A rudder install doesn't have to be all that complicated for it to work well. Those used on very pretty strip built boats tend to hide the mechanics to the greatest extent possible, but it again doesn't have to be done that way. Easy enough to add a rudder having the rudder cables run across the back deck to a internal (just behind the cockpit) rudder shaft to make it easy for the peddles to turn that and thus the rudder.

Bill H.