Hand signals remain the most widespread method of underwater communication despite fancy devices that allow you to actually talk with and listen to other divers, providing they have compatible equipment. You could spend big bucks on this type of equipment or indulge in dive slates. For safety purposes, you should still recognize the common hand signals, a form of sign language. You never know when a diver, who doesn’t have a communication device other than his or her hands, will try to tell you something urgent like, "I’m out of air!" Unless indicated otherwise, keep your hand in front of your body when signaling.
Here are some of the signals you will most likely encounter:
1. OK. Raise your right hand to shoulder height. Then, with an open palm, make a circle with your thumb and forefinger.
2. OK? OK. These are surface signals to ask if another diver is all right and to reply that you are all right. If both hands are free, raise them together at the top of your head to make a circle. If one arm is free, bring it up in an arc and touch the top of your head.
3. Going Down. Raise your right hand to shoulder height. Make a fist and extend your thumb downward.
4. Going Up. Raise your right hand to shoulder height, with palm toward your body. Make a fist and extend your thumb upward.
5. Go That Way. Raise one hand to shoulder height, with palm toward your body. Make a fist and extend your forefinger in the direction that you wish to go.
6. Which Way? If you don’t know which way to go, raise one hand to shoulder height, make a fist, extend your thumb, and swivel your hand back and forth to indicate your confusion about the intended direction.
7. Stay There. Raise your right hand to shoulder height, palm forward and fingers extended, like a traffic cop signaling you to stop.
8. Come Here. Raise your right hand to shoulder height, palm toward your body and fingers extended. Beckon slightly.
9. Under. Over. Around. With your hand palm down, indicate your intended route to go around an underwater object or formation.
10. You Lead, I’ll Follow. With one hand out to the side and the other in front of your chest, point in the same direction with both forefingers.
11. Get Closer to Your Buddy. Make fists with both of your hands, extend your forefingers, and bring them next to each other (parallel and pointing away from you) in front of your chest.
12. Slow Down. Extend your hand in front of you, palm down, and make a ‘low’ motion with it.
13. Hold Hands. Clasp your hands together in front of your chest.
14. Level Off at This Depth. Raise your right hand to chest level, palm down and fingers extended.
15. Watch Me. Point to your chest.
16. Look at That. Point to your goggles with your index and middle fingers, and then to the object.
17. Something is Wrong. Raise tour right hand to shoulder height, with palm down. Splay your fingers wide and move your hand up and down.
18. Danger! Raise your arm straight out, to the side, to or just above shoulder level and make a fist, as if you are going to pound on an invisible table.
19. Low on Air. Bring your right hand close beside your regulator and point to it.
20. Out of Air. Bring your right hand to your throat and make a horizontal throat cutting motion.
21. Buddy Breathing Needed. Raise your right hand to collarbone height, palm toward your body, and point to your regulator or take your regulator out of your mouth and point to your mouth.
22. How Much Air Do you Have? To ask, point to your instrument console. To answer, look at your air gauge and raise one finger for every thousand pounds you have left.
23. Help! This is a surface signal. Raise one hand high above your head to alert the boat crew that you need immediate assistance.
24. I’m Cold. Cross your hands in front of your chest, grabbing your upper arms with opposite hands to indicate a chill.
25. Can’t Clear Ears. Point to your ear with one forefinger.
DIGITAL ANSWERING SYSTEM TO AIR SUPPLY, DEPTH, BOTTOM TIME & OTHER HAND SIGNALS
Air Supply
1. Round downwards to next hundred number.
2. Give readout of psi in hundreds.
3. Respond by showing figure for "tens" digits then "ones" digit. For zeros, show same sign as OK! signal.
Example - air supply 1840 psi - round down to 1800 psi, change to 18 (hundred), show 1 finger, then 8 fingers
Depth
1. Respond by showing fingers for "hundreds" digits, then "tens" digits, then "ones" digit.
2. For zeros, show same sign as OK! signal.
Examples - depth of 105' - one finger, zero (OK! signal), 5 fingers depth of 78' - 7 fingers, then 8 fingers
Bottom time
1. Give all readouts in minutes.
2. Respond by showing fingers for "tens" digits then "ones" digit.
Example - bottom time of one hour and ten minutes - convert to 70 minutes, show 7 fingers then zero (OK!
sign.)
Night Diving
Hand signals are possible while diving at night with a change in procedure. To attract attention to yourself, move
the light beam from side to side. To signal an emergency, cover and uncover your dive light with your hand
repeatedly so as to create a flashing effect with the beam. Remember never to shine your light in other divers’
eyes as you will greatly reduce their night vision for a considerable time. Shine your dive light on your hands to
give signals.