#3720
To go CCR Rebreather,... or not?????
tstormdiver - 10/06/2015 6:38 AM
Replies: 20

Ever had the thought, " I might like to have a rebreather"? Well,... they are tools to an end. I am not one to say that someone should or should not have one, but they do warrant some serious considerations first.
1. They are a very expensive investment. For a new CCR unit, they start at about $7,000 & up. A used unit can be a bit less in the $4,000 range for a much older unit. Not saying better deal can’t be found, but this is the ballpark. 2. There are also maintenance costs. Just my Prism alone costs me about $500 to maintain yearly ($100 for rebuild kit, $75 for labor & to replace the 3 Oxygen sensors is nearly $100 each). A 44 lb container of CO2 absorbent costs about $120- $150. 3. A diver must pay attention to the tiniest details. Even a small miss can be deadly. Check lists are a MUST! If you can not or will not take the time to properly go through a check list, a rebreather may not be for you. Nearly 100% of all accidents on a rebreather can be traced back to operator error. 4. there is extensive pre- dive & post- dive maintenance that must be done to keep the unit safe. If you are not prepared or willing to do this maintenance, then you may want to rethink why you may want one. Rebreathers require an extensive investment in time, training, attention and money.

Now for the cool parts- 1. Longer bottom times, 2. no bubbles, so you don’t scare the marine animals, 3. Quiet- Until you have been on a rebreather, you just don’t know how loud open circuit really is (It’s deafening), 4. With a Nitrox mixing machine on your back, you have the best possible mix for the dive at all times, & 5. They are just soooo cool looking!!!!

Here is an article by Harry Averill & TDI that goes into more depth about the Pro’s & Con’s of rebreathers: tdisdi.com/is-ccr-diving-right-for-you/?utm_sour..._medium=social_media
#1269
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NORTHEAST - 10/06/2015 7:08 PM
As you know Tammy I just crossed over to the pitch black side ;) I was already on the dark side of technical oc but now it’s even darker and I have to say I love it. Can’t wait to do my Meg ccr course. And yes guys I’m one of the guys who went the $5000 dollar route and got a used machine. With the Initial mod 1 training I’m already at 7k
#3720
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tstormdiver - 10/06/2015 8:14 PM
Hopefully your instructor will verse you well about knowing the proper millivolts of your oxygen sensors at both high & low PO2’s & how they should read linearly as the PO2 changes. When I was going through my CCR course, my instructor kept me on my toes for months (I got my CCR in the winter, so used the local indoor pool to get myself thoroughly comfortable with the unit until the following spring, when the waters warmed up). He would continuously quiz me on gases, PO2’s Procedures & emergency procedures. I had close to 50 hrs on the machine in the pool, before I ever took it to the water.
#1269
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NORTHEAST - 10/07/2015 9:21 AM
Wow! Yea the only thing that’s gonna suck is going back to the quarry with this thing. I feel like I’m taking a step back but I have to look at the big picture! At least there will be no more looking at my spg every 5 mins!
#1107
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Btrax - 10/07/2015 10:57 AM
I certified and purchased a Hollis Explorer last spring. I have been diving with it ever since. I absolutely love it. I recently went to Dutch with a friend. We did 3 dives. He blew 3 100 tanks of nitro. i was still going on one 40 cu ft bottle and the same scrubber. If you are looking for a rec unit and want to give it a try this is a good one to start on. 15-20 min setup and teardown once you get used to it. It is go or no go and any issues underwater that are above minor call for bail out. You can pick up a used one for 2700-3500 and they can use a CO2 sensor to monitor loop CO2.
Almost no bubbles. Next year i am looking into full closed circut RB
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tstormdiver - 10/07/2015 11:46 AM
From Btrax: I certified and purchased a Hollis Explorer last spring. I have been diving with it ever since. I absolutely love it. I recently went to Dutch with a friend. We did 3 dives. He blew 3 100 tanks of nitro. i was still going on one 40 cu ft bottle and the same scrubber. If you are looking for a rec unit and want to give it a try this is a good one to start on. 15-20 min setup and teardown once you get used to it. It is go or no go and any issues underwater that are above minor call for bail out. Yo...

