In tranditional side mount, do you keep the tank you are NOT breathing on or off? If off, do you stow the 2nd stage?
It's normal to leave both regulators on, for most agencies. Turning regulators off is pretty specific to the UTD Z-manifold.
When setting up sidemount with the intention to closely replicate (
and thus more easily match protocols with...) back-mounted technical configurations; the left-side hose will be on a short hose, routed behind neck and stowed in bungee necklace. The long hose routed 'hog' up from the right-side and clipped off when not being breathed.
The sidemount diver would typically donate the long-hose. If breathed at the time, the donation would be identical to back-mount. If not breathed at the time, they would disengage the bolt-snap (hence, breakaway connection) and donate.
I teach my sidemount courses with a 40" left-side regulator hose (the same as I have for my deco tanks). I ensure the regulator is detachable from the necklace. That way, should a mixed-team back-mount diver get confused between 'from the mouth' or 'from the long hose' donation, they can take either and immediately access gas. Either way, I have an immediately accessible regulator to switch to.... and because I am well practiced at regulator swapping (
a core sidemount skill, repeated every 20bar consumed on every dive), this poses no problems. I can swap the receiver onto my long-hose once they have recovered composure from air-depletion.
This is, typically, the same protocol that most technical divers would follow if sharing air during deco.
...this makes me thinks that if the tranditional side mount divers are more in the mind set of solo divers, self proficient and less team oriented?
I've never encountered a problem air-sharing on sidemount and do dive in mixed teams. I am very team orientated and train my student to be so also. Sidemount students (non-UTD) grasp it pretty quickly. Backmount divers grasp it pretty quickly (when learning deco/tox procedures) too...
Sidemount air-donation is simply: Donate the long-hose.
Backmount air-donation is simply: Donate the hose being breathed (the long hose).
Decompression donation is simply: Donate the hose being breathed (not the long hose).
Ox-Tox symptom donation is simply: Donate the long-hose (in most cases).
That small distinction between long-hose donation breathed/stowed (a 4" variance in location) shouldn't cause undue complication (to any competent diver). If it does, then intelligent configuration of the short hose covers the contingency of confusion.
If someone comes to me and signals OOA, they'll get my long-hose and receive gas.
If someone comes to me and snatches the reg in my mouth, they'll get whichever hose....
and receive gas.