I have never liked this silly 'coined' term Triox.
Agree. There is air. There is nitrox. And, there is trimix. You could argue heliox, but really they are all flavors of the core three.
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I have never liked this silly 'coined' term Triox.
All the NAUI books are metric-enabled. In fact, they usually write things like, "...still for actual depths from 21 meters (70 feet) to 33 meters (110 feet),..." (p. 55). Examples may be in "U.S./Imperial", but they are usually accompanied by metric examples (or "The procedure is identical in an S.I./metric calculation." for some that are trivial). All the charts are either multi-system (dive tables) or in pairs (figure 4-1a in fsw, with figure 4-1b in msw right below).
(They're called "NAUI Worldwide", so it'd be a crying shame if we couldn't work in meters and bars. On second thought, forget the meters. )
Well, I seem to be flat out of firstborn, for one.
Recreationally speaking, you are wrong. Run a 120 fsw dive for with 15 minutes of bottom time utilizing ean30 and then trimix 30/10. The END for ean30 is 103, and the END for 30/10 is 83. The NDL is the same, but the narcosis level is 20 feet less. What you speak of comes from He ongassing quickly and offgassing quickly. On decompression dives this is important with much longer and deeper dives, but for recreational dives, it isn't. The only big thing to remember when diving recreational trimix vs nitrox is to utilize a very slow ascent rate, which you should be anyways.
Trimix is an extension of nitrox and solves the remaining problem, narcosis. I didn't mix it into the NDL discussion, but merely made an insignificant comment. But thank you for allowing me to show your ignorance on the subject since you would like to expand on the conversation. BTW, Recreational Trimix is a course and is aimed at NDL diving. I'm starting to wonder what level of diving you actual do? You sound like the antagonists of nitrox back in the day.
I never said anything about extending NDL by using trimix. Where did you get that from? I said trimix has all the benefits of nitrox without the narcosis. You obviously have a hard time understanding a simple sentence like that. Go get some education on the matter.
a little bit off-topic here, but: could someone please explain to me why nitrox is not optimal past 100 feet (or another number close, like 110 feet). i see people always mentioning that you shouldn't use it once you go past a certain depth. why not? and what would you want to use instead? trimix?
You increase the bend risk significantly by mixing helium into your mix, and should you get a hit, it's likely to be more severe. Sounds like a great idea for the average recreational diver, doesn't it?
Trimix does solve narcosis, but narcosis is not a problem within recreational diving limits.
Maybe so, I'm not an expert on the physiology. In the TDI training I did, the mantra was 'A fast ascent on air and you'll hurt. On Trimix, you will almost certainly die' - Now of course this applied primarily to missed deco and fast ascent, but the point was that Helium is less tolerant to rapid ascents because it bubbles quicker. This would be because it comes out of solution quicker. Blood is also a tissue in terms of the deco obligations, which has similar characteristics to water - We've all seen the coke bottle example, and helium fizzes more than CO2, so you make up your own mind..That's debatable. When helium deco tables first came out, they penalized it because it is light. However since Helium isn't very soluble in our tissues, it's not really a problem.
I've been narced enough in cold water at 90-100 feet that I couldn't swim in a straight line (midwater no visual references).
Maybe so, I'm not an expert on the physiology. In the TDI training I did, the mantra was 'A fast ascent on air and you'll hurt. On Trimix, you will almost certainly die' - Now of course this applied primarily to missed deco and fast ascent, but the point was that Helium is less tolerant to rapid ascents because it bubbles quicker. This would be because it comes out of solution quicker.
Hey, I'm diving in the UK, so know where you're coming from. Midwater free ascents in strong current, bugger all visibility and cold water can be really sucky sometimes... - However, although narcosis can be noticed at 30 m (100ft), it is nowhere near as debilitating as it is on 50 -60 meters
The owner of one of the shops in town won't even let his employees dive with regular air unless they are just going to be in a pool training.
empirical evidence shows that if the Partial Pressure of O2 reaches about 1.6, there is a strong possibility of Oxygen Toxicity, which causes convulsions and may therefore cause you to spit your regulator out and you will die unless your buddy can save you by keeping your regulator in your mouth and taking to a shallower depth.
But if it were possible to suck on pure oxygen at 150 feet for an hour, it could bend us.