Hi Sinbad,
I saw you have gotten some great answers to your questions so I kind of just wanted to tell you about my experience with rebreathers. I tried my first rebreather, the Titan CCR, in a demo pool session two years ago. I've always been somewhat interested in technology. I was fascinated with the rebreathers. They were a completely different world than what I was used to in OC diving. I was intrigued enough to do my first unit certification several months later on the Poseidon MKVI. The first time I used the unit underwater, I started laughing. It was incredible! I heard absolutely NOTHING. My instructor and I were talking...errr mumbling to each other through the DSV (mouthpiece). I could not believe how much closer wildlife got to me to! On my first OW dive in the unit an eagle ray literally almost ran into me.
I'm a full Tec 50 Deep Diver. I was looking into doing my trimix course but then I heard you can spend $300 gas alone for a single dive! With a rebreather, you don't spend nearly as much on gas! One of my instructors spends like $20 on helium for deep dives while his buddies are all in the hundreds. You can also get much less decompression obligations. Check out this article from my instructor, Jeff Bozanic who is an authority in the world of rebreathers. He also has a fantastic book called "Mastering Rebreathers" if you see it on the shelves at a store, look over it and read the first chapter. It will answer a lot of your questions.
Tech Diving: Rebreathers Offer Great Advantages to Tech Divers | California Diver Magazine
The learning curve depends on you. Diving rebreathers takes a totally different mentality. You have to be like OCD on your equipment and make sure you do your pre and post dive checks thoroughly. If you buy from a larger manufacturer, you can get your cylinder and sorb when you travel. Otherwise you CAN travel with everything. Check the manufacturer for the gas requirements the unit will accept. Some will take a lower FO2, others require pure O2.
I just ordered my first type T CCR, the Hollis Prism2. It is "depth rated" to 100m but this unit has passed tests at depths to 1000 feet. Hollis chose that depth because it is a 3 to 1 safety ratio. I have a friend that is a trimix CCR instructor that has done dives to 700 feet on his Prism2. Its an awesome unit and I cant wait to dive it again! Let me know if you have any CCR or SCR questions!
