water in sandwich deck

[segelklaus2]

i sail an lm 30.
water penetrates the foam core of the deck.i have installed drainage hoses on both sides, which indicate to me that half a cup of liquid penetrates after a heavy thundershower. genuaschine and püttinge are freshly sealed. you can see tiny hairline cracks of a few mm in length, actually only visible with a magnifying glass. is anyone aware of this problem?

[Brian & Glenda]

I don't know where you drilled the drainage holes, but perhaps it isn't your deck that is leaking, and instead it is your windows. If you drilled the holes through the headliner in the main salon, (especially if they were drilled near where the headliner joins the hull) please be advised that the headliner is a separate piece of fiberglass suspended below the deck, and the following story from an earlier post of mine may be of use.


When I bought my LM32, I noted some fore and aft micro cracking in the gel coat only, emanating from the hardware that affixes the aft shrouds to the deck. I negotiated that the vendor would have backing blocks installed under this hardware to reinforce the aft shrouds with the hope that this would eliminate any increase in the severity or extent of this cracking. Effecting this repair necessitated cutting a neat rectangle through the ceiling pan in the salon under each fixing point. Once that was open, we found water in the space between the bottom of the deck, and the top of the ceiling headliner. We mopped up that water, but subsequently noted that it reappeared after each significant rainfall.

I too had found water in my salon cabinets, and on further investigation I also found a puddle on the top of the salon cabinet. How that puddle got from the top of the cabinet into the cabinet I never did figure out, but I did figure out where that water was coming from in the first place.

I had also noted some water in the small ledge / hand grip below the main salon windows. I determined that the salon windows were leaking, and discovered that fixing the leaking windows, eliminated both the leaks into and onto the top of the cabinets, and the water in the space between the bottom of the deck and the fiberglass salon headliner.

I believe that:
1) Some of the rainwater made it's way between the glass and the rubber seal of the leaky windows, and subsequently ran down the interior of the cabin top sides and across the ceiling pan, where it eventually dripped onto the top of the cabinets.

2) Some of the rainwater makes it way between the rubber seal and the aluminum window frame. The aluminum window frames have holes in the base of the U shaped channel that retains the glass in the rubber gasket. These holes drain into in the space between the deck molding, and the fiberglass salon headliner. I believe that this is how the water entered the space between the underside of the deck, and the fiberglass headliner.

Resealing the windows isn't easy, but it is not impossible. I currently have a minor leak in only one of the ten windows that I have resealed. I'll be working on that one day soon.

Hope that helps!
Brian

[segelklaus2]

hello
this is the current status:
a boat builder came on board for advice. we pumped air into the drainage openings with a compressor and wanted to search for leaks with leak spray. however, this was not necessary, as there was a clear hissing sound at the windows in the cabin and a mixture of water and air was also leaking inside under the aluminum frame.

i removed the main windows of the cabin again. i scraped out about 1 cm of the foam from the laminate of the deck superstructure and filled these edges with epoxy filler. then i installed the windows again and put them in with sikaflex despite the new seal.

according to the boat builder, the original windows from the 70s/ 80s are not a good construction. despite bends in the superstructure, they have glass in the middle and therefore tend to leak without additional sealants. in addition, the shipyard neglected to seal the edges of the window cutouts.

[Brian & Glenda]

So glad to hear you got that sorted! Thanks for sharing your solution. Brian

[alexander]

I have the same problem of leaking after heavy rainfall with one of the main salon windows of my LM27. I was never sure where the water enters so until now I didn't dare to remove the window to reseal it, I thought it entered somewhere else probably and just came out at the aluminium frame of the window... But after reading what you guys wrote I will reconsider to finally remove that one window and give it a try to reseal. (or let it do somebody more experienced, maybe).
Thanks for sharing!
Alexander