Yacht Thruster bow and stern thrusters are installed outside a boat’s hull, as opposed to inside a conventional thruster tunnel. This 1) makes for much easier installation 2) allows greater flexibility as to where the thrusters can be located 3) reduces noise and 4) increases run times, since the surrounding water helps keep the electric motor cool.
A single 2in-diameter hole in the hull is all that’s needed for running cables to the units, which are available in single and duplex configurations. The thrusters can be used on sailboats from 20 to 65 feet and reportedly create surprisingly little drag. From $4,700. Yacht Thruster