Prism2 vs rEvo?

[stuartv]

I have the opportunity to train on and get certified on both of these units at no cost. Air dil, no deco, for now. Thus, I am GOING to train on both and get certified on both. My long-term plan is to eventually go CCR, so why not get as much education and experience with them as I can?!

I will start on one (probably not until some time in Sept, though, but it's certainly possible I will start sooner), do the training, and then dive it for a while to get some feel for it (25 - 30 hours? I don't know) and then do the training and dive the other unit for a while. Once I'm comfortable with the other, then maybe switch back to continue getting a feel for what I like and don't like about them. Both would be with current Shearwater electronics. My shop may add the DR O2ptima to their offerings, in which case I could/would train on that one, too, but that's only a maybe right now. At some point later, I would very likely buy one of the 2 (or 3).

Since I don't know what I don't know, that means I probably wouldn't know what things to really pay attention to as far as comparing pros and cons go. Kind of like someone who knows nothing about HD TVs won't necessarily pick up on any of the subtle but important differences between different brand/models of TV. At least not until someone really shows them what to look for.

The question for you is, can you give me some idea of the differences between the units that I should especially pay attention to as I start training?

I know the Prism2 I will train on has FM (or OTS) CL. The rEvo has BM. But, I read somewhere that the Prism2 can be configured with BMCL. True?

I did a demo dive last year on an O2ptima with FMCL and I really did not like the cluttered feeling around my face. That is already prejudicing me against the Prism2. But, I definitely want to train on it and get as comfortable as I can with it so that I don't blow off a good choice because of one short newbie experience that I didn't like.

Thanks for any wisdom you can share to help me maximize my learning during my training!

 

[decompression]

Well, this is an area that I don't have a lot of experience in, only a few hours on a few units so I'll let others chime in. However, there is a revo for sale ($4000) on FB.......

 

[KevinNM]

I think this is a great idea. Multiple people have mentioned that they couldn't really understand the difference between units and why stuff was important until they had gone through a CCR course. I don't have the experience to tell you what to ask about, but I think it's a great idea.

 

[stuartv]

Well, this is an area that I don't have a lot of experience in, only a few hours on a few units so I'll let others chime in. However, there is a revo for sale ($4000) on FB.......

Ha! I won't be buying a unit any time soon. Not until I have gotten all the free time I can stand on all the units I can try for free, and have spent all the time on them that I can stand in the quarry. When I have done all that, then I might think about buying a unit. The places I go for fun diving pretty much require being prepared to go deeper than 100' (NC wrecks). The first level of CCR training (air dil, no deco) has a max depth of 100', so I won't be looking to buy until I've either also gotten certified for deco helitrox CCR or am at least ready to do that training, have identified an instructor, and have the money. Not being able to go past 100' means all CCR diving will be a quarry-only thing for me in the meantime.

Maybe by next summer.... I have NO desire to rush anything related to CCR diving.

 

[sea_ledford]

I think you'll learn more by diving them than from anything you'll get here. Since you'll be doing full classes on both, you should have a good feel for how each of them behave with your particular style of diving. I could list all of the things I love about the Prism (never actually dove one, so just as an example), but you might decide that packing the scrubber is a PITA and that alone outweighs all the other benefits of it.

I would say keep in mind the long term maintenance of each unit; the rEvo has a bajillion cells that need to be changed annually, Huish might discontinue support of the Prism. If you lose local support where can you get parts, cells and service? Find out what people who have had them a few years DON'T like about them. Figure out what part(s) you can leave out that will kill you (or at least result in scrubber bypass), but the positive and negative checks won't find. Don't forget those parts.

I'll say why I ended up not getting either one (both were on my short list):
rEvo - too negatively buoyant for most of my diving (usually 3mm wetsuit), don't like the more cells are better approach.
Prism- scrubber packing- it really is one of the few things that can kill you if you do it incorrectly, I wanted it to be as easy as possible. Didn't want OTS counter lungs (other options weren't available when I made my decision). Prism was my second pick, if I didn't have a friend that got me into an SF2 I would have gone with a Prism.

Those are pretty minor nit-picks, and I'm sure I would have liked either one of them. The nice thing about using units you didn't buy is that you'll be more open to the stuff you don't like. It's a good way to go!

-Chris

 

[Tassi Devil Diver]

The first level of CCR training (air dil, no deco) has a max depth of 100', so I won't be looking to buy until I've either also gotten certified for deco helitrox CCR or am at least ready to do that training

With TDI at least if you have done OC deco procedures the first level of CCR training allows air dil deco to 45m, I think you even have the option of helitrox now as dil for that entry level CCR course, an option I would have taken up if it was available when I did my first CCR course.

the rEvo has a bajillion cells that need to be changed annually

Not true, the recommended cell replacement procedure for the rEvo is a new cell every 6 months, so two cells a year. rEvo wrote a great paper modelling the various cell replacement regimes which explains it all very well

Having done a bit diving in the tropics with a rEvo (micro titanium model) in a 3mm I have not found the unit too negatively buoyant.

