I have been looking for LED replacements, and have them for all the lamps on board but the nav lights. My nav lights are the little deck-mounted ones (see my post above) and they take a 1004 bulb, which has a small spherical glass envelope. All the potential replacements seem to be too big.
There's not a lot of advantage to using LED nav lights, since you only run them when the engines are turning, so power use is not an issue. Reliability is, tho, and I can see that the leds have the edge there.
1975 32' Flybridge Sedan, twin Perkins 6-354 diesels, 1:1.53 velvetdrives, 16 X 19 props. Merritt Island, Florida