- Messages
- 20,561
- Reaction score
- 14,946
- # of dives
- I'm a Fish!
Sorry, I've lost the bubble, starting at Tom's post #61. I thought the idea was to stay OUT of deco, not to compare how long you are IN deco with various GF pairs. 30 mins at 100 ft is only an NDL dive for a GFhi of 99, maybe 95. So what is the discussion about doing that dive with a GFhi of 70, for which it IS a deco dive and therefore the 30/70 and 70/70 bottom times WILL be different. Seems like a bunch of apples and oranges.
@KenGordon summed it up pretty well.
I have three examples of "NDL" diving at 100ft on EAN32 using different gradient factors to show how changing the GF hi would adjust the NDL, but also how GF lo would adjust it. I put the first NDL in quotes because I'm using GUE's deco planner and NDL isn't an option so you have to play with it and the minutes may be off by one or two, but it's all relative using the same variables so your planners may give 28 minutes instead of 30, but it's close enough.
What I understood the OP to be asking is how to maximize NDL, so I did that with GF99 and a 5 minute safety stop to show what the GF would be when you got to that stop at 15ft and then what it would be at the surface.
I then added a "safety stop" *which is actually planning a multi level dive* to get the surface GF ratio's to around 70 which is what he said he was doing. I then took the same bottom time and just ran it on 70/70 which is what I think they should be doing.
All of that to say that one profile yields more decompression stress on the ascent, and only serves to prevent the computer from showing a mandatory deco stop. I have said for years that if you are going to try to manipulate the computers because of fear mongering and ignorance about NDL, which is what this is, then you should just take a decompression procedures course and dive the profiles that you want.