Turning isn't the big issue, if the rudder wasn't there at all the boat would tend to go in circles because the prop acts like a big paddle wheel. A properly set up boat usually doesn't require alot of force to turn, but rather the strength is needed to straighten the boat out, especially a rigger or scale as the servo must overcome the not only the tail end coming around from prop walk but that big meat cleaver called a turn fin hanging off the right side as well. Also in the bigger nitro outriggers & gas boats often a standard case size servo struggles to get the job done over a larger quarter scale servo even though the standard size is rated at the same, or even more torque. Why? Simple, the quarter scale servos have the advantage of the bigger gearset which yields more leverage. I can't tell you how many times I've proved this point and still continue doing it to this day. B)