Although, yes, the Hollis SCR is overall safer & quicker on the set- up, break down & maintenance, it does have many limitations that the Prism does not have. The biggest is, you are limited to the MOD of the drive gas. I do like the idea of the CO2 monitor & wish they could incorporated it into the Prism2. The placement of the counterlungs tend to really change the work of breathing when in certain positions. Yes, they are out of the way in the front, but it does affect work of breathing,... I would (personally) rather put up with the conterlungs in front. I have done a 20 ft, 4 hr dive (the limit of the scrubber) with two 23 cuft bottles (air & Oxygen). Both were started at 2000 psi & I finished the dive with 500 psi in the O2 bottle & still had 1700 psi in the air diluent. On shallow dives, CCR’s are not very efficient & use much more Oxygen. I agree the Explorer may be a better choice for the recreational diver,... but the Prism is much better suited for the technical diver.
#948
Curtis - 10/07/2015 7:14 PM
"Ever had the thought, " I might like to have a rebreather"?

No, since I don’t do exploration, major penetration, serious marine life photography or very deep, be hard for me to justify. Open circuit serves most quite well.
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tstormdiver - 10/08/2015 2:31 AM
Nothing wrong with staying on Open Circuit,... if that is what suits your style of diving.
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NORTHEAST - 10/08/2015 3:38 AM
By the way Tammy I went with the butterfly plate/d ring on the crotch strap for sidemounting the bailout bottles. Along with the nomad bungee and choker system. Reason is if I had put a butt plate on like I have on oc now then it would be hard to sit into the unit on a boat. And it’s cleaner on the unit. Also I got the new halcyon triangle ccr wing. Has tons of lift at the bottom and tapers off to the top. Also my with the halcyon harness and back plate. And two 3liter bottles new. Listen I’m not a "DIR" I can’t think for my self type of person but for once the big H makes sense for this system.
#3720
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tstormdiver - 10/08/2015 4:29 AM
I use the butterfly D-ring on the crotch strap. Works well for me, since I have rather short arms. I can reach that. The Butt plates I have used, tend hang too low from me to be able to easily reach. All’s I used for the valve loops is a loop of thick bungee bungee run through a small quick link that goes through a hole, high up on my backplate. The bungee loop knot catches in the quick link to hold it in place. I just stretch the loop over the cylinder valve handle & it snugs it up right under my arm pits. Works perfectly. My wing is now a triangular Hollis SMS75 wing that is bungee’d at the top & free at the bottom. Changing this, allowed me to drop from 10 lbs of trim weight that was in pockets high up on my shoulders, down to 4 lbs to trim out perfectly with 2 AL 80 bailouts. The lift in the rear, is just what I needed (& I bet cheaper than the Halcyon).
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Btrax - 10/08/2015 5:58 AM
apologies, didn’t realize you were talking tech. One of the reasons i started with the explorer was because of the co2 unit. I am surprised that hollis has not incorporated it into the prism. And licensed out the technology for other units. I am taking the tdi tech course (advanced nitro and deco next on oc) then will move to ccr tech. The prism is the unit i will be moving to. On the subject of bail out bottles, i had a stand made for my explorer, it has a couple of d rings welded to the bottom of the frame for the lower attach point of my bail out bottle. it also gives me about 8 inches of height on the unit when getting in and out of it especially on a boat. If I’m not mistaken Add Helium has stainless steel stands for sale for the prism also.
i use a bungee strap at the top to keep my bail out bottle tucked under my shoulder
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Btrax - 10/08/2015 6:27 AM
Tstorm a quick question. How do the front mounted counter lungs affect the wob as mine are back mounted. I noticed in certain positions (head up especially) the wob gets extremely difficult.
#948
Curtis - 10/08/2015 9:44 AM
From tstormdiver: Nothing wrong with staying on Open Circuit,...

Of course not. OC is good to well beyond most diver’s ambitions.

From tstormdiver: ... if that is what suits your style of diving.

That almost sounds condescending. (I hope I mis-read it, most of your postings I like)

Rebreathers are just an expensive toy most divers do not need. Glamorizing them to newbies is about sales, and about akin to glamorizing dead boat solo diving, IMHO. Yes, they have their place, you should replace pro #5 with they slow heat loss during very long deco, another thing most divers will never do, and "looking cool" makes me think of exposed boxers / pants below the buns.
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tstormdiver - 10/08/2015 12:19 PM
Curtis, Not being condescending at all. Matter- of- a- fact, yes. I dive Open circuit also, quite a bit. Each style of diving has it’s merits & limitations There is absolutely nothing wrong with diving OC or CCR. That is why I put this in the Technical Diving area. Most Newbies are not immediately looking to dive technical. I understand, Yes, they are expensive to buy, yes they are expensive to maintain, yes, The training is expensive & they do require an intense attention to detail. I have already mentioned all this in the original post. Even so, there those that are interested for one reason or another. Just because something does not suit you, does not mean it does not suit another. If you are good with OC diving & it suits your purposes, that’s good. If others want to dive different ways,.. that is good also. Please stop reading things into my posts that are not there.
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tstormdiver - 10/08/2015 12:26 PM
From Btrax: Tstorm a quick question. How do the front mounted counter lungs affect the wob as mine are back mounted. I noticed in certain positions (head up especially) the wob gets extremely difficult.

