Building a Wooden Jon Boat…pt.4

Today I am making some progress. I am currently waiting on an order of epoxy to arrive, so while doing that and twiddling my thumbs, I decided to build the strongback frame outside to get the boat ready to assemble. I should have prepared a little better and ordered my supplies in advance so I could work sequentially and in order. But that sometimes happens in boatbuilding, so I am jumping ahead and trying to stay busy while waiting for the UPS truck to deliver the goodies.

The strongback is just a simple temporary framework that holds the bulkheads in the proper position while the plywood is glued into place. This way you know that the frames are square to the boat centerline. Once the hull is completed the boat will be lifted off the strongback and turned over for completion of the interior and topsides. Now is the time to use a batten stick to check the frame bevels and shape as seen in the photo.

Also I have nearly completed the assembly of the transom frame. The transom is the most important part of a powerboat as it carries the weight and thrust of the outboard motor. It has to be built substantial and strong to do this. Another thing about the transom is the careful design to avoid future problems of wood rot. If you look at the various boat repair forums, the subject of transom rot and replacement ranks among the top subjects of conversation. The transom is subject to rot because this is usually the lowest point of the interior of the boat where rainwater collects and stands if not drained periodically. Also there are always several holes drilled into the transom to mount the motor and various things and the can be prone to water intrusion.

To avoid these problems it is important that you completely encapsulate the wood in epoxy and seal any drilled holes properly. A little extra effort now will pay off big dividends five years from now. After construction of this frame, I have filleted the seams with thickened epoxy and fiberglass tape for strength and to keep water out. Also it is important to keep all of the seams smooth and rounded to facilitate easy cleaning later.

Now where is that danged UPS truck?