Mac 25 Gelcoat cracks and leak into v-berth

[jbrock]

I have a couple of substantial rain water leaks into the v-berth from the deck. It appears to be from cracks in the gelcoat. Any experience with this? Do I just have to repair the gelcoat, re-glass, or what? Thanks.

While we’re at it, any ideas for getting the black stuff off of the non-skid? It’s probably from living under trees for a while in my backyard. Now she’s much happier at a slip.

 

[THECUSCUS]

those gelcoat cracks are probably not the source of the leaks. The leaks look like saturated core plywood dripping in through the lower layer of glass mat. Are there soft spots on your deck (tap with a screw driver handle, should have a nice solid sound not a dull thud)? The deck is cored with plywood under all the blue areas. Try a bleach/water solution and a green scuff pad for the black marks or a magic eraser.

 

[jbrock]

Thanks. I’ll check for soft spots. What do I do about the saturated core? I wonder where the leak is then if not through the gel coat cracks. Any ideas?

 

[Project_Mayhem]

Try mixing a batch of die tracer that plumbers use with some water to find the source of the leaks. It's non-toxic and should glow under blacklight. I would recommend acetone for removing stuborn marks on fiberglass. It's pretty impressive stuff. I've also heard that MEK will work about the same but wont evaporate as fast but I havent tried it. The typical solution for a saturated core is cut away the glass layer and wood then replace

 

[srimes]

A pressure washer is great on mildew.

When looking for soft spots on the inside stab the area with a screwdriver. If it goes in it's bad.

It takes more than a gelcoat crack to leak. Fiberglass should be watertight without any gelcoat. The usual culprit is an intentionally drilled hole. Look for where stuff is mounted through the deck and remove-inspect- re-bed them. Bed-it butyl is great stuff. https://shop.marinehowto.com/products/bed-it-tape

 

[Project_Mayhem]

A pressure washer is great on mildew.

If there are deck fittings that aren't sealed properly this might be a bad idea. It may also cause poorly sealed fittings to leak. I think it'd be ok if you didn't get too close to deck hardware and whatnot. Otherwise pressure washers are awesome on fiberglass!