I have not found any position that impedes work of breathing on the Prism. When doing a barrel roll, the Automatic Diluent Valve will sometimes activate. The biggest minus to over- the- shoulder counterlungs is it is a bit more cluttered in the front. Hollis was working on the back mounted counterlungs for the Prism, but had to scrap it & start over.
#4322
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caves4me - 10/08/2015 5:52 PM
Due to the depth and the restrictions of the cave we are exploring a sidemount rebreather is the only option!
#3720
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tstormdiver - 10/08/2015 5:58 PM
From caves4me: Due to the depth and the restrictions of the cave we are exploring a sidemount rebreather is the only option!

Very interesting. I bought mine (backmount) to extend my bottom times & further my penetrations into the more popular "tourist caves". At this point, that is all I plan,... but then I can remember when I had said there was no way I would ever cave dive... :) It is very cool how configurations can be altered in so many ways to fit different dive objective needs.
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caves4me - 10/08/2015 6:20 PM
Hey tstormdiver, Yeah the stuff we’re pushing, the first 100 feet is under 12inches, it’s not too bad because of the sediment, and it does get larger in some areas but then it drops in depth. As for altered configurations we have to tail mount our stages, not the best idea but it works in certain areas that we are mapping. My buddy shot this video a few weeks ago: vimeo.com/138554789
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tstormdiver - 10/08/2015 6:38 PM
From caves4me: Hey tstormdiver, Yeah the stuff we’re pushing, the first 100 feet is under 12inches, it’s not too bad because of the sediment, and it does get larger in some areas but then it drops in depth. As for altered configurations we have to tail mount our stages, not the best idea but it works in certain areas that we are mapping. My buddy shot this video a few weeks ago: vimeo.com/138554789

Very interesting. Looks pretty nasty (silt- wise in the bedding plains). If you ever look at some of the older maps, my instructor is on there (his company- Aquatech (Larry Babcock)). He helped with some of the older mapping 15- 20 yrs ago. It’s been several years since I’ve seen Vortex. It was what almost killed me,.. but also, in the end, got me on the correct path of training,.. so the place still weirds me out a bit. I’ll readily admit, what I did then was not good, not correct & it almost cost me dearly. I was fortunate,... I got a second chance & decided to go by the right path.
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caves4me - 10/09/2015 2:59 AM
The system we are surveying is always a solo dive with a braille dive exist. We resurveyed the known system up to the 5th restriction, all our numbers corresponded with the previous survey teams. The unknown side that we are exploring was considered a terminal fill, nobody knew it existed. We were lucky that Vortex is a transitional cave, and we pushed it when the time was right. Vortex is a tough cave, there’s no doubt about it, and the section we are exploring is all technical sidemount. Now we are at stand still for further pushes deep within the system.The decision to go to rebreather was the only viable solution. Training and experience on that piece of equipment will take lots of time. The nice thing is we found several places that are no mount, that should keep our team busy for a few months!
#948
Curtis - 10/09/2015 8:39 AM
From tstormdiver: That is why I put this in the Technical Diving area. Most Newbies are not immediately looking to dive technical.

Maybe listed as Technical Diving, but it comes up with all posts.

I personally would not have read it if I had to search Technical.

Newbies do go through a "stupid" phase. Have you not done things you now consider foolish? I admit I have, pursuit of that concept should go to a new thread.

From tstormdiver: Just because something does not suit you, does not mean it does not suit another. If you are good with OC diving & it suits your purposes, that’s good. If others want to dive different ways,.. that is good also. Please stop reading things into my posts that are not there.

Posting lacks voice inflections and visual clues as to connotations. I’ve been mis-interpreted myself on a few occasions. Sorry if I am misreading your position.

I am very aware of the importance of the proper usage of a very important and useful tool, I have been witness to highly successful rebreather usage. But firmly stand by the idea that they are often marketed for profit without reflection, right of ownership being a different issue.