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If you are not surfacing with a GF greater than 80, why not just set GFHi to 80? Then the computer will adjust the NDL or deco depths and times to bring you to the surface at or below 80.

In my above post I chose two dives with GFLo/GFHi of 30/80 and 80/30 because the graph I included used those GF's. Using the same profile as above but changing the GF's to GFLo/GFHi = 70/90 and 90/70 gives these results for a profile using: air to 180 ft for 20 min, 60 ft/min descent rate, 30...

Some studies indicate that some deep stops were maybe too deep. So, the tendency now is to make the first deco stop shallower by setting GFLo higher. But, reversing GF's so that GFLo > GFHi is not the way to plan for shallower first stops. In fact depending on the GF's used could result in a...

Yeah. It's not how you look getting into the water, it's what you look like under the water that counts.

Fixed it. Clicking on the link above will work.

I forgot about TTS (time to surface). Of course, an assumed ascent rate is needed to calculate the time it takes to get to the surface without exceeding GFHi. I was thinking only of the calculations for ceiling and NDL NDL doesn't need to predict the ascent rate because it is concerned solely...

That's correct. At the current time, there are no dive computer options you can download that mimic crystal balls.

The dive computer makes calculations based on the current conditions of your dive. No calculations are done based on assumed future data (i.e. ascent rates). The dive program is on a loop that repeats every second (this could be faster or slower on some computers). Every second, tissue...

When the group does a deco dive do you decide on a plan using the same algorithm or do you let each student follow their own plan using their own algorithm and settings?

Is it monotonic or monotonous?! :)

Well, because of the gravity of the situation it's all relative anyway.

The faster TC's (tissue compartments) are already set for higher m-values throughout the entire dive. Take a look at the m-value tables for Buhlmann ZH-L16 in the paper "Understanding m-values" by Erik C. Baker, P.E.. Included are values for half-time (HT) and slope. Unless you're doing a very...

For any change we make, especially a change made to the models, we have to ask: What benefit do we get out of it. Setting GF's for 16 tissue compartments makes things more complicated and may have unattended consequences for our safety. We already don't know exactly how conservative a dive will...

This is the key answer. Personally, I will not go through any swim through restrictions that are over about 6 ft. unless my buddy(s) are on long hoses and everyone has discussed the hazard pre-dive.

I added the altitude capability to my spreadsheet. You can enter the final destination altitude and the time it takes to get there and it will happily calculate all the tissue compartment pressures, CurGF, SurGF, and more. It adds an altitude segment after the surface interval (air and O2 if...

I think the rule of "don't drive over a 5,000 ft mountain pass" after a dive has to do with the lack of tracking the pressures in your tissues as you ascend the mountain. Whereas, on a dive at 7,000 ft altitude your dive computer is tracking your tissues and will adjust the NDL time accordingly...

Sorry, I wasn't clear. The last few sentences of my post above refer to people at the shore diving under a breaking wave to escape it, NOT scuba divers out at sea.

One more piece of information on waves I found fascinating. There are generally two types of waves: wind-driven and tsunamis. As indicated by the description wind-driven waves build up by the wind. You can always dive under these waves to calmer water below although for very large waves you may...

The current version of my scuba dive excel spreadsheet allows entry of an altitude and all calculations will be based on using that altitude. It also supports two nitrox gasses for accelerated deco and breathing 100% O2 on the surface followed by an air surface interval if needed. Each dive...

The book I read is called "The Power of the Sea" by Bruce Parker a former chief scientist of the National Ocean Service. You can get it from Amazon. Another interesting fact regarding waves the book mentioned is their power. Wave power goes up by the fourth power of the height. For example...