Hey Jerry:
These oval courtesy light fixtures were made by Cantalupi. They are now distributed by IMTRA.
Pretty early on in the life of our 2008 boat, I started having bulbs burn out and, especially, the fixtures that were on our swim step were exposed to more salt air/water/spray and they corroded, so replacing the bulbs sometimes worked and sometimes not. I contacted Cantalupi directly and we did a group purchase among several owners and they delivered LED replacement fixtures (where it's not an LED bulb in the same fixture, but a sealed LED unit). They have worked flawlessly for 15 years.
Here's the IMTRA equivalent LED fixtures:
It will obviously be cheaper if you can find LED bulbs to put into the old fixtures, but I didn't want to do that because of the problems with corrosion and vibration making the bulb/fixture contacts unreliable.
So.....just an option if you want to solve the problem once and for all.
By the way.....the ONE thing that I've found with even the LED fixtures is that with time, the lenses that are exposed to the sun (mostly the ones, again, on the swim step) start turning yellow. Fortunately, when I swapped out the incandescent fixtures for the LED fixtures, they all came with new lenses and I saved the old ones that were still in perfect condition. So....every few years, I take off the old yellowed lenses and put one of the "fresh" nice white ones on. It doesn't really have any functional difference. It just looks better. So.....if you swap the fixtures, save the lenses.
Mark Tilden
Selene 60-20 "Koinonia"