Our Dinghy Refit

We have a Fatty Knees brand hard dinghy. We like it a lot. It is roomy, and stable, and rows great, moves fine with a 2 hp outboard, and we have a sailing rig for it. Amazingly, almost as many boating people recognize it by her lines as recognize the Westsail. We're used to being hailed, "IS THAT A FATTY KNEES?" It's the only item we own with a brass plate that lists the name, address and phone number of the builders. They must be proud of what they do.

A disadvantage of the Fatty Knees is that it is delicate, and easily damaged. The fiberglass is very thin. This keeps the weight low. However, we carry her up on deck under the boom. She suffers inevitable dings and bashes from launching and retrieving operations, and bumps from other dinghys at the dinghy dock. So far, I've patched a dozen or so small holes and dings in the hull. By the way, JB Weld make a product called Water Weld that is perfect for such jobs. You can even apply it under water!

Lately however, the forward trunk of the dinghy started to show major cracks and separation from the hull. This is much more serious than dings. Repairs and reinforcement were sorely needed.

We did the project at the dock at the Blackbeard Sailing Club because we could take her off Tarwathie's deck without putting it in the water. I prepared for the project by buying epoxy resin, hardener, and fiberglass tape. The major repair was to lay down fiberglass tape over all the parts of the forward trunk that are subject to strain. I also wanted to improve my repair of minor dings by giving them a coat of resin.

The picture collage shows some of the pre-repair cracks, and also our preparations for the project on the dock.

I had never done fiberglass work before, so I was a little nervous about it. I mixed up the resin and hardener according to instructions. I was supposed to have 20-25 minutes of pot life plus 90 minutes of working time before it hardened.

At first, things went smoothly. I painted on the resin, laid down the fiberglass tape, then brushed on more resin on top of that. It worked well for about 10 minutes and I though, "This is easy. No problem." Then, the pot of mixed resin began smoking and got too hot to touch. In less than 90 seconds, the whole thing had hardened in to a solid block of plastic. See the picture below. I suspect, that it happened because the outside temperature was 80 degrees instead of 70 degrees.

Anyhow, I mixed up a new and smaller batch of resin and hardener, and used that to finish the job. This batch took 2 hours to harden, even though the temperature was the same. I'm pretty sure that the ratio of resin to hardener was 5:1 in both batches, so I can't explain the difference in behavior.

By evening, the epoxy had dried hard enough for us to put the dinghy back in her place under the boom on deck. She can have several days to cure before being put to use. If the repair doesn't last, I'll write about it here.