Can't find leak!

[braol]

OK...so after yesterday's big rain here in Chicago (2.5+ inches yesterday morning in some places) I went out to my boat to do some work. The boat is tight as a drum when it comes to leaks...so i thought....but I noticed the port-side cabin cushion was REALLY wet. I ran my hand all around the headliner and the non-opening portlight just above that area and it was BONE dry... I also have no water stains/rust marks anywhere above the cushion.
The cushion was dry the other day when I was there, so there is definitly a leak somewhere. It's a real puzzler. Guess I'll have to go out there and sit inside in the rain to see first-hand where the water could be coming from. It has to be a significant leak though because the cushion was not just damp. I'm just shocked that there was no visible water anywhere above to give me any clue.

 

[KrustyKrab]

Do you have any dome lights in your headliner? I have a leak somewhere on deck that is getting into the headliner and actually dripping out of some of the dome lights.

 

[braol]

There is no dome light above the cushion...that's not to say that water's not leaking out from it and then travelling down headliner. The other funny thing is that it is definitely leaking only on the cushion because even after the heavy rains my bilge is dry as a bone.

 

[Bill Roosa]

The school book solution is to:
identify where the leak is ending up
got vertically up and locate where the drip was coming from
follow the most vertical contour (line a drop of water would follow) to the next opening in the headliner
given that the headliner and deck are pretty parallel to each other you can assume that the leak is "upstream" from the opening. But since you can't get in there.........a generous mittenfull of guessage is useful.

 

[Steve Dion]

2.5 inches of rain and wind could make water go just about anywhere.

 

[newsguy1]

A good way to find a leak is to use food coloring placed at a suspected source. Works great. Just put something on your cushions to protect them.

 

[braol]

I never thought of the food coloring idea. Thank God for the Internet. Can't wait to see the faces of the guys at the boat yard when I dump a bucket-full of colored water all over my boat!

 

[woodster]

better use the non permanent kind or you may be very unhappy

 

[kito]

I got to say...dumping colored water on my boat does not appeal to me. With the amount of water you are talking about it is most likely a port light. I am guessing they are the Grey ports lights which are a bad design to start with based on the face full of water when opening after a rain. You may not see water on the outside of the headliner (around the mounting flange) but these ports are mounted from the inside. The void between the port and the cutout needs to be filled. If there is leak, it will work it's way into this area and run down between the outer fiberglass and the headliner. A hard driving rain made it even worse. I had wet cushions too and didn't go away until I pulled out all ports and re-bedded them with Dow 795. Also make sure the port lense is actually sealing against the rubber seal when snugging them down.

 

[braol]

The good/bad news is this:

Good: All my portlights that open are leak free. I recently replaced the rubber window seals on all 5 of them (highly reccommended) and now they are bulletproof. They were always leak free (surprised) but the new seals from this site's store are REALLY nice and better than the originals. The old seals were at their end and I am still shocked that they worked at all.

Bad: The leak is most likely coming from a port side window in the main cabin although, for the life of me, I still have failed to locate a leak of any kind. I'll have to enlist my wife to sit below while I spray the boat with water. Although I'm sure that with all the time I've spent working on the boat she'd love to spray ME with water...

 

[kito]

The lenses may not leak but you may have water coming in from under the outside trim ring. When I pulled my trim rings off, I found that the PO used anything he could find on sale to fill the gap with and didn't do a great job at that. Everyone I pulled out had wet plywood between the fiberglass and headliner.