The front piece is shaped to match the curvature of the deck.
I marked it out from its pattern and cut it to shape.
Here I am shaping its bottom edge with a saw rasp, which turns out to be the best tool for making a concave curve.
Next I cut it to the correct width, and made the cut outs which allow the rear of the slide to pass over the companionway sill on the cabin roof.
Here I am cleaning up the cut outs in the vice with a chisel.
I drilled screw holes with the pillar drill and assembled the slide frame to check alignment, like this.
I labelled the pieces to avoid confusion on reassembly, and took the frame apart. Here are the four pieces with their labels.
The sides also need to be bevelled to match the curved top.
The bevels are marked in on these pieces.
I mark all bevels with the cutting gauge and run along the cut with a pencil to make the line clearly visible.
Here is a side piece in the vice, with its bevel being cut by the block plane.
And lastly here is the rear piece in the vice, with its bevel being cut with the jack plane.