The thought of getting list or separated form your diving buddies is more than just terrifying. The best alternative is to have a plan.
It is not uncommon to get separated, left behind by your dive boat or even just simply lost while out on a dive. I am not sure the probabilities are for getting left behind by your dive boat, but it is much higher than you would expect (see our previous post about being lost while diving).
Naturally the key to handling being lost or separated during a dive is to have a plan. However, we must not overlook the fact that this plan must be shared with your dive buddies to be effective.
Your dive partner should be able to openly discuss with you what the plan of action will be if you get separated from each other in the water. Beyond that, there should also be a plan in case of injury. If you are diving in a more remote area, should one of you go for help and leave the other behind, or should you leave together? These are basic things to take into consideration.
If you are actually lost at sea. In other words, the dive boat has left you behind. The key here is to remain calm, stay in a group and maintain a positive buoyancy until you are rescued. In this scenario you are best prepared by having an emergency radio such as the nautilus Life Line or another signaling device.
Typically, boat captains will tell divers what to do if they return to the surface and the boat is gone. These types of things can happen if an injury or illness causes the boat to need to leave quickly for emergency support. In cases such as this, divers are often told to wait at a mooring buoy or together on the surface because another vessel will be sent to pick up anyone left behind.