Thursday, January 2, 2014

Side planking? Well, almost...

Happy New Year to you! Last fall, I’d made it my goal to have at least one side of the Utility fully planked by the end of the year. I didn’t quite make that goal, but I’m close.

Over the Christmas holiday season, I made incremental progress on the boat. I trimmed off the aft ends of the side planks, where they extended past the transom. This was largely done sanding it by hand to avoid splintering the Meranti plywood... something Meranti is a little prone to doing, although not as badly as I’d thought. Now I’ve got a nice, flat surface on which to add a layer of the 1/4” Meranti on top of the 3/4” Douglas Fir plywood transom. The goal is to have matching, bright-finished transom and foredeck.

The transom; sanded & ready for a layer of 1/4” Meranti.

Starboard plank at the transom.

I also did enough rough fitting / shaping of the forward starboard side plank to use it as a template to mark and cut the plank for the port side. That plank is now temporarily clamped into position.

The next step was to fit the butt block on the starboard side, in preparation for attaching the forward plank.

I started by cutting a 9 x 19 inch piece of the 1/4” Meranti. The 9” width was to allow for a 4.5” overlap on either side of the butt joint of the planking. The 19” height was the general distance between the chine and sheer at the location of the butt joint. The problem is, the chine and sheer are not parallel, so my rectangular piece had to be trimmed to fit.

I marked and drew the centerline on the butt block, and held it in position with one hand. With the other, I marked the location of the chine and sheer onto the butt block. Then, drawing a line between these marks gave me the trim lines to cut in order to fit the butt block into position.

Next, I used one of the reversible Irwin clamps as a spreader bar to press the butt block into position, matching the curve of the aft plank. Then I marked and drilled two rows of offset holes, spaced approximately 2” apart, and screwed the butt block into position with 3/4” silicon bronze screws.

Fitting the butt block into position. Note the spreader bar pushing the butt block into the curvature of the aft plank.

Finally, on New Year’s Eve, I disassembled the butt block, coated the mating surfaces with epoxy, and put it back together. Cold temperatures led to a rather slow curing of the epoxy, which had me concerned as the last minutes of 2013 ticked away. However, I was happy to find the next morning that the epoxy had cured perfectly well.

NOW I can finally get around to attaching that forward starboard plank.

Butt block after being epoxied into position.

The 3/4” screws were a little longer than needed. I’ll have to sand all these ends off later.

Fitting the forward plank into the butt joint with the aft plank.


  1. Looking great Mike. I'm curious how the butt block curvature worked out. I've been wondering about this very same thing as I get closer to this point on my build. I was thinking I was going to have to steam form the panel first to avoid a flat spot. But your approach is much simpler. From the photos, it appears to have maintained the curve.

    Thanks for posting the update.

  2. Hi Carl! The butt block curvature worked out very well by using the spreader bar. The trick is to extend the spreader bar "just enough" to press the butt block into the installed plank.

    Also, when I added the epoxy, I once again held the butt block into position with the spreader bar while I drove the screws back in. I'm thinking that the curvature of the 1/4" plywood vs the pre-tapped holes was a big reason why so many of the screws got cross-threaded. In any case, I removed the spreader bar before the epoxy cured, and the butt block held its curvature just fine.

    I have begun driving screws into the forward side of the butt block now, and I'm very happy with how well the forward plank is matching the curvature of the aft plank. It's working out just as I had hoped.