Recently I had my bow nav light go out on my classic Whaler. In those days they ran a 3 wire cable through the foam with the 3rd wire “just in case” you had a problem with one. Well 45 years later they finally corroded through!
The solution is to buy a 3 pc rubrail from Boston Whaler and run a new cable through the rub rail. In order to prevent water intrusion where the wires pass through the hull, I made some fiberglass tubes by wrapping some glass sheets around a 3/8 PVC pipe and letting it set.
These were inserted through holes drilled through the rail and to the bottom of the nav light in front, and through the side rail at a down-sloping angle (for drainage) in the rear. Then they were set in place using resin mixed with fairing material and sanded.
Next, the rub rail was installed using stainless screws that came with the kit. I purchased the kit through TwinCities Marine for about $180 - the rubrail is OEM. These screws have a coating that helps seal them against water intrusion and they are self tapping.
I am really happy with how it turned out and it gives the boat a newer look. I am still holding off on the major redo of the glass (as you can see it has plenty of crazing as is typical for this vintage Whaler). I’m having too much fun with it to take it out of commission for 6 months 
Here are some pics. I am sorry I didn’t take any in-progress pics…
A view down the length, its pretty straight
This shows the rubrail at the corners. A heat gun is a must for this portion of the project. Thanks BOSN for lending it to me
This shows the access hole in the rear where the cable passes through the side and into the rubrail - completely water-tight
I always enjoy the project thre