I found these Drawings of the rudder by Pearson in 1963 on my Google drive. I hope they help in the recent conversation.
If you purchase 5/4 honduras mahogany which will be finished at 1-1/8" thick and then fiberglass, you will end up with the 1-1/4" max thickness called out on the drawing. When sanding the wood blank, reduce thickness to account for the fiberglass skins..
Sorry, I do not know how to get these on the forum in a PDF.
Ward