Help with simple deco algorithm project

[FreeFlyFreak]

Hi @FreeFlyFreak

I apologize, it turns out you were correct, The minor variations in NDL seen in the planner are due to differences in barometric pressure. I made additional observations, making careful note of the pressure. Due to a recent storm, I had a reasonably broad range from 986-1006 mbar. The shortest NDLs were at the lowest barometric pressure and the longest were at the highest pressure. There was a nice gradation between the two. I contacted Shearwater technical assistance, they confirmed this to be the case. Here is a summary table of my recent observations.

Thanks, and good diving,

Craig
View attachment 547928

Thanks for posting, makes perfect sense.
Lowered atmospheric pressure is just the same as diving at some elevated altitude and should lead to shorter NDL's, and the opposite for high atmospheric pressures.

It is also the reason that Shearwater recommends turning your computer on prior to diving even though it will turn on automatically a few feet down. It is safer for the computer to know the current pressure at the surface. That could always change though if a storm or front rolls through while you are diving.

Standard sea level atmospheric pressure is 29.92 inches of hg or 1013mb (rounded)