The cockpit sole of my new to me 78 C16 has a break in the fiberglass that I need to repair. The previous owner caulked over it and went sailing but I want a more permanent and less flexible solution. I've never done any fiberglass repair but did build a wood stripper canoe a bunch of years back, so I'm not completely without experience. The break extends across the footwell to within about an inch of each side and is about 10 inches back from the forward end of the well. My thought on how to fix it is to cut an oval about 1 inch wide around the break and then lay a Plexiglas scrap taped at the edges and then sandbagged to keep it in place across the hole. Then from the underside of the footwell, I'll paint on gelcoat, let that set up, add layers of fiberglass tape and polyester resin until the hole is flush and then an oversized patch - say an inch all around.
So first question - Is this how you'd do it? If not, how?
And second, the rest of the sole is textured and I would like my patch to be also. Is there a way to do this?
Thanks for any thoughts or how to information.
Geeman,
Ahhh. The delightful foray into the world of fiberglass boat repair! Here is a link to the West Systems fiberglass repair manual pdf. https://www.westsystem.com/wp-content/uploads/Fiberglass-Manual-2015.pdf
This is a good place to start and it's free.
I have found that the more I work with fiberglass and Epoxy resins, it becomes a bit easier with each repair or project.
Download the pdf and enjoy!
Chris
Go to Boatworks Today on youtube. He has videos showing how to address each of your questions.
Glassing overhead can be a pain especially in a small space. I think what I would do is to permanently fasten, with epoxy, a stiffening stringer, maybe a piece of 1x3 spruce on the flat, under the crack and all the way from side to side. I'd then V out the crack and fill with a resin /silica mix leaving room for a layer of gell coat.
I looked though the west system .pdf that Chris D posted a link to. It talked about not creating hard spots. If I made a beveled patch of say 3 layers of cloth and epoxy on my workbench and then epoxied that to the underside of the sole, do you think it would work as well as the 1 x 3? I would rough up the bonding suface, but not bevel it and place the patch oriented with the largest piece of cloth next to the bonding surface. Once that is cured, I'd proceed as you talked about. Is this an error or will it work as well?
Well, first question, why do we think it cracked there? There haven't been a bunch of posts about people making this repair to that same spot, so why did yours crack? Is there a large block of foam in the cabin under the cockpit sole? If that is removed it might explain why the crack developed.
A picture would help.
Assuming you just want to make a good structural repair and don't want to spend a bunch of time and effort, here is what I would do. If there is no foam under the cockpit sole I would cut a piece of plywood the width of the cockpit sole and somewhere between 2 feet long or the length of the cockpit sole if the sole feels a little bouncy when you walk on it. Either use marine grade plywood or good quality from hardware store and coat it well with epoxy. If the bottom side of the sole is painted, you'll need to sand the area where the plywood is going to go (if you haven't figure it out, you're going to epoxy the plywood to the underside of the sole). If it isn't painted, then you just need to clean it with some water. Then mix up a bunch of epoxy and thicken it to a peanut butter consistency and spread it over the plywood evenly. Use some car jacks or blocks of wood to hold the plywood up to the underside of the sole while the epoxy cures. You want enough epoxy on the plywood that some oozes out as you jack the plywood up. But don't jack it up so high that it squeezes all the epoxy out. If you want you could make a post (or posts) that permanently get wedged between the hull and cockpit sole for extra support of the sole, but it might not be necessary, the plywood might give the sole enough rigidity on it's own. This step reinforces the sole so that it will hopefully not flex and crack again.
Next you take a dremel and widen the crack in the cockpit. If the boat has been painted you could just widen it, clean it (per epoxy directions), then poor the crack full of epoxy, wait for it to dry, sand it flat and paint it. If the boat hasn't been painted and you want to try to match the gel coat you would widen the crack and use a gel coat repair kit. Or you could use a UV resistant clear epoxy and just leave it as-is.
You could just do the second part, widen the crack and fill it, and hope it goes another 30 years before it flexes and cracks again.
Instead of the plywood reinforcement you could use multiple layers of fiberglass mat but it is going to be a messier and harder project to do, especially upside down. If you go with fiberglass mat, I would do a pretty large large, 2 foot long by the width of the cockpit. Don't worry too much about creating hard points, that won't really be a problem for this repair.
