Scamp bottom is expected to be almost 3300 mm long but the plywood sheets available are just 2500 mm. So, you have to joint two sheets together with epoxy. I chose a half lap scarf joint by routing 5 mm from the two sheets of 9 mm. Ratio of the join was about 8:1.
I made an epoxy mix using SP 106 product family. The mix had resin and slow hardener in the ratia 5:1 as guided by the manual. Then I mixed in microfibers and coloidal silica. Naturally I wore protective gloves and glasses and a respiratory protection mask (A2 class). After mixing around one minute I applied the resulting epoxy on the both joint surfaces and then pressed the surfaces together with weights. Cut plastic bags were used to protect wooden support planks under the joint.
The line resulting from routing resulted a bit inaccurate line that left a narrow slit between the sheets. It had to be filled, but first I lofted outline of the bottom onto the plywood.
I filled the slits (on the upper and lower sides of the sheet) with epoxy and then cut the bottom with a Japanese hand saw. The result looked pretty good, although some unpleasant sanding of epoxy was needed.