I run the generator all night to run the A/C, 4 whole gallons for the night. The A/C is on a 30 amp line, draws around 20 to 25, then their is all the other equipment running, like the rest of the lights, the electronics, microwave, ect. The halogen light is on a 15 amp line, probably draws 6 amps (what's the LED draw ?), at best. It will take years for the LED to pay for itself.
I agree with you that, especially in your case, with a generator running, that the power savings of the LED system would not make sense. The LED's also seem to have a much lower brightness over distance. If you look at the lux values at distances they start out much lower and get lower faster the farther you get from the boat. Some lux value comparisons from Wikipedia:
Examples
Illuminance Surfaces illuminated by:
0.0001 lux Moonless, overcast night sky (starlight)[3]
0.002 lux Moonless clear night sky with airglow[3]
0.27–1.0 lux Full moon on a clear night[3][4]
3.4 lux Dark limit of civil twilight under a clear sky[5]
50 lux Family living room lights (Australia, 1998)[6]
80 lux Office building hallway/toilet lighting[7][8]
100 lux Very dark overcast day[3]
320–500 lux Office lighting[9][10][11]
400 lux Sunrise or sunset on a clear day.
1000 lux Overcast day;[3] typical TV studio lighting
10000–25000 lux Full daylight (not direct sun)[3]
32000–130000 lux Direct sunlight
In theory they should, however, be much more reliable (no resistive metal filament to break from vibration and often 100% potted connections for moisture/corrosion resistance) and they have an inherent longer life (low operating temperature). They might be a better choice for the OP, Gregs, for his application, new installation, smaller wires, less power use, only used occasionally for lighting nearby objects or for lights used around the boat near the deck for fishing where they get a lot of salt spray.
I would post the question to all of you out there that fish commercially or regularly, how often do you need to replace the current light fixtures due to corrosion? How much does that cost in time and money compared to an LED fixture? I don't have a dog in this hunt but I am curious about real life comparisons.