After our discussion here several weeks ago I have been looking into the LED navigation light retrofit at great length. There are a few articles, one in particular in Good Old Boat about this.

There are a couple of schools of thought that more or less substantiate the discussions here. Sticking a typical white LED replacement bulb into a colored or bi-colored fixture is just trouble. The LED gives off light in the 6500 - 7000k range which is bright white but lacks the green and red spectrum. Therefore, the colored light appears dim. However, the "bright white" lights are more than adequate for clear navigation/anchor/steaming lights giving off light with a brightness exceeding a 25w incandescent bulb.

They also market a direct replacement LED bulb called a "warm white" that is in the 2700-3500k range, or equivilent to an incendescent. These supposedly will work fine in a colored or bicolored light fixture. The overall thought on this is that if you really want a bright red or green nav light though, you really need to have a red or green LED behind it.

The issue of USCG certification is the real sticking point. According to what I have found, in order for any nav light to be USCG certified, it must be tested with a specific bulb. The original paperwork that came with our boat says that in order to be certified, our AquaSignal must have a specific brand bulb in it. In theory, by using a different brand, my certification is void. The LED bulb suppliers say that they do not have the ability to certify their bulbs in all fixtures.