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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...

I read in a book about the dangers of storms at sea. The research said that non-breaking waves (swells) can never capsize a boat no matter how large. However, waves that break will always capsize a boat if the wave height is as high or higher than the boat is long. Also mentioned were three...

So, let's keep the conversation focused on the calculation of NDL. I'm currently diving at a depth of 60 ft. I glance at my computer to discover that my NDL is 30 minutes. At that point in time I have three options: (1) I can stay at the current depth, (2) I can go deeper, or (3) I can go...

Yes. However, you must realize that you are applying a human trait to a computer program that cannot do any thinking. The dive program simply processes real-time data based on sensor input, stored dive profile parameters and past data. An assumption implies that there is a possibility of another...

Compare it to another analyzer known to be accurate.

I took the same course a few years ago. The book (copyright 2010) that came with the course was quite good except for the section on decompression theory. There were some outright errors and misleading statements. For example, on page 3-13 in regards to dive computer calculations we have this...

$1500 + luck + 25 years is not very encouraging.

We all need to trust someone at least to some degree. In regards to analyzing the O2 in the tank he can read the %O2 himself rather than taking someone's word for it. Also, to substantiate that the person has properly analyzed the tank he can ask someone else at the shop to analyze it. If both...

Sure. And that is another viable option but not for the novice or vacation diver unless you've got money to burn. I can see it now. "Honey, you know that expensive boat cruise with the dinner we were going to take, and that day of guided sightseeing? Well, we can't do it because I have to buy a...

Right, but my point was what instructors are doing. There are some instructors here on SB that still teach tables. Now, whether the students actually use them is a different matter. I still carry tables in my dive log book as an option. If my computer fails and I cannot rent one my preferred...

And for too many people the cell phone is their substitute brain. Back in 2011 when I got re-certified as OW I was taught tables. I didn't have any trouble understanding and using tables and even used them for a year before I bought my first dive computer. Looking back I can appreciate the...

I would highly recommend "The Complete Diver" by Alex Brylske. It's an everything you want to know about diving book.

I haven't read all 38 pages so maybe this has been addressed earlier. If you don't need to look under the water why not inflate your BCD/wing so that you ride higher above the water?

During your OW/AOW course your instructor (should have) taught you to check your gas remaining and NDL time remaining frequently especially as you go deeper. A very low NDL is not a concern for panic. For example let's say you get distracted and check your gas and NDL. Gas remaining is good but...

No stop limit (NSL) and no decompression limit (NDL) are the same. I prefer NSL as that term conveys the idea more accurately. In the calculation of NDL there are no assumptions, estimates or guesses. The calculation is based on the amount of inert gas the CTC (controlling tissue compartment)...

I think you're confusing GF with GF99. As Dmaziuk has already pointed out GF increases from GFLo to GFHi. It never decreases. You keep saying total ambient pressure. The total ambient pressure in the inspired gas includes both N2 (and possibly He) and O2. O2 does not contribute to DCS. It is...

What do you mean by "your chosen GF"? GF99 is calculated the same way that GFLo and GFHi are using the inert gas pressures. If we determine the first stop according to GFLo and follow a continuous ascent to the surface arriving at GFHi, the computer would need to calculate a current GF based on...

The more I think about it there would be a step change because the inert gas at ambient pressure is changing instantly at the switch from 52.14 to 0 fsw.

No. It won't be a step change because the new value of inert gas in the tissues is not just defined by the difference but by the half-time of the controlling tissue compartment according to Schreiner's equation.

Actually, it would be the opposite. GF99 would increase because the rate of off gassing would increase. For example: breath air (21% O2 + 79% N2) at 33 ft of sea water until the tissues are saturated, then switch to 100% O2. Let's neglect the MOD of the O2 for arguments sake. The total pressure...