Oh, right. I’m modeling the Sultana replica, which has a diesel engine. So I need a cutout in the rudder.
After looking at some reference pictures, I tried creating the cutout, which is roughly elliptical. It didn’t look quite right.
Here is a screencap, cropped and flipped horizontally, from the YouTube video “Sultana Haul Out”.
I see what’s wrong now. On the replica, the rudder has been extended back to make up for area lost to the cutout. As a result, the back edge is nearly vertical. Also, another detail is that the bottom edge of the rudder is higher than the bottom of the keel. And a little bite will need to be taken out of the sternpost.
(Also interesting is that, in 2013 when this was recorded, the Sultana’s hull was painted red below the water line. It was all white when launched. I don’t know when the red color was added and whether or not it’s still like that. I have noticed other changes in the paint job as well.)
Here is the revised rudder. The Schooner Sultana book says that the prop is 32 inches in diameter. At 1:64 scale, that’s 12.7mm. I checked and the cutout is large enough.