[JohnG]

You can use fiberglass cloth and it will be stronget than using a peice of cotton rope.

Here is a technique that I have used to patch some of these type things with good success. First you get the area ready for the patch by roughing it up so the fiberglass will hold. Next tape off the area a litle past where you intend on making the repair. this will help to keep the mess localized. The mix your resin and lay it down, then lay the cloth over it (The cloth should be pre-cut to the correct size for the repair) The put mor resin right on top of the cloth. It should soak the cloth so it almost disappears. Then you place a piece of regular glad wrap over the patch keeping the glad wrap wrinkle free and use a roller to compress it. Leave the glad wrap there until the patch is dry. It peels right off. The gald wrap leaves it with a smooth finish that is easy to rough a bit for painting.

You will of course be bulking that area up a little but it should be small enough to be unnoticeable.