The basics: Icebreaker ships (icebreakers) have a unique sloping bow shape and powerful engines that push the bow onto the ice. The ship’s weight, when combined with the force from the engines, exerts a downward pressure on the ice, causing it to crack and break. This creates a clear pathway for the ship. Icebreakers have solid, reinforced hulls that can contact thick sheets of sea ice at speed without damaging the hull. The specialist design of their hull pushes ice away from the hull as it travels through it.
So now you know the basics, let’s delve deeper.
After a recent expedition on the icebreaker Le Commandant Charcot, I was captivated by the role of icebreakers in polar exploration. These ships, with their sheer ability to navigate where others can’t, are the epitome of adventure and discovery. Witnessing an icebreaker plough into sea ice at 14 knots is an experience that ignites the spirit of exploration.
In this article, I take a deep dive into what makes icebreaker ships unique, their technology, and the factors that drive their construction.
If you would like to experience an icebreaking ship for yourself please see our unique Icebreaker Cruises.
An icebreaker ship, also known as an icebreaker, is a specially designed ship that can navigate through heavy sea ice. Unlike an ice-strengthened boat, which can enter specific sea ice concentrations and push it aside, an icebreaker ship can cut through heavy sea ice, sometimes up to 3 metres in thickness.
For a ship to be classified as an icebreaker, it must have three distinct differences: hull strength, shape, and mighty engines that give the ship the power to create forward momentum in heavy sea ice.
Icebreaker Le Commandant Charcot parked in the sea ice in East Greenland
The hull of an icebreaker ship needs to be able to withstand the incredible force and impact of hitting rock-solid ice at speed. Icebreakers are built from high-strength steel much thicker than typical ships, up to 5cm thick, and can withstand extreme temperatures. They have a higher concentration of internal ribs to strengthen the structure.
The bow of an icebreaker, where the impact of the ice occurs, is further reinforced. The bow of the Icebreaker Le Commandant Charcot is 60mm thick, which is six times the thickness of a regular ship, and has a Polar Class 2 rating (PC2), the first for any cruise ship.
Some icebreakers, such as 50 Years of Victory, are double-skinned and contain a water ballast between the hulls to make them even more robust.
Yours truly checking out the bow of Le Commandant Charcot in East Greenland. Note the height of the ice reinforced belt which is taller than me.
Icebreaker ships are easily identified by their unique hull shape. The bow is shaped to ride up on the ice and then use the ship’s weight to split it as it moves forward. Icebreakers are built much wider than typical ships and have a far greater weight to break the ice.
Another essential factor about the design of an icebreaker hull is that when the ice is broken, the hull design pushes the ice away from the ship, allowing it to pass through without damaging the propellers.
Modern Icebreakers like Le Commandant Charcot have a hull that can break ice in both directions. Thus, they can also break the ice while moving in reverse, allowing them greater manoeuvrability.
Due to the sheer force they need to break ice, Icebreakers feature some of the most potent engines in maritime. Russian icebreakers such as the Nuclear Power 50 Years of Victory boasts 75,000 horsepower, which never fails to impress.
Le Commandant Charcot, powered by hybrid electric engines, follows up with a formidable 52,000hp. Without this sheer engine strength, icebreakers would not have the necessary power to break through the ice and sustain forward momentum.
An icebreaker’s primary technique to break the ice is the force of its engines pushing the hull onto the ice and then using the ship’s weight to crush it. The engines play a vital role in sustaining forward momentum to ensure the icebreaker does not grind to a halt and become stuck in the ice.
Another technique icebreakers use is ‘ramming ‘. If they encounter sea ice too thick to pass on the first attempt, the ship will have to reverse and then drive forward at a fast speed and ram different sections of the ice ahead. This involves the ship’s bow forcefully striking the ice, using its weight and momentum to break it.
Depending on the ice thickness, this can take several attempts until the ship can pass through. This explains why an Icebreaker such as Le Commandant Charcot is built to ram the ice in both directions.
On a recent expedition to the East coast of Greenland, the ship lost forward momentum due to the thickness of the ice. To pass, we had to back up several times and then ram the areas of ice in front of the ship.
After several attempts, enough space was cleared in front of the ship to pass that particularly thick section of ice.
Some icebreakers are equipped with warm water jets along the hull’s waterline. These jets spray warm water onto the ice, assisting its melting and making it easier to break.
This Video by the Canadian Coastguard provides an excellent overview of how icebreaker ships work.
The thickness of the sea ice that an icebreaking ship can push through depends on the characteristics and ratings of a particular vessel. For example, 50 Years of Victory, with the sheer might of its nuclear-powered engines, can go through ice up to 2.8 meters in thickness. Le Commandant Charcot can break thick, multi-year sea ice up to 2.5 metres.
Smaller icebreaking ships, such as the Arctic Explorer, which weighs 400 tons, can break ice up to 50cm thick. To give you a perspective, one of Le Commandant Charcot’s Azipod electric engines weighs 300 tons, showing that a ship’s size and weight ultimately determine the size of the ice it can push through.
