Interesting looking at the feedback.
It has only now occurred to me that I was never really taught a deco' signal as such. Not with TDI, IANTD, or any of the other tech agencies I did courses with. But my training with these organisations was way back in time.
The interesting thing is that apart from my initial qualification (PADI OW), I have always been involved in dives that may, or may not involve decompression.
The only hard rules for No Stop Dives, are Ocean Divers and trainees. Also, anyone that states they don't want to do any compulsory decompression. As a general rule, the amount of decompression we do is dictated by my buddy, and the dive being done.
Point of interest, all dives I do with those qualified at Ocean Diver, I run the dive and ascent as if we had compulsory stops anyway. i.e. controlled ascents, stop (safety stop), then 1m stops to the surface from 3m. Even if they struggle with the buoyancy control, they get it into their mind that control on ascent is important, and there is an expectation that they should be able to stop at any depth for as long as required at any time during the ascent.
On the actual signals used, I guess I use a variety, dependent on who I'm diving with. An interesting observation, is that I don't do as many dives now that require me to do compulsory decompression. Mainly because I generally am on CCR, and my buddies are generally on OC. So I generally can follow rather than lead on the decompression. Similarly, MOD is generally dictated by my buddies, rather than me. Other than I would prefer to have a squirt of Helium if we are dropping below 40m. As a rule, dives beyond 40m are pre-planned, so I have the right gas (both DIL and bailout), before I leave home.
My signals vary.
Generally, I believe the signal I use is the Hawaiian.
So that would be an Up, Hawaiian, then depth.
The other is a two handed signal, up, with the thumb, in contact with a flat palm from the second hand. Followed with the depth.
A variation of the second with one hand is up, followed by stop, followed by depth.
Someone commented on not liking the OK signal, or at least frequent OK's.
I used to dive with a buddy who would give one distinct nod when you looked at him, or if you signalled OK. Interestingly, if your OK was a proper question, rather than a check he was cool on the dive, he would signal OK (I wonder if that makes sense). Really chilled guy to dive with.