3 Bottle dives

[MonkSeal]

3rd deco gas on such dive is unnecesarry. Bigger 50% bottle then AL40 would be better. Overall too long deco. On such dive I usually do:

220ft -25
2 up to deep stops
160-1
150-1
140-1
130-1
120-1
110-2
100-2
90-2
80-2
70-7
60-5
50-4
40-5
30-8 on backgas
20-30 (12 on, 6 off, 12 on and up)

Involving unnecesarry gases for sure is not DIR. I would consider it for a dive deeper then 270.

I don't understand problems with backgas stage or AL80 for 50%. Drag? Screwing around at depth? You just switch from stage to backgas and stove the hose. Empty stage supports 50% bottle. Bottles are rotated somewhere during deco after 50% switch e.g. at 50.

 

[RTodd]

I am probably going to get some of the current GUE guidance on this wrong, which is good. Those of you that know it, chime in.

First, diving 119s so plenty of gas. My rock bottom would be enough to lose a teammates backgas and still ascend comfortably. Is this the current teaching? A little bit of padding for a partial loss of a deco gas or a hoove due to stress (personally, I wouldn't do dives with anyone over 150' where this is a real risk) is in there but that cluster would be handled more with cutting back on deco.

I have never had a dive where I accidently violated my set floor. Never. So, I consider this a skills issue or a terrain issue where you don't know exactly what the depth is going to be. In the latter, plan the dive for worst case. Otherwise, I don't worry too much about huge excesses of gas to handle going way deeper than planned or having significantly more deco.

I wouldn't bother with the 120 bottle on this dive. I also am not seeing the need for a stage.

At depth, speed is everything. When I first started diving in Mexico and stopped doing much in Florida, I was doing gas and scooter switches faster than Danny and Chris. But, they were much cleaner. I was used to the deep cave mentality where everything had to be fast. The beauty of the shallow stuff is there is no need to rush and you can really work on being really clean. Now, I am slightly slower than these guys and still not as clean but much better than I was. The trick for deep stuff is to practice over and over so you can do the switches quickly but comfortably. Just trying to move fast tends to make a hash of things.

The point of that is, until you can cleanly do a switch at depth and not impact your dive, I agree the stage isn't the way to go. We used to do all sorts of silliness, leaving used stage regs over our neck so we could switch to a second stage without coming off the trigger, etc. Practice on shallow dives, doing a proper pause and a smooth quick switch. Figure out what you can do in advance in terms of getting your light clipped off while still on the trigger, positioning your scooter to stay where it needs to, going to backgas (at first your backup so you can shut off the stage) just before the stop so all you are doing is stowing the reg, etc. Once you can comfortably do this, then add the stage to these dives. Until then, why screw up the dive, just shorten the time if needed.

 

[rjack321]

Regarding the floor, 240 is the now we need a shovel floor. 220ft is the expected average, top is 200ft. I can't tell you exactly where the interesting stuff is so I can't say what the eventual average might be. Deeper than 200, but 230 or shallower.

As far as the bottom stage goes... I don't wanna deal with it. I have scootered, running line, and switched off the stage with drygloves on and it sucks. Its not that's its dangerous, its just a major hassle at ~midpoint of the dive. At that time, the bottom stage was along mostly because I was using smaller doubles. I hadn't found them to be that much hassle, but on that day I brought 2x 80s (backgas+50%) and a 40 of O2 and the drag was really pronounced in the current.

While the 120 bottle ends up being padding, that time is mostly just the deep stops anyway. Trying to do this dive on 95s/119s alone gets rather marginal gaswise. Without the 120 bottle I have a rock bottom of 108cf (SAC of 0.75cf/min * 2 - I still pad the "stressed SAC" just not by a whole lot.). Still, using about 115-120cf of backgas on the bottom plus for breaks. So pretty much everything is allocated from a 3500psi fill. To me, this is more borderline than using 2300psi from an Al40 of EAN50 on a dive with in-water support (sorry forgot to mention that earlier, there's support for 70ft and up.) We could add 120ft support but its harder to keep them out of deco then and I don't think that's required anyway.

BTW,
If I only did 12-6-12 on O2 I would be bent. I need more shallow time than that.

 

[RTodd]

This is really lame that, given the number of people that claim to do these dives, we are talking to each other. I get the hassle part and it is why I said don't bother until it gets easy. I don't do dry glove dives, but even with those I would think wit sufficient practice it would get easy. The drag comment doesn't make sense to me though. Yes, every bottle adds drag, and it is noticeable with 2 al 80s but it doesn't get that significant until you go to 3 al80s and are dragging one behind you. Al40s are basically freebies. We are talking Gavin's, correct? My guess is there is a little tecnique to improve there. Slight changes start making much bigger differences once you have two full sized stages.

 

[TSandM]

This is really lame that, given the number of people that claim to do these dives, we are talking to each other.

I don't understand this comment. Do you not think you should be talking at all, or do you think people doing these dives shouldn't talk to each other, or not in front of the rest of the hoi polloi?

 

[JeffG]

I don't understand this comment. Do you not think you should be talking at all, or do you think people doing these dives shouldn't talk to each other, or not in front of the rest of the hoi polloi?

I'm going to guess that he means that not very many people are doing the dives and it gets boring talking to the same old people.

 

[RTodd]

I'm going to guess that he means that not very many people are doing the dives and it gets boring talking to the same old people.

Actually, I thought there was more than two people on here doing these types of dives and I don't consider myself one of them.

 

[Bismark]

Rich, is this one of the dives we are looking at up here?

No need for the 120 deco gas.

I would be (am) taking an al 80 for 50%, not enought margin for error with an AL 40. Also a 40 for 02 but boosted to 3k (Not enough margin with the 2200 psi fill from a T bottle transfill).

Lots of gas in 130's for this dive.

Same general profile as Monkseal but my 70 and up is more like 5,3,4,6,8 (some of the 8 on backgas but not all of it) and then about 30 and 6 up on 02.(12's and 6's or 10's and 5's for you heretics.... Extra 02 on 6 up should help you out.


Midwater support..............same day, same ocean..............;-) If we are talking about the same dives here. If not, I stand corrected.

 

[rjack321]

Midwater support..............same day, same ocean..............;-) If we are talking about the same dives here. If not, I stand corrected.

Nope different dives. This particular example is local-er.
I would love to do this on 130s but I am supporting some out-of-towners with tanks as well. There are only so many big loaner doubles to go around so we need to dip into the cache of 95s/119s (esp. for the girl, 130s are ridiculous for her).

Actually, I thought there was more than two people on here doing these types of dives and I don't consider myself one of them.

And I am barely one of them, my local waters are just too damn cold for these kinds of hangs. This one special tho. The only reason I brought it up at all was because people were sick of talking about whether folding or straight snorkels are DIR lol

 

[Cave Diver]

Actually, I thought there was more than two people on here doing these types of dives and I don't consider myself one of them.

I've done dives in the 200-220' range, but it's not something I do often. I carry two bottles, not three and typically start my dive planning well in advance. Because it's not something I do on a weekly basis, I like to re-familiarize myself with the numbers and the dive plan and build it up with a few shallower dives.

I haven't participated in this thread, but I've watched it to see what information I might pick up about the use of 3 gasses, or how other people might be approaching dives like this.

I'm not sure how many people on this board actually do dives in this range, and of those people I'm not sure how many of them participate in this forum, so that may be one reason for the low response rate.

Consideration might be given to starting a spin off from the Dive Alert thread and talk about something like how to go about making a boat DIR with procedures and protocols. There might be more people that can relate to that and it may garner more audience participation.