Well I believe that is obvious, the transom will be additionally reinforced and insulated for sound on the inside. The rudder and gudgeon, I think, should be strong enough for the job.You realize that all of the motive force will be transferred to the hul through the rudder post.
There's a reason airplane wings don't have sharp edges on the leading edge of their wings. A sharp edge will try to change the direction of the fluid too quickly, causing a stall.The only thing I see is that the leading edge of the rudder is sharp.. It probably should mimic the radius of the original (maybe something like 1/2 or 7/16 radius).. The problem you may see is it will stall much quicker than if it had a bit of radius on the leading edge.
To be honest I didn’t want to invest too much time before I knew it would work. That being said the drag factor is minimal and similar to the original saildrive.I guess my only question would be : What is the advantage of having the 95+, or so, pounds dragging through the water full time? Wouldn’t it be better to raise it up and out of the water?
I believe Seaward did that on one or two of their smaller models. Small boat with a small motor, probably 5hp max. Never sailed one but they probably worked ok when motoring. When sailing and heeled over though, the weight of the ob would pull the rudder to leeward. Looked like a bad idea to me.I've never seen that done with an outboard and I can't really imagine it working. First problem is that you'll have a huge weight on the side of the rudder, and when the boat heels it's going to want to swing strongly. The other problem is that all the torque of the engine will be trying to turn the rudder when you want to go straight, which seems like it would be a big fight to counter.