Posted by Gerry Smith on March 05, 2001 at 15:38:15:
In Reply to: Re: Enough nicities...what's the procedure for the multilevel NDL computatio posted by Kendall Raine on March 05, 2001 at 12:04:21:
I suppose I was looking for more detail than the presentation called for in regards to recreational DIR. Another post mentioned that after I left JJ blessed streamlined consoles and short hoses for recreational divers. Thats the kind of stuff I was wanting to hear. I see that Mike has posted something about on the fly computing and I'll wade through that next.
Let's talk about the streamlining issue. What I saw in JJ's cave video was a real eye opener. The pictures show a diver hanging behind a scooter being dragged effortlessly through the cave. The diver is essentially motionless, just hanging in the slipstream. I understand that this is what's required to go three and a half miles back into a cave, and that a relatively small increase in drag could be significant in that situation. But how applicable is that to our local diving? I try to spend more time doing than traveling. Either I'm crawling around looking for goodies (animal, vegetable, mineral, or brasseral) stuffing said goodies in a bag, or kneeling on the bottom watching a student go through skills. Sure, the streamlining factor applies, but to a much lesser extent for us recreational types. Then there's the thing about squaring the area to get drag and cubing it to get work. Somebody needs to take a course in fluid dynamics 'cause that idea enormously overstates the work. (hint: "drag" and "work" are the same, just change the sign.)
Again, thanks to you guys for an informative session, wish I could have stayed for the last half.
GS