Discover

:''For the journal of digital typography, see 'TUGboat'.
:''For alternative meanings of ''tug'', see Tug (disambiguation).''

A 'tugboat', or 'tug', is a boat used to maneuver, primarily by towing or pushing, other vessels (see shipping) in harbours, over the open sea or through rivers and canals. They are also used to tow barges, disabled ships, or other equipment like towboats.

Contents

Tugboat design

Tugboats in fiction

Gallery

References

External links

Tugboat design

Tugboats are quite strong for their size. Early tugboats had steam engines; today diesel engines are used. Tugboat engines typically produce 750 to 3000 horsepower (500 to 2000 kW), but larger boats (used in deep waters) can have power ratings up to 25 000 hp (20 000 kW). The engines are often the same as those used in railroad engines, but typically drive the propeller mechanically instead of converting the engine output to power electric motors, as is common for railroad engines. For safety, tugboats' engines feature two of each critical part for redundancy.
Tugboats are highly maneuverable and various propulsion systems have been developed to increase maneuverability and increase safety. The earliest tugs were fitted with paddle wheels but these were soon replaced by propeller-driven tugs. Kort nozzles have been added to increase thrust per kW / hp. This was followed by the nozzle-rudder which omitted the need for a conventional rudder. The cycloidal propeller was developed prior to World War II but was only occasionally used in tugs because of its manoeuvrability. After World War II it was also linked to safety due to the development of the Voith Water Tractor; a tugboat configuration which could not be pulled over by its tow. In the late 1950s the Z-drive or (azimuth thruster) were developed. Although sometimes referred to as the Schottel system many brands exist: Schottel, Z-Peller, Duckpeller, Thrustmaster, Ulstein, Wärtsilä etc. The propulsion system are used on tugboats designed for tasks such as ship docking and marine construction. Conventional propeller/rudder configurations are more efficient for port-to-port towing.
The Kort nozzle is a sturdy cylindrical structure around a special propeller having minimum clearance between the propeller blades and the inner wall of the Kort nozzle. The thrust:power ratio is enhanced because the water approaches the propeller in a linear configuration and exits the nozzle the same way. The Kort nozzle is named after its inventor, but many brands exist.
A new type of tugboat has been invented in the Netherlands. The so-called carousel tug consists of a design wherein the flexibility and effectiveness of the tugboat's maneuvers is determined not by the propulsion system, but by a steel construction on deck, consisting of two steel rings. The inner ring is fixed to the ship, and the second ring rotates freely and carries a hook or winch. The ship can therefore maneuver freely and independently of the towed ship, and since the towing point rotates towards the point nearest to the towed ship, the tug can capsize only with difficulty. One prototype exists presently, but the first new tugs are expected to sail in spring 2007.

Tugboats in fiction

To date there have been two childrens's shows revolving around anthropomorphic (living) tugboats. In the 1980s 13 episodes were made of TUGS. One of the creators of that series went on to make Theodore Tugboat. On Tugs the models were able to move their heads and eyes and didn't have motors. On Theodore Tugboat, the models have motors and moving eyes. Tugboats have also been featured on Thomas and Friends however they have been reused from Tugs and have no face nor a hat.
The spaceship Nostromo of the movie ''Alien'' could be considered a tug.

Gallery

References

★ ''On Tugboats: Stories of Work and Life Aboard'' / Virginia Thorndike - Down East Books, 2004.

★ ''Under Tow: A Canadian History of Tugs and Towing'' / Donal Baird - Vanwell Publishing, 277 p., 2003 - ISBN 1551250764

External links

★ Novatug Carrousel Tug
Some pictures of tugboats and tugboat building

★ 18 m. Steel Tug Boat Dilovası pn dry dock and harbor

★ 25 m. Steel Tug Boat Dogancay on the sea

★ Huge propellers of 32 m. Steel Tug Boat Captain Emre Omur

★ Hull of 32 m. Tug Boat Sheba

★ You can find some more tugboat examples from here

★ NYC's Annual Tugboat Races