Harbor Tug

A tug that berths, unberths, and maneuvers ships inside port limits and assists in confined channels. Modern harbor tugs use azimuth stern drive (ASD) or tractor (Voith-Schneider or forward azimuth) propulsion for full thrust in any direction, working in direct (push and pull) and indirect (lift) towing modes. Performance is rated by bollard pull, commonly 30 to 90 tonnes, measured to the ABS or class bollard pull procedure. They carry firefighting (FiFi) capability and a render-recovery winch, and operate within a port rather than on coastal or ocean passages.