What about electric laser "flares"?
Handheld flare for night time location signalling. We've been very interested in electric flares as an alternative to pyrotechnics since we staged a demonstration of flare use at our yacht club more than a decade ago. That demo showed us how dangerous it can be to have flaming magnesium dripping out of a flare that is held from an inflatable life raft. Pyrotechnic flares were invented in the mid-1800s.* A technological alternative that won't melt your vessel around you seems like a good idea. Flares have two applications: the first is to attract attention and alert others to an emergency situation, the second is help locate the person or vessel in distress. So two types of flares are needed for day and night: those that shoot high up into the sky and those that are held close by after the alert has been spotted. The convention of Safety of Life at Sea (SOLAS) has standardized the signalling device recommendations to increase the chances of rescue anywhere in the world.