Tank Bangers

[brutus_scuba]

My instructor showed me a way to cup my hand so that my pinky is really tight and each finger is in a little looser fist as your get closer to your thumb so that there is empty space in your hand and you take your other hand and use the palm to slap the thumb and pointer finger at first it wont' make a sound but as your practice a lil bit it willmake a popping sound that you can hear for about 10 to 15ft. Of course this assumes your relatively close to your buddy as you should be.

 

[ChrisA]

I use my divelight. You can paint a circle on the ground right were the other diver is looking and then gesture with the light boeam. Of course this works best at night but it works OK in the daytime too. If you are within sight of the other diver you are within reach of your light too. The other trick is to pull on his fin or tap a shoulder.