Why Is the Buddy System So Important?:
So what's the big deal? In the worst-case scenario of an out-of-air emergency, a diver needs immediate assistance from his buddy. If the troubled diver cannot call his buddy's attention and breathe from his alternate air source in time, he will have to execute an emergency swimming ascent (or worse, a buoyant emergency ascent) which he probably hasn't practiced since his open water course. Before arguing that in an emergency a diver can hold his breath for a long time and swim to his buddy, remember that an out-of air diver discovers his plight after he has exhaled and attempts to inhale against an empty tank. An out-of-air diver has little or no air in his lungs to start with, and must reach his buddy in this state. This gives troubled diver significantly less time to reach another diver than if he had a lungful of air.
A dive buddy also provides an additional brain to solve problems in emergency situations.
Buddy Separation Fatality Statistics:
To drive home the point, according to the "Diver's Alert Network (DAN) 2010 Dive Fatalities Workshop Report," 40% of diver fatalities occurred during a period of buddy separation. Could a buddy have helped prevent these fatalities? At least some cases, I imagine so.
Tips for Effective Use of the Buddy System:
How close should members of a buddy team stay? Close enough to call a partner's attention and reach him in the matter of a few seconds. Here are some tips on how to stay near your buddy and maintain buddy awareness.
1. Choose your buddies wisely.
The ideal buddy should feel that the buddy system is important. If you are partnered with a random buddy on the boat only to find that he is a lone wolf and deserts you underwater, stick close to the divemaster and ask for a different buddy for the next dive.
2. Discuss your dive plan with your buddy before the dive.
Let your buddy know if you are likely to have any issues that commonly lead to buddy separation, such as ear equalization trouble on descent (I frequently see one diver drop like a rock while the other is stuck at 15 feet attempting to equalize his ears). Discuss how you will deal with these situations should they arise.
3. Talk about about your dive objective.
If one member of the team stops to take photographs and the other wants to race over the reef in order to cover as much ground as possible, a compromise as to the dive pace will need to be made.
4. Pick a side.
Choose what side of your buddy you will remain on, and then remain on that side. This might sound silly, but it is easy to become disoriented underwater and knowing where to look for your buddy is helpful.
5. Pick a leader.
Even if there is a divemaster, decide who will make navigational decisions during the dive. One buddy swims to areas he finds interesting, and the other follows his lead. If the follower wants to check out a specific spot, he simply notifies the leader and they move together. This makes the dive more organized and more enjoyable.
6. Discuss a way to attract each other's attention.
This could include underwater noisemakers, rapping on the tank with a metal ring or clip, or even shouting into the regulator. If you and your buddy know what to listen for, you are more likely to be able to get each other's attention underwater.
7. Familiarize yourself with your buddy's gear and refresh emergency procedures together.
This doesn't have to take a long time, a simple "my weights are released here and my alternate air source is here" and a brief review of the gear you are using usually covers the equipment. A quick discussion of emergency air sharing procedures takes about 30 seconds.
8. Communicate during the dive.
Discuss hand signal communications and then use them. Ask your buddy if he is okay periodically, point out interesting aquatic life to your partner, and communicate your tank pressure. Divers who are in constant communication tend to stay closer together and more aware of their partners.
Scuba instructors teach the buddy system for a reason: a diver using the standard single-tank equipment configuration can not solve all emergencies himself. Stay close to your buddy and stay safe!