Thank you for your post. Attached is a photo of the crack. There is nothing beneath the sole and I wondered also why it cracked there. That's likely going to remain a mystery. I hadn't considered putting plywood under the length of the footwell. It doesn't flex very much except when I get in the vacinity of the break and that is what was driving my thought to just reinforce the area near the break. Was aiming for a patch that would basically restore the structural integrity of the sole and allow about the same amount of flex as the rest of it. As I said, when I step on it away from the break, I really can't feel it move. i'm 165 pounds and it seems solid. You and the others that responded have given me a good start to figuring out what I'm going to do. I'll reread the west epoxy .pdf and go forth with epoxy. Thanks to all!
If that's the stern to the right in the photo, the crack may be from the support that is normally underneath at about that point. This view is looking aft down the bilge.
(http://teamcattwo.rdwalker.com/pix/2011_09_24_ComPac16/support.jpg)
If it's not there, then someone took it out. I believe its job is to provide support to the cockpit floor, so it's not supposed to put a lot of pressure on the floor, just keep things in shape. Something went wrong for a crack to form there.
Here's a link to what it looked like under the cockpit in my 1975:
http://cpyoa.geekworkshosting.com/forum/index.php?topic=9242.msg69630#msg69630 (http://cpyoa.geekworkshosting.com/forum/index.php?topic=9242.msg69630#msg69630)
-Justin
Thanks for the photo. The underside of mine is very similar to the photo you attached. The break is forward of the support, approximately half way between the support and the forward end of the footwell. The crack is a mystery. It doesn't appear to be from impact but I'm at a loss to think how else it could have happened. Regardless, I'm going to patch it and see how it does.
I wonder what year they went to putting a giant foam block under the cockpit sole? My early 1980s (it was either an 80 or 82 I think) had a big block of foam, it didn't have that plywood support.
However you decide to procede with the repair, afterwards i suggest you build a cockpit grate. After a swim it will allow the water brought into the cockpit to run out the back without you standing in it and possibly slipping, but more important, it will spread the weight out so if someone is standing directly over the repair, it will relieve some of the stress on it.
Thanks for the advice. The grate will be an excellent winter project. I'm shooting for getting the boat in the water by fall and I think I'll likely run out of time before I run out of projects!
I started the repair process today. Anyone know what the green layer under the gelcoat is? It is quite soft. The photo doesn't show it too well, but I ground a taper and the green substance is quite a bit thicker than either the gel coat or the fiberglass layer. It appears in the photo to have some definition to it - is it perhaps mat with some sort of colored resin? The thinness of the fiberglass cloth layer was a surprise - very thin. Maybe that's why it failed?
That's foam core to provide stiffness at lower weight. If dry you can fiberglass right over it. If saturated with water you should scrape the wet area out and replace. Defender stocks it in several thicknesses, such as part number 752568.
Wes
OK. Thanks Wes. It is dry. Tomorrow morning before it gets so hot, I'm going to try my hand at laying fiberglass in resin. I've got the patches cut and stuff laid out so a little coolness is all I need now I think.
Agree with previous posts that you also need more stiffness underneath. Doesn't have to be beautiful. I'd wipe off the gray bilge paint with an acetone soaked rag, rough up the surface with #80 grit, and epoxy a piece of 3/4" plywood over the existing area from below.
Wes
I figured that's what I would do after I put the patch on the upper side. That was until I put a piece of plastic covered plywood underneath the repair area today. The sole isn't anything like flat. I know thickened epoxy will fill the gaps, but all I can picture is how messy all that resin squeezing out would be. So I'm thinking about using mat as NateD mentioned. My idea is that I'll wet out a piece of mat on the bench, lay it on a piece of ply wood covered in heavy plastic sheeting, place it and hold it to the underside of the sole with a jack. Let it cure and then repeat. Just seems to me that the mat will conform better. Am I about to make the job harder/messier doing it that way?
You can certainly build up several layers of cloth rather than plywood. You definitely don't want to allow each layer to cure individually though. Apply the next layer as soon as the previous one has kicked off. You want all the layers to achieve a chemical bond while curing together. I would use biaxial cloth, not chopped mat, but that's just me. I would also use thickened epoxy to reduce dripping. It will wet out the cloth just fine.
Wes