When you let go of the controls a tank stops, end of story.
With a boat it requires continuous input from the operator as wind and maybe currents play a part in what the boat is doing. I find it incredibly interesting manoeuvring a boat and getting it to dock just where you want it. When a single screw boat goes into reverse the rudder usually has very little effect however the prop will always 'walk' the back end one way or another making it always easier to turn the boat one way or another when it is confined.
With a twin screw set up the props will be contra-rotating so you do not have this benefit. If you do not have independant props manoeuvring a twin screw can be more difficult than a single screw boat.
As I said a tank stops!!!!!! |