Icebreaking

An essential service of the Canadian Coast Guard

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Icebreaking Video Transcript

Canada boasts about 244 000 kilometres of coastline and challenges mariners with some of the harshest marine conditions in the world. The Canadian Coast Guard plays a vital part in ensuring that our waterways are safe and accessible.

This ranges from aids to navigation and marine communications and vessel traffic services, to search and rescue and dredging to keep channels open. The Coast Guard is also responsible for ensuring that marine spills are effectively cleaned up.

A large portion of our waterways is covered with ice at various times of the year, so the Coast Guard is also called upon to break ice along shipping routes.

For this essential service, the Coast Guard maintains a fleet of thirteen icebreakers. Two of the vessels are heavy-class icebreakers, four are medium-class and seven are in the light class.

The fleet escorts ships through ice-covered waters and frees others trapped in ice. Frozen harbours are broken out, and ice jams are broken up in the spring to reduce flood risk.

Between December and April, much of the fleet breaks ice in Atlantic Canada, the Gulf of St. Lawrence and the St. Lawrence Seaway, as well as the western and eastern Arctic. From June to November, seven icebreakers assist with resupplying Canada’s northern communities.

Breaking ice calls for specially designed vessels. Icebreakers are not actually meant to cut through ice. They are wide in the beam and they have rounded reinforced hulls, with a very gradual upwards slope at the bow. This allows them to ride up over the ice. Once there, it is the weight of the ship that does the work. The greatest contributing factor is their incredibly powerful propulsion systems.

Ice horns protect the rudder and the propellers when the vessel is backing up, and ice knives in the front of the icebreaker protect it when it is moving forward. They also have features like strengthened hulls and special low-friction coating that allow the ship to slide more easily through the ice.

Some icebreakers — as the heavy-class Terry Fox shows us here — are equipped with a bubbler system. These are designed to blow compressed air out from under the hull. This not only pushes the ice up, but reduces friction on the hull as well.

The ice being broken here by the medium-class Des Groseilliers appears to be multi-year, which means the ice is more than one year old. Some of this ice is 8 to 10 feet thick.

Momentum is also key to effective icebreaking. Regardless of their class, most icebreakers will eventually lose momentum as they move through ice. When that occurs, the vessel reverses straight back into the path it has just created, then moves forward again, picking up momentum to ram the ice and begin the process all over again.

As a coastal nation with a vital commercial fishing industry and maritime transportation system to trade goods and keep its economy strong, Canada looks to the Canadian Coast Guard to make sure our waterways are safe and accessible. Icebreaking is just one of the Coast Guard’s many services that are essential to Canadians.