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    Should TDI Helitrox replace AN+DP?

    From these reports (as well as the previous years' and BSACs) I see that most fatalities are related to cardiac problems, low level of fitness, in combination with "being alone in the water" (group fell apart, diver with problem was alone). Now about deep air, if 150ft "deep" air dives were so...
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    Should TDI Helitrox replace AN+DP?

    Of course there were many fatalities when they chased deep air records in the 1990s when Gilliam made his successful 450ft record air dive, and the 1980s with Exley's cave dives to 360ft with air. That was far deeper than the range you're discussing here. They wouldn't have called 150ft "deep...
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    Should TDI Helitrox replace AN+DP?

    IIRC, IANTD Advanced Recreational Trimix certifies you to 51m / 170ft, whereas Advanced Nitrox is only to 42m / 140ft, isn't it? Anyway, the classes are almost the same. So it makes sense for the student to take ART instead of AN no matter what he's diving after class.
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    Article on deep stops

    Buhlmann's experimental dives in lakes and ocean were done to 350m (1150ft). He worked also with Hannes Keller, for his record dives to 230m (750ft) in 1957 in the Lago Maggiore, and to 305m (1000ft) in 1962 near Santa Catalina island. Buhlmann's work was funded by Shell Oil. They were not...
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    First cave dives

    How about this concern: you guide an inexperienced customer first time into a cave and he stirs up silt and panics. Or there's some other "minor" inconvenience such as getting lost for a short time, swimming into a dead-end, and he panics. I think this is more likely than most gear failures and...
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    Article on deep stops

    Yes it should matter a lot. The question whether your first deepest stop is too deep due to loading slow compartments depends a lot on whether you do that stop on 18/45, air or EAN50. Therefore any strategy of choosing GF_low independent from gases used doesn't make much sense to me.
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    Best Mix VS Standard Gasses (split from a GUE fundies course report)

    OK got it. I'm all for clarity of the definitions, can only make the discussion easier. When calculating the gas in IANTD class, MOD and END were both considered, I didn't notice that "best mix" refers only to MOD. So you would say that both air and 21/35 are best mix at 56m (185ft) with...
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    Best Mix VS Standard Gasses (split from a GUE fundies course report)

    The link you gave were for SDI Nitrox class, of course without helium. See for example: Custom Mix vs. Standard Mix: Best Mix is a question of balance - SDI | TDI | ERDI they don't make that distinction for deeper dives with He, best mix / custom mix / optimal gas all the same, END and MOD are...
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    Best Mix VS Standard Gasses (split from a GUE fundies course report)

    Now you confuse me. You don't call a gas "best mix" because there's helium in it? These best mix calculations lead to the easy mixing of banked EAN32 and He instead of O2 blending for dives below 30m: At MOD with pPO2=1.3bar and END=30m (pPN2+pPO2=4.0bar), you get pPO2/(pPO2+pPN2) = 1.3/4.0 =...
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    Best Mix VS Standard Gasses (split from a GUE fundies course report)

    maybe time for another thread split ... deep air is not best mix. ^^this. Standard gas vs best mix is ease-of-use vs optimality (deco, cost per fill). A personal situation-dependent choice.
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    Best Mix VS Standard Gasses (split from a GUE fundies course report)

    P.S. I'd say every best mix is EAN32+He because this gives the right END at any MOD. Standard gases are just a once arbitrarily chosen subset of best mixes. Regarding the argument of changing dive plans on a boat: say everybody has 18/45 on the boat and you're the only one showing up with...
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    Best Mix VS Standard Gasses (split from a GUE fundies course report)

    This is all true and convenient, but works with many mixes such as 28/15, 26/20, 24/25, 22/30, 21/35, 19/40, 18/45, ... Standard gases are a subset of these. Others like 30/30 are not in this set.
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    Article on deep stops

    Buehlmann's experiments included chamber dives to 575m (1890fsw). His model was particularly developed for very deep dives.
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    Panicked diver this weekend

    So you lead and the beginner follows, swimming behind you where you don't see him. Not good. Why not swim next to each other along the line? The diver in the back is actually solo diving. He may be in serious trouble but nobody notices. If you had swum for 20s longer before looking back...
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    How much of a factor is age in scuba deaths

    When you look at the DAN Annual diving report (2018), the largest group are men aged 50-59, but as long as we don't know the distribution of the overall diving population we don't know the risk. Regarding the solo diving aspect of fatalities, most dives in DAN list "Unknown", while among the...
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    Accidental DECO and mild panic in a non tech certified diver.

    I'd wish so too, but the problem of the OP's sister is different: she didn't even follow PADI OWD training for the case that you accidentally exceed NDL time (= know your computer, abort dive, don't panic, follow your computer). OWD stuff has to work first before going into planned deco diving.
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    Why do you need training for normoxic trimix?

    Isn't the progression also about handling more stages? ART: 1 stage, normoxic: 2 stages and avoid switching error, hypoxic: leash, ...
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    How much of a factor is age in scuba deaths

    When you look at BSAC's annual scuba accident reports, most fatalities (~2/3) are probably related to a medical problem in combination with the victim being alone in the water incapacitated. "Being alone" is not only intentional solo diving, but includes divers lost by inattentive buddies while...
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    Best super macro lenses for Sony Rx100 IV

    Anyway the easiest approach is probably to start with the weak +6 diopter and get a sharp picture first. With the RX100 at 70mm tele zoom setting, the subject needs to be in a distance between roughly 5cm and 15cm I guess. The stronger diopters will only allow you to get closer for a better...
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    Best super macro lenses for Sony Rx100 IV

    Were you close enough? Macro lenses limit your maximum distance to the subject, 165mm for the UCL165 , 90mm for the ucl09, about 60mm for both stacked, or 40mm for the UCL900Pro. Anything further away can't be sharp. A stronger diopter will make things worse if you can't get close enough.
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