Tugboat

The tugboat Woona in Sydney Harbour, Australia
Fleet tug USS Tawasa (1,255 tons, 205 ft) which towed a nuclear depth charge as it was detonated in Operation Wigwam in 1955.

A tug (tugboat) is a boat or ship that maneuvers vessels by pushing or towing them. Tugs move vessels that either should not move by themselves, such as ships in a crowded harbor or a narrow canal, [1] or those that cannot move by themselves, such as barges, disabled ships, log rafts, or oil platforms. Tugboats are powerful for their size and strongly built, and some are ocean-going. Some tugboats serve as icebreakers or salvage boats. Early tugboats had steam engines, but today most have diesel engines. Many tugboats have firefighting monitors, allowing them to assist in firefighting, especially in harbors.

Types

Swedish harbour tug Svitzer Freja in tug-operation (3,600 kW / 453  gross register tons (GRT))
Dutch river tugboat "Mascotte II"
German harbour-tug and DDR quick-freighter Karl Marx at Rostock harbour

Deep-sea

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

  1. The standard seagoing tug with model bow that tows its "payload" on a hawser.
  2. The "notch tug" which can be secured in a notch at the stern of a specially designed barge, effectively making the combination a ship. This configuration is dangerous to use with a barge which 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 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 under tow.
  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. 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 operating on the east coast customarily displays navigational lights of a towing vessel pushing ahead, as described in the 1972 ColRegs.

Harbour

San Francisco harbor tractor tug "Delta Deanna"

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 includes 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 boat pushing a log raft near Vancouver (May 2012)

River tugs are also referred to as towboats or pushboats. Their hull designs would make open ocean operation 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.

Other Languages
العربية: زورق قطر
azərbaycanca: Yedək gəmi
беларуская: Буксір
български: Буксир
català: Remolcador
čeština: Remorkér
dansk: Slæbebåd
eesti: Puksiir
Ελληνικά: Ρυμουλκό
español: Remolcador
Esperanto: Trenŝipo
euskara: Atoiontzi
français: Remorqueur
Gàidhlig: Bàta-slaodaidh
galego: Remolcador
hrvatski: Tegljač (brod)
Bahasa Indonesia: Kapal tunda
íslenska: Dráttarbátur
italiano: Rimorchiatore
עברית: גוררת
Lëtzebuergesch: Schlepper (Schëff)
Bahasa Melayu: Bot tunda
Nederlands: Sleepboot
日本語: タグボート
norsk: Bukserbåt
polski: Holownik
português: Rebocador
română: Remorcher
русский: Буксир
slovenčina: Remorkér
slovenščina: Ladijski vlačilec
српски / srpski: Реморкер
srpskohrvatski / српскохрватски: Remorker
suomi: Hinaaja
svenska: Bogserbåt
Türkçe: Römorkör
українська: Буксир
Tiếng Việt: Tàu kéo
ייִדיש: שלעפשיף
中文: 拖船