Icebreakers: Cracking Through the Cold

On land, snowploughs are used to clear snow off roads. At sea, an icebreaker serves a similar purpose: carving a free path through ice for other ships to follow. Unlike an ice-strengthened ship, these are designed explicitly with cutting ice in mind. These sturdy vessels operate in polar waters and other waterways that are frozen over during winter. They are thus essential for maritime safety in those regions and a small but key part of the overall maritime economy.

Icebreaker Stephan Jantzen in Rostock, 2010. Image by Grand Duc, Wikimedia https://en.wikipedia.org/wiki/User:Grand-Duc. https://commons.wikimedia.org/wiki/File:Icebreaker_Stephan_Jantzen_in_Stadthafen_Rostock_2010-12-28_perspective_correction-GD.jpg

People have used waterways for trading since the dawn of civilisation. However, before the Industrial Revolution, when those waters froze, until the thaw came, there was little people could do. In the 11^th century, the Pomor people of Karelia used a one- or two- mast boat called a koch to help them navigate Arctic waters. It was specially built with a belt of ice-resistant planking to help it cut through ice 1. Later, there are records of vessels helping manual labourers break ice in 14^th-century Bruges, and evidence of an iron-tipped heavy barge breaking ice on the canal between Bruges and Ghent in the 18^th century 2. However, these were limited in their use. Only in the 19^th century, with expanded global trade and the advent of steam power, do vessels designed for ice breaking began to gain traction.

The first vessel dedicated solely to this task was the modified tug Pilot, fitted with a specialised hull in 1871 to clear ice outside Kronstadt port near Saint Petersburg. Between 1871 and 1890, the United States, Sweden and Finland all saw their own icebreakers being built 3. The ice-resistant ship Bear, built in 1874, served first the US Navy then the Revenue Cutter Service around Alaska, though it was not a true icebreaker but a modified cutter 4. The first polar icebreaker was the British-built, Imperial Russian operated Yermak in 1898. It was primarily used in the Baltic 5.

Yermak in 1899, from a postcard. Photo in public domain. https://commons.wikimedia.org/wiki/File:Yermak_icebreaker.jpg

Other Arctic nations like Canada followed suit with icebreakers such as Minto and Scotia. The First World War interrupted icebreaker innovation, but after it, the newly minted Soviet Union and the recently liberated Baltic states took interest in ice breaking again. Soviet enthusiasm centred around the exploration of the Arctic as a commercial waterway for carrying goods. Their first attempt in 1933 sank, but they ordered more in 1935. With them, they opened up the North-East Passage along Siberia, which Russia still uses as a shipping route to this day 6.

Meanwhile in Sweden, the icebreaker Ymer in 1932 became notable for being the first diesel-electric icebreaker, a feature found on many current such vessels7.

Ymer in 1932. Photograph number. Fo11284A from the collections of the Naval Museum of Sweden. https://commons.wikimedia.org/wiki/File:Icebreaker_Ymer_(1932).jpg

The year 1936 was important for US icebreakers, as President Roosevelt signed an executive order directing the Coast Guard to keep up ice breaking to maintain commercial operations8. This was fulfilled in 1966, by which time all icebreaker operations in the US were managed by the Coast Guard9. An innovation in icebreaker technology came in 1957, when a nuclear-powered Soviet icebreaker, Lenin, was built. Its power source enabled it to be large, allowing it to ram ice to break it 10. However, the adaption of nuclear as fuel for icebreakers remains limited to this day. In modern times only Russia operates nuclear-powered icebreakers.

There are around 179 ships classified as icebreakers around the world as of 202411. Finland is the premier nation for icebreakers, with 80% of them designed in the country and 60% also built there12. Recently, they designed one which could break ice in any direction13, adding new capability to icebreaker technology on top of everything else this vessel can do.

Icebreakers have several key features that differentiate them from any other ship. A shallow draft and stubby profile due to their wide bows gives them a shape that is unique among vessels. They have strong, thick double hulls and reinforced bows, which are rounded instead of pointed to push ice underneath them. This way they use the ship’s weight to break ice before pushing it out behind14. Ice moving behind risks jamming up the propellers, resulting in many broken shafts. An icebreaker therefore has at least two, three or even four propellers, mounted on different parts of the stern. These attach to powerful, rapidly accelerating engines to provide power to get through ice15

Propellers of the Finnish icebreaker Voima in 1954. Suomen Laivasto 2/1954 page 27, Public domain, via Wikimedia Common. https://commons.wikimedia.org/wiki/File:Voima_bow_propellers.jpg

In addition, the vessel may also have air-bubbling systems to help move ice out of the way or heated jets of water to spray below the waterline to weaken the ice16. Contrary to popular belief, icebreakers rarely plough through ice, only doing so in the thickest ice at a crawling speed17. In modern icebreakers, standard ship features like sensors, electronic charts and AIS18 help with assessing the ice and allowing crew to keep track of whatever vessels they are escorting. Electronic charts especially are useful for crew in determining whether another ship in the ice needs their help and where it is19.

By carving paths through the ice, these ships support all sorts of operations around the world. Icebreakers provide paths for commercial vessels in winter, such as cargo ships and ferries, but also assist with scientific endeavours, provide rescue operations and assist in exploration20. They may also be used to supply remote settlements in the Arctic in winter21. Even icebreaker cruises are now available22! Yet this is only their use so far. Icebreakers have potential to do more. 

As the world warms, icebreakers may seem to be less relevant, and yet, paradoxically, they may be more needed than ever. New routes are opening around the poles, as shipping tries to navigate the Arctic, fish move north, and polar cruises become more popular23. These will need support in case of accidents, especially ruise ships, as there is a need for better risk management and international coordination to ensure safer cruise operations.24Furthermore, as the climate changes, Arctic research will be increasingly important, with nations such as China, Japan and Russia conducting scientific missions into the region for either climate study or potential resource exploration25.

Polar ice is not completely gone, so icebreakers will be needed to aid the new traffic that can travel through the North. If the Arctic shipping route is not made unsafe due to geopolitical issues, it will require a significant increase in icebreaker fleets to make it viable, even with climate warming taken into account26. Canada, whose icebreaker fleet is second largest after Russia, is hoping to add new vessels to its 16-strong cohort and replace those that are ageing27. However, icebreakers are expensive to build due to their technical requirements, with Canada expected to pay $8.5 billion for two new vessels28. Yet they and other Arctic nations clearly see the need to invest in more of these vessels, both for their current and future use. The icebreaker has come a long way and has become essential to any winter maritime operations in polar or near-polar regions. Time will tell if the number of these unique vessels will increase.

Icebreaker CCGS Des Groseilliers at work in Franklin Sound, Nunavut, Canada, 2017. Sebastian Moser, CC BY-SA 2.0, via Wikimedia Commons. https://commons.wikimedia.org/wiki/File:CCGS_Des_Groseilliers_in_Franklin_Sound.jpg

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