Looks OK for very small power, maybe a trolling motor, but if for a trolling motor, turning and reversing is already solved with conventional trolling motors. The tiller concept with the Kitchen Rudder you show is OK, and the mechanism that brings the two submerged pieces together (I call them "cups", don't know the right actual name) can work OK, however there are healthy forces needed to keep those pieces in desired position. To that end, locking notches to hold a rudder setting would be necessary as a minimum. For anything over a couple horsepower, human strength would probably need a screw thread arrangement with a hand crank to position the two cups for reversing/maneuvering. The Kitchen rudder is useful where a reversing transmission is unavailable, but in today's world, even a simple belt drive reversing arrangement (with a conventional rudder) would be available for about the same expense, and with far better propulsion efficiency available in the conventional arrangement.