also the fastest to off-gas, meaning N2 is depleted from them quickly AND they can tolerate higher pressure gradients, which means shallower stops.
Okay, how this has affected my diving is simple; I do long stops on every dive, particularly any dive where I'm pushing NDL at any point. I know that if in fact I do have enough N2 to risk DCS if I surfaced, the long stop is going to be very helpful in off-gassing. I've found that I experience way less fatigue after several dives if I do this. Besides, what's the hurry? I'd rather be hanging at 10 feet watching the underwater world go by than on the boat anyway.
---------- Post added January 21st, 2013 at 12:43 PM ----------
I generally dive solo. We chose our own level of back up, I've not had to use mine to date
Good diving, Craig
Fair enough! I wasn't trying to rib you about using the back ups.
