alo100:
Currently I am using bp/w setup, if I start on rebreather do I need to buy a new wing?
Generally speaking, yes, you could still use your bp/w setup, at least if it's a horseshoe wing you're using. Most single tank donuts are to slim and long for rebreathers, you'll end up with the wing pushing into your sides when inflated and the RB stitting on the wing when deflated.
Some rebreathers, such as the manually controlled KISS CCRs or the electronically controlled Megalodon and Optima CCRs come without a BCD and will accept anything with 11 in spaced mounts ("tech" BCD or bp/w). Below pictures of my Sport Kiss CCR with a Dive Rite ss bp and Oxycheq 40 lbs wing next to my single tank Dive Rite alu with 45 lbs Oxycheq setup.
Other rebreathers, like the OMG and Dräger SCRs and AP and PRISM CCRs are equipped with BCDs from the factory. They can be replaced, and adapters are available from several aftermarket sources.
The reason is, I saw some people using rebreathers, and I noticed that they have exhaust valves on both sides of their shoulders to dump air. The device on his shoulders seem to add some extra floatation, and this is not seen in regular bp/w setup.
Some rebreathers, such as the Inspiration, PRISM and Meg have their counterlungs positioned over the shoulders and down the chest. Counterlungs are needed to breath from and into (flexible), and are equiped with an overpressure valveon the exhalation side and usually manual gas addition valves for the O2 and diluent (like drysuit valves, to operate when the electronics won't). The head/scrubber, breathing bags and DSV (mouthpiece) are connected by corrugated hoses that look like inflator hoses, though usually have a wider diameter. That pretty much completes the breathing loop and indeed since it contains gas it adds bouyancy. For such units special D-rings are available that come out from under the side of the bags.
Other rebreathers, such as the KISS, Dolphin and Azimuth have the counterlungs in the back and your chest stays clear.
