The aft deck zigzag floor boxes are looking very nice. Next I need to cut and fit some pretty 1/4″ ribbon-stripe mahogany plywood to go across the transom and hide that ugly spray foam insulation.
First, I broke down the 4×8 1/4″ plywood panels into manageable sizes
I’ll need three panels to span the transom. I considered going with two panels joined at the centerline, but that would take more effort to get a good fit along the 3D curve of the deck and 2D curve of the top of the transom. It’s easier to pull off with shorter panels.
First trial fit
I marked off the bottom edge to match the curved deck. The technique I use to match the curve is to press the panel into position, use my fingers as a sort of tri-pod while my thumb holds a mechanical pencil at the bottom right corner of the panel, which is highest away from the deck. Then I pull my hand along the deck, which curves up in this case. I keep my hand in the same position as I move it across the bottom of the panel. By the time I get to the left side of the panel, there’s a pencil line all across the bottom that matches the curve of the deck. I usually check my work by measuring the height of the gap on the right side with the height of the pencil mark on the left. If they’re roughly equal, I’m done.
This might make more sense in a video…
My Makita jigsaw quickly removed the material on the bottom edge to match the deck curve
When cutting fancy plywood, always make sure you set the orbital feature of your jigsaw to zero. It takes longer to cut but leaves a nicer edge and generally no tear-out.
Next, I marked off and rough-cut the corner where it will join to the zigzag floor box
Looks good. Time to mark off the top
Getting closer to the final size
I don’t know how the pros do it, so my general approach is to rough-cut first, then make additional cuts as needed to get the final fit. That’s especially necessary on 3D curving panels, where what looks like a straight line in 3D ends up usually being a curved line when the panel is flat.
Getting closer
Next, I trimmed a bit of a wedge off from the top right corner to the bottom, which closed the gap you can see at the bottom of the panel in the picture above.
That’s nice fit
Next, I marked off the step-through cutout. I also left plenty of material there, because I need to make some mahogany pieces to fill the gap between the mahogany plywood and the aluminum transom.
Nice!
I need a vertical mahogany cleat here for the panel edge to but up against
Just like that…
One panel fitted, two to go
Panel 2 pressed in place at the top and gently screwed in at the bottom
Ready to cut the deck curve
I only had to remove a bit of curved material for this center panel
Since I knew I was only removing a small amount of material to match the deck curve, I rough-cut the top at the same time.
Nice!
3rd panel with the top and bottom edges cut to match the deck and transom curves
First, align the pencil with the lower edge of the panel, where there’s a gap…
then run your hand up the panel you’re fitting against, marking off a line to the top, keeping your fingers in the same relative position from top to bottom
Rough cut the corner for the zigzag box
I then marked the top edge for the final cut
Done!
I’m holding off on making the final width cut on the starboard transom panel because I first want to make the mahogany pieces to fill the gap at the transom step-through. Once I know the port side panel is exactly where it needs to be relative to the step-through, I’ll do the final fitting on the center and starboard side panels. But first, I need to dig into my 8/4 mahogany lumber stash and make some sawdust.
Next up in our 1969 Chris Craft Roamer 46 Refit: Transom Step-through Mahogany Filler Pieces
1969chriscraftroamer46 