I’m curious what kind of dives you’re doing that require 180 cft of gas. Are you decompression trained? Diving in overheads that prevent you from having surface access? Sometimes recreational divers think that the more gas, the safer, and that is simply not true.
You are diving a system that seems pretty complex and I’m not sure if you’ve defined the specific role of each of these three tanks or the protocols for using them. Typically, someone carrying 3 tanks is doing so because each cylinder has a specific use, and the diver is trained in their use, as well as in other ways to mitigate the increased demands of dives that require that much gas.
And BTW, I wouldn’t say an AL 40 is a ‘standard’ bailout bottle. On Internet forums there are always plenty of threads about carrying that much gas as a bailout on recreational dives, but in reality the VAST majority of recreational divers using a single tank just use a buddy for their emergency gas. Solo diving, that’s another story of course, but even then you see way more small ponies like 13s and 19s in the real world, and TBH if that’s not enough gas to get you out of trouble on a recreational, NDL dive, you’re probably pushing limits pretty aggressively.
I’m not trying to get down on you, I just think that the system you’ve described is not appropriate for NDL recreational diving without specialized technical training, and if you were to get this training, you’d almost certainly learn that there are much better systems already in use.
No worries, you didn't come across as getting down on me. The dives I'm doing are shore dives, most starting at 20' with the majority of the time spent at an average depth of 40'-50'. There are a few that drop to 85' but those are the exception. Excepting the few deeper dives, I plan on staying down for a few hours NDL permitting, mainly to get the site mapped in one go, or two at the most. I have 15 sites to map over the winter so want to be as productive as possible.
You are not alone in the feeling that this is a horribly complex system, and I will be honest with you, I am not able to see what the issue is. I need one redundant air source to be self reliant, that's not up for question. Whether it's a 40 or a 13 is something that's been debated elsewhere many times, people can be pretty entrenched in camps at both ends of the spectrum. About the only thing that everyone can agree on is that a "spare air" is a horrible idea. For me, I'm in the 30/40 camp, if I'm going to take along a redundant air source I want it to be at least 30. When its rigged the way I have it now, for me, the 40 is no more difficult to manage than a 30. So I think other than debating the size of my redundant air source, we are mostly in agreement up to this point.
As far as the VAST majority of divers relying on a buddies air source, well that's fine for them, but not something I agree with. You won't convince me that swimming to your redundant air is safer than just switching regs. In any case, its not applicable here, I'm diving alone.
And then we add a second 40 to the other side and everyone's head explodes at the thought of a horribly complex system. This is what I am not seeing, to me it is a minor addition, sure it doesn't need to be there, but then again it brings a few things to the table. I now have even more redundancy which I welcome when diving alone in cold north east Atlantic water in the winter. I also welcome the extended bottom time NDL permitting of course. And lastly, it is fun for me to play with the rigging for the 40's, getting them just the way I like, and practicing the use of them, seems like a win/win to me. I recognize that I seem to be the only one who sees it this way, it truly surprises me that this extra 40 is so controversial.
