7 of the Most Impressive Icebreaker Ships and How They Work

What is so special about icebreaker ships? And what is the biggest one in the world? Let's find out.
Christopher McFadden

Shipping is a very important part of the global economy. But some of the most direct shipping routes are covered in ice for part of the year. 

Ice, as history has taught us, is one of the major hazards to merchant shipping in the regions where it forms. This is where specialized icebreaker ships play a critical role in keeping ice-prone shipping trade routes clear for the benefit of all. 


Why are icebreaker ships called "icebreakers"?

Icebreakers are specialized vessels designed to, well, break-through sea ice. They have specially designed reinforced hulls and prows that enable some of them to cut through even the thickest sea ice with ease.

These ships are critical for opening up normally inhospitable paths for other ships through ice-covered waters, thereby making them navigable. This is especially the case in polar regions, where sea ice is a perennial problem.

the icebreaker Otso
The Finnish icebreaker Otso (fore) escorting a merchant vessel (aft) through the Baltic Sea. Source: Kalle Inkinen/Wikimedia Commons

Most modern merchant vessels are designed to be able to navigate icy water in areas like the Baltic Sea, the Saint Lawrence Seaway, the Great Lakes, and such. But seasonal conditions can make it difficult for them to do so. This is where icebreakers come into their own, by clearing the way and escorting commercial vessels through these treacherous waters.

Icebreakers are also widely adopted to support research programs in polar regions. 

The term "icebreaker" normally refers to large ships, but can also be applied to smaller vessels that perform the same function. In order for a vessel to be considered an icebreaker, it must have three traits that normal ships tend to lack. 

These are: 

  • A strengthened hull - For obvious reasons, especially at the bow. The ship's hull is also usually bulkheaded in case of getting holed. 
  • An ice-clearing shape - Often they are wider at the bow (front) than the stern (rear) to open a wide channel in their wake. They will also typically have a sharp, heavily-reinforced prow. The bow typically curves upwards too to enable the ship to "ride" over ice sheets and use its weight to help break the ice. 
  • The power required to push through a body of sea ice - These ships are typically powered by a mixture of diesel-electric or nuclear-power. 

They may also have heated water jets just below the waterline, as well as air-bubbling systems to assist in weakening ice sheets. 

Icebreakers are not a new concept, and have been around for a very long time. Some historical records point to specialized ships performing a similar function back in the 11th-Century. Known as a kochi, they were used to open up sea lanes in the Arctic Ocean and Siberian rivers.

While primitive by modern standards, the basic design of these ships would inspire future ships, even to the present-day.  

icebreakers kochi
A 17th-Century example of a kochi. Source: Кузнецов/Wikimedia Commons

Modern vessels work by plowing straight into sea ice or pack ice, causing it to flex and ultimately break apart, or "riding over" the top, breaking ice under their own weight. Often, this can occur without a noticeable change in the vessel's trim (the forward and rear angle of the vessel to the water).

However, there are some occasions where broken ice can build up at the front of the ship. This can slow the ship down considerably if not dealt with.

For this reason, many modern icebreakers have a specially-designed hull shape to direct broken ice around, and under, the vessel. Such design considerations are critical to the efficacy of the ship, and also help to prevent damage to the vessel's propulsion system (propellers, shafts, etc) that could easily be damaged by sea ice. 

What thickness of ice can an icebreaker break?

How thick a body of sea ice, or pack ice, that an icebreaker can break depends on the size, design, and power of the vessel. Of course, larger versions will generally be able to cut through thicker ice than smaller ships.

icebreakers leading the way
The Russian icebreaker Krasin leading an American merchant vessel to McMurdo Station, Antarctica. Source: Struthious Bandersnatch/Wikimedia Commons

But for the sake of providing some metrics, icebreakers like the Russian 50 Let Pobedy are capable of plowing through ice sheets as thick as 16.4 feet (5 meters). Other examples, like the RV Polarstern, are capable of smashing through sea ice up to 5 feet thick (1.5 meters).

What are the coolest icebreakers in the world?

And so, without further ado, here are some of the most impressive icebreaker ships in the world. This list is far from exhaustive and is in no particular order.

1. The USCGC Mackinaw is one of the world's biggest

icebreakers mackinaw
Source: United States Coast Guard/Wikimedia Commons

The United States Coast Guard's Mackinaw (WLBB-30) is definitely one of the world's coolest ice-breaking ships. She is around 240 feet (73 meters) long and displaces around 3,407 tons

This vessel should not be confused with her predecessor of the same name, the Mackinaw WAGB-83, which was decommissioned in 2006 and is now a museum. 

This ship has a crew of 47, and 9 officers, and is capable of breaking through 32-inches (0.8 meters) of level sea ice at 3 knots, or 10-inches (0.25 meters) at 10 knots ahead. The Mackinaw can break apart 8 foot (2.4 meters) thick brash ice and is powered by two ABB Azipods coupled with a 550 HP bow thruster.

She was launched in 2005, and mainly serves in the North America Great Lakes. 

2. This Russian nuke-powered icebreaker is huge

icebreakers russian nuke ship
Source: United Shipbuilding Corporation

Yes, you read that right. Russia is currently developing a nuclear-powered icebreaking ship. Dubbed the Ural, she is planned to help clear sea ice in the Arctic circle, the ship has been commissioned by Russia's State Nuclear Agency.

She is part of series including the mighty Arktika and The Sibir, called Project 22220 (P2X40). The Ural is currently under construction by the St. Petersburg-based Baltic Shipyards, and she will be the largest icebreaker ever built when completed.

The Ural is 568 feet (173 meters) long, 111 feet (33.8 meters) wide, and is equipped with two nuclear reactors capable of kicking out an eye-watering 350 MW of energy. This should give her enough power to smash her way through 9-foot (2.8 meters) thick ice sheets.

3. Arktika is widely considered the world's biggest icebreaker in service

icebreakers arktika
Source: Hanko/Wikimedia Commons

Since we've mentioned her sister ship the Ural, it is only fair to also talk about the Arktika. Recently completing her maiden Arctic voyage earlier this year, she is currently the largest icebreaking ship in the world.

The first of the Arktika-class heavy-icebreakers, she is more than 568 feet (173 meters long), 111 feet (34 meters) wide, and is claimed to be capable of smashing through ice sheets as thick as 9.1 feet (2.8 meters). According to some sources, Russia plans on creating a fleet of 13 similar ships over the next decade, or so. 

Like her sisters, the Arktika is power by a RITM-200 twin-reactor nuclear powerplant with 175 MW capacity. This gives her a cruising speed of 22 knots.

4. The United States Coast Guard's Polar-Class USCGC Polar Sea icebreaker is very impressive

icebreakers polar star
Polar Sea with her sister ship Polar Star. Source: Dmcdevit/Wikimedia Commons

Commissioned in 1977, The USCGC Polar Sea (WAGB-11) is one of the world's most powerful, non-nuclear icebreaker ships. Part of the US's Polar-class of icebreakers, she features a diesel-electric and mechanical propulsion system that includes six diesel engines and three gas turbines, producing up to 13,000 kW and 45,000 kW respectively.

She weighs in at just over 13,000 tons, is almost 400 feet (122 meters) long, and is capable of cutting through 6 ft (1.8 meters) of ice at 3 knots ahead. The Polar Sea is crewed by 102 people,  24 officers, and 20 chief petty officers.

She mainly serves as a scientific research platform and has specialized onboard laboratories for various scientific disciplines. 

5. RV Polarstern is another impressive icebreaker

icebreakers RV Polarstern
Source: Hannes Grobe/Wikimedia Commons

Another research-based icebreaker, the RV Polarstern was first commissioned in 1982. Primarily used by the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, she has a double-hull design and a length of 387 feet (118 meters).

The RV Polarstern is powered by four engines, each producing 20,000 HP and enabling the ship to reach 16 knots in open water. She can operate in temperatures as low as -58 degrees Fahrengheit (-50 degrees Celsius) and is capable of breaking through 5-foot (1.5 meters) thick ice. 

6. The CCGS Louis S. St-Laurent is an older, yet still very capable icebreaker

icebreakers Louis S. St-Laurent
Source: Verne Equinox/Wikimedia Commons

The Canadian CCGS Louis S. St-Laurent was first built in 1969, but recently underwent an extensive and costly modernization and refit in the late-1980s. During the works, she was lengthened and had new propulsion and navigational system installed.

She has a total length of 393 feet (120 meters). In 1994, she was the first North American surface vessel to reach the North Pole. Louis S. St-Laurent has a very efficient icebreaking system and has a displacement of around 11,440 tonnes

She is named after a former Canadian President, and is classified as a "Heavy Arctic Icebreaker". 

7. The 50 Let Pobedy (50 Years Since Victory) is another of the world's most impressive icebreakers

icebreakers 50 let pobedy
Source: tupsumato/YouTube

And lastly, but by no means least, the 50 Let Pobedy, meaning "50 years since victory" in Russian, is one of the world's biggest icebreaking ships. Sister to the equally impressive NS Yamal, both are older series Arktika-class (not the newer series described above) nuclear-powered icebreakers. 


She is 525-feet (160 meters) long and has a gross tonnage of just under 23,500. Construction commenced in 1989, but the ship's construction was abandoned during the 1990s after the fall of the Soviet Union.

She was finally finished in 2003, and she made her maiden voyage in 2007. She is so big that she is able to break up ice up to 16.4 feet (5 meters) thick. The ship is powered by two nuclear reactors and can travel at a top sped of 21.6 knots in open water. 

So, next time you are struggling to think of a way to start a conversation—in need of an icebreaker if you will—why not bring up the subject of icebreaker ships? Who knows where the conversation will lead. 

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