Question SCR Semi Closed Rebreather

[broncobowsher]

With the desire to go to CCR, I would recommend skipping the SCR step.
The SCR market is super thin, almost no desire for it. If you got into it you would likely find yourself stuck with whatever gear you bought for that step or find yourself dumping it for pennies on the dollar. As others stated, the window where SCR shines is pretty small, long duration shallow recreational dives. 90% of the complexity of CCR with 10% of the benifits.

CCR dives just fine in recreational limits. That is how I dive mine most of the time. I find the CCR a more comfortable dive in recreational limits than OC.

 

[Centrals]

the window where SCR shines is pretty small, long duration shallow recreational dives. 90% of the complexity of CCR with 10% of the benifits.

I hate that part(complexity). One of the main reason that I did not progress to CCR.
I am glad I learnt it(SCR) but have never suggested to anyone to try it.

 

[davehicks]

Don't do it. Everyone i know that got suckered into an SCR either dumped it or moved onto a CCR. Of course this was all over 10 years ago. I didn't realize any company was even making SCR units anymore. No doubt there are many lightly used misfit toy SCR units rotting in closets and garages around the world.

 

[GiraffeMarineSalvage]

If you can afford it and will be diligent in gear maintenance and prep I would make the jump to CCR, otherwise I would stay OC with addition of decompression, smart use of nitrox, and larger tanks (all of which combined would still cost less than your first CCR...). Two steel 120s and rental tanks served me well for many years of diving before my pretty recent switch to a chestmount CCR.

 

[Heat Miser]

Hey all I am looking for some basic information on SCR units. I am looking for extended bottom time within Recreational diving limits(my current depth limits are 130FSW and no decompression).

Thoughts on going with an SCR at this point in my dive career?

Obviously I know nothing about your diving interests ... so obviously speak to a good instructor knowledgeable in both those and what I am saying ... however what amazes me when I see people buying, say Horizon SCR's, is how quickly they outgrow them.

I would look at buying a Choptima CCR and doing a No Deco Air Dil 30m course on it, in single tank back plate and wing (so very similar to a GUE) recreational setup with the CCR chest mounted at the front.

That way If you do progress down the teck route you don't have to completely retool. You just have to add a sidemount wing, or a set of doubles dependent on your preferred rigging style (at that time)

 

[Marie13]

You can go straight to Helitrox if you are already AN / DP.

Helium and rebreathers were made for one another

Some instructors will and some won’t. My instructor believes there’s so much going on that students need to get the basic cert under their belt without worrying about depth and deco. That’s not to say you can’t do the upgrade to Helitrox soon if you’ve already got OC deco training under your belt and are ready for it.

 

[Dann-Oh]

@lermontov
My LDS does not sell SCRs that I know of but the shot tech does have a few that he said I could use. I want to wait until the kids are older so that I can actually get out and use the gear I purchased and not forget the training. I have a 16month old right now and I only get out to dive about once every 6-8weeks, that to me is not enough use to stay sharp with something as complex as a SCR/CCR, maybe I'm wrong as I'm not trained in the subject.

@tbone1004 @OTF
I'm usually limited by the need to go pee ;-) jokes aside, my SAC rate is approx. 23psi/min, I'm sure it has gotten a little worse since I've gained some weight after having a kid (he is 16months old). I recently have made the switch to sidemount, I don't have AI for my side mount kit so I am not too sure how diving sidemount has affected my SAC rate just yet, I typically do not remember to check my ending pressures once I'm out of the water. I feel like I'm being limited by my NDL when I get to deeper dives (deeper than 90ft) but I have no data to back that up with. I sounds like I need to get trained in the use of Nitrox so I can sidemount Nitrox in my LP72s. Unfortunately I can not use back mounted doubles due to should mobility issues (cant reach isolator valve with my right hand) so that's what lead me to sidemount for larger gas supply, sidemount 72s vs my back mounted HP100.

@Asheron @GiraffeMarineSalvage
Yes I'm starting to understand that there is not really a benefit of the SCR for my ideal diving. The Chest Mounted CCRs seem to be the next step in my progression, I'm currently diving sidemount with LP72s. I think Id need a new wing though as Im diving the SMS75 and I really don't like that it only has dump valves on the upper (shoulder) side of the wing, I really prefer a butt dump valve. I also don't know if the SMS75 has the capacity (it has 40lbs, I've been looking at the XDeep TEC but it only has 42lbs) to lift 2x 100s or 120s plus a deco cylinder.

@broncobowsher
Thanks for the input. it seems to be the general consensus that SCR is not for me. Although it does sound like the perfect tool for something like Farnsworth Banks near Catalina, California, USA, its a pinnacle dive site where the top starts at 80ft and drops down to really deep. I've been to 120FSW at this site and really wished I could stay MUCH MUCH longer so that I could really focus on my camera and get a few really nice photos of the purple hydrocoral.

@Heat Miser
The two wrecks I mentioned in my original post are the only reason I want to get into deeper diving I have zero desire to just go deep. I am told there are several wrecks in my area (southern California, USA) that are just outside rec limits. I also want to head up to the great lakes (lake Huron) and dive some of those wrecks but I believe many of them are in the 150FSW region so that's at least a level 1 tech class (or whatever its called). I mentioned above that I cant use back mounted doubles due to limited mobility in my right shoulder so I think Sidemount with a Chestmounted CCR would be the logical progression for me. Is the DiveRite Choptima the only Chestmounted CCR on the market? I dont really hear of any others but Im also not in the rebreather scene just yet.

@lostsheep
I think I need to get the N before I can add on the A for AN/DP ;-).

 

[rx7diver]

... Is the DiveRite Choptima the only Chestmounted CCR on the market? I dont really hear of any others but Im also not in the rebreather scene just yet. ...

The DiveRite Choptima is a chest-mounted eCCR (electronic CCR). The Triton is a chest-mounted mCCR (manual CCR).

rx7diver

 

[tbone1004]

@Dann-Oh what is SAC in cfm? You don't say what tank your 23psi/min is on so it doesn't mean much. It sounded like that's on a HP100 though so that would be roughly .67cfm which is on the high side of normal but fairly reasonable.
You certainly need nitrox cert to dive an SCR, that's non negotiable but if you're NDL limited on air at depth then nitrox will help alleviate some of that.
120ft with that SAC rate and LP72's should let you stay down there for 30-35mins which will still exceed NDL on EAN32 for the first dive, certainly for repetitive diving, I wouldn't worry about a CCR anytime soon based on that.

Butt dump in sidemount sucks, very difficult to get to, don't prioritize that. The SMS75 dumps quite easily. CCR's are essentially neutral and the SMS75 has more than enough lift to deal with that.

O2ptima CM is the only commercially available and supported chest mount unit in the US. It is far from the only chestmount unit in the world as most of the worlds militaries use them as O2 rebreathers and there are a handful of units in the EU/UK that are available but the O2ptima is the only one really supported in the USA.

 

[lostsheep]

@Dann-Oh

You should get that “N” now. There’s really not much reason to be diving air…ever. Only time to dive air is in a pool or if you just can’t get nitrox. That’s my 02psi , ymmv