on what caused a collision of a sailboat and commercial boat with loss of lives focused on radar and radar reflectors but a widely repeated finding was interesting. It found that the plastic lenses of the navigational lights on the sailboat had become opaque over the years from sun and salt and decreased the effectiveness to an unsafe level. I just bought a used sailboat. The surveyor was careful to check all lights --so that they actually worked, but he did not check them (nor could he) for candlepower (brightness), nor do I know if anyone without special equipment can do so.
This spring I am going to take the lights apart and clean and inspect the lenses. Thanks for the jogging the memory, Max.