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Thank you for these links. The slides about yo-yo diving profiles add faster compartments to the model but don't show experimental data, so they can't show if the modified model has an actual impact on real-life DCS risk of yo-yo diving. RDP is interesting in that they really tested it with...

Bühlmann did a ton of experiments, dives with varying depth and duration, in order to come up with the a/b values in the ZHL model. Slow vs fast compartments may differ in how sensitive they are to DCS, but this is reflected in the model coefficients because they were fitted to experimental...

The safety stop after the NDL dive effectively reduces your surfacing GF. Hence, you pick a higher GF for NDL time calculation than for a deco dive.

Even if your computer does not extend the duration of the safety stop, you may of course overstay voluntarily and I found that this makes a difference to me, feeling better after surfacing. So if there's some jellyfish or a school of fish below the boat to watch for 10min, please do so and don't...

no, please see Doolette's paper https://apps.dtic.mil/sti/trecms/pdf/AD1215316.pdf p.28 last paragraph: "(...) , before a diver sets out to perform a repetitive series of three dives, each with 2.3 % PDCS , the risk of DCS on at least one of the dives is the binomial probability of no DCS on...

Please consider that iso-risk here means risk *per dive*. If you do three short recreational dives on one day with 2% risk each, then you have 6% risk on that day. Your friend did only one long tech dive on that same day with 6% risk for that one dive. Both of you had the same risk of DCS on...

I think when comparing BCD jackets vs BP/W the suit is very important. Note how different the shape of their bladders is. Drysuit divers love BP/W because they need a lot of lead and BP/W allows them to put a lot non-ditchable on the back. They also don't need BCD jackets' pockets because...

Batteries in devices with an internal charger (Qi, USB, ...) are usually not user-replaceable for safety reasons. The notable exception is the HW "OSTC plus" dive computer, and the accident happened at a trade show in 2019: somebody inserted a non-rechargeable battery, misconfigured the device...

Tillytec style. Very reliable, and can't turn on accidentally.

If you're mostly doing NDL dives at daytime then a LCD display will do and the issues that deco divers have with the Suunto style computers don't matter. As an older diver you may like the larger display of the Mares Quad.

I've used seal-on-seal gloves for some time now. drawbacks: needs practice and must trim the seals correctly in order to don and doff easily by yourself. Better practice at home before first dive. advantages: found it very reliable, easy to check if they're sealed (no wrinkles), never got wet...

If your last stop was on O2 at 6m/20ft, then you should ascend very slowly like 1min per 1m/3ft. Maybe that's what he meant with adding a few more minutes. I set my computer to a not super conservative value like GFHi=80, then add conservatism manually depending on the situation and environment...

note that it's not only the illness itself but also side effects of medication that can make diving unsafe. We had a fatal accident in a nearby lake in 2014 where a diver told her buddies she wants to return, swam back alone, fell unconscious and drowned in shallow waters only 30ft from shore...

It's not clear to me either what is the best factor to use. The rules of the Deco 2000 tables created by Bühlmann's coworker Max Hahn and used by German/Austrian/Swiss sports divers even ask for a factor 1,5x on the bottom time (+50%) for dives with longer phases of hard work, which has been...

got it, agree. If you use 50/80 initially, you could go down to 50/70 for working dives and that makes sense to me, too. Fits also to the concept with virtually extending bottom time: For example, say we have a 20min@40m (130ft) dive with air only and get a decompression schedule with GF50/80...

I don't hold to that theory and wouldn't suggest to move time from shallow to deep, like 20/80 or VPM does. I think that exertion at depth increases the decompression obligation in every tissue, fast and slow. That's an argument to prefer for example 40/70 over 50/80, but not a reason to pick...

Standard answer ;-) : You never want to on-gas more. You want to keep fast tissues from bubbling too much, in order to avoid an early in-water DCS hit. His specific problem is that due to high work load in a short bottom time, his medium-fast tissues may be more saturated than usual compared to...

Your choice of GF_low was a reason why I brought up the little test with work load and extending bottom time in MultiDeco. If you assume faster on-gassing in your medium-fast tissues by exertion at depth, then you want to pull your first stop a bit lower and GF_low=30 is not as over-conservative...

different idea: since you have a small group of divers repeating the exact same profile many times, why not bring a Doppler bubble monitor and record their bubble grades? That could be interesting for them to see, how does it relate to exertion at depth, and also to adjust the decompression...

Funny, isn't it? But +50% more perfusion is not excessively pessimistic for a strenous working dive in warm water. Looking at DCS incidents statistics, exertion at depth such as swimming against a current is a major contributing factor to "undeserved" hits, indicating that this problem is...