Tugboats: A Maritime Workhorse

An enormous tanker or cargo ship, pulled along by a boat a fraction of its size. Impressive as it is, such a sight is common in many ports and channels around the world. Those tiny boats are tugboats, the workhorses of the maritime world. Those enormous cargo ships could never dock in port by themselves as they are too cumbersome to execute the required fine manoeuvres. However, manoeuvring large ships is not all tugs do. They are multitalented and have performed many roles from their earliest days to today.

Cargo ship at Victoria Quay, 2013. Photograph by Gnangarra. , CC BY 2.5 AU, https://commons.wikimedia.org/wiki/File:Victoria_Quay_gnangarra-18.jpg, via Wikimedia Commons

Historically, the role of a tug was fulfilled by living beings. A draft animal or a team of people on shore either pulled a barge along by rope, or were physically tied to it. A rotary mechanism attached to a tow rope, called a capstan, could also be used. An experienced captain could use it to dock if they had judged the tide and wind correctly1. If all else failed, the ship would drop anchor and goods could be ferried ashore with small boats. With the advent of the steam engine, however, the tugboat made this work obsolete. Indeed, modern tugs owe their entire existence to steam; the first ever tugboat was also the second steam powered craft ever built. This was the Charlotte Dundas, which began service in 1801 for use on the Forth and Clyde Canal in Scotland2. 

Charlotte Dundas cross section showing steam engine. From the collection of Museums Victoria. https://commons.wikimedia.org/wiki/File:Drawing_-_Steam_Vessel,_William_Symington,_1800.jpg

However, the technology did not become popular due to fear that the boat’s paddle wheel would erode the banks, and Charlotte Dundas was scrapped a few years later. Nevertheless, the idea stuck around. A second tugboat, the Aaron Manby was launched in the Severn in the UK in 18193. The technology would spread and be adopted in New York harbour, with the John W. Griffiths being used in the East River to tow and help with the manoeuvring of larger ships4. 1836 saw the Norwich come into service on the Hudson, serving another purpose tugs still do today: as an icebreaker. Many of these, including Norwich, were converted passenger boats5.

All of these tugs ran on coal-fired steam engines, but by the early 20^th century, diesel engines began to come into use6. Iron and steel hulls replaced wooden ones for even more strength. Many of the old steam powered tugs were converted to an internal combustion engine. A good example of this was the Koos No.2 in Oregon, which was fitted with a Cummins V-12 marine diesel engine in 1958, that served her for 30 years before her retirement in 19877.

Diesel engines are still used to this day. However, the tugboat has not escaped conversations around the climate impact of shipping. Hybrid or even fully electric tugs have been proposed as a clean, efficient solution. Tugboats only need to operate at full capacity when they are towing, and they operate in coastal waters only, making them ideal for hybrid engines8. Full electric tugs also exist around the world. Europe’s first was launched in May 2025 in the port of Antwerp9. It is yet to be seen if this will become the norm.

Throughout the years, one thing has been true about tugboats: their beating heart is its powerful engine.

US Army Corps of Engineers Tugboat Billmaier’s 2150 HP engine. Pete Markham from Loretto, USA, CC BY-SA 2.0, Pete Markham from Loretto, USA, CC BY-SA 2.0, via Wikimedia Commons https://commons.wikimedia.org/wiki/File:Tugboat_Billmaier_Main_Engine_(2885827751).jpg

On average, a tugboat’s engine can be between 680 and 3,400 horsepower, with some larger, deep-sea tugboats exceeding 27,000 horsepower10. Moreover, a tugboat is almost all entirely engine, with few if any extraneous pieces in its design that do not aid its purpose of being the strongest craft around11. Today’s tugs can generally be divided into three categories: conventional tugs, tractor tugs and azimuthal stern drives, or ASD for short12. Conventional tugs are less manoeuvrable, as they have fixed propellers, but they are still useful for smaller tasks. Tractor tugs are more suited for towing, being stronger and having a large winch attached to them. ASD tugboats are the most sophisticated of them all, as they are the most advanced and most manoeuvrable. Their engine is connected to hydraulic or electric propellers that can turn 360 degrees independent of each other13, giving them a wide range of motion. A tug like this can even move backwards when slowing or stopping14. Furthermore, the propeller action can be automated, giving it even finer motor control than any pilot can do. It is a highly optimised and sophisticated piece of engineering suited for many tasks.

The role of a tugboat is surprisingly varied. Their primary use is helping manoeuvre large craft such as tankers, cargo ships or barges through ports, channel and harbours, whether through towing or pushing. Both functional ships and salvaged ships can be helped along into port by a tug. Not just ships: some of the most powerful ocean-going tugs can tow heavy equipment and even oil rigs into position15. To give an idea of their strength and ability, in 2012, a team of five tugs transported a massive 160,000 ton oil platform into position in the Russian Pacific16. Large ships and equipment need the help of tugs: their size already makes them ungainly, but at low speeds their rudders become less effective due to less water flowing over them17. In tight spaces like ports, where it is easy to bump into something, the small, agile tug is needed to guide them and help them make the difficult turns that docking requires. Ships carrying dangerous cargo, such as oil tankers, require a tugboat to help escort them, or assist them should they come into distress18. Tugboats are essential to maritime port safety and preventing disasters.

However, the uses of a tugboat do not stop there. As well as shifting cargo ships, tugboats serve as firefighting and rescue craft19. They have been essential in firefighting operations, with specialised tugs equipped with powerful hoses for such a purpose20. In a port or dealing with tankers, where a fire would be catastrophic, this role is crucial. A tug’s power and strong hull also makes it perfect for ice breaking. The Norwich demonstrated this in 1836. Other uncommon but not unheard of uses for a tugboat are patrol boats, crew transports, or even survey and research vessels21. There have also been a few novel, more light-hearted uses for the tug. Every year for its anniversary, the port of Hamburg hosts a “tugboat ballet”, an event where the port’s tugboats show off their manoeuvrability by “dancing” in formation in time to classical music22. While whimsical, this highlights the extreme versatility, agility, and manoeuvrability of the tugboat. It truly is a universal workhorse, without them the world’s shipping would grind to a halt.

Tugboats lined up for the tugboat ballet in Hamburg, 2016. Photo by Buonasera. https://commons.wikimedia.org/wiki/File:Hamburger_Hafengeburtstag_2016_-_Aufstellung_zum_Schlepperballett_-_Nahaufnahme.jpg

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Hayton, Mark. “Marine Electrification Is the Future: A Tugboat Case Study”. Proceedings of PIANC Smart Rivers 2022. Edited by Yun Li et al. Lecture Notes in Civil Engineering, Springer Nature Singapore, 2023, pp. 868–879, https://doi.org/10.1007/978-981-19-6138-0_77.

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Quandt, Adam. “Benny Cenac of Houma and the History of Tugboats.” Boating Industry, 17 June 2020, boatingindustry.com/features/2020/06/17/benny-cenac-of-houma-and-the-history-of-tugboats/.

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