Good question!
I personally think Rubicon is a good platform, and I think Google-searches (scientific articles!) are a good tool.
I also think
Diving and Hyperbaric Medicine is a great source of knowledge; and they even make
publicly available all their journals after one year.
For earlier access, one can join, and there are also a number of good books available online relating to the topic.
I think in either case (hardcopy or soft), making such purchases are generally inexpensive in a scuba context, and a great way to support further developments in the field.
I wanted to avoid the mudslinging on these forums and ask one of the most knowledgeable people in the world, a known critic of deep stops and an occasional visitor to these forums Dr. Simon Mitchell. I asked him that while we are all appreciative of the fact that shallow stops are safer but exactly how safe are they? In other words, how dangerous are these UTD guys who are constantly bashed on scubaboard for their still "deeper than most" shallow stops? The answer that I got from Dr. Simon Mitchell was exactly what I have heard from UTD people who never visit these forums.
"if you did the same decompression time, but distributed your stop time shallower, then you would almost certainly have less risk, The actual difference in risk might be relatively small, and perhaps not worth arguing about." (Dr. Simon Mitchell to me during one of our personal chats.)
If memory serves, Dr. Mitchell can be quoted for more public statements of similar nature.
My understanding of it is, any risk difference may very well be neglible, and in either case, not presently quantifiable.
That is, we can't quantify the risk delta - but it's been attempted in this string and others (
in my opinion, crudely and oversimplifyingly so) with basis in the Spisni-trial[1].
Interestingly, this month, the Spisni-trial has become
publicly available in Diving and Hyperbaric Medicine as one year has lapsed since it's publishing. Link posted in reference below.
Rather than carry on the discussion on that particular perspective, I would invite anyone curious about the study and it's findings, to read the report which is now publicly available.
At recreational level, I did a few dives with UTD divers who were using bottom timers while I was using my computer. My computer did not give me any additional bottom time compared to Min-Deco that they were coming up with on their bottom timers. None!
Agreed, in either case, I think things need to be scaled up and aggregated (think NEDU-methodology)[2] to show any difference. At the rec level, we can even argue that maybe DANs recommendations (previous or current) pro deep stops take into account other factors than what we're discussing here; e.g. recreational divers' capacity for making a rapid ascend and a shallow stop, or rather the risk of missing that stop due to uncontrolled ascend. That may have been a factor that's been weighed up against any possible difference in risk relating to deep stop emphasis.
Much the same logic as when your doctor advises 5 pieces of green/fruit per day. Hardly an "optimal" diet, but in a world of contemporary dietary "solutions", a step in the right direction.
I attended a seminar by Nuno Gomes who was telling us about his nearly 1000 ft cave dives. He was asked what algorithm he used at those depths and he said that all these algorithms are reliable down to 500 feet. After that, they become unreliable and you will be surfacing with symptoms no matter what algo you use. You have to note down your symptoms and then modify your next dive based on your symptoms from previous ones and have an understanding of decotime vs bottom time ahem... RATIOS.
As per my understanding the notion that RATIOS are more reliable than computers and established algorithms also comes from this context where the limits of all algorithms have already been exceeded. Agencies who propagated the idea of abandoning computers, monitoring symptoms and using ratios were doing extreme exposures where decompression algorithms have already collapsed.
A fair point - I just feel it's safe to say that we'd do well to keep in mind where any difference would actually manifest itself.
And which divers would be doing those dives. And how many other real world factors would probably have a greater impact.
Scubaboard unite might well rather spend it's time bashing divers who eat bacon (talk about inflammation levels!).
On scubaboard folks seem to think that these agencies do not trust computers because electronics are not reliable! Some are saying that carrying a back up computer will eliminate the need for ratio deco and You can see pages after pages of debate about how a modern computer is actually more reliable that an SPG. No one looks at the extreme dives that Jarod Jablonski, Sheck Exley and Nuno Gomes were doing. No computer would get them out from the mess they were putting. It would be gauges, ratios and symptoms from previous dives that would guide the way.
Yes. I agree that it hasn't anything to do with trust or lack thereof, in electronics. My bottom timer is electronic. I'd happily sell or promote a backup light with an electronic switch. No problem.
It's just that I see practical utility in Ratio Deco, not least in relation to diver development. But Scubaboard seems to have a very strong opinion against it, seemingly because of a video on Youtube.
On a final note, a hat tip to Mr. Davis;
The irony being that the manual has been neglected from any update since 2003?
[1]
A comparative evaluation of two decompression procedures for technical diving using inflammatory responses: compartmental versus ratio deco. Spisni et al. Diving and Hyperbaric Medicine, 47(1), March 2017
[2] Redistribution of decompression stop time from shallow to deep stops increases incidence of decompression sickness in air decompression dives. Doolette et al. US Navy Experimental Diving Unit Technical Report 2011-06
