Aft deck hardtop question

[Zydeco IV]

I've owned the boat for 11months now, a '78 53my in generally great condition based on a good survey and relatively trouble free operation of all systems so far. Now this: mildew is showing up in about 8-9 spots around the ceiling of my aft deck. About half of the spots appear to correspond to the location of fittings drilled into the top of the deck for dinghy chocks and stantions for the stainless railing around the flybridge. But the other mildew spots don't appear to be directly related to any one particular intrusion on the top.

Now one of the above mentioned "unrelated" spots has begun to leak a greenish fluid that looks like outboard motor oil as it hangs from the ceiling leak area, but doesn't have the viscosity or smell of lubricant. And worse still it's now dripped onto my wife's new Tommy Bahama deck furniture leaving stains that's put my marriage in deep peril.

What's up?

[SKYCHENEY]

Sounds like water intrusion into the core. The green stuff is probably from bronze fasteners that are corroding from the water and then leaking down. I noticed on a 1979 53MY that I looked at before I bought mine that it had water intrusion through the dinghy chock area. It showed signs of water leaking out at the aft edge of the hardtop even though the chocks were further forward. I would pull the chocks off and check in those holes for wet core. Good Luck. Its not fun to fix, but if it hasn't gotten too bad yet then it might be okay, if you get the leaks stopped.

[MikeP]

I don't know if the deck is solid or cored; I assume the 53 decks are cored. But yours sounds like a typical description of water intrusion. The water reacts with the coring or resins in the FG, producing brown or green "boat soup" and weeps out of whatever orfice is available. If the deck is solid fiberglass, it probably doesn't matter but if it's cored, it does. Here is a good article about such problems:
http://www.yachtsurvey.com/hardware_attachments.htm

(read all of Pascoes articles about coring...and everything else for that matter)