Cthippo
Contributor
I recently heard about a bunch of wrecks at around 120' FFW in Lake Washington. It will probably be another year or two before I am ready to dive them, but I figured I would take a stab at the planning process for this sort of dive. I was also curious about the utility of nitrox at depths of 100-130', and so I am self teaching tables.
Before someone asks, no, I am not nitrox certified. I am trying to teach myself the process of this because I will have a better understanding from figuring it out on my own before I take the class.
So, working from the NOAA air tables a 120' dive on air would give me a NDL bottom time of 15 minutes, and no possibility of a repetitive dive within a reasonable surface interval. If I stayed to 20 minutes, I would have a 2 minute deco penalty at 20'.
On the other hand, if I used EAN28, that would give me a NDL bottom time of 20 minutes at a PPO2 of 1.3. If I stayed to 25 minutes, that would incur a 3 minute deco penalty.
EAN 30 would increase my PPO2 to 1.39 without changing NDL times.
Questions: 1, do I have this right? And 2, does the fact that this is fresh, rather than saltwater make any difference at these depths?
Before someone asks, no, I am not nitrox certified. I am trying to teach myself the process of this because I will have a better understanding from figuring it out on my own before I take the class.
So, working from the NOAA air tables a 120' dive on air would give me a NDL bottom time of 15 minutes, and no possibility of a repetitive dive within a reasonable surface interval. If I stayed to 20 minutes, I would have a 2 minute deco penalty at 20'.
On the other hand, if I used EAN28, that would give me a NDL bottom time of 20 minutes at a PPO2 of 1.3. If I stayed to 25 minutes, that would incur a 3 minute deco penalty.
EAN 30 would increase my PPO2 to 1.39 without changing NDL times.
Questions: 1, do I have this right? And 2, does the fact that this is fresh, rather than saltwater make any difference at these depths?