Tugboat

Fleet tug USS Tawasa (1,255 tons, 205 ft) which towed a nuclear depth charge as it was detonated in Operation Wigwam in 1955

Seagoing tugs (deep-sea tugs or ocean tugboats) fall into four basic categories:

1. The standard seagoing tug with model bow that tows by way of a wire cable or on a rope hawser. These are known in the industry as "rope boats" or "wire boats."
2. The "notch tug" can be secured in a notch at the stern of a specially designed barge, effectively making a combination ship. This configuration is dangerous to use with a barge that is "in ballast" (no cargo) or in a head- or following sea. Therefore, "notch tugs" are usually built with a towing winch. With this configuration, the barge being pushed might approach the size of a small ship, with the interaction of the water flow allowing a higher speed with a minimal increase in power required or fuel consumption.
3. The "integral unit", or "integrated tug and barge" (ITB), comprises specially designed vessels that lock together in such a rigid and strong method as to be certified as such by authorities (classification societies) such as the American Bureau of Shipping, Lloyd's Register of Shipping, Indian Register of Shipping, Det Norske Veritas or several others. These units stay combined under virtually any sea conditions and the tugs usually have poor sea-keeping designs for navigation without their barges attached. Vessels in this category are legally considered to be ships rather than tugboats and barges must be staffed accordingly. These vessels must show navigation lights compliant with those required of ships rather than those required of tugboats and vessels undertow.
4. "Articulated tug and barge" (ATB) units also utilize mechanical means to connect to their barges. The tug slips into a notch in the stern and is attached by a hinged connection, becoming an articulated vehicle. ATBs generally utilize Intercon and Bludworth connecting systems. ATBs are generally staffed as a large tugboat, with between seven and nine crew members. The typical American ATB displays navigational lights of a towing vessel pushing ahead, as described in the 1972 ColRegs.

Svitzer Tyr, a Danish tugboat, built in China in 2011, pictured in 2018 in Ystad harbour

Compared to seagoing tugboats, harbour tugboats are generally smaller and their width-to-length ratio is often higher, due to the need for a lower draught. In smaller harbours these are often also termed lunch bucket boats, because they are only manned when needed and only at a minimum (captain and deckhand), thus the crew will bring their own lunch with them.[2] The number of tugboats in a harbour varies with the harbour infrastructure and the types of tugboats. Things to take into consideration include ships with/without bow thrusters and forces like wind, current and waves and types of ship (e.g. in some countries there is a requirement for certain numbers and sizes of tugboats for port operations with gas tankers).[3]

River tug pushing a log raft in British Columbia near Vancouver (May 2012)

River tugs are also referred to as towboats or pushboats. Their hull designs would make open ocean operations dangerous. River tugs usually do not have any significant hawser or winch. Their hulls feature a flat front or bow to line up with the rectangular stern of the barge, often with large pushing knees.

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-to-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.

The cycloidal propeller is a circular plate mounted on the underside of the hull, rotating around a vertical axis with a circular array of vertical blades (in the shape of hydrofoils) that protrude out of the bottom of the ship. Each blade can rotate itself around a vertical axis. The internal mechanism changes the angle of attack of the blades in sync with the rotation of the plate, so that each blade can provide thrust in any direction, similar to the collective pitch control and cyclic in a helicopter.

• 
  The head tractor gets a heaving line from the container ship
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  The bow line with messenger is taken from the container ship
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  The stern line is passed from the rear tractor
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  A crew member of the container ship takes the stern line and fastens it
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  The stern tow line is fixed to the container ship Manila Express, the drag is started

Vintage tugboat races have been held annually in Olympia, Washington since 1974 during the Olympia Harbor Days Maritime Festival. Tugboat races are held annually on Elliott Bay in Seattle,[11] on the Hudson River at the New York Tugboat Race,[12] the Detroit River,[13] and the Great Tugboat Race and Parade on the St. Mary's River.[14]

South African Naval tugs perform a "ballet" when welcoming a new member of the fleet.

Since 1980, an annual tugboat ballet has been held in Hamburg harbour on the occasion of the festival commemorating the anniversary of the establishment of a port in Hamburg. On a weekend in May, eight tugboats perform choreographed movements for about an hour to the tunes of waltz and other sorts of dance music.[15]

The Tugboat Roundup is a gathering of tugboats and other vessels in celebration of maritime industry. The Waterford Tugboat Roundup It is held in the late summer at the confluence of the Hudson and Mohawk Rivers in Waterford, New York. The tugs featured are river tugs and other tugs re-purposed to serve on the New York State Canal System.[16]

Theodore Tugboat, the titular hero of a children's show, was popular enough that a fullsize replica was constructed

To date, there have been four children's shows revolving around anthropomorphic tugboats.

• In the late 1980s, 13 episodes were made of TUGS, a series depicting the life of tugboats in the 1920s.
• An American adaptation using edited footage from Tugs followed: Salty's Lighthouse.
• In the 1975's Soviet short animation musical film В порту/ In the sea port a tugboat sang a song: "Through a harbour area"
• One of the creators of Tugs went on to direct Theodore Tugboat.
• Animated preschool series Toot the Tiny Tugboat started broadcasting on Channel 5 Milkshake! in 2014 and on Cartoonito in 2015, with a Welsh-language version airing on S4C Cyw.

"Tugger" is a tugboat in the animated series South Park. He appears in the episode "The New Terrance and Phillip Movie Trailer" as a sidekick for Russell Crowe in a fictitious television series entitled Fightin' Round The World with Russell Crowe. Tugger follows Crowe as he engages various people in physical conflicts, providing emotional support and comic relief. At one point Tugger even attempts to commit suicide, upon being forced to hear Russell Crowe's new musical composition.

(Alphabetical by author)

• The children's book Scuffy the Tugboat, written by Gertrude Crampton and illustrated by Tibor Gergely and first published in 1946 as part of the Little Golden Books series, follows the adventures of a young toy tugboat who seeks a life beyond the confines of a tub inside his owner's toy store.
• The Dutch writer Jan de Hartog wrote numerous nautical novels, first in Dutch, then in English.
  • The novel Hollands Glorie, written prior to World War II, was made into a Dutch miniseries in 1978 and concerned the dangers faced by the crews of Dutch salvage tugs.[17][18]
  • The novella Stella, concerning the dangers faced by the captains of rescue tugs in the English Channel during World War II, was made into a film entitled The Key in 1958.[19]
  • The novel The Captain (1967), about the captain of a rescue tug during a Murmansk Convoy, sold over a million copies.[20]
  • Its 1986 sequel, The Commodore, features the narrator captaining a fleet of tugs in peace-time.
• Little Toot (1939), written and illustrated by Hardie Gramatky, is a children's story of an anthropomorphic tugboat child, who wants to help tow ships in a harbour near Hoboken. He's rejected by the tugboat community and dejectedly drifts out to sea, where he accidentally discovers a shipwrecked liner and a chance to prove his worth. This story was animated as part of the Disney movie Melody Time.
• Farley Mowat's book The Grey Seas Under tells the tale of a legendary North Atlantic salvage tug, the Foundation Franklin. He later wrote The Serpent's Coil, which also deals with salvage tugs in the North Atlantic.