Arctic Ocean, 3 September 2026

Icebreaking at sea is uncharted territory for me. Before coming aboard, I had some idea of how it worked, but that idea was rather vague and, as it turns out, quite inaccurate. It is far more intricate than I had imagined and something of an art in itself. The interplay between a well-designed icebreaker and its captain and officers accounts for much of the vessel’s capability.

Oden is powered by four engines, connected in pairs to the same drive shaft and propeller. Together, they provide a total of 24,500 horsepower. Depending on the thickness of the ice, two, three or four engines can be used while underway. The more power that is applied, the thicker the ice that can be broken. Makes sense.

The propellers are also mounted inside what are known as propeller nozzles. These are large iron rings that protect the propellers while increasing thrust at low speeds – something that comes in handy when breaking ice.

Water helps Oden through the ice

In addition to its engines and propellers, Oden has two other systems deep inside the vessel that assist with icebreaking.

The first is the hull-washing system in the bow. Two enormous pumps draw up seawater to continuously flush the hull. The water acts as a lubricant between the hull and the ice. It washes both the hull and the snow from the ice, reducing the friction between them.

The second is an enormous water-transfer system. More than 300 cubic metres of water are pumped through pipes between the starboard and port sides. This causes Oden to roll from side to side, heeling by as much as 12 degrees. In this way, the ice is broken not only by the bow but also by the vessel’s sideways motion.

When the system is operating, a strange, wailing sound can be heard aboard the ship. It comes from air pipes connected to the heeling system and is known among the crew as “Oden’s song”.

Speed, power and weight

Last but not least, there are Oden’s captain and officers, who represent the human element of icebreaking. They have three important components to manage: speed, power and weight.

But even though Oden is a powerful icebreaker, much of the job involves finding the easiest routes through the ice. Radar and the human eye are essential tools.

The aim is to follow the route set by our colleagues aboard the Canadian icebreaker, weaving from side to side along it like a snake to take advantage of weaker passages through the ice.

When the ice brings us to a halt

Here in the Arctic, ice thickness and concentration vary with location. The thickest multiyear ice – ice that does not melt during the summer but instead grows thicker with each passing year – is found north of Greenland and the Canadian Arctic Archipelago. Oden is not capable of breaking this type of ice. Only nuclear-powered icebreakers can venture into those areas, so we keep our distance from them.

However, the journey is not always entirely smooth. Sometimes we have to reverse and build up momentum to cross thicker sections of ice. At other times, ice becomes lodged between the hull and the propeller nozzles. When that happens, the entire hull shakes violently.

The other night, there was a great deal of commotion for several hours as the crew worked to dislodge a piece of ice the size of a minibus that had become stuck beneath the hull.

Situations like these require experience, inner calm and a steady hand on the controls. Oden’s captain and officers have all three.

The rest of us can turn over in our bunks and safely go back to sleep.

Text: Henrik Swärd, teacher