Icebreaker ships require massive amounts of power and have specialist-built engines capable of creating the vast drive needed. The primary fuel types for icebreakers are nuclear, diesel and, more recently, LNG.
A nuclear reactor powers Russian icebreakers such as the 50 Years of Victory, with two reactors producing 159 MW each. Amazingly, they consume just 200g of Uranium fuel daily and can travel for 13.7 years without refuelling.
Smaller icebreakers, such as the Canadian Coastguard vessel CCGS TERRY FOX, are powered by four diesel engines.
When launched in 2021, Le Commandant Charcot became the world’s first icebreaker powered by dual-fuel hybrid electric engines running on LNG and diesel. Two giant Azipod thrusters propel the ship forward, weighing 300 tons. Unlike conventional propellers, Azipods can rotate 360 degrees under the ship, giving them advanced manoeuvrability in the ice.
Liquified Natural Gas (LNG) reduces emissions with 25% less carbon emissions, 85% less nitrogen oxide emissions and 95% less fine particles, helping to reduce the ship’s environmental footprint.
Icebreakers serve several purposes and are used in frozen waterways and oceans throughout the planet, but they are used mainly in the Arctic and Antarctica.
One of the primary purposes of icebreakers is to clear navigational routes and keep shipping lanes open to regular ships that don’t have icebreaking capabilities in the polar regions. Icebreakers often work in a convoy, opening up the ice for the cargo and supply ships that follow them.
Icebreakers are often employed in research and scientific missions in the polar regions where the extreme climate requires an extreme ship. The RSV Nuyina is an Australian research icebreaker launched in 2023 to support Australia’s research stations and scientific research in Antarctica. Icebreakers can reach places off-limits to regular ships and provide the ideal platforms for polar research in the high Arctic Ocean.
Icebreakers are also used in search and rescue, military operations, and oil and gas exploration in the extremities of the polar regions where it would not be feasible to navigate with a non-icebreaking ship.
Although a recent invention, icebreakers are also used in tourism. Since the 1990s, adventurous travellers have been able to reach The Geographic North Pole on an icebreaker cruise about the Yamal and then the the 50 Year of Victory during the summer when the ships are not employed in keeping shipping lanes open.
Since 2021, Le Commandant Charcot has introduced a new world of luxury icebreaker tourism. The world’s first icebreaker built as a cruise ship, Le Commandant Charcot takes travellers to some of the world’s most extreme polar regions, from the thick sea ice of East Greenland to the frozen Weddell Sea of Antarctica and voyages to the Geographic North Pole. Here you can search some of the fantastic icebreaker cruises.
Icebreaker ships are specially designed to sail safely through ice-covered waters. A combination of strengthened steel hulls and reinforced bows prevent the ship from becoming punctured by the ice.
Each icebreaker has a rating for the thickness of the ice it can encounter. Modern ice navigational charts and good seamanship also play a role in ensuring safety whilst sailing through ice.
While an icebreaker ship can become stuck if it encounters a thick ice pack, several solutions exist. The first is to backtrack and ram the ice with the ship’s powerful engines.
The second is to wait. Sea ice is constantly moving and shifting with the wind and tide. If wind pushes ice tightly together, it could trap a ship, for example, Ernest Shackleton’s Endurance (which wasn’t an icebreaker), but the same happens in reverse. A ship can be released as ice drifts away from it on the wind and tide.
The third solution is prevention. The latest generation of icebreakers has technologically sophisticated satellite ice charts. That shows the thickness of the ice and where there is open water. An icebreaker captain has excellent knowledge of ice movement and, using charts and weather forecasting, can predict areas where the ice may be too thick and the ship could become stuck.
Icebreakers are often equipped with helicopters that can be used for scouting ahead to find a passage with a lead in the ice.
Le Commandant Charcot was one of the most expensive expedition cruise ships ever built at a cost of over $430 Million (2.7 Billion NOK)
Icebreakers are much more expensive to build than regular ships due to the sheer amount of material required, such as the extra steel for hull thickness, powerful engines, and the specialist technology required for the design and testing of such a ship.
Globally, the countries boarding the polar regions, such as Canada, Russia, Finland, and Denmark, have the largest fleets of icebreakers.
According to Aker Arctic, “As of 1 January 2024, the complete list of icebreaking ships includes 243 ships: 179 in service worldwide, 29 under construction, and 35 in the shipyards’ order books or included in various procurement programs”
Yes, it is possible to travel on an icebreaker ship. Here at North Pole Cruises, we offer a variety of icebreaker expeditions in the Arctic, including Greenland, the North Pole, and Antarctica. You can see our icebreaker cruises here.
If you visit Finland, taking a short day trip on The Arctic Explorer is possible.
I hope this article gives you some insight into how icebreaker ships work and inspires you to want to travel on one.
Thanks for reading, and happy exploring.
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