Cow Springs penetration

[aainslie]

Thanks for the info, everyone. Cindy, I'm glad you mentioned the syphon - I was thinking of exploring it with leftover gas at the END of a dive. I guess I won't be doing that!!

Gary, that's great info - thanks! I only dive sidemount in the caves. I'm goint to try to do it on a single stage. I really don't like the idea of taking a stage much past the end of the rope.

Mike, I'll be by to look at that map.

The trip is 6 weeks away but I promise to call, Cindy!

Here's a video from my last trip. I turned it at 1800 feet:

http://andrewainslie.com/videos/cow_big_file.wmv

It's BIIIG - 120 MB - so be patient!

[Gary]

I only dive sidemount in the caves. I'm goint to try to do it on a single stage.

The old mainline end should be easily reached with just a single stage. If you have trouble getting a copy of James' survey map send me your e-mail address, I have a freehand that includes the sidemount passages.

For a sidemounter putting a tank with EAN50 in the basin would allow you to do practically all your deco in the downstream.

[tomhauburn]

Nice video..thanks for the post.
Tom

[Angie Reim]

On the He - last time I used leftover gas from an Eagle's dive to do a Ginnie dive. It shocked me how much more clear headed I was with about 20% He in my mix at 100 feet. I know it's expensive, but it sure makes a difference. Still, thanks for letting me know that PO2 is cool.

HAH! You are not the only one that has discovered the benefits of normoxic mix at only 100'. I use it routinely in Ginnie and Little River (when LR water levels are up). Yes it's more expensive but I find the ability to remember details of the dive and the lower respiration rate due to lack of narcosis to make it all worthwhile.

I usually start with a 32/30 or 30/30 mix and back fill with 32EAN to get a second dive out of the tanks. Gas rule calculations tell me that I benefit from a HE concentration down to ~15%. After that, it's either dump the tanks to start over or go to a facility that will mix for you (bring your own calculations) over what is left. HE analyzers are handy dandy here.

[Angie Reim]

Also, I forgot to mention that I learned kind of the hard way to surface more slowly on that HE from the ~100 dives. I know we all know to do that on the EN etc. type dives, but its the 1ft/sec rule we forget sometimes between the 40-30-20-10' stops.

[sskasser]

Also, I forgot to mention that I learned kind of the hard way to surface more slowly on that HE from the ~100 dives. I know we all know to do that on the EN etc. type dives, but its the 1ft/sec rule we forget sometimes between the 40-30-20-10' stops.

Good reminder, Angie, thanks!

its the 1ft/sec rule we forget sometimes

I don't get it.

That's twice as fast as the maximum ascent rate taught in Open Water. 60 ft/min was taught back in the eighties, but it's been 30 ft/min for years now.

Or did I miss some allusion?

[Tegg]

its the 1ft/sec rule we forget sometimes

I don't get it.

That's twice as fast as the maximum ascent rate taught in Open Water. 60 ft/min was taught back in the eighties, but it's been 30 ft/min for years now.

Or did I miss some allusion?

Helium is smaller then nitrogen, thus you can double your "normal" ascent rate.

DUH!!.......

[Angie Reim]

Excuse me guys. I meant 1/2 ft/sec. I usually just count 1001, 1002 etc while ascending.

My point was for me with HE it seems to work best to move more slowly between stops of 10' increments. I've seen people finish a 40' stop and move comparatively quickly to the next stop and so forth. They still fulfill their decompression obligation and are limiting ongassing but also maybe youth makes the difference regarding outgassing, etc. It was just a reminder and an addition to the info I'd already given.

Yes the HE atom is smaller and comes out more quickly from the tissues so maybe an ascent rate of 1'/sec is okay, but I envision that means that bubbles can form more rapidly. I have no documented evidence of this. I just know that I feel so much better if I make a slow ascent also between stops.

This decompression stuff is not yet fully understood. I still don't understand how J. Mc got bent. I'm not sure he does yet either. Undeserved hits still happen.

DUH!!.......

You put helium in your deco bottles?