Time to re-core?

[Bigjim]

I bought my boat a couple of years ago after it had sat on the hard for 10 years or so. It has lots of leaks all over and I've been fixing them over the last year or more.

I noticed a crack in the deck near one of the chain plates (below) that was not there when I bought the boat. The wood below the chain plate was discolored from water leakage and then I noticed that the interior is deflected upward (below) near that chainplate. I created a version with red lines to show the proper deck level.

The deck on the starboard side is straight and level. The exterior deck on both sides is not bulging, so I think the wood core in my deck has dissolved on the port side.

So, is it enough to cut the deck open by the chainplates and replace the core?

[Cheechako]

Boy, it's just hard to say. I have drilled small holes from below to test wetness. Maybe a 3/16 bit. Drill through the thin interior layer into the core only. Then squeeze the wood from the drill bit between your thumb and forefinger. You will see it if there water in there. Move around until you find the extent of it.

[Thumbs Up]

The crack could be the result of the wet core freezing. Not seeing an actual bulkhead that the chainplate is bolted to. Tapping the area with a plastic mallet (or the plastic handle of a putty knife or similar) should give a clue as to how far the problems extend.

[Bigjim]

Originally Posted by Cheechako

Boy, it's just hard to say. I have drilled small holes from below to test wetness. Maybe a 3/16 bit. Drill through the thin interior layer into the core only. Then squeeze the wood from the drill bit between your thumb and forefinger. You will see it if there water in there. Move around until you find the extent of it.

In other places on the boat the wood was so wet for so long that it was mostly dissolved. That's what happened around the windows. I took out those windows and made new ones. I gouged out the rotten wood and replace it with thickened epoxy.

I could drill up from below, but I have a feeling there is no wood left in those areas. If you look closely at the photos the starboard side is deflecting up about 1/2" or so, about the thickness of the plywood in other parts of the boat.

[Bigjim]

Originally Posted by Thumbs Up

The crack could be the result of the wet core freezing. Not seeing an actual bulkhead that the chainplate is bolted to. Tapping the area with a plastic mallet (or the plastic handle of a putty knife or similar) should give a clue as to how far the problems extend.

I tend to agree with you. But I also think that the crack is the result of upward pressure of the chain plate. I feel there is little or no wood core and the pressure of the chainplate is being concentrated in a small area below the deck in that spot.

The chainplate is attached to the wood structure of the shelf and cabinets below the deck. The wood is supposed to distribute the load of the stays to the deck. I'll have to tear things out a bit to see what type of connect there is to the hull, if any. There is no full length bulkhead there as you might expect. I don't even know if the chainplate structure is even glassed to the hull. So, it may all hinge on the deck structure and strength and therefore that's why it is deflecting upward.

[Bigjim]

If you look carefully at the attached photo I circled the location of the chainplate which is inside the cabinet. This is the location of the deflection you can see in the background.

I added horizontal red lines to indicate where the shelf should be.

[Thumbs Up]

I found this online: https://www.thevirtualboatyard.com/2...ment.html#more

[Thumbs Up]

Looks like you would have room to tab in a full height bulkhead.

[Bigjim]

Originally Posted by Thumbs Up

I found this online: https://www.thevirtualboatyard.com/2...ment.html#more

You are amazing. That is the same boat that I have. That is exactly the problem we're experiencing. Problem and solution. That's the same solution I was considering! Wow.

Thanks

[Bigjim]

Well, the process is underway. I pulled out the old chainplate. Had new ones made and cut open the deck at the aft chainplate. The wood was either sodden or completely dissolved.

I remove a 12" x 18" section of the deck and could have continued for a ways.

Replaced the rotten wood with marine plywood and coated it all liberally with West Systems epoxy.

Only thing left now is fairing the patch and gelcoat.