After a couple of hours of attacking the tiller with a little hand plane and some sand paper, this is the result. Note that the hardwood end is still oversize, other than thickness, and it will be trimmed once the rudder has been made up.
The next image shows the piece of hardwood laminated with the Huon Pine. The Pine boards are about 8 mm thick. The ‘cheeks’ of the outer boards have been cut down with the router to 3 mm, and the piece of Tassie Oak has a tenon of 8 mm thickness. The tiller is 1″ wide and tapers to 1″ x 1″ with all edges rounded over. The assembly seems very strong, and there is no flex in the tiller. Nevertheless, I might add a strip of glass tape to either side for the first 18″ or so. The tiller will get a couple of coats of epoxy for now, and it will be finished with varnish later.