Did I miss some mysterious calculation? I don't follow why a 34 mins 19 meter dive will make pressure group P. Firstly I thought my eRDPML maybe defective so I borrowed another one, got PG "O", and I tried the traditional RDP, it says "O" as well.
I completed the Dive Theory Online program last week, and had a similar issue with the Imperial version of the same problem. I concluded there was an error in this problem, and noted it on the survey I received after completing the course. But, I now think it is actually a bit more complicated. There are two interesting variances:
1) In the Imperial version of the problem, the first dive numbers are 63 feet and 34 minutes. OK, makes sense. Sixty-three feet converts to 19.2 meters. And, working in Imperial mode in the eRDP, you do get a Pressure Group of P (rather than O) after entering the data. So, I figured the problem with the Metric version had something to do with rounding (19.2 meters down to 19), and went back and entered 20 meters for 34 minutes, assuming it would give a 'P' value. Nope, still Pressure Group O. Which causes me to wonder if there is an error in the eRDP ML.
2) At the same time, in the Imperial version of the problem, the answer choices are different from those in the Metric version: a) 36 minutes b) 20 minutes c) 21 minutes d) none of the above. In the Imperial version, the initial pressure groups also work out correctly - 'P' after the first dive, and 'R' after the second dive. But, when you use the eRDP to calculate the necessary SI for an R diver to go to 50 feet for 40 minutes, it gives 25 minutes. If you answer, 'None of the above', you are told that is incorrect, and that the actual answer is 21 minutes. Problem is, if you resort to the 'old fashioned' way, and use the RDP, Table 2 indicates that you need to be in Pressure Group L in order to go to 50 feet for 40 minutes. Using Table 1 of the RDP, the minimum SI necessary to go from Pressure group R to Pressure Group L is 25 minutes.
My conclusion is that there is a glitch in the Metric mode in the eRDP AND, there is an error in the DTO problem. Maybe someone else knows a secret we are missing.