 

[Scott]

I'm sure you'll get some good response here. You may also want to consider posing the question on Rebreather World or CCR Explorers.
Good luck. I've tried a rEvo in a pool with a couple other brands, so no real input from me.

 

[stuartv]

With TDI at least if you have done OC deco procedures the first level of CCR training allows air dil deco to 45m, I think you even have the option of helitrox now as dil for that entry level CCR course, an option I would have taken up if it was available when I did my first CCR course.

Right. I have TDI Helitrox, so I meet the perquisites for starting from the get-go with Deco Helitrox CCR. But, my shop's CCR instructors are not certified to teach that. So, for my free training it will have to be air dil for now. At least, until one of them gets certified to teach helitrox CCR (which could be soon, actually).

 

[doctormike]

Right. I have TDI Helitrox, so I meet the perquisites for starting from the get-go with Deco Helitrox CCR. But, my shop's CCR instructors are not certified to teach that. So, for my free training it will have to be air dil for now. At least, until one of them gets certified to teach helitrox CCR (which could be soon, actually).

I think that it's a good idea to get certified before buying a unit. That's what I did. You really can't understand the tradeoffs and questions very well before you are certified, so I trained on a rental unit. Yes, it cost me an extra $600, but I think that it was worth it. I ended up buying the unit I was trained on - I dive a JJ, and I absolutely love it, but you are in a situation where you can take advantage of free training, so go for it.

One thing that I don't think is a good idea, or even understand how it is possible, is the idea of doing deco CCR training without buying a unit. Do you also have free use of a CCR to get your hours in with air-dil, no deco? Or were you planning on renting? Being tech trained on OC does NOT mean that you are OK to just go right to CCR deco without really getting comfortable with CCR diving, and that means hours. It is - as I suspect you know - VERY different in many ways. I was deco trained when I started with the JJ, and I'm just doing Mod 2 now after about 50 hours after certification - my instructor insisted on that.

I'm glad that you are doing this! Your posts always show that you bring a huge amount of analysis and thought to your diving, and you don't do anything casually. Yeah, you are moving fast through training, but I think that you have the right attitude to become an excellent rebreather diver. Keep us posted, and maybe try the JJ. Who knows, you might like it enough to pay for training!

 

[stuartv]

One thing that I don't think is a good idea, or even understand how it is possible, is the idea of doing deco CCR training without buying a unit. Do you also have free use of a CCR to get your hours in with air-dil, no deco? Or were you planning on renting? Being tech trained on OC does NOT mean that you are OK to just go right to CCR deco without really getting comfortable with CCR diving, and that means hours. It is - as I suspect you know - VERY different in many ways. I was deco trained when I started with the JJ, and I'm just doing Mod 2 now after about 50 hours after certification - my instructor insisted on that.

I'm glad that you are doing this! Your posts always show that you bring a huge amount of analysis and thought to your diving, and you don't do anything casually. Yeah, you are moving fast through training, but I think that you have the right attitude to become an excellent rebreather diver. Keep us posted, and maybe try the JJ. Who knows, you might like it enough to pay for training!

Thanks!

Yes, I will have free* training, including use of the units. I'm assuming I'll need to pay for sorb, but I get free fills on all tanks anyway, so I think sorb is the only thing I would have to come out of pocket for. And since I gave the shop 1/3 of a jug of Sofnolime the other day that my buddy left with me when he went back to England, maybe they wouldn't even charge me for sorb. We'll see. I think that means I can also use the units for free after the training class is over, to get time in at the quarry. But, you raise a good point there, which I will need to clarify. If I have to rent, I'll rent. I don't think they would charge me much to rent.

TDI standards say that, because I'm already certified for OC Helitrox/Deco (which is to a max of 45m/150'), I could start with my first CCR class being the TDI Deco Helitrox CCR class (also to 45m/150'). If my instructor were able to teach that cert, I would definitely start there. He is not, so I won't. But, even if I started there, don't think for a minute that that means I would go through the class and then immediately start going out and doing deep (okay, deep-ish) deco dives! However, it would be nice to be able to work my way up to eventually being able to do that without having to take another class. If I could start with that cert, I would do the class and get a bunch of time in at the local quarry first (max 90' and doing NDL only). When I (and my instructor as a mentor) both felt like I was ready for ocean diving, I would go to NC (or similar) and dive the CCR there (presuming they would let me borrow or rent one). With only an air dil cert, I would be limited to 100' max and ocean diving would not be a feasible option for me. With the deco helitrox cert, I could use the helitrox to maintain a max END of 100', dive the wrecks there that are in recreational limits, and do the dives as NDL dives. After sufficient practice time in the quarry, that seems like a safe progression. After a decent amount of hours of that and when I felt confident in a solid ability to hold deco stops, THEN I could move up to doing deco dives and possibly going a little deeper. I would almost certainly buy a unit before I went on to get MOD 2 certification.

*free = I'm working as a DM for shop, helping with OW classes, etc.. "Free" training is part of my "compensation". I feel like I'm getting a huge amount of value from the shop with all this training at no charge. I am and will be working hard to try and make sure they feel like they got good value from me in return.