Is a SCR or CCR right for me?

[Mr.X]

We had 2 rebreather divers on board too. Both had a bottom time of 67 mins. Just playing around with numbers and v-planner, in order for me to do a 67 min bt I would have to carry up to 2 130s and 2 al 80 stages (assuming a loss of all my deco gas) or make a direct assent depending on the contingency plan and what not. On a rebreather, with a direct assent its a 40 of 100% and a 40 of bottom mix to do the same dive or an 80 to return to the anchor line.

That's the point i'm making. Can I SM 130s and drop stages as I go, sure. But there seems to me a more efficient way of doing the dive I want. HP 100s are the perfect SM tank for me. They are really the biggest I want to go.

So my next immediate goal is 170ft. I need to be trimix certified for that dive. The chances of actually making it out on the wreck on the day planned is 50/50 (as always). On OC that means I have a very expensive mix in my tanks that will probably not get used on the right wreck or I'll be diving a $300 mix on a 100ft dive, which just pisses me off. With a rebreather (SCR or CCR) it doesn't matter.

Does this make sense? Are my numbers totally off or is my bailout plans too conservative or not enough?

---------- Post added July 24th, 2015 at 08:48 AM ----------

I should also add, I'm not 100% sold on doing two very long divesand that's why I usually don't just bring an extra set of 100s with me.

If you're planning on doing epic deeper dives and plenty of them - I would opt for CCR. The plenty part refers to the cost of gas you will save over time. However, much like the Prius vs. high mileage gas engine car - does the cost of a more efficient unit (and inherent safety) outweigh the higher cost of a CCR (initial), additional training and longer term use.

I have used all manner of CCR over the past twenty + years starting with the CIS Lunar, Meg, Kiss, Prism. LAR etc. and now I am back on OC for the piddly dives I tend to do nowadays. For research, commercial and epic deeper dives and serious exploration I would not hesitate to get a CCR. If I am a recreational diver (not doing serious work, or on a extended project) on NE local quasi-deeper dives which get blown out with regularity I might just go OC and do away with the hassle of CCR. And I certainly understand the crap feeling when you lay out $$$$ for mix and not getting a chance to use it.
Also, CCR is not the magic bullet. On some of the deeper stuff I often took a redundant CCR because sometimes these things go funny and when money is on line you can't screw yourself, or the client out of the dive.

So in ending - some of my best dives on the Arundo, Resor, San Diego, Oregon were on OC. Cleaning afterwards was easy. I used CCR and scooter on U WHO, Doria, & Oil Wreck, Texas Tower. Some of those were film jobs where I needed max bottom time.

 

[ffdiver]

Just an update to the thread...

I ended up buying a second hand Meg with older electronics. I start my course in two weeks down in Florida!