transom light water intrusion
 

As I sat on the tie bar behind my boat on the pier lift today, waiting for water to drain from the bilge, I looked at the Lumitec transom light that my boat mechanic installed in July 2019 and pondered the issue of water intrusion. I noted the 3 screw holes around the light and on a whim grabbed a screwdriver, crawled back out behind the boat, and tested the bite of the screws. The way they backed out didnt give me the feeling they were sealed with 4200, not that they were loose but they just didnt feel locked in with sealer. The transom felt solid when tapped with the screwdriver but I grabbed my moisture meter and it read saturated beneath the light at the bottom of the V of the transom. F*%$!

I got in the spring when I was repairing some rot in the corner of my hatch, and although 40 bucks I found it to quite accurately confirm the wet core spot in my hatch, and is definitely worth having. Of course I checked the transom when I got it, and noted it was overall quite dry, reading a steady +/-10% except for the the very bottom of the V (below the light and above the drain plug), where it read 30% but didnt set off the "saturated" alarm (a light and beep go off in that case). I wasnt sure but figured it might make sense for this area to have more moisture since its at the bottom of the bilge.

But now after4 weekends out on the water its already reading as saturated with the red light and alarm beep going off when I run it over that spot.

All this leads me to believe that my boat mechanic didnt fill the screw holes with 4200 and they are taking in water every weekend that I'm out. Im pretty sure he did put 4200 between the light body and the hull, just not in the screw holes (and who knows what he did on the the bilge side). Im thinking that this water intrusion has been going on the last 2 summers since he installed it, the reason it didnt read saturated in the spring is that it dried out some during the off season, and now that im using the boat its gotten wet enough again to set off the saturation alarm on the detector.

So what to do now? I am figuring to shoot 4200 up in the screw holes and tighten them back up until the off-season when I put it back on land again. But what to do for the longer term? I *think* its not yet rotten, just damp. I already have a good idea that in the very best case it will dry out to that 30% dampness that it was at this last spring, not good enough? Should the fiberglass skin be ground off to allow it to dry (or if rotted, replace the wood at the bottom of the core) and fiberglass it back up? Or might a less aggressive intervention be warranted?

Appreciate the advice from the glass experts on here. And yeah, I sure wish in hindsight I hadn't gotten bothered getting this GD light.

https://cimg4.ibsrv.net/gimg/www.off...873a3df9f8.jpg

sorry I should have put this in fiberglass & paint, don't think I can move it.

I can :drink:

Thanks Griff

Didn't use SS screws neither huh? This is why I do all the work I can on my own.

Nope, which is confounding since im pretty sure it had SS screws in the package.

With you on that, now anyways. Finally built up the courage and started doing glass & gel repair last year, so going forward I only have myself to blame if its not done right.

I had a small area in my 382 where the trim tab indicator cable goes through the transom. I removed the tab, cleaned up the whatever goop was used to seal the area. I had a small vacuum pump in my shop. I taped up the inside hole and set up the vac pump and sealed the hose in the void. I ran it for 3-4 days. It dried out the wood really well. I let it set for another few days and then reinstalled the tab.Worked great for a small area. On the lumitec issue. They did have a sealing issue that allowed water leakage into the led area behind the lens, I could see the water inside the light. They replaced all three lights no arguments, Good company.

Of the opinion to have as few through transom holes as possible so I went with a drain plug light for that 2-3 times a year I run at night. Much easier to replace in the event of failure as well.

The feeling I get from turning the screws is that the wood around one of the screwholes is a little soft. The meter indicates moisture below and directly next to the transom light. I want to be sure to get it completely dry and sorted and nip this in the bud. Is it a bad idea to grind off the outside layer of fiberglass, remove any soft wood, fill the void, and glass it back up with epoxy? It seems to be limited to just a few inches next to and below the light. I ask about doing it from the outside as I wasnt planning on pulling the engines this winter.

Glass Dave if you're out there, would love to hear your thoughts on it.