This is the sixth video of the FRS12 how to build a boat series where we build a plywood boat. We cover installing floor supports and the outer shear bumper. This is the final step before flipping the boat over to fiberglass. These plywood boat plans and more are available for purchase, and come with full size patterns.
How to Build the Boat
We’ve installed our floor supports that are 1×1″ cypress strips. To mark their location we used a straight edge on top of the stringers and transverse frames and marked it with pencil. Then we cut our pieces to size and dry fitted them.
We notched the floor supports so the wood would take the shape easier. The notches are about 1 inch apart and half inch deep. After they were dry fitted, we pull them off, applied thickened epoxy to the back of the cypress strips, then re-installed them using screws from the outside. Don’t worry about the holes, they’ll be covered up when we glass the outside.
Then we clean off all the thickened epoxy off the top and bottom of the floor supports, so it’s easier in preparation for putting our floor down.
How to Install the Shear Bumper
Next we’ll install our shear bumper. I’ve chosen to use cypress, and mine is half inch thick by one inch tall. The first thing you want to do is dry fit the shear bumper. You’ll take the end and set it up at the stem, and without any clamps, you’ll roll it around. I like to start at the front bulk head. Then I’ll work my way back, following the top of the boat. Now that I’ve got it held in two places, I’ll come back and work my way forward.
The plywood can be wavy in an unsupported section, especially along the shear. That’s why we go ahead and install the outer shear bumper. At the front, once you secure it, you’re going to want to stand back from the boat and look at it to make sure the shear bumper is in a fair curve. Chances are, there might be a few imperfections. That’s normal, and if you need to tweak it, and sand down the top, that’s ok.
So once the shear bumper has been dry fitted, we’ll mark where it goes. We’ll pull it apart, and apply thickened epoxy, and clamp it back on. We’ll let it cure before we flip the boat over and fiberglass it.
How to Install a Stem
We installed a stem at the front of the boat to reinforce it. We cut it down to shape and glued it in with thickened epoxy. Whenever we mount a d-ring on the front of the boat, it gives us something to drill in and something for our bolts to bite into.