I rented a 42 ft. canal boat on the Erie Canal for a week and it came with a bow thruster. Using just the motor and rudder the boat behaved sort of like a full keel sailboat under power. What a cool thing that thruster was! You can even make the boat go sideways. Getting into and out of small places was easy as pie. I cant imagine forking out the money it would take to put one on a sailboat but if I had a boat with one on it I sure as hell wouldnt take it out.