Instead of a dive plane why not put props on the top, bottom, and sides of the engine nacelles. Put them on the front and rear pointing up, down and to the side. That way you can move the sub in all three planes with out having to move foward. Just take a look at any deep submersable to see what I mean. Just a thought, since you already made a prop it would be easier to clone the prop and move it around than to make the dive plane, position it and then make a rudder or two as well. Good looking sub, by the way. Keep up the good work.