Trim with 3 deco cylinders?

[Miyaru]

Thanks for the input on my theoretical concept of switching back to 10/70.

I'd argue that you shouldn't be doing those dives on OC anymore

I agree. And I won't be doing any OC dives requiring 10/70 because of the crazy amounts of helium required.
My CC adventure will start in April next year, so any deep dives will be postponed until after that adventure.

 

[PfcAJ]

Stage to stage has VERY few benefits. Possible exception would be deep (probably deeper than 200’) multi stage dives where you’d be really digging into your backgas reserves during accumulated switch time.

No one is really doing those any more.

Shallow (20ft) with very hypoxic gases (10% or less) presents a challenge. Generally, if you’re doing that kind of thing you’re a grownup and can manage the slight added complication. Or accept that a .16 for a few mins is fine. Even if you’re diving a rebreather, depending on your config, you might be juggling 10% on OC if/when you bail out.

 

[Wibble]

I don't use cylinder position as indicative of anything. The actual switching procedure -- noting depth, confirming MOD on tank, pulling reg, tracing hose back to the regulator/valve, turning that specific valve, etc. -- wasn't my point of confusion.

I always put my analysis sticker (gas + date + MOD) on the neck of the stage cylinders with the MOD clearly visible to me, just offset from the regulator hoses. That way it's close to the valve and easy to trace the hose back to that reg and see the MOD. If diving with others I may add the MOD on the base of the cylinder. Wondering if others do this?

Resetting the hoses after switching is straightforward; what else have you got to do at deco! If it's the inner cylinder then it can be unhooked at the bottom and swung forwards. Only difficult if empty and exceedingly floaty (e.g. bottom gas for bailout).

 

[stuartv]

So you deploy the 2nd stage's regulator off bottle #2, check it and then there's only one place for it to go - it ends up around your neck cause otherwise it'll dangle in the silt.
Remove the 2nd stage in your mouth (from bottle #1)
Now you have 2 loose 2nd stages around your neck and also your long hose which is clipped off

Why would you take the reg that you're breathing from out of your mouth and let it go, and then "look" for the next reg to put in your mouth?

Why not one of, either:

While holding the reg you are switching TO, you spit out the one you're breathing from and insert the one you are switching to? Then deal with the one you spat out.

Or,

Using one hand, hold the reg you are switching to with thumb and two fingers, then grasp the reg in your mouth with the other two fingers and palm, remove it from your mouth, and insert the one you're switching to. A one-handed switch like that is not hard. For persons doing the kind of dive you are describing, that should be a simple skill to perform.

Having no reg in your mouth while also not having a reg in your hand that you are switching to seems, umm, less than ideal.

 

[stuartv]

Also, y'all keep talking about having 2 regs loose around your neck, but don't you mean 3?

You do still have your alternate 2nd stage for your back gas also under your chin, right?

With 3 regs that you could conceivably breathe from (not counting the primary, which is clipped off and not right under your chin), that seems like all the more reason you'd want to NOT take a reg out of your mouth and just let it go, then start looking for the one you are going to switch to.

 

[Wibble]

Cylinders on LHS. Do switching drill to ensure the reg's breathable. Hold in right hand out in front of you. With Left hand, take reg out of mouth and hold it right out to the side of you with your outstretched hand/arm. With Right hand, wrap around neck, purge and breathe.

Doesn't tangle

 

[inquis]

I always put my analysis sticker (gas + date + MOD) on the neck of the stage cylinders with the MOD clearly visible to me, just offset from the regulator hoses.

I do analysis tape on the neck easily visible when slung and MOD on the side. Side MOD uses more permanent stickers, which I would cover with tape if not appropriate for the actual contents.

 

[Garth]

GUE makes the best analysis tape in my opinion. The concept of addition and analysis as a separate section puts ownership on the one who will be diving the gas to analyze the mix.

I guess since I don't have massive back gas cylinders on my back surrounding my rebreather I don't switch to back gas between mixes. Can one have a back gas if it's on their side? Asking for a friend.

 

[Wibble]

I find white 2" duct tape works wonders. About 20 times cheaper.

If you write it properly it isn't confusing.

 

[Garth]

I find white 2" duct tape works wonders. About 20 times cheaper.

If you write it properly it isn't confusing.

I find duct tape leaves behind a terrible mess if its left on there for a long time. Some of my fills aren't used for a while if its a bailout gas. The $30 roll of GUE tape is well worth it in my opinion. I wouldn't have thought that but after using it for a while it really lasts a long time. The white duct tape costs about $4 so you are correct on duct tape being less expensive.

I suppose if you are diving open circuit and your gases are constantly being used it would make sense. Have you tried the GUE tape? (I'm not GUE so i'm not advocating any of that training or mindset which is also probably better than most training though - also very much more expensive than standard training)