A Long time ago, when I was a young Captain of a Ocean Tug, I learned the same trick to tow in parallel or go alonside with full control. If you lead a spring from a winch ( like a jibsheet winch), forward to a cleat close to the boats pivot point then aft, you can toss it to the dock and use either engine power or the winch to bring you snugly alongside, either a moving vessel or a dock. As long as you are close to the pivot point it will always work, and always keep you under control.