You can replace bulbs of existing fixtures with LED's from
I did this on my last boat and they work great, cheaper than the whole fixture.
That is good if you want to upgrade your present lights, but will not help the corrosion problem as posted.
You would still be plugging the newer LED type bulb into the existing socket which is the cause of most problems. The fixtures are watertight enclosures, so your only 'work' is to make sure that the wiring leading to the fixture is good.
Anyone that is considering either of these upgrades needs to remember to keep the fuse in line or add one if there is none. Although the newer LEDs work on much less draw and run cooler, a short is still a short.
It may even be wiser to drop the amp rating down if replacing with the LEDs as to have them blow sooner!