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Aaron Harmon

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I am new to rebreathers (so new I haven't even dove one yet) but I am completing the TDI training next week. In any case, I have been reading a lot about the various brands and I have some questions regarding attitudes/beliefs and trends.

JJ, Meg, fathom, Revo, Defender, Optima, and Kiss are mentioned very often, whereas Posieden and AP appear to be less frequently discussed. Also, when people recommend systems, they frequently discuss some of those same systems and again, the others are not as frequently mentioned.

Why is that? I've seen data (not sure how old it is) that listed AP as by far the most sold rebreather. Based on that, I would expect them to be mentioned more often. Unless I am missing something, these all cost about the same new so I don't suspect price is the major factor (though I could be wrong).

Thanks in advance,

Aaron
 

rddvet

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For me Poseidon has never been a consideration because it’s full of proprietary stuff. You have to buy a new battery just to change the depth limits you can dive. Hell no to that.
AP I don’t know much about. They’re popular in England I understand but not super popular here. I have several friends that dive them, but they only dove them because the university they do research through requires CE certification. None of them love the ap and all dive different rebreathers when not working.
 

tbone1004

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@Aaron Harmon
What is important to remember is that the rebreather divers on this forum are almost all true technical divers and most of us are cave divers.

The Poseidon wasn't really designed for technical divers and was biased heavily towards being able to achieve PADI type-R status. Pros and cons, but it is a rebreather designed to be used by amateurs and not really professionals. Not to say you can't use it for big boy stuff, but it wasn't designed for it. It has what is probably the best BOV on the market, and I VASTLY prefer the 2-cell concept to 3-cell as I seriously don't think that 3-cells with eCCR's is smart or really even safe. Poseidon invested in injection molding to mass produce this rebreather and a lot of technical divers feel that it is "fantastic plastic" vs. the machined delrin/aluminum units on the market. It doesn't make it inferior, just feels like it may be. It also required a scrubber cartridge which is rather wasteful and very expensive compared to packing your own. Until the M28 it also only had the paddle on there which was not great...
Support for this unit prior to Salt Blue was not great in the US either which caused some issues.

APD is used by many universities like @rddvet mentioned and I am required to use one when doing scientific diving as well, but it's not one that I like for personal diving. It is also designed to be a bit of a babysitter unit flown from the computer as proven by the fact that the HUD doesn't actually give you ppO2, just "good" and "not good". Their unit requires a tremendous amount of modification to be halfway close to streamlined for cave diving.
Support for the unit in the US is through Silent Diving in Maine and they've had some issues over the last 5 or so years.
 

Aaron Harmon

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@tbone1004

Thanks for the thoughtful response. I am just getting into technical and rebreather diving and obviously have a lot to learn. In any case, I read a lot of posts where people discuss having this or that for their second or third rebreather. Obviously, given the cost, I'd like to buy new and get it right the first time. I live in NW Ohio and diving is done either (miserably) in a 7 mill wetsuit or in a drysuit. Most "training" type dive are completed in quarries that have very poor visibility for much of the year. I have not started diving the great lakes but plan to soon (hence the desire for technical and rebreather training). I also like to travel and dive (to much warmer climates) and frequently take two trips per year.

I have several wreck penetration dives under my belt but have not dived caves yet (though would also like to do that as well).

I know that these threads are all over the place, but given what I've told you, what would you do if you were in my position?

The trainer that is coming up next week is a TDI instructor who will train me on an AP unit. I wont get into the details of what we've discussed because I'm not sure how copacetic that is. I will say that he works for silent diving and I have discussed purchasing a rebreather from him. I also have the option of renting the unit for the training, and making a purchasing decision later. That said, even renting the units is costly.

So far he (the trainer) has been super responsive, very friendly and very helpful.

Ultimately, I can "afford" to do whatever I choose but I also do not wish to spend money on something that I am going to want to replace in a year or two if I find that it is not fitting my needs. While I don't "need" my wife's permission to spend $15,000 or so training and equipment, she is very supportive and has fully endorsed my decision to get into this (she has been 100% supportive all along). The same may not be true if a year from now I am discussing spending another $10,000 on what to her will be nuanced differences.

Thanks in advance for sharing your knowledge, expertise and perspective.

Aaron
 

tbone1004

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@Aaron Harmon

Here's my high level take and instructors like @kensuf have some similar and some different opinions, though I would pick his brain if you can.

No diver is qualified to evaluate a rebreather in the water until they are actually certified on a rebreather. Try dives are almost completely useless because of the amount of time it takes to actually be comfortable on a rebreather and get it fit to you so it breathes the way it is supposed to. Taking a try dive on a rebreather is like asking a 16yo to do a bunch of test drives to figure out their first car. Sure you can look at the different radios and how nice the leather seats are, but you are not qualified to gauge how it handles, brakes, etc. because you don't really know how to drive a car yet. With that, I recommend that people take their Mod1 course on a unit that they THINK they might like with an instructor that they mesh with *i.e. if you really think you want a Meg, but you really like Ken as an instructor, then you take a Fathom course with Ken because it's "close enough" and THEN you can do a try dive on a Meg to see if you like it. He'd probably tell you to just take a Meg class from Ted McCoy, but that's besides the point*. If the instructor works for Silent Diving then it should be a cheap unit rental for the week, and that will then qualify you to evaluate units.

The AP is fine, it is referred to as the yellow box of death or YBOD because of how many morons offed themselves on it 15+ years ago, but it's a very different rebreather now than it used to be. Here's what I would do. Negotiate with the instructor that says I want to rent the unit, but if I buy a unit from you I want the rental cost credited back. This is common in cave country with rebreather instruction. This will help you figure out if CCR is actually for you, and if the APD is the unit that is right for you with fairly minimal risk as far as cost is concerned.
 

Tracy

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Speaking specifically with the two units you mentioned. Poseidon doesn't gather much support as it is a recreational dive shop unit. There is no diver level support. Typically, but definitely not always, people moving in the rebreather direction are technical divers looking to expand into something they couldn't feasibly do with open circuit. The Poseidon doesn't fill that role.

As to AP, They make a very good unit, and I understand they have great support in Europe.
They have basically no support in the US. When the unit breaks, and they all do, you will be sending it across the pond for service.
Hopefully they have parts, I have a dive buddy who has been waiting on his replacement HUS for 5 years now. He bought another unit of a different brand with US support. It was a very expensive lesson.

Every unit has pros and cons, some a made poorly, some are supported poorly. Some are flood tolerant, some aren't, some are bulky, some aren't. Some units are built and supported well, but they weigh more than the boat you are getting on. There isn't a unit made that everybody agrees is perfect.
 

Aaron Harmon

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Speaking specifically with the two units you mentioned. Poseidon doesn't gather much support as it is a recreational dive shop unit. There is no diver level support. Typically, but definitely not always, people moving in the rebreather direction are technical divers looking to expand into something they couldn't feasibly do with open circuit. The Poseidon doesn't fill that role.

As to AP, They make a very good unit, and I understand they have great support in Europe.
They have basically no support in the US. When the unit breaks, and they all do, you will be sending it across the pond for service.
Hopefully they have parts, I have a dive buddy who has been waiting on his replacement HUS for 5 years now. He bought another unit of a different brand with US support. It was a very expensive lesson.

Every unit has pros and cons, some a made poorly, some are supported poorly. Some are flood tolerant, some aren't, some are bulky, some aren't. Some units are built and supported well, but they weigh more than the boat you are getting on. There isn't a unit made that everybody agrees is perfect.

I thought Silent Diving handled service and support here in the U.S. Is that not the case? If I had to wait 5 months for a replacement part, I'd be pretty aggravated. Heck, 5 weeks is too long...

Aaron

P.S. Out of curiosity, what do you dive?
 

Wibble

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You learn on one rebreather as your "MOD1" course will be linked to that machine.

Reality is all are great rebreathers and you need to choose one and stick with it for some time so you can properly learn how to dive with a rebreather. Chopping and changing is not a good thing as they're all very complex machines and will quite happily kill you if you're not on top of them (actually it'll be you that kills you; the box isn't sentient).

The only rebreather that matters is the one on your back. Every rebreather, and I mean every rebreather, has pros and cons. None are perfect in every way.

Any of those you listed are fine machines with plenty of people diving them.

Regarding AP: they're incredibly popular in the UK, but they're made in the UK. They are cheaper than a lot of other rebreathers. Change that ugly plastic yellow box though; most people swap it over for a G-box or other similar cage. They were the first popular rebreather and have sold orders of magnitude more than most other rebreathers. Later ones are quite different from the early "classic" ones (which aren't supported any longer -- certain spares aren't available).


Personally I've seen a rebreather as being the cost of a motorbike. From a few thousand upwards. There's old dogs around -- caveat emptor, buyer beware -- and some great modern ones with all the bells and whistles. There's also a bunch of antiques and really esoteric old ones (Mk15.5 with "spheres").

Just stick with the common ones you've listed. Any will be fine.

What you must factor in is the cost of training. This is the initial "MOD1" course of about 5 days plus it's worth doing some coaching days. You must get on with your instructor as you'll be after doing the "MOD2" course (circa 60m/200' on trimix) with them. You really want an instructor who dives all the time and has plenty of decent stories to tell. This isn't an open water DiveMASTER journey; this is a serious commitment on your part, both financially and time wise.

You must practice with a rebreather; the number of hours count as well as the number of ascents, which is the most important and difficult phase of a dive. Never ever get complacent -- that's when it'll have a go at you.

Have fun.
 

Aaron Harmon

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You learn on one rebreather as your "MOD1" course will be linked to that machine.

Reality is all are great rebreathers and you need to choose one and stick with it for some time so you can properly learn how to dive with a rebreather. Chopping and changing is not a good thing as they're all very complex machines and will quite happily kill you if you're not on top of them (actually it'll be you that kills you; the box isn't sentient).

The only rebreather that matters is the one on your back. Every rebreather, and I mean every rebreather, has pros and cons. None are perfect in every way.

Any of those you listed are fine machines with plenty of people diving them.

Regarding AP: they're incredibly popular in the UK, but they're made in the UK. They are cheaper than a lot of other rebreathers. Change that ugly plastic yellow box though; most people swap it over for a G-box or other similar cage. They were the first popular rebreather and have sold orders of magnitude more than most other rebreathers. Later ones are quite different from the early "classic" ones (which aren't supported any longer -- certain spares aren't available).


Personally I've seen a rebreather as being the cost of a motorbike. From a few thousand upwards. There's old dogs around -- caveat emptor, buyer beware -- and some great modern ones with all the bells and whistles. There's also a bunch of antiques and really esoteric old ones (Mk15.5 with "spheres").

Just stick with the common ones you've listed. Any will be fine.

What you must factor in is the cost of training. This is the initial "MOD1" course of about 5 days plus it's worth doing some coaching days. You must get on with your instructor as you'll be after doing the "MOD2" course (circa 60m/200' on trimix) with them. You really want an instructor who dives all the time and has plenty of decent stories to tell. This isn't an open water DiveMASTER journey; this is a serious commitment on your part, both financially and time wise.

You must practice with a rebreather; the number of hours count as well as the number of ascents, which is the most important and difficult phase of a dive. Never ever get complacent -- that's when it'll have a go at you.

Have fun.


Thanks a bunch.

Aaron
 

Big-swede

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It's a little bit like vaccine and gradient factors, people read stuff online and don't trust research.

The poseidon still carries the burden of early baby faults and bad customer service from when the unit first came out about 15 years ago.

Yes you can buy it in recreational setup but to complain that it wont do 150m dives in that setup is like complaining that the octopus you bought doesn't have two first stages.
If you want tech setup then just get that straight away and change the depth limits yourself in the computer.

And repackable scrubbers have been the only option for several years and an option for even longer.

I think one of the main reasons you don't hear much talk about them is that most poseidon divers are happy with their gear and don't bother getting in to discussions with people who don't know what they are talking about and still want to throw trash around.
 
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