Damaged lower fiberglass skin.

[Peter Jackson]

This Spring I discovered that I had water damage to the core in the foredeck of my CD 25. After drilling pilot holes (and finding black rotten core) I determined that a section of the core needed to be replaced. After making the cut to take the fiberglass top skin off I found I was looking not at the lower skin, but into an opening that shouldn't be there. The depth of the cut was the same all the way around and I hadn't come close to the lower skin anywhere else. In the small area around the hole through the skin, it was not balsa core, but solid laminate. I had already made my cut around it, so I proceeded to clean the laminate (probably my 1st or 2nd mistake!) out so I could replace it with new balsa core. In the process of doing that I opened a bigger hole in the bottom skin. Unfortunately I now have an 11" x 1.5" section of my repair area with no bottom skin (Picture attached). It seems the only way to access it from underneath is to cut out a piece of the head liner in the V berth which I am hesitant to do.

I am hoping that those of you far more skilled than I am can give me some insight into how I can fix the bottom skin. I tried a method suggested in the West System manual of using a flat piece of laminate and epoxying it in by pulling it up from above with screws and string, but I couldn't get it to seat properly. Any and all suggestions gratefully accepted.

Thanks.

Peter
Buglight CD 25 #845

[SV Tatyana]

would it be possible to grind a taper into the adjacent solid glass and tie in new layers of glass from the taper over the hole to the bottom skin.. since there probably wouldnt be room for the balsa after this is done you could just fill with low density thickened epoxy and then new glass over for the top skin.

[Russell]

Looks too wide to fill with thickened epoxy. On my CD36 I have found a lot of similar voids between the core and the headliner. In what your photo is showing, I would cut a long wedge shaped peice of the new coring material and push it into the void and put thickened epoxy fillets on each long edge and then continue as normal for the rest of your repair.

[c1josh]

That's not "an opening that shouldn't be there". The core does not got all the way to the edge on purpose. If it did, then all the fasteners for the stanchions and hull to deck joint would be compressing a balsa core. This would fail eventually. The thick, multi-layer edge of the deck is part of the structure.

I suggest that you grind a taper in to the solid part of the deck, to within an inch of the toe rail, and lay down a bunch of heavy layers of fiberglass+resin. You could do a light, first layer to bridge the gap, and when this is cured, proceed to build up the structure that you cut through. Once this is fixed then you can do the normal damaged deck core repair.

I just fixed a corner of my cockpit and it turned out decent for a first deck repair. It's not cosmetically perfect, but it is solid.

Josh

[SV Tatyana]

sorry if what I wrote was confusing I was not meaning to put only thickened epoxy to fill the gap, first a layer of fiberglass should be put down to cover the hole, I guess what c1josh said is a bit more clear, I see no reason why this wouldn't work... are you planning to paint over the gel coat after the repairs?

Rich

[pete faga]

Josh
Do you have any pictures of your repair?
Pete

[c1josh]

Yes, I have a set of pictures. I'll try to get them up today in a new post.

Josh

[Peter Jackson]

Thanks everyone for your input. I went with the method I read about in the West Systems manual with a small modification. Originally I made a small piece of laminate to slip in the void and epoxy it in by pulling it up and using string to affix it in place. The piece was too big to get it to seat properly, so a friend suggested that I cut it into smaller pieces. I cut it into 2 pieces and used small threaded eyelets screwed into the pieces of laminate. I applied the epoxy on both surfaces and tied it off. After it cured I put down a layer of epoxy to strengthen the patch and make the lower skin even. It worked great.

My issue now is that the replacement core sits a little high in places. It's the same thickness as the original core, but it seems high. I'm assuming it's okay to sand it down as everything I read says it's better to be lower than higher.

[SV Tatyana]

Peter,

Going by the pictures here you still have a lot of left over material from the old balsa on the lower skin that needs to be ground/chiseled out. All the tan colored material and white cloth material need to be removed...you should see only the green colored laminate of the lower skin...after this is done the new balsa should sit just low enough for the top skin. Will you be laying down new cloth or reusing the top skin? If your looking for some good info/pics definatley flip through Tim Lackey's site if you haven't already...here's a recore of a CD27 http://www.lackeysailing.com/angelina/march11/31511.htm

-Richard

[Peter Jackson]

Thanks for the link Richard, it's very helpful.

[SV Tatyana]

no problem, I just finished recoring a few sections on my 25D and his site really helped