Just learning ASL isn't the right approach, I think because far too many of the signs require moving both hands, which makes it pretty useless for night diving. In my opinion if you can't use a sign both day and night (ie... one handed) then it's not a good sign.
Diver0001- you are correct that ASL signs are either one handed, two handed where both hands are doing the same thing, or two handed where one hand is non-dominant, and the other dominant hand is doing the action. However, in actuality, Deaf people don't always stick to these "rules" when signing in real life, just as us English speakers don't use "proper" English 24/7. When a Deaf person has something in one hand, they will modify a 2 handed sign to be done with one hand. This is what I tend to do while diving anyway, since I usually have one hand on a guage or resting on my stomach while diving.
Sospotato- In my Damselfish example, the fish had already swam away before I turned to check in on my buddy. So if not for ASL, the story would have had to wait til we were on the surface. It sounds like that would have been fine for you, but part of my enjoyment of Scuba isn't just what I see, but I also like to be clued into what my buddy is experiencing while it's happening. It's just a matter of preference. I don't enjoy Scuba because it's my solitary time. It's my chance to be in my favorite place (underwater) with my favorite person (husband) and share an experience together. We're not sitting underwater chattering away the entire time, but when I see something interesting or my buddy does, we like to be able to clue each other in. This is why I think that couples or established dive pairs would find ASL especially useful. Sometimes you can't get close enough to your subject to just point it out, because that particular fish will swim away. So with ASL you can make references to things that aren't in your immediate vicinity.
Another example of something that would not have been readily communicated with traditional signals is when I had an issue with a fin strap. The strap felt loose, but it wasn't broken nor visibly coming apart. If I'd just pointed to my fin and signaled that there was a problem, it would not have been obvious to my buddy because nothing was
visibly wrong. But with ASL I could clearly communicate that I f
elt that particular problem, and buddy was able to fix it, just in the nick of time before my fin came off. Also, with ASL, I was able to talk about my fin without having to point to my foot, thus throwing off my bouyancy or balance. I simply used an ASL classifier which allowed me to use my arm to show my leg and my hand to show my foot and where the precise problem was.
