What do you mean by 'tucked'?
Obviously an octopus must be visible, available and held away from the bottom. Let's assume a competent diver so we can leave out the 'perhaps'.
I've seen octos secured two different ways - one is some sort of clip that secures the second stage to the diver's BC. The other way is, some BCs have pockets where you can "tuck" the octo hose. In either case, I think the idea is that if you grab the octo second stage, the entire thing should deploy easily.
I see a couple of potential problems. First, if the octo gets uncliped or gets untucked, who knows where that regulator will be in the case of emergency. Or, even if it stays clipped, the diver might not find it the first time he reaches for it. (This very thing happened to me on a dive. I went to my buddy, he reached for his octo and it wasn't exactly where he thought it was. In fact, the octo has gotten tangled in some kelp.) Second, I imagine that its possible for a tucked octo to get caught on something as you are deploying it.
One other thing... why assume that you or your dive buddy will be able to execute flawlessly in this situation (or to put in your words, is a competent buddy)? If someone is out of gas, the situation is already frantic. The last thing I would assume is that things will go perfect. Which is why you would want this stuff to be as brain dead simple as possible.
KenGordon:
A lot of primary taking by the OOG diver here, who trained them to do that?
Any dive shop that pushes the scubapro BC/reg/air 2 package. Because you know, nobody is donating that air2 to an OOG diver.
And any dive shop that pushes an air2 similar combo backup reg/inflator. For the same reasons.
KenGordon:
I wouldn't argue with a primary donated long hose as the stowage advantage is real, but for a short hose this seems just like a random collection of techniques and kit configs flung together with a couple of major disadvantages:
Non standard in any system (or course I can't claim to know all systems so I could be wrong) and so unexpected and unfamiliar to a new buddy.
Involves taking a reg out of the donor's mouth so putting two people at increased risk.
Requires the donor to pay attention and notice the issue.
It is still a short hose so none of the typical hog loop advantages like space or ease of replacement to make up for the disadvantages.
Its not fair to assume that your dive buddy was trained to take an octo in an OOG situation. As I mentioned, tons of divers are trained to take the primary in open water class.
But even if they were, this is how the conversation goes, "If you need gas, come to me, don't go bolt to the surface. Signal to me that you need gas and I will give you the reg out of my mouth. If you don't have the time/composure to signal, just take the reg out of my mouth." That's it. 15 second conversation.
Your reg can wind up out of your mouth for a hundred reasons. And uh, any diver that cannot take a reg out of their mouth without finding themselves in *danger* should not be a certified diver.