Rocks & mirror
Encyclopedia of Marine and Energy Technology



A vessel used for keeping a navigable passage open through ice. Icebreakers are grouped in ice classes according to the thickness of the ice to be broken. They are heavily built to withstand the shock of ramming the ice or of running up on it at the bow and breaking it by virtue of their weight. Icebreakers are provided with several propellers, not merely at the stern, but sometimes also in the fore part of the ship. Air-bubbler system becomes a part of the standard equipment of a modern icebreaker. This process involves the expulsion of compressed air through holes in the lower part of the hull. The ascending bubbles then loose ice pieces reducing the ship resistance through the ice. The thrusters can be used to create a propeller wave, which pushes the broken ice away from the hull and creates a wider channel.

The patented icebreaking solution, ARC 100 concept, which has been developed by Aker Arctic Technology, features the oblique (sideway) design with an asymmetric hull and three Steerprop pulling azimuth propulsors that allow the vessel to maneuver effectively in all directions. Oblique icebreakers are able to operate obliquely with sideways movements as well as ahead and astern.

The first oblique icebreaker, Aker Arctic’s ARC 100, is due to be delivered by Arctech Helsinki Shipyard in 2014. The hull form has an unique design and can proceed in 1.0m thick ice ahead and astern. In the oblique mode the vessel will be able to forge a 50m wide ice channel in 0.6m thick ice.