rudder size for long keel 50ft WLL

[ongolo]

Hi all,

I am trying to find any info related to rudder size in percentage or whatever relationship to the underwater profile/ lateral resistance, is used.

The rudder is transom hung, but not directly onto the keel, there is a large opening for the prop and the rudder sits quite far back for better leverage to turn, the lower bearing being on an extention of the keel about 800mm from the dead wood ( -steel?)

Initially, I had made a plate ruder, it was one of these times :I got to finish this before I go away" , then I decided to give it a Nac0000 profile and overed the plate rudder with Iroko.

Now I have decided to go from a 45mm shaft to a 60mm shaft, larger flanges etc., because I might go down to Antartica.

The rudder is balanced about 20/80 the rigg is a Gaff schooner with only 120sqm (narrow hull).

Any Opinion most welcome. Thank you.

regards ongolo