I'm also working on a boat and found this link http://www.windline.net/how_to.htm in another thread. So far it has been very helpful
Post some pictures and it will be easier to advise you.
Those are two simple fiberglass repairs that were not done properly.
But they do give you a foundation to build on.
Pick up the West System book on fiberglass repair, it explains what you need to do.
For tools, you need a 4.5" or 5" grinder with a sanding disk, a 5" or 6" random orbital sander with 80, 150, and 220 grit disks, a long board with fine and medium grit paper, and the normal fiberglass stuff.
If you grind all the way through, you will need some spray foam like great stuff, or something to use for backing to support your fiberglass as it set up.
There are a bunch of thread on fiberglass repair in here. Unfortunately, the moderator, mixes them up with the other discussions, making it harder to find such information.
The first step is to start removing gelcoat from around the damage. Keep going until you find good fiberglass.
To illustrate, the hole is obvious. The lighter "yellowish" color of the fiberglass is all damaged. The darker greyish color is good fiberglass.
Now this si from the original fiberglass, right? The fiberglass I am talking are repiars and most look kind of yello-ish and kind of translusent. Is this normal? If not: Yikes! I got a lot of "fiberglassing" to do
If it's not from the factory, it could be pink for all we care.
Here's a more close up pic of damaged glass. You see how it doesn't look nice and happy? The yellowish color isn't consistent like it would be if it was a good solid patch. There's the hole, yes but things started delaminating because the seal was compromised. And before I sanded off the gel coat, it looked like much less damage than what was really there.
I have repaired several sunfish with similar damage. Where your problems are a parts of the boat that take a lot of stress. If you grind out the hole to make a one or two inch flange around the edge of the patch area it will give your new repair enough suface area so that the new patch will not just crack around the edge. The other thing you need to do is make sure your patch is thick enough. When you actually make the patch you have to put fiberglass mat in it or it will just crack. You should use fiberglass resin to do the patch not epoxy. To want to make the patch a little thick. After the patch hardens you can sand it down to be even with the hull. When you finish the patch will not be perfect. I was always mad when icould see the imperfections in the patches. But a couple years ago I was recommended by my neighbor to use a final coat called evercoat everylass. This is a little expensive but it gives you a flawless patch and the gallon of it lasts forever.
I was also just wondering if that is a 1983?
http://sites.google.com/site/picturesofsunfishproject/
Here are some pictures of what I have been doing. This is my first attempt and I had no idea I would be able to handle it. I would say that the key is to be patient and make sure you do all the prep work.
http://minifish-restoration.blogspot.com/
And this is minifish's blog, that was helpful for me in doing some of my repairs.
You want to make the patch a little thick. After the patch hardens you can sand it down to be even with the hull. When you finish the patch will not be perfect. I was always mad when icould see the imperfections in the patches. But a couple years ago I was recommended by my neighbor to use a final coat called evercoat everylass. This is a little expensive but it gives you a flawless patch and the gallon of it lasts forever.
I would stick to ordering marine supplies. If you are going to do it you might as well do it right.
I have found that resin is stronger and stiffer than epoxy which is what is required in this application. When it comes to the brand of resin I have found there to be little difference in the resins except their name. The only thing you really need to look at what the label says about water resistance. If the label states waterRESISTANT Do not buy that resin. You want a resin that says waterproof. I personally use a cheap resin from home depot.
Sometimes that's true, sometimes it's not.When you buy a marine product to put on your boat you may not be getting what you expect.