Hello Kortes,
I am so happy to see the construction of your tiller and the way you have made it is outstanding. If you remember, I told you that I was so inspired by your build that I looked for information and/or plans to one day build one. I did find plans and drawings for the Catharina and I did notice that the angle of the tiller may have to be changed a little bit so that it has room to clear the walls of the seating area. You are following the example of the first photo below in which the angle of the tiller is relatively straight. If you look at the second photo below of the Catharina, you will notice that the angle of the tiller is a little higher in order to clear the seating area walls. I hope that it is clear enough for you to see the difference.
Best regards and respect, Raymond