From rec to tec - a noob's reflections
- Thread starter Rhone Man
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TDI does not promote 80%, it's the choice of the instructor. From what I've seen there are essentially two camps in TDI, one using 36/80 and the other with 50/100, generally speaking. If your instructor is pushoing 80% you should ask why and at least have him explain the benefits/drawbacks of 80 vs. 100. I have always found that the benefits of 100 outweight any perceived benefits of 80.
And rjack is right, "nitrox" can mean 22% or 95%. Colored regs don't mean anything at depth (ROYGBIV) or in low vis. Your best bet is to clearly mark MOD and have a solid gas switching protocol that eliminates the possibility for confusion. Just my .02.
Agree about colour issues at depth. But lean left and rich right seems good to me, as a gas switching protocol - as opposed to reading stickers or MOD? I don't see how marking MOD is helpful at depth?
I don't disagree with you at all, and the only markings on my bottles are MOD, contents, and VIP (plus O2 label for the O2 bottle). I completely understand (and agree) that a banner doesn't tell you anything useful. No banners, colored regs, hose wraps, or neon signs to make sure the whole world knows that I'm an uber "TEC" diver.
My instructor wasn't a hardliner at all, so we had open discussions about the different options and the arguments behind them. TDI's texts justified 80% on the grounds that computer modeling showed that there wasn't much difference between the effects of 80% and 100%. However, having studied inherent unsaturation, I determined that "not much difference" wasn't a good enough reason not to use 100%, and 50% at 70 made a whole lot more sense to me.
Perhaps it's local flavor, but most people I've come across who have taken TDI around here end up with the 80% and mark their tanks in precisely the same manner as appears in Rhone's picture. I'm sort of the odd man out with my 100%.
My intent wasn't to hijack RhoneMan's thread; just to explain why he may have marked a certain way.
Many folks feel that a tank on the right can get in the way of easily deploying the long hose. Multiple tanks on the left are easy to deal with, no problem, so it's really nice to have the right side clean. Following a good tank marking and visual inspection of a properly marked mod sticker, including spg verification and conformation from team mate is a completely reliable method of assuring you will be on the right bottle all the time. We all know there have been deaths due to breathing the wrong gas, but I have never heard of even one where the above protocol was followed.
Highly safe and a clean right side for LG deployment and light cord management. That seems like a good reason to me.
JeffG
Contributor
Really?
Blackwood
Contributor
At the risk of having the thread split,
I know my deco plan calls for a switch at 70', so I go to the bottle with the big 70 label on its side. I know my deco plan calls for a switch at 20', so I go to the bottle with the big 20 OXYGEN label on its side.
It's helpful because it tells you directly what depth range that bottle is for.
It also acts as a verification. When I pick up my gas, I affix a temporary label (usually duct tape) listing the as-analyzed contents. Before I splash, if the sticker on my 70-bottle says 99%, I know a mistake was made, and I'll re-analyze my bottles to sort out the situation. In the water, I read both the permanent and temporary labels before breathing any bottle. It's as simple as looking down and to the left, and lifting the tank ever so slightly.
With RRLL, how do you catch a mistake (i.e. accidentally put rich left and lean right) in the water? I would assume you also look at the bottle markings, but your post suggests otherwise.
I know my deco plan calls for a switch at 70', so I go to the bottle with the big 70 label on its side. I know my deco plan calls for a switch at 20', so I go to the bottle with the big 20 OXYGEN label on its side.
It's helpful because it tells you directly what depth range that bottle is for.
It also acts as a verification. When I pick up my gas, I affix a temporary label (usually duct tape) listing the as-analyzed contents. Before I splash, if the sticker on my 70-bottle says 99%, I know a mistake was made, and I'll re-analyze my bottles to sort out the situation. In the water, I read both the permanent and temporary labels before breathing any bottle. It's as simple as looking down and to the left, and lifting the tank ever so slightly.
With RRLL, how do you catch a mistake (i.e. accidentally put rich left and lean right) in the water? I would assume you also look at the bottle markings, but your post suggests otherwise.
JeffG
Contributor
Last edited:
Nice write-up, Rhone Man. I agree that the shop loaning you the gear instead of renting it to you is unusual...
So, if you do go further into trimix training, how long before you set up trimix facilities at your store in BVI?
So, if you do go further into trimix training, how long before you set up trimix facilities at your store in BVI?
OP
It occurred to me that if I go to trimix I'll have to learn how to blend it myself first. Heck, we don't even have nitrox out here yet unless you homebrew it...
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