Re: DIR/Computer Use? Square No, air yes.

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Posted by Kendall Raine on March 09, 2001 at 09:59:21:

In Reply to: Re: DIR/Computer Use? Square No, air yes. posted by Steve on March 07, 2001 at 19:38:40:


Your follow-up post adds a few important details. For manual purposes, your dive was not 126 for 31' as stated in your original post. I still don't know what it was since I don't know when you started your ascent from 100 fsw-was this at 17 min?. Also, since you say the TRT was 31 and you only did 3-5 at 15 fsw, you must have spent a goodly amount of time between 100 and 15. If you made a leisurly ascent, you effectively conducted deep stops by using such a slow ascent rate.

So as not to duck the question; however, were I to do this dive, I'd probably compute my NDL based upon a max depth of 110 since your time at 126 was 3 min or less. I'd assume I was at 110 for roughly 15 minutes.

Now, getting back to the question of where you spent the extra ten minutes or so of the dive-you didn't say-I'll assume you used a slow ascent rate and the average time/depth would equate to 40 for 10 min. Using time weighted averaging, I'd then assume my dive was something like 80-85 fsw for about 22-24 minutes with a 5 minute safety stop. A dive within the NDL. Naturally, if I did the dive, my times/depth would be a lot more precise since I'd remember them (no, I don't have my slate out and write all this stuff down). I'm making an educated guess in your case. A dive to 80 fsw for 24 min with a five minute safety stop at 15 gives about the same proportional neo-Haldanean tissue loadings as the dive I'm assuming you did. I actually suspect it's better since the actual dive employs a really slow ascent for which the neo-Haldanean models only give partial credit. Nevertheless, out of conservatism, I would use this as a basis for repetative dives.

Just so you know, I would not have done this dive on air in the first place, so my NDL's would have been different, but I think you were asking about methodolgy.

I hope this helps.


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