Stage juggling advice

[Steve Clark]

Oh, lights. Those things on your helmet that light up your hands as you're tying things off!

Think it's the UK conditions which leads one to question strictly following DIR which was developed in very different conditions than found here.

DIR is totally inappropriate for UK cave diving. You can’t realistically crawl or abseil with a twinset so that rules it out before you’ve even made it to the water.

Even in the big French caves it becomes a pain as soon as you have to get out of the water. The GUE team exploring sump 3 in Cabouy / L’Ouysse have a major logistical challenge getting past just 400m of dry caving with RB80s. This year the team spent 5 days camped between sump 2-3 to support the dive in the sump (120m depth). A very well thought out and safe way to conduct the dive, with logistics (u/w stretchers etc) to evacuate any potential injured people through 3km of sump. They returned with a exceptionally good survey of the whole system.

Rick Stanton & Jason Mallinson did a very similar dive in the same sump, 15 years ago, by themselves, in a day, using a lightweight approach and huge caving experience.

[JonG]

It works tolerably well in UK mines Steve, except that only Croesor really merits trimix so the leash and heavy nitrox stages becomes an issue.

Where it evolved in the depths of Tallahasee Power Cave it all just worked.

Why use the RB80 Steve if the JJ would be a better tool for the job?

[Steve Clark]

For the team at Cabouy, I think they have been diving RB80 for a while prior to the GUE-JJ becoming a thing. I’m not involved at all and can’t really comment.

For our project at St Georges, the RB divers are/have moved over to the JJ. Less deco, easier logistics. A bit lighter for moving out of the water, although they are still rigged with D7 or D12s anyway and it’s 5 stages of bailout each to carry and setup.

There is a limit on scrubber duration. I think the JJ is officially 3hrs(?), RB80 12hrs(?). Ressel sump 1 is 3hrs+ each way. Some friends did it on the JJ a couple of months ago, but I guess 6-7hrs is approaching the limit in cold-ish water. In Florida, the WKPP divers are sticking with the RB80. The really big dives need an RB80 for the dive and deep deco and then another RB80 for the deco. Some of these dives are 20hrs+ and 1000% CNS. That’s where DIR is in its element.

[graham_hk]

...

[Peg-mollester]

For the team at Cabouy, I think they have been diving RB80 for a while prior to the GUE-JJ becoming a thing. I’m not involved at all and can’t really comment.

For our project at St Georges, the RB divers are/have moved over to the JJ. Less deco, easier logistics. A bit lighter for moving out of the water, although they are still rigged with D7 or D12s anyway and it’s 5 stages of bailout each to carry and setup.

There is a limit on scrubber duration. I think the JJ is officially 3hrs(?), RB80 12hrs(?). Ressel sump 1 is 3hrs+ each way. Some friends did it on the JJ a couple of months ago, but I guess 6-7hrs is approaching the limit in cold-ish water. In Florida, the WKPP divers are sticking with the RB80. The really big dives need an RB80 for the dive and deep deco and then another RB80 for the deco. Some of these dives are 20hrs+ and 1000% CNS. That’s where DIR is in its element.

Rresel siphon1 in 3hrs is very slow, unnessary exposure IMO.

Even 2hrs is taking a while.

[cathal]

The RB80 is untested so you can say whatever you like for duration . CCR2 JJ divers have a way of extrapolating the CE 3h test out beyond 3h.

Just curious, has the extrapolation process for extending the JJ scrubber been tested or validated for its results ? And can I ask who formulated the extrapolation process, JJ or GUE or another party?
Cheers

Cathal