Already some good experiences and input out there. I'll chime in as well.
I spent a month research project where we had an even split between divers using metric and divers using imperial.
We spent a 10min evening going over air protocols such as
- what minimum psi/bar we would be on the surface
- what a full tank measured at pressure wise
- what a half tank measured at
- using rule of thirds
It was pretty easy. The bar users were 200 full tank, 100 half tank, 50 be on the boat. (even though 50bar equals 750 psi roughly)
Also keep in mind that even bar pressure gauges use the same reference as our 5000psi gauge. The red zone will be at 0-100bar just like our red zone will be at 0-1000psi.
Our half mark 1500psi is around their half mark of 100bar.
So really the only change on the pressure gauge is the reference numbers.
If you must insist on using hand signals instead of just showing your gauge or trusting that an OK meant they were in fact still on the air plan, then keep it simple.
- Show in 5's and round up to the nearest 1000psi or 100bar. So showing (2x) 5's is 100bar or 1000psi.
Or in psi (3x) 5's is 1500psi. If you have 1400psi, then it's (2x) 5's plus 4 fingers at the end.
- Another method is to simply show how many on 2 hands (but for me this takes a second of processing to coordinate between two hands. (yes....I know, I call narcosis on that one =P).
- Yet another method is to signal for each digit. Palm facing the viewer is 1-5, but palm facing the signaller w/ the hand turned sideways is numbers 6-9. So if you see me signalling and my palm isn't facing you: 2 fingers equals 7, 3 fingers equals 8 and so on.
If your buddies are english better show 7 as the thumb and index finger, unless you want to give them the english version of a flip-off.
To solve the safety stop protocols (we did 3 safety stops because of our daily profiles) All of us agreed to switch to metric. While you don't have a quantitative reference of your actual depth, if you have a dive profile to follow, it isn't all that daunting. Just memorize what 10's of feet are in meters.
So 30ft = 9m
40ft = 12m
and so on.
I spent a month research project where we had an even split between divers using metric and divers using imperial.
We spent a 10min evening going over air protocols such as
- what minimum psi/bar we would be on the surface
- what a full tank measured at pressure wise
- what a half tank measured at
- using rule of thirds
It was pretty easy. The bar users were 200 full tank, 100 half tank, 50 be on the boat. (even though 50bar equals 750 psi roughly)
Also keep in mind that even bar pressure gauges use the same reference as our 5000psi gauge. The red zone will be at 0-100bar just like our red zone will be at 0-1000psi.
Our half mark 1500psi is around their half mark of 100bar.
So really the only change on the pressure gauge is the reference numbers.
If you must insist on using hand signals instead of just showing your gauge or trusting that an OK meant they were in fact still on the air plan, then keep it simple.
- Show in 5's and round up to the nearest 1000psi or 100bar. So showing (2x) 5's is 100bar or 1000psi.
Or in psi (3x) 5's is 1500psi. If you have 1400psi, then it's (2x) 5's plus 4 fingers at the end.
- Another method is to simply show how many on 2 hands (but for me this takes a second of processing to coordinate between two hands. (yes....I know, I call narcosis on that one =P).
- Yet another method is to signal for each digit. Palm facing the viewer is 1-5, but palm facing the signaller w/ the hand turned sideways is numbers 6-9. So if you see me signalling and my palm isn't facing you: 2 fingers equals 7, 3 fingers equals 8 and so on.
If your buddies are english better show 7 as the thumb and index finger, unless you want to give them the english version of a flip-off.
To solve the safety stop protocols (we did 3 safety stops because of our daily profiles) All of us agreed to switch to metric. While you don't have a quantitative reference of your actual depth, if you have a dive profile to follow, it isn't all that daunting. Just memorize what 10's of feet are in meters.
So 30ft = 9m
40ft = 12m
and so on.
