Delamination

[Erwan]

I own a 32 year old Mallard and I just found major hull delamination underneath the inside liner.
It goes from just below the waterline to the top of the hull and from the galley area to the forward cabin.
Could anyone tell me if this is repairable?

[paulk]

On a boat, anything is repairable. The question is whether it is worth fixing. That depends upon you and how much you want to spend in time or money to fix it. Joshua Slocum got a really decrepit, old and worn-out fishing boat, fixed it up, and sailed around the world. Our cabin top had 2 delaminated sections about 1' x 10' where the handrails had leaked, rotting the balsa core. We fixed it. Our hull had a 2' diameter "spongy patch" below the waterline on the aft starboard quarter: I fixed it. There'll be more to do next spring somewhere else, but we think we can keep ahead of it (and perhaps work to prevent some of it too.) Fixing things in your case are made tricky by the inside liner. ", You may be able to take all or part of it out to access the area, or you may have to work from the outside. If your core is rotted, it will need to be replaced. If it's simply "unstuck", you'll need to goop it up (epoxy sticks better, but using polyester resin may help avoid hard spots that could cause problems later) and figure out a way to press everything together until the glue kicks off.
Read a few books and talk to several people who repair boats to get an idea of what is involved. You may decide it's time for a different boat, or you may decide she's worth fixing. Your choice!

[mitiempo]

To my knowledge Joshua Slocum didn't have to deal with delamination!
Erwan
Seriously, it is repairable. Is your hull cored? Is it a full liner that is just loose? Delamination is when the two skins of a cored hull (or more commonly deck as few hulls are cored) separate from each other. Liners on the other hand are usually placed inside the hull with polyester paste holding them in place - both to stiffen the hull and to provide molded attachment points for interior furnishings. If it is not delamination between skins but just a loose liner it's pretty easy to fix. Epoxy is a much better choice than polyester as it gives a much better bond. It is also not as brittle as polyester when cured. Pictures would help. But if you can access the inside of the liner in as many loose places as possible, preferably where it is in cabinets or wherever it won't be seen later. the trick will be to make access holes to pour in epoxy mixed to a mayonnaise consistency. You want it thick enough to not all run to the bilge but thin enough to get in the access holes and fill the gap between the hull and the liner. When a builder installs a liner it isn't attached everywhere - just in a consistent number of places to remain attached and stiffen the structure. If you can access the top of the liner to pour into the gap between it and the hull that would be best - Just put a small (1/4" or so) wedge in all along the join and pour the thickened epoxy in, let it run down a ways and pull the wedges. Use slow hardener to get a longer working time so the epoxy can cover a larger area before it sets. Hope this helps.
Brian
ps What is a Mallard?

[Erwan]

Thank you for your answers, but my problem is even worse.
The three inner fiberglass layers of the hull are spongy and the resin used to laminate is sticky. And this is spread over an area of aproximately 3.5 sq meters over the port side of the hull. I'm not sure if I did right, but I already took some of the liner off in order to check the extent of delamination.
By the way, Mallard is a french make. They used to make sailboats, such as mine which is a 9 meter. I think this make still exists, but they don't make sailboats anymore.

[mitiempo]

Erwan
Is the hull of core construction?

[Erwan]

No, it is fiberglass only

[mitiempo]

In my opinion there is no way that the inside 3 layers of a solid fibreglass hull should ever become "sticky" unless the original layup was done with the incorrect materials or contaminated in some way. I would suggest having a local fibreglass repair tech look at it and give his opinion on how to repair.