It's not
Scott,
The question is not necessarily one of legality. The USCG will certainly NOT be checking your bulbs only checking to see that you use them.
The question of matter comes into play with our US legal system. If you are involved in a nigh time accident it will likely become your job, and your expense, to prove in court that your fixture met the color, beam, angle sectors and distance standards. Any good maritime lawyer could attempt to make his entire case based on your use of non-certified LED lights especially when there are now plenty of "certified" options.
I was personally involved with a night time boating death (best friends father was killed). The forensics testimony, on just the nav lighting, was two full days of testimony. Both boats had legal certified bulbs and it still went on for two days. Imagine if you had non-certified bulbs..
It's not the USCG you need to worry about it's the Jim Sokolove's of the world.. __________________
Here are the standards nav lights need to meet to get certified:
From 33 CFR 84:
Colors
� 84.13 Color specification of lights
(a) The chromaticity of all navigation lights shall conform to the following standards, which lie within the boundaries of the area of the diagram specified for each color by the International Commission on Illumination (CIE), in the "Colors of Light Signals", which is incorporated by reference. It is Publication CIE No. 2.2. (TC-1.6), 1975, and is available from the Illumination Engineering Society, 345 East 47th Street, New York, NY 10017. It is also available for inspection at the Office of the Federal Register, Room 8401, 1100 L Street N.W., Washington, D.C. 20408. This incorporation by reference was approved by the Director of the Federal Register.
(b) The boundaries of the area for each color are given by indicating the corner coordinates, which are as follows:
(1) White:
x 0.525 0.525 0.452 0.310 0.310 0.443
y 0.382 0.440 0.440 0.348 0.283 0.382
(2) Green:
x 0.028 0.009 0.300 0.203
y 0.385 0.723 0.511 0.356
(3) Red:
x 0.680 0.660 0.735 0.721
y 0.320 0.320 0.265 0.259
(4) Yellow:
x 0.612 0.618 0.575 0.575
y 0.382 0.382 0.425 0.406
Intensity
� 84.15 Intensity of lights
(a) The minimum luminous intensity of lights shall be calculated by using the formula:
l = 3.43 x 106 x T x D2 x K-D
where:
I is luminous intensity in candelas under service conditions, T is threshold factor 2 x 10-7 lux, D is range of visibility (luminous range) of the light in nautical miles, K is atmospheric transmissivity. For prescribed lights the value of K shall be 0.8, corresponding to a meteorological visibility of approximately 13 nautical miles.
(b) A selection of figures derived from the formula is given in Table 84.15(b).
Table 84.15(b)
Range of visibility (luminous Minimum
range) of light in nautical luminous intensity of light
miles in candelas tor K = 0.8
D I
1 0.9
2 4.3
3 12
4 27
5 52
6 94
Horizontal Sectors
� 84.17 Horizontal sectors
(a)
(1) In the forward direction, sidelights as fitted on the vessel shall show the minimum required intensities. The intensities shall decrease to reach practical cut-off between 1 and 3 degrees outside the prescribed sectors.
(2) For sternlights and masthead lights and at 22.5 degrees abaft the beam for sidelights, the minimum required intensities shall be maintained over the arc of the horizon up to 5 degrees within the limits of the sectors prescribed in Rule 21. From 5 degrees within the prescribed sectors the intensity may decrease by 50 percent up to the prescribed limits; it shall decrease steadily to reach practical cutoff at not more than 5 degrees outside the prescribed sectors. (b) All-round lights shall be so located as not to be obscured by masts, topmasts or structures within angular sectors of more than 6 degrees, except anchor lights prescribed in Rule 30, which need not be placed at an impracticable height above the hull, and the all-round white light described in Rule 23(d), which may not be obscured at all. (c) If it is impracticable to comply with paragraph (b) of this section by exhibiting only one all-round light, two all-round lights shall be used suitably positioned or screened to appear, as far as practicable, as one light at a minimum distance of one nautical mile.
NOTE to paragraph (c): Two unscreened all-round lights that are 1.28 meters appart or less will appear as one light to the naked eye at a distance of one nautical mile.
Vertical Sectors
� 84.19 Vertical sectors
(a) The vertical sectors of electric lights as fitted, with the exception of lights on sailing vessels underway and on unmanned barges, shall ensure that:
(1) At least the required minimum intensity is maintained at all angles from 5 degrees above to 5 degrees below the horizontal;
(2) At least 60 percent of the required minimum intensity is maintained from 7.5 degrees above to 7.5 degrees below the horizontal.
(b) In the case of sailing vessels underway the vertical sectors of electric lights as fitted shall ensure that:
(1) At least the required minimum intensity is maintained at all angles from 5 degrees above to 5 degrees below the horizontal;
(2) At least 50 percent of the required minimum intensity is maintained from 25 degrees above to 25 degrees below the horizontal.
(c) In the case of unmanned barges the minimum required intensity of electric lights as fitted shall be maintained on the horizontal.
(d) In the case of lights other than electric lights these specifications shall be met as closely as possible.
If you feel you can go up against Jim Sokolove or his buddies, who would likely be prancing about a courtroom with the above standards for nav lights, or feel this would never happen to you than by all means use non certified bulbs.
Again, it is NOT the USCG who will care but the lawyers will if and when you are involved in a nigh time accident. It is NOT the USCG you'll need to worry about it is the ambulance chasers who are looking for a case, any case, to show why their drunk defendant deserves to get off scott free. As far as I know there has not been a case yet with non-cert LED's but with the increasing popularity it probably won't be long before we hear of one.
If you have read the above CFR for nav lights and believe you can meet these horizontal, vertical, color spectrum and intensity parameters than you're good to go...
Let's run this scenario: (sort of similar to my friend Kim's fathers death just without LED's)
You are at sailing back home with the family after a great day on the water and it's now dark. You switch on your new non certified, blueish colored LED stern light that you saved big money on by purchasing it from an eBay store. Joe six pack in his 32 foot Baja with 550 H.P. has been drinking all day and is blasting home when he plows into your boat and kills your dad. Fast forward about two years to the trial where the lawyer for the defendant is blaming you, and convincing the jury that because you were a cheap skate, you are the reason your father is dead because his drunk defendant could not see your stern light and though perhaps it was a star...
A stretch? Maybe not. I sat through two days of this type of testimony during the trial of the defendant who killed my friends father. It was two days of nav light testimony only these were certified nav lights, and yes that was brought up, and the bulbs were examined by a forensics expert to determine if the bulb was on at time of impact. The case would have been made much easier if Kim's dad had simply installed aftermarket LED's as it would have given the lawyers food for fodder. Forensics proved the nav lights were on at the time of the accident..
and somebody got hurt 
