Expedition Pacific Abyss on discovery now...

deepreef

Absolutely! I used to make this point over and over again to people who used to think that reef diving was a breeze compared to, say, cave diving. The points I always used to make were:

1) You can't always come home by the same path that you got there (i.e., your point above);

2) The direction of water flow is not predictable, and can change (dramatically) within the course of a dive;

3) Except in Hollywood movies, in a freshwater cave you're usually not part of the food chain (though I guess in some places gators pose a theoretical risk).

[P.S. No -- I am not going to engage in a "my diving is more dangerous than your diving" debate. The take-home message is that different environments require different strategies for optimization.]

Again, agree completely!

I had one major loop flood:
14may97log
...but I was able to recover it for deco (handy-dandy waterproof canister feature).

In more recent years, we've had problem of dust build-up on the canister membrane causing partial "lock up" of the breathing flow (a problem that can be mitigated with thorough canister cleaning every once in a while). I don't think any of these situations has required an OC bailout, but it came close a few times, and in one case I finished the deco on OC only because it was easier at the time (could have finished the dive on CC if I needed to).

I guess my biggest concern would be premature CO2 absorbent failure -- perhaps due to a bad batch of 'sorb. Hasn't happened to us yet (touch wood), but it's always a possibility.

All things considered, I want to make sure I have a second pathway back to the surface, and in most cases this means having sufficient OC bailout gas supplies on hand, and such that you can reliably access them if you need to.

Aloha,
Rich

silent running

Yes Rich, none of us are too smart to learn from a dumb mistake, glad your flood was not a more serious incident. My only total loop flood was on a Dolphin with a P-Port that was tight enough to pass -/+, but I forgot to give it a tug and it came off during descent, BO'd and surfaced fine. I always give a good tug to my hoses now, just like a smart guy...

As for sorb, how long do you go on a fill of the Cislunar scrubber in warm water?

And have you heard of anybody who has gotten a bad tub of sorb that was within it's use-by date? I have yet to hear of it happening, but I suppose it's possible. Thanks, -Andy

deepreef

I pretty consistently go about 12-13 hours before I start to feel it. And since "feeling" it means I've gone way overboard already, I generally change after 8 hours. So far, I've never had a problem with that approach.

I have no first-hand knowledge of it, but I remember at one of the Rebreather Forums someone describing an incident where on a test dive (in a chamber, I think) a canister lasted something like 2 hours when it should have lasted over 10. The canister was re-packed from the same bucket of sorb, and went the appropriate amount of time. If I remember correctly they surmised that the seal was bad on the bucket, and the top layer had been spent.

I'm sure the details are somewhere in the Proceedings from the forum.

Aloha,
Rich

silent running

Thanks for the info Rich. 8hrs is enough for 2 good days of diving and a solid 12 days out of a keg of fine mesh sorb, which easily fits in a checked bag.

Very interesting story about the bad sorb. A bad seal sounds like a good possibility, or maybe the top layer was exposed to the hot sun while sitting out? I try to make sure to purchase sorb from a supplier who handles the stuff correctly and knows how it was handled before they got it-hopefully never left sitting out on some hot asphalt somewhere. Another reason to bring your own instead of shipping ahead to the tropical location of your choice... -Andy

Pipnaintez

Was a great show Rich! I watched the show with my 8yr old son. He got a kick out of the fish stealing incident.

What FFM and comm units did you guys use on the dives with the CCR?