hi wor Billy
Included a 'scribble' to try and explain - looking at Dicky's picture, which is the clearest of the two - we can make out a rudder support strip which is fastened to the lowermost SKEG. Whether this rudder support strip runs further forward and is welded to the main hull, I am unsure. However, if it was me building this - I would make a collar/tube which fits outside of the propeller shaft and to this collar - I would solder two vertical brass strip supports. One of these supports which is marked number 1, would go through the main hull and it would be bonded to the Keel. The other support which is numbered, 2, would go to the outermost of the SKEG and be soldered to the brass rudder support strip. This whole assembly would then be clad in either balsa wood or plywood or come to that it could even be clad in plastic and shaped to an aerofoil shape.
I hope the scribble is of some help.
aye
john e
bluebird