Tugs

A tug, or tugboat, is a compact, powerful vessel designed to move larger ships by towing or pushing them, or by guiding them through confined waters. Tugs operate in ports, inland waterways, and offshore fields, and are essential for docking, undocking, mooring, and towage of barges or ships.

Most tugs are purpose-built for specific roles. Harbor tugs assist ships in confined harbor channels and at berths. Ocean-going or offshore tugs move ships between ports and tow larger vessels or floating structures. Escort and icebreaking tugs provide protection and assistance in challenging conditions. Firefighting and rescue tugs may carry equipment to combat shipboard fires or perform search-and-rescue tasks.

Propulsion and gear: Modern tugs are typically diesel-powered and may use azimuth thrusters or conventional fixed propellers with bow or stern thrusters to achieve high maneuverability. They may carry more than one engine and power source, and some use electric or hybrid propulsion. Towing gear includes towing winches, capstans, heavy mooring lines, and strong towing hooks. Fenders and rub rails protect the hulls of both the tug and the vessel being moved. Bollard pull is the standard measure of a tug's towing power.

Operation and crew: Tugs work under the supervision of harbor pilots or vessel masters. Crews include a master or captain, engineer, deckhands, and a bosun, with additional specialists on larger vessels. Training emphasizes maneuvering skills, line handling, and safety.

History and development: The first steam-powered tugs appeared in the 19th century, with diesel-powered, highly maneuverable vessels becoming dominant in the mid-20th century. Advances in propulsion, such as azimuth thrusters and dynamic positioning, have expanded offshore and salvage capabilities.