First rebreather choice

[tbone1004]

Yes right I get it, you had a fabulous super advanced MOD1 that was Cave CCR all in one!

The reality is that at the end of MOD1 you had basically the same number of hours as me so <10. SCR BOs from an overhead on a new CCR is too much too fast.

cave CCR was a separate course, but I don't think it was a "super fabulous super advanced mod1". It was actually pretty "normal" when talking to various people that have taken their mod1 in cave country. That last drill was arguably a little excessive, but other than that as the final "kick my ass" dive, everything else including a good bit of SCR time seems pretty standard from the instructors down there and has been echoed by several other cave divers in this thread. I don't think it's something to spend a bucket of time on, especially for OW divers, but if you intend to cave dive with the unit, it's incredibly important.

 

[rddvet]

I

I'd say if you need SCR to calmly exit, you need to carry more BO in the first place.

It's not needed to calmly exit, since I won't be pushing bailout, but it's nice to know that I can take my appropriate bailout and extend it out even more in certain failure modes. We do the math and add in safety factors, but when crap is going wrong, it always seems more crap goes wrong to slow you down or screw you even more. So knowing that I can extend gas during an issue in case another issue is to arise is comforting in my opinion. We discussed and did SCR drills in mod1. We actually swam out in SCR mode and rather than adding/flushing dil every X amount of breaths, we actually just watched how long it took for the dil p02 to degrade while in SCR mode nin cave crossover. It was much longer than I ever expected. It's not a cure all, but just a nice additional safety factor.

 

[kensuf]

Yes right I get it, you had a fabulous super advanced MOD1 that was Cave CCR all in one!

The reality is that at the end of MOD1 you had basically the same number of hours as me so <10. SCR BOs from an overhead on a new CCR is too much too fast.

Agree. I teach my MOD1 students two basic rules: Always know your PO2. Bail the eff out when anything is wrong. While I cover SCR mode in MOD1, it's not heavily emphasized. Basically, the way I teach MOD1, the answer to just about every problem is BAIL THE EFF OUT.

Cave CCR we use SCR mode quite a bit for gas extension with at least one 500-700' cave exit. If you've used an Apeks 1st stage in the past few years, you'll know exactly why losing O2 is a given of when, not if.

In terms of personal config, typically, for the cave, my DIL is part of my off-board bailout and has a gauge. My O2 also has a gauge. Diving in the ocean, if I run on-board DIL it's got a gauge.

 

[_Ralph]

cave CCR was a separate course, but I don't think it was a "super fabulous super advanced mod1". It was actually pretty "normal" when talking to various people that have taken their mod1 in cave country. That last drill was arguably a little excessive, but other than that as the final "kick my ass" dive...

I have a feeling that many CCR instructors in cave country tailor their courses to be a bit ‘extra’

With my Mod1, while done in cave country, as the unit I was buying was located down there, the instructor has some pretty serious dives with that unit as well.

I’m still pretty low on the Cave totem pole, but we spent quite a bit of time more tech orientated, spending the last dive on a 40min OC ‘deco’ bailout, as that is what the dive I would be doing with the CCR.

While of course spending some quality time in the caverns, hovering and bubble-less checking out every nook and cranny. Making me feel like I would really enjoy advancing to full cave/CCR cave..


_R

 

[Germie]

Mod1 is a course to learn how to prepare it, how to dive it, how to deal with problems (Bailout) and how to clean it. Next courses are more demanding. I agree that sometimes too much courses in diving in general are sold(specialties), but ccr can be really tricky. This is why mod1 costs more time than most other tech courses. But yes also in ccr diving, some things can be learned by being and autodidact. But not all people are that. So if you don't be an autodidact, a good course is really needed to dive it safe.
I don't know if ccr courses differ in cave country from europe. In standards not. I think it depends on the instructor. I did my techcourses (oc, ccr, trimix, cave, sidemount) sometimes based on instructor (more demanding), sometimes on price, sometimes on easyness (as I already did the dives, I am an autodidact), sometimes DIR orientated, etc. This all together gave me a bright vision on how diving is done and how it can be done. Sometimes DIR works, sometimes not, I learned to be a thinking diver. And that is important in ccr diving.

SCR is only a good choice option at decostops of a trimixdive as you don't change depth then. But in caves it is a really handy tool, there you have a big chance of diving tunnels without big depth changes and it saves you gas. Of course not with a flooded unit or CO2 hit.

 

[KenGordon]

Hey all,

I'm thinking about buying a rebreather between now and a year. It would be nice to hear some opinions from the experienced rb divers on this forum.

The reason i want to switch to a rb is simply to make wreck dives between 40 and 80 meters (130/200 feet) using helium. dive time from 90 tot 180 minutes. Ofcourse after i have enough hours and experience on the unit.
I started tech diving about 4 years ago, but the last 2 years i've been leaning towards cave diving in Mexico.
For the same price of deep wreck diving a week in Europe (helium price), i can fly to Mexico for a few weeks (cave diving on 32%). I know a rb is expensive to purchase but i know for sure if i buy one the step to go wreck diving would be a lot smaller.
I'm not interested in cave diving with a rb (yet). All my cave dives i did so far are made in Mexico, and i like oc here for it's simplicity.

The unit i was thinking about is an inspiration, why?
- My instructor of choice teaches on this unit (I know, this is the worst reason)
- It's easy to get parts in The Netherlands for this unit
- Easy to find a decent 2nd hand model
- Heard that it has a good wob and that its a versatile unit
- Edit: I also will be flying with the unit, so size/weight does matter in this case

I'm looking to get a try dive on this unit somewhere this year. But i can't compare it to other units, cause it will be the first unit that i dive.

So my question is, how well will this unit do for deep wreck diving? any cons and pro's? any advice from experienced rb divers will do, especially if you have experience on diffrent units. Are there better options?

Thanks in advance!

Beg or borrow a unit. Consider travel within Europe or even the place soon to be the Former U.K. (Wales).

Faced with your choice I did a try dive where I saw exactly how complicated the insides of an AP unit were, basically day one of the course. I had a think about the nasty mono controller and the big plastic box and bought a JJ instead. I am more than happy with the JJ, although I see the XCCR has a better solution for looking after the cells post dive.

You could join BSAC and do a the course on one of BSAC’s loan AP units, again you’d need to come to the U.K. but the cost of the unit is just the shipping. Of course that would be a BSAC course and with a fairly narrow selection of instructors. Those units are all very close to the factory and essentially marketing assets, so all fully tricked out and up to date.
.

 

[fsardone]

Faced with your choice I did a try dive where I saw exactly how complicated the insides of an AP unit were, basically day one of the course. I had a think about the nasty mono controller and the big plastic box and bought a JJ instead. I am more than happy with the JJ, although I see the XCCR has a better solution for looking after the cells post dive.

.

I am puzzled. All the APD rebreathers I know have double controllers.
The classic had double pendant also (controller was in there) while the subsequent models (vision) had them in the head, with a single display input unit.

Which unit are you talking about?

 

[KenGordon]

I am puzzled. All the APD rebreathers I know have double controllers.
The classic had double pendant also (controller was in there) while the subsequent models (vision) had them in the head, with a single display input unit.

Which unit are you talking about?

Monochrome.

 

[fsardone]

Monochrome.

Monochrome display has Vision: two controllers two batteries and keeps working after the display dies. you know ppO2 by HUD ...
Maybe your try dive was too quick and did not explain the unit.

 

[KenGordon]

So

Monochrome display has Vision: two controllers two batteries and keeps working after the display dies. you know ppO2 by HUD ...
Maybe your try dive was too quick and did not explain the unit.

Let me explain. At the time, before the 2020 handset, the Vision handset was a very nasty monochrome display which you would have considered state of the art in 1980. The JJ had a colour TFT handset. I didn’t fancy paying 7k for such a nasty UI. The plastic box was another issue. A third was that I was seeing lots of Visions rebuilt like a JJ, so concluded that I might as well start with the JJ. At the time my preferred instructor did not do the JJ but when I hassled him it turned out he was in talks with them so it was all good in the end.

The AP has the advantage of a factory BOV, but it still has the plastic box. I would expect to break that. Also it looks like a prop from 1970s Sci Fi.