Hogarthian configuration question

[Cindy]

All of the above. Contacting the ceiling is the biggy, and as the space gets tighter and the viz gets lower, the potential for contact increases.

Bumping the ceiling once normally won't rotate the left post closed very much, but you can get an impressive amount of roll off when gently going through certain restrictions where the valve knob may be gently in contact with the ceiling for several inches.

Consequently, I check after any contact with the ceiling that may have resulted in a roll off. I don't often find a partial roll off, but I do find it often enough to reinforce the need to keep looking. And, I have never had a full roll off, in part because I always check.

My thoughts are that there are probably a few divers who are never in contact with the ceiling and who will never have a roll off. But there are also a lot more divers who have partial roll offs and never know it as they never check. The latter are the divers who will someday have a full roll off, because they never check.

Thank you, I understand now. Oh and thanks to everyone for this info, I needed a refresher on how to rig back mount. I don't do it often. Cindy

[fixxervi6]

I've had some roll off on backmount but never a full roll off.

When I dove back mount the rule was any time you check your SPG you check for roll off, after a while its habbit and no big deal, also good go keep your flexibility going.

There were times I had some roll off and wasnt' aware I had contacted the ceiling, just a very light brush just enough to turn the knob is all it takes with rubber knobs, it doesn't have to be a "GONG" to get roll off. A great example is your coming out of a tight spot coming out with flow and you tilt yoru head up and see your right on the ceiling then look down again, that moment of tilting your head up can roll a valve knob quick and easy without any banging.

It is possible to roll off with sidemount as well

[Line Squirrel]

It is possible to roll off with sidemount as well

Not if you have you knobs pointed up.

[fixxervi6]

Not if you have you knobs pointed up.

Don't like em up