Clipper's Vera Cruise Build

Clipper's Vera Cruise Build

Saturday, April 13, 2013

Adding Floor Timbers

The last part to add to frames 5 and 6 are the plywood floor timbers. Other frames will also have these but I haven't completed assembling the other frames yet. Floor timbers are similar to gussets in that that they reinforce a joint on the frame assembly. But they also serve other functions as well.

First and foremost  they provide a mounting point on the building form for the frame when I start assembling the boat hull. They must be mounted on the frame at a precise location measured from the keel point (the bottom most portion of the frame). I had laid out these measurements on my layout board several months ago and they were used to make the parts in the first place.

These parts also serve eventually as the mounting location for the floor in the boat. And finally they provide a means of attaching the frames to the keel. They are made from thicker 3/4 inch plywood instead of the 3/8 inch plywood used for the gussets.

Now that I am assembling the frames, I needed some way to keep the frame and the floor timbers in position as I glued them together. Because of the gussets being glued to both sides of the frame, I could no longer use nails through the frame parts to hold the assembly in position.

The solution was actually quite simple. I first lined up the frame assembly with the chine and sheer points on the layout board and then used small nails at the outside edges to keep it from moving around. These nails were driven into the layout board but not into the frame parts. Then I nailed two small pieces of 2 by 4 lumber on the line where the floor timber must line up to. I could then simply butt the floor timber against these when I was ready to glue it down.

The floor timbers are attached using epoxy  and screws rather than boat nails. The screws are silicon bronze wood screws which I had previously acquired from Glen L Marine. After marking the floor timber with lines indicating where the underlying frame parts are, I laid out the locations for the screws. I wanted to insure that the screws had a good bite inside the pilot hole so I purchased a special tapered drill bit made especially for wood screws. They make these for different diameter wood screws but I found that I needed to use 2 sizes smaller in order to leave enough wood for the screw to bite into.

I had to search around for these drill bits because the local big box home stores don't carry them, nor did any of the other hardware stores. I finally found them at a local Woodcraft store here in Austin. Just a side note, if you're into woodworking, that store has a fine selection of quality woodworking tools as well as speciality woods.

Anyway, after applying the epoxy to both parts, I placed the floor timber into position and making sure to keep it in the correct position, drilled one pilot hole and installed one screw. I did this for one more screw, and then drilled all the remaining pilot holes and installed all the remaining screws.

Then I cleaned up the glue lines as best I could and covered the part with wax paper and several cinder blocks to hold it down.

Here is the floor timber for frame 5. One of the things I wanted to make sure I did was to keep the screws far enough away from the outer edge of the frame because that edge will eventually get quite a bit of material removed  when prepping for the skin. I wanted to make sure that I didn't end up having the screws too close to the final edge at that point. There will also be batten notches cut into the bottom edge and I wanted to leave room for them as well.

The next several weeks will be continuing the process of assembling the frames, gussets, and floor timbers for the remaining frames 0 through 4. The process is essentially the same as I've shown in the last several articles. It's a bit of a slow process because each glue up requires that I wait 8 hours before doing the next one. So I am only able to get a little done each day.


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