I understand the confusion because the total side panel length shown on the sidepanel drawing? indeed doesn't match the length of all the station offsets added. There must be a miscalculation somewhere ? Bernd can you comment ?
For my build I took a bit different route for the side panels. I took the numbers from the drawing 4.1. I made the panels? a bit oversize, matched them to the top of the bulkeheads, and trimmed them back flush after glueing to the bottom.?
This is a different building procedure from the one Bernd uses, and probably more work, but I didin't have the side panel drawing at that time (I was the first builder and a bit in a hurry, so the plans were not finished yet).
For the bottom plank I used the info from the drawing and that seemed to fit.
Cheers, Hans
