Question Trying to decide on a rebreather unit

[mr_v]

OP, it is hard to recommend a unit w/o knowing your preferences. As you're diving in SoCal, I presume it is going to be mostly wrecks and nature, i.e., beach or boat entrances. Start with a backmounted unit.

None of the units you've mentioned are on my top 3 list. But preferences differ.

Your best bet is to get a gently used CCR that has local support. Dive it as much as you can so that you can learn what you like, then sell the it at a small loss and get something else.

 

[Dann-Oh]

@Dann-Oh - the best rebreather is the one you are using and have experience of diving.

Assuming from your post that you've not dived rebreathers before and you've no experience with them. That's good; we all started from there

Correct assumption. I'm just starting to research RB units.

Rebreathers need a LOT of practice and constant diving. They're not like changing from single-tank to twinset to sidemount; rebreathers are very different than open circuit. This implies that you'll need to select one rebreather and dive it regularly for a couple of years or more, especially as you're talking about deep diving (100m/330ft).

You've mentioned three different styles of rebreather: backmount (good for boat/wreck diving and deep), sidemount (specialist, awkward) and chestmount (not good for deep).

My personal advice to you is to choose a common and well-regarded backmount unit. Only when you're experienced with diving a rebreather -- meaning at least a couple of hundred hours/dives -- should you then consider something different.

Common units that are well regarded are probably the ones you've seen on your dive boats already. For example the JJ and Revo. Many others are available.

My diving is on a Revo; I dive in the UK (cold water) predominantly off of dive boats for the past 5 years down to 75m/250ft. This works very well and the Revo has been a very reliable unit which I've no intention of changing. It also works well in overhead environments provided they're not too wriggly.

As long as you choose a common and well regarded unit, it should suit you well for boat diving.

You must budget for the training and practice diving you will need. I've no idea what your current diving is but the Divemaster qualification is of no real benefit. When diving a rebreather, you'll naturally want to dive deep (meaning trimix) and long (meaning substantial decompression). If you've those skills already, then you'll be well prepared for some aspects of rebreather diving. If you've been predominantly diving to NDLs and nitrox; there's a lot more to learn before you can head down to deep and long.

I have about 200 dives in the last 4 years, Ive gone through Padi up to Rescue & DM. Im switching over to SDI/TDI for the rest of my training (My instructors teach both Padi and SDI/TDI)

The first course will be your "MOD1" which is how to dive the unit and do some light decompression, possibly with trimix but normally you'd probably get qualified on nitrox to either 30m/100ft or 40m/130ft.

Once you have MOD1, you must do 100 hours of diving on it in different locations including shallower locations where you constantly run through your skills and get the buoyancy sorted out. Buoyancy on a rebreather takes a lot of time and effort to master and be comfortable, especially shallow 6m/20ft (which you'll be spending a lot of time at whilst decompressing from deep dives).

Only after getting very comfortable in your unit and mastering the various skills learned on your MOD1 will you move on to MOD2. Doing this early is not recommended as it will be a miserable experience (just like doing twinset skills if the basics aren't good).

I feel I will be at MOD 2 for quite a long time. There is lots to see here in Southern California above 130ft. Id really love the extended bottom time at 100-130ft depths to enjoy the sights.

MOD2 is about decompression diving and staying alive on the unit when you've a considerable decompression obligation. You'll be bailing out to open circuit trimix and practising endless skills for keeping your unit running if, for example, you've run out of gas, there's been electronic failures, etc. MOD2 dives are generally around the 2h to 3h duration with 1h to 2h30 decompression times.

Again, after MOD2 you'll need to do a lot of practice and actual dives to master those skills. At least you'll now be "qualified" to do 70m/230ft dives, so well set to develop your wreck diving experience.


Rebreathers are massively useful tools for diving; incredibly flexible and quite cheap to run in comparison with open circuit. They come at a cost of complexity and greater levels of planning and preparation.

It would help if you've a friend/buddy you could do the journey with. Someone to "play" and practice with is an excellent help, especially when doing the endless skills practice.

This is going to be my challenge but I think I know enough people (all way more experienced than myself) to be able to get out regularly to run through rebreather skills.

Selecting the rebreather is the easy bit!

 

[Dann-Oh]

You also need to decide electronic (solenoid injection) vs manual (leaky or needle valve) control of PO2. Some with an eCCR unit will perform frequent manual O2 injections (push a button) and leave the solenoid as a backup (so called "parachute mode").

Do you know if there is a list of manual vs electronic units easily accessable?

The eCCR category is pretty well represented by earlier posts. The Fathom is an example of a backmount unit with needle valve. Some can be setup as hybrid (leaky valve and a solenoid).

There are pros and cons to each type. Keep this in mind when going through the numerous earlier threads in the RB section.

Ill add the Fathom unit to my list to review.

 

[Dann-Oh]

OP, it is hard to recommend a unit w/o knowing your preferences. As you're diving in SoCal, I presume it is going to be mostly wrecks and nature, i.e., beach or boat entrances. Start with a backmounted unit.

I prefer diving sidemout vs backmount when on OC. I currently do a lot of beach diving, I enjoy boat dives as well but beach diving is free.
I don't really know what my preferences would be for a rebreather because I haven't dove with one, not even a pool session.

None of the units you've mentioned are on my top 3 list. But preferences differ.

After chatting with a few on here and really thinking about it I think the Sidewinder is off the table as a starter rebreather unit.

Your best bet is to get a gently used CCR that has local support. Dive it as much as you can so that you can learn what you like, then sell the it at a small loss and get something else.

 

[inquis]

Do you know if there is a list of manual vs electronic units

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[Dann-Oh]

InDEPTH’s Holiday Rebreather Guide 2023

Making a list. Checking it twice. Gonna find out which breathers are naughty or nice. That’s right! It’s time again for InDEPTH’s Holiday Rebreather Guide. This season, we are featuring 24 brands and 36 models of rebreathers for your shopping enjoyment. So, get out your Pre-Buy Checklist, and...

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Thanks a ton.

 

[Wibble]

Correct assumption. I'm just starting to research RB units.

I have about 200 dives in the last 4 years, Ive gone through Padi up to Rescue & DM. Im switching over to SDI/TDI for the rest of my training (My instructors teach both Padi and SDI/TDI)

I feel I will be at MOD 2 for quite a long time. There is lots to see here in Southern California above 130ft. Id really love the extended bottom time at 100-130ft depths to enjoy the sights.

CCR comes into its own as you’ve effectively no limits for dive time. Actually the main diving limit is the amount of bailout gas you can carry.

For the shallower dives of 30m/100ft you can get well over an hour on the bottom with 30 mins of decompression.

I prefer diving sidemout vs backmount when on OC. I currently do a lot of beach diving, I enjoy boat dives as well but beach diving is free.
I don't really know what my preferences would be for a rebreather because I haven't dove with one, not even a pool session.

The good news is you’ll be diving sidemount with your decompression cylinders You’ve no longhose on your right hand side, so diving with balanced stages, lean left, rich right, with bungees to pull them back under your armpits for streamlining and to not snag on the wreck.

 

[happy-diver]

Who said that for every other rebreather out there is a breaking marriage

 

[BoltSnap]

chestmount (not good for deep)

Why not?

 

[Wibble]

With large bailouts, maybe with more than two ali80s, the chest area will become mightily crowded.

Backmount keeps the box with your three smaller cylinders (oxygen, diluent and drysuit air) behind you so your front and sides can be cluttered with bailouts.