Posted by seahunt on March 05, 2001 at 21:55:50:
In Reply to: And here I thought we were making progress ;-) posted by MHK on March 05, 2001 at 17:25:06:
****I believe that you are the only one who left that room thinking that we had secrets to keep ****
No one else in the room was interested in what I was interested in and that's why, quite appropriately, Jerrod said almost nothing about what I was interested in. What he did say was almost only in response to what I asked. He did have a lot to cover.
*****But either way the tank issue that we were discussing, much to the distraction of everyone else in the room due to the length, was that you were 38 lbs of lead and a 7 lb negative steel tank, which means you are wearing 45 lbs of weight with a wetsuit. The concern, of course, is that if your baldder fails can you surface, why so much weight, and your stated explanantion that you need to continually keep moving to stay off the bottom.*****
Actually, that was a one on one discussion at the time and it was 38 pounds with an AL tank. 45 was never mentioned. Bouncing on the bottom was without any BC, which is an unusual case for me, though I do usually go negative. Perhaps you're a bit confused on those points. I'm not sure what Robert heard, but I did wonder some that though I kept repeating that I carry ditchable weight, He never registered it. If that is dumped by releasing the easily reachable clip, my buoyancy characteristics change dramatically and swimming towards the surface is going to be a much easier problem... Or did my ditchable weights get forgotten like my weight belt got increased?
*****
As for the GUE and/or WKPP website not being informational
*****
I reviewed those sites, point by point, for the Cosmology of DIR essays. About the points I am interested in, (steel tank and deco) almost nothing is mentioned except on George Irvine's site that says use a stage bottle if you want more air than an Al 80 provides. I also said that point for point, not all that much of it is relevant to CA sport diving. That is true. The points about gear are relevant, but EANs and ENTs
usually aren't. Helium gas mixes aren't. Team diving methodology isn't and they weren't talking about 2 person buddy teams. Extreme physical conditioning isn't either. I don't remember all the other points at the moment, but like the DIR Demo, much of it wasn't about sport diving... Remember, the tape on before the class was about a cave dive. The tape of the mine dive was not sport diving. Jerrod, didn't know that NITROX has only recently become available in CA (sort of) and that deco diving is not generally allowed on CA charter boats. He was talking about somewhere else and a different kind of diving.
Your point about it being free is correct, but then I thought that that was a point of DIR. Really, I suspect that it comes down to how much effort and time they want to devote to the site. Reasonably that is limited... Actually, though I don't think that there was a lot of content, there probably was more than on most other sites.
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Furthermore, JJ suggested to you that you *top off* with air after you use your Nitrox tank that you brought on the boat, thus providing for added F02's.
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Well, yes. You guys were there as were other CA divers. Why didn't you tell him why that doesn't happen? It's obvious if you've gone through the hoops that local stores make you go through for NITROX.
That was a blow it on the NITROX membrane cost. I figured that out quickly. What I remember most about the discussion was about the surprises like that once Larry got the membrane system, he found out he needed a whole new compressor... then a new generator to run that. His costs were far more than estimated.
****
Michael... as for the deco... you said almost nothing during the entire demo... quite politely. It showed good self control. (I'll add a point or two here relating to your Calc on the Fly post) I think it was Terry... maybe it was you that brought up depth averaging..finally. I had changed to that Nic example, beause Terry had suggested something in his earlier post that pointed out that that would be more difficult for your system to evaluate than a pinnacle dive. I understand just fine that on the Eagles reef dive, the the computer has an advantage beause it averages and I could even figure an easy on the fly way to calculate it. What you never caught on to was that the reason why I changed to the Nic example is that that area is one of the flattest rock dive areas in CA. What I missed initially, was that you were basing your method on depth averaging. You notice that I did pick it up. As I pointed out, in regards to what you are doing, depth averaging, by itself the model you use doesn't matter near as much as how you use it and what it implies. It is seperate from the model.(that is why I never bothered to consider what model was being used. It was not the issue.) That is also true for your description. What you are doing is fairly easy to describe. Why you couldn't simply do it, I'll never know. Why you can't get clear what I am saying, I'll never know.
Why did you never simply say that you are doing depth averaging for your data collection method?
Why did you never say that you were trying to match computer BT using the same algorithm with a table? Those two simple facts would describe most of your manual deco calc method. The rest is details. They are not too trick to describe. They are far easier to describe than to learn, true, but they are still both simple concepts.
I'm little surprised that you think I didn't pick up what you were saying there, though since I did have to fight for every scrap of hard information, I guess it was understandable. But I got what I needed to guess the rest of what you were talking about. Really, I think that you did a normal thing and have gone into this stuff long enough that you forget the basics of what you use. ***Gas laws are linear in respect to temperature, pressure and time*** The simple basic parts are what are needed to explain it to someone else though. If you had posted those two points (averaging and profile matching) a while ago, the rest could have been figured out easily from that. I don't know what to make of your methods. They seem sound enough even if they do seem to present some potential problems. Actually, I would say you came out well in the discussion. It ought to be called progress. If anyone asks about DIR manual deco methods, I at least, can give them enough of an idea of the methods, to indicate that it is more than arm waving. As a matter of fact, my description, made up of guess work and perhaps one fair error, would even allow a person to start to test the idea and start learning some of your method.
Enjoy, seahunt
PS. By the way, I also said that the two computers could not be compared... at all. Please get it straight.