I'll have to check when I get to my laptop, but I think I'm using 20 and 90 as gradient factors. Whether I tell the program to compute the last stop at 10' or 20' I get the same number of minutes between the two. Since I do them all at 20', it doesn't matter how I have the program tell me the total amount. I don't discard the 10' stop, I add it to the 20' stop.
I start deep stops at about 2 ata off the bottom depth (e.g. for a 200' dive I would do the deep stop starting at about 140'). I also stop for a minimum of 5 minutes for gas changes.
I spend 3 minutes at 10', after having done the 20' stop, just as a way of slowing the final ascent. Actually, it is more of 3 minutes to go from 20' to the surface.
Usually my profiles do not require 5 minutes at 70'. Since I switch to 50/50 nitrox at that depth, I do the 5 minutes and then can trim that extra time off of the deco curve. If you look at the shape of the curve you will see that the number of minutes at each 10' stop increases in a pattern similar to the fibonacci sequence. As a result, if I added several minutes of deep stops, plus 4 minutes at 70', I might knock off a minute at 40', a minute at 30' and two minutes at 20' based on staying extra at depth.
Note that I am not giving you exact deco for a precise dive, since it takes understanding of what you are doing, and an understanding of your individual susceptibility to DCS (based on how you feel after diving), before you can figure out how and where to trim or adjust deco. Take a GUE Tech 1 class.
A minimum deco for my dives would tend to be 5 minutes at 70', a minute each at 60', 50', 40', 30', 5 minutes at 20' (gas switch to 100% oxygen) and 3 minutes at 10'. Deep stops are additional.
Jan
I start deep stops at about 2 ata off the bottom depth (e.g. for a 200' dive I would do the deep stop starting at about 140'). I also stop for a minimum of 5 minutes for gas changes.
I spend 3 minutes at 10', after having done the 20' stop, just as a way of slowing the final ascent. Actually, it is more of 3 minutes to go from 20' to the surface.
Usually my profiles do not require 5 minutes at 70'. Since I switch to 50/50 nitrox at that depth, I do the 5 minutes and then can trim that extra time off of the deco curve. If you look at the shape of the curve you will see that the number of minutes at each 10' stop increases in a pattern similar to the fibonacci sequence. As a result, if I added several minutes of deep stops, plus 4 minutes at 70', I might knock off a minute at 40', a minute at 30' and two minutes at 20' based on staying extra at depth.
Note that I am not giving you exact deco for a precise dive, since it takes understanding of what you are doing, and an understanding of your individual susceptibility to DCS (based on how you feel after diving), before you can figure out how and where to trim or adjust deco. Take a GUE Tech 1 class.
A minimum deco for my dives would tend to be 5 minutes at 70', a minute each at 60', 50', 40', 30', 5 minutes at 20' (gas switch to 100% oxygen) and 3 minutes at 10'. Deep stops are additional.
Jan
