|This is a simple rudder solution: Slap a piece of 2x4 centered
on the top edge of your stern transom, drill a hole through
it, and drop a bolt through it - you are done.
Of course, the rudder head is a fairly important component
The cheeks are simple 'C' shaped affairs made out of 3/8
plywood (I don't feel comfortable with 1/4 ply, but then,
I never tried it.)
The tiller is just a 1x2 set on edge. It runs all the way
to the end of the cheeks and is as long as you need it. I
make my rudders out of 3/4 stock (or layered ply) and sand
'em to shape, so the tiller also serves as a spacer.
I have a little strip of reinforcement 1x1 on the inner part
of the 'C' of the cheeks - again, more of a spacer than anything.
At the bottom of the 'C' I have another stump of 1x2 - this
helps distribute the force exerted on the bolt. My first attempt
at this was a 'L' shape, and the force twisted the rudder
head so much it broke at the tiller.
You'll need a 3/8 bolt at least 7" long.