Communication means 'common understanding' and there are many ways for divers to communicate, both under and over the water. There are many signals and variants of signals that divers need to understand and practice to promote that common understanding.
Attracting Dive Buddy Attention
Attracting your dive buddy's attention underwater can be difficult, especially if they are engrossed in something. Try the following:
- Touching and grabbing.
- Shouting into your regulator.
- Banging your cylinder with a knife or stone or use a dedicated tank banger.
- Clapping hands with one hand fisted.
- Using your torch.
- Banging stones together.
- Air sirens (these devices attach to an air hose, usually on your BC jacket).
Underwater Hand Signals
Once your buddy's attention is gained, communication is usually in the form of Underwater Hand Signals, or writing on a slate. It is important to remember that hand signals must be clear, slow and deliberate. They should all be acknowledged to inform the sender that they are received okay. It is good practice to agree on any hand signals before the dive.
Diver Rope Signals
When diving with you buddy on a line, you can also use Diver Rope Signals via the line to signal each other. When using a "buoy line", those on the surface can be communicated with via rope signals.
Boat Based Signals
When in a dive boat then other means of signalling come into play.
Marine Flag Signals
There are some important Marine Flag Signals you should know about when on a dive boat.
Marine Radio Operation
Having a VHF marine radio is an essential safety aid, and having 27 MHz radio is often useful as well. But the most most important thing is knowing about Marine Radio Operation.