Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
I'm Air Force helicopter rescue pilot that has searched for many a lost diver over the last 20+ years. .... At night, night vision goggles are so sensitive these days that we'll even see a mirror flash off of moon light. Strobes are ideal. Movement is what catches a searchers eye. One of the best low tech signaling devices is a 12 hour, preferably red chem glow stick (green will work) tied to 4-6 foot length of line. When one spins it over their head, the motion can be seen for miles by searchers on night vision. .... with the right signaling devices it's almost easier to find someone at night vs in the day, so advise folks to stay calm after the sun sets, it won't take long to be found.