The modifications are broken into sections:
BRASS RUDDER SUPPORT
Here is a .pdf that you can print out on sticker paper
and use as a template to make your brass rudder support. Make sure
when you print it out that you go into the print options to make
sure the print job is not beind scaled to fit your page. It should
wind up being about 4.9" tall.
Robbe-U47-Rudder-Support.pdf