Weeping Fiberglass

[DBBRanger]

I developed a leak in the forward cabin aft of one of the stanchions - the mouse fur was wet on the hull and the water had drained down onto the shelf behind the bolster cushions. I took off the ceiling mouse fur/panel in order to see where the water was coming from. I assumed it was coming through the stanchion base plate, but I could not verify it by spraying water on it. I was able to pull the mouse fur back enough such that I had a clear look at the area all along the hull/cabin interface. I then thought it must be coming in the screws connecting the cabin to the hull, but again no evidence there. Yet as I was spraying water on the outside, water was still wetting the mouse fur. To make a long story even longer, it turns out there are two pin holes in the hull fiberglass that the water was weeping though - not through holes from the outside in, just on the inside. As shown here:


The weeping did not stop when I stopped spraying. Apparently, water is getting into the fiberglass above this area most probably through a hull/cabin screw (which BTW are not the screws holding the rub rail on - they are under the rub rail). It then must seep down THROUGH the fiberglass until it reaches the pin holes and exits into the mouse fur. Is this possible? I didn't think fiberglass was porous like that. Can there be another explanation?

 

[R Baker]

The deck is no doubt cored. I would enlarge those interior holes to ensure there was a clear drainage point. If drainage is partially blocked then water can find its way elsewhere between the glass laminate and core. The concern would be an area of delamination. Tapping with a plastic hammer or screwdriver handle should locate any delamination if there is any. Keep lookin for the source of water - it may be further from the inside holes than you might think. You can leave the inside holes open to help drying out that area. In fact a few more small holes wouldn't hurt.
I think I would take out the screws (a few at a time) holding the ss rub rail and if you find a wet one, then that should be the source. Replace the screws with a bit of fresh sealant - 4200 or Boatlife, on the threads.
Your pic does not show the base of the stantion - I assume it comes right thru the deck with a fitting or sorts on the base. You need to examine that as well and probably before pulling out any screws.

 

[DBBRanger]

The deck is no doubt cored.

Thanks for the response. The weep holes are in the hull, not the deck, but even so, I can see shadows of things on the deck, so I don't think the deck has a core either. If there is no core, I'm wondering how water can weep out of "solid" fiberglass.

 

[DBBRanger]

The weep holes are in the hull, not the deck, but even so, I can see shadows of things on the deck, so I don't think the deck has a core either.

My comment was based on my thought that the hull does not have a core. Is that true? If it is cored, then I can understand how water would weep out on the interior fiberglass.

 

[R Baker]

This is a mystery... The core in the deck would stop some inches from the edge of the deck; there it would transition to solid fibreglass. If the hull to deck joint is mechanically fastened, then you will have to expose those fasteners. Removing the s/s rub rail should be fairly straight forward. You might ask the factory for some direction before proceeding.

 

[Connerkip]

On my cutwater30 I have a core in the hull. I pulled off a port light window and could see it in the exposed cut edge, although the factory had told me previously this area was solid glass.

 

[S. Todd]

The picture sure looks like it has a white core mat in this section. If that is not a core mat, what are those evenly spaced dots that appear to be the holes in the core mat for the resin to migrate through?

 

[Spinner]

What those regular marks look like to me are the woven fiberglass fabric that is the reinforcing material.

 

[R Baker]

Google "images of coremat" - it sure looks like it.

 

[DBBRanger]

Thanks for all the responses. I guess my conclusion is that the hull in this area is cored and therefore water is seeping down from one of the fastener holes. Unfortunately, I am cruising the Florida Panhandle at the moment - it is definately NOT dry here. Will have to wait until I get home to dry Colorado before I address it.

By the way, I can see the shadow of a screwdriver shaft through the deck when it is backlighted by sun. Does that mean it is not cored?

 

[Pilotnavigator]

If you can see light and shadows then it is not cored. The only core on the 21ec deck that I can find is down the middle of the deck where the cleat is located. Not sure how the water is getting through the glass and out where your picture shows. It looks to be solid glass. There must be a void in there some where. Better figure out before winter in Colorado!