Help with 48 LRC deck construction and repair

[Capt Paul]

I have stress cracks around the base of my mast. In addition, there was a hollow sound upon ringing. So, my initial thought is that water has leaked in around the fittings and rotted the core. However, that is not the case. When a section of the fiberglass deck was cut out and removed it lifted right off of a plywood core and that core had no rot and appeared brand-new. In addition, the mast had no bedding or caulk between it and the deck. I had thought the deck would be adhered to the core but it appears that perhaps a mold release was used in the initial construction which allowed the skin to lift off. Perhaps over the years the plywood has shrunk or the weight of the mast has compressed it leaving just a little gap enough to allow movement and cracks. It is amazing to me there was no evidence of water intrusion. I am now trying to determine the best way to ensure I can put this back together with no future stress cracks. Ideas?

 

[SKYCHENEY]

Perhaps it was "fixed" once before.

 

[oscarvan]

Perhaps it was "fixed" once before.

That was my first thought.

 

[Capt Paul]

Perhaps it was "fixed" once before.

Perhaps but sure doesn't appear to be. I can't find evidence of previous repairs from either above or below. I have the headliner out below. And I don't want to keep cutting the deck away to find the end of the plywood either because I don't want to cut the entire boat deck out. Does anyone know for sure details of the original build?Regardless of previous repairs, I still need a course of action. I am kind of leaning towards something but would like any fresh perspective or firsthand knowledge if anyone has some.

 

[dsharp]

I would rough the plywood and the underside of the glass panel with a #36 grit disc then bed it with thickened epoxy. After it dries grind a 6" strip around the perimeter and wet out 3-4 layers of chopped mat.Then grind, fair and paint.

 

[drburke]

I would do as dsharp suggested, but absolutely apply penetrating epoxy to the wood first to promote adhesion.

My deck was "repaired" in Mexico before I bought it, and is delaminating--not rotten wood, just letting go of the core.

DAN

 

[Capt Paul]

OK, great tips. Pretty much the conclusion I had come to as well. Question though, I would have ground maybe a 3" bevel all the way around BEFORE bonding the skin. Is there a preference to doing so after?Mine doesn't look like it delaminated, it looks like it never was laminated. Only two little spots that pulled a little wood and both right by the bolthole. It's as if a mold release was used and some got squeezed out around the hole. It is very curious to me. And the thickness of varies on the skin so it was fared in place over the core.

 

[dsharp]

The deck was made upside down in a mold . They probably have a balsa wood core on the rest of the deck and put the plywood in certain places where they needed to be able to thru bolt the mast or seat bases. The balsa would just crush. The only problem I see is you cut a little close to the vertical part. It will just make it a little more difficult to fare. You can use some short pieces of angle aluminum and sheet metal screws to keep the cutout piece level with the existing deck. That will hold it level while you grind your bevel. Makes me itch just thinking about it.

 

[Capt Paul]

The deck was made upside down in a mold . They probably have a balsa wood core on the rest of the deck and put the plywood in certain places where they needed to be able to thru bolt the mast or seat bases. The balsa would just crush. The only problem I see is you cut a little close to the vertical part. It will just make it a little more difficult to fare. You can use some short pieces of angle aluminum and sheet metal screws to keep the cutout piece level with the existing deck. That will hold it level while you grind your bevel. Makes me itch just thinking about it.

Fortunately the yard doing the work will have to do it. There was really no way around cutting near the vertical piece because that's where the mast is.

 

[Pete]

As a fellow owner of a 48 LRC I have a question. On my boat there are two stainless supports that run from just outside the upper corners of the watch bunk window to just under the radar platform on the mast. Do you have these supports on your boat, and if so were they snug before the problem appeared? I have seen boats where these loosened and bad results followed.

Pete

 

[34Hatt]

I would rough the plywood and the underside of the glass panel with a #36 grit disc then bed it with thickened epoxy. After it dries grind a 6" strip around the perimeter and wet out 3-4 layers of chopped mat.Then grind, fair and paint.

When using Epoxy you need to use a special mat for Epoxy so just use a 1208 cloth has a LOT more strength .

 

[Capt Paul]

As a fellow owner of a 48 LRC I have a question. On my boat there are two stainless supports that run from just outside the upper corners of the watch bunk window to just under the radar platform on the mast. Do you have these supports on your boat, and if so were they snug before the problem appeared? I have seen boats where these loosened and bad results followed.Pete

Yes I have them and yes they were tight.