The perfect icebreