Beginner question for rebreathers

[emilmutz]

Hi all,

my higest qualification is TDI adv nitrox diver (you can see my bio for all my qualis).

I have 2 questions regarding rebreathers:

1.)
Maybe it`s a waste of money but I thought I`d like to start not w a "full-scale rebreather" (200m on trimix) but one which is designed for air/nitrox only.
Maybe you can call it a recreational-rebreather? My goal is diving on max 45m or take longer dives on 20m.
My focus is also on the weight: I want to travel light and as I am only 1,70 tall I had problems with carrying around 2x 12 liter full filled air bottles. So my aim is not only the rebreather itself but to have something lighter than 2x full filled 12 liter bottles. Also I disliked the underwater drag from the heavy tec equpiment. I am 170 cm with 68 kg, so yes, the weight was an issue for me.
My question No 1:
Are there rebreathers for air/nitrox with focus on light weight?

2.)
I learned from my tec diving that it is IMPOSSIBLE to choose the right diving equipment for you on the internet, you always have to experience everything in real dive.
As this is easy with open circuit equipment (avialable everywhere) it looks difficult with rebreathers.

My question No 2:
How do I proceed? Do I choose 1 rebreather and take a training cours on this specific one and then the next class on the next rebreather?
Or is it common in the rebreather-world to test dive 2 or 3 rebreathers, choose the I liked most and start the training course?
I live in Austria, EU. So my possibilties are limited.

Thank you for your help!

 

[lermontov]

do you know at this stage what sort of technical diving you want to achieve ?
do you have any friends that have ccr or maybe peoples you know that you might dive with
ccr diving demands a lot of attention both in and out off the water -is this you ?
tech diving is expensive -be warned

 

[tomsch]

I'm from Austria too, here the rebreather used by the most divers is the JJ-CCR. For trying out a rebreather there are instructors in Austria or in neighbouring countries for X-CCR, Divesoft Liberty, Kiss Sidewinder, JJ-CCR, Poseidon SE7EN, AP CCR, SF2. So even for trying out some you have quiet some options.

There are not really any options for nitrox rebreather which make sense, mares has the horizon ccr which is a REC rebreather but except that you can do nearly everything with every rebreather. Rebreather grow with you and will most probably never limit you in what you can do.

Also because rebreather may require way more problem solving and clearness of mind underwater even 45m on a CCR are not recommended on air and you should use helitrox for that. With Air the "hard" limit resulting from pO2, END and Air Density is 40m.

For drag underwater, for most deco dives you will require at least two stages + CCR.

For training you normally have 4 Stages. Air Diluent, Deco Procedures/Helitrox, Nomoxic Trimix, Hypoxic Trimix. Because you have AN/DP, you can start with Deco Procedures/Helitrox. That's the starting point. After some amount of dives/hours you can do your normixic trimix and after some more dives/hours you can do your Hypoxic trimix course. You can do all of that with the same rebreather. Also if you want to switch to another rebreather you can do what's called a crossover, for which you would have to consult the standards of your organisaton, which makes it easier to get to for example to Hypoxic trimix then it would be if you had started new all over again.

Talking about organisation's it's more important that you pick the right instructor then that you pick a specific Organisation for your CCR Training.

P.M. me if you have any questions regarding local instructors and places where you can try out ccrs.

 

[tbone1004]

Hi all,

my higest qualification is TDI adv nitrox diver (you can see my bio for all my qualis).

I have 2 questions regarding rebreathers:

1.)
Maybe it`s a waste of money but I thought I`d like to start not w a "full-scale rebreather" (200m on trimix) but one which is designed for air/nitrox only.
Maybe you can call it a recreational-rebreather? My goal is diving on max 45m or take longer dives on 20m.
My focus is also on the weight: I want to travel light and as I am only 1,70 tall I had problems with carrying around 2x 12 liter full filled air bottles. So my aim is not only the rebreather itself but to have something lighter than 2x full filled 12 liter bottles. Also I disliked the underwater drag from the heavy tec equpiment. I am 170 cm with 68 kg, so yes, the weight was an issue for me.
My question No 1:
Are there rebreathers for air/nitrox with focus on light weight?

2.)
I learned from my tec diving that it is IMPOSSIBLE to choose the right diving equipment for you on the internet, you always have to experience everything in real dive.
As this is easy with open circuit equipment (avialable everywhere) it looks difficult with rebreathers.

My question No 2:
How do I proceed? Do I choose 1 rebreather and take a training cours on this specific one and then the next class on the next rebreather?
Or is it common in the rebreather-world to test dive 2 or 3 rebreathers, choose the I liked most and start the training course?
I live in Austria, EU. So my possibilties are limited.

Thank you for your help!

1. This is really just a SCR vs CCR debate, any "full-scale" rebreather is going to be a CCR and the functional difference is the addition of 2 gases vs. 1 gas *Oxygen CCR's being excluded*. Weight and drag are going to be comparable with either a CCR or SCR as a set of twin 12's since you still need to carry bailout with you, same issue with drag.

2. we will have to agree to disagree with this statement since it is possible to make near fully informed decisions without diving the specific gear and often times the dives may not be done properly and will give you an inaccurate opinion. This is particularly true of rebreathers where getting them fitted to you properly is critical and you will have a less than optimal experience otherwise.

How to proceed? I would recommend staying with open circuit for now and focusing on minimizing the issues you have with OC. Plenty of the highest level divers in the world are petite females, much smaller than 1.7m and move around with twin 17L steels without issue on boats and shore dives, not including the decompression/stage cylinders that go with those twinsets. Get your body in shape to move the kit around properly and it won't feel so heavy. If there are physical limitations then sidemount may be an option to avoid carrying the tanks, but twin 12's are not heavy and you don't mention any physical issues other than not being strong enough to carry them around, so get stronger!
The drag issues aren't going away so learn how to streamline your gear and focus on the fundamentals of buoyancy/trim/propulsion and you can counteract most of the drag that way. GUE Fundies or similar *UTD, NAUI, ISE, etc* would likely go a long way to helping with this.
Stay off of the rebreather route until you become limited by the twinsets either with helium for depth or quantity of bottles for duration because they truly do not make the whole rig lighter/more streamlined. The CCR itself is less streamlined than the twinsets are and you still need to carry extra bottles with you so the net rig weight is still about the same until you get into some serious extended range diving where there is some gear savings *over 5 bottles total*

 

[AJ]

My advice: don't focus on a air/nitrox rebreather. A 'full scale' rebreather is at the same price level and can do anything you want, now and in the future. If weight and size is a real concern for you, look at Choptima, Triton of KISS Sidewinder ccr. They are really light weight and travel friendly. But remember, you always have to carry bailout which adds weight to your whole config.

I dive a JJ-CCR which is about 35 kg dive ready for every dive imaginable. The beauty of rebreathers is that the weight does not change with depth. They always weigh the same and are a lot lighter than a D12.

But as already has been said. Choose your path wisely. Rebreathers are whole different animal when it comes to diving.

 

[emilmutz]

Thank you, guys!

My diving teacher told me the same regarding the weight - bailout tanks issue.
But this was 10 years ago (I got a child and had no time to dive anymore) and I thought maybe some game changing rebreathers came on the market since then.

I also thought that maybe in the last 10 yrs some "kind of recreational" RBs came out.

But its still the same like 10 yrs ago: RB bring risks w them, and as long as i can do my depth w 2x12 liters OC there is completely no meaning in switching to RB. Thats how I understood you.

My diving teacher even did all his heliox tec diving on OC as he completely distrusts RBs. Thats also why I wanted to ask here for a second opinion.

@tbone1004 : I also saw my physical weakness issue. Since 2 yrs I`m going to the gym twice a week.

 

[AJ]

But its still the same like 10 yrs ago: RB bring risks w them, and as long as i can do my depth w 2x12 liters OC there is completely no meaning in switching to RB. Thats how I understood you.

My diving teacher even did all his heliox tec diving on OC as he completely distrusts RBs. Thats also why I wanted to ask here for a second opinion.

Wise decision. As long as you can do the dives with D12, it's the way to go. I still love the simplicity of a single tank air dive compared to my RB. It almost a zen feeling versus working hard. On deeper dives however, I love my CCR.

An RB really comes into it's own with longer and deeper dives and a doing lot of them. The view on if a RB is more dangerous than OC at greater depth is a personal view imho. Diving deep is dangerous, no matter your skill level and equipment. Ik believe OC and CCR have their own inherent dangers. It's up to you which dangers you want to mitigate.

 

[emilmutz]

Thx.

Still, RBs themselves are a fascinating topic, even if I just study them theoretically

 

[emilmutz]

One more question:

does all this applies to SCR as well?
I guess SCR delete some complexity but adds on the weight as you have carry more gas?

 

[broncobowsher]

Few things to remember. You will ALWAYS be carrying bailout. That is just what it is with a rebreather. There are things that can go wrong in the blink of an eye that can suddenly weight you negative with nothing to breath. How much bailout depends on how big of a dive you do.

You can always dive a technical rebreather recreationally, but you can't dive a recreational rebreather on a tech dive.

A recreational rebreather has the same limitations and complications as a techinical unit, Often with even more limitations. So the answer is yes, just go straight to the full scale rebreather

As for the added drag statement, so what is my answer. You are not in a speed race. You are on a rebreather and have lots of time. So there is drag and you don't move as fast. If you need speed, add a scooter.

You can do a recreational rebreather dive with just a small bailout, I use a little AL40. Small enough you don't really notice it is there. More and bigger as I go deeper and into deco.

SCR, KISS has one. Marketed as a gas extender more than a rebreather. Hollis tried the Explorer, lots of those sold, few actually got much use. The Mares Horizion has been out for years now and there is almost no talk about them. Never seen one outside of a trade show. I've seen just about every other rebreather out in the wild. They really don't fit in with the diving profile of normal rebreathers, nor do they fit the fit in with the diving profile of OC. You have to search out others who dive SCR, and they are so few and far between that you will just be by yourself. There are a few niche places where they are the right tool for the job. But a CCR is a tool that will do many more jobs.