In the course of researching this a few years ago, I discovered that nav lights are tested and receive their Coast Guard approvals based on the complete light being tested with its originally specified bulb. Replacing with any other type of lamp would technically void the certification, and thus you would not have Coast Guard approved lighting. Are LED bulbs certified to be the equivalent of the original OEM bulb, by the Coast Guard? At the time they weren't. I don't know about now. Would it ever matter? I doubt it. ...unless somehow there were an accident involved claiming somebody did not see your nav lights, because they were too dim or whatever. In my case, I made sure the replacement was as bright as the original, and changed them all out. Most did not fit the old sockets, so I just soldered them directly in place. But technically, the light is certified with the original type bulb, as a complete assembly. Changing that would void it.