I single hand my boats about 90% of the time AND they are small boats but have found the same thing on a 32' cutter at 20k. I just cannot seem to get into the spring line concept, I guess. It's just more to do right at the moment when I want to be on the helm, working the throttle, and shifting forward or reverse. Even for the ten years I sailed my little barge out of and into my slip with no motor I never used a spring line. Tried..but could not be happy. My preference when motoring is to learn to use the motor, the shift, the throttle to make the boat go where you want it to.

Likely heresy, I know, and on smaller boats. But IMHO....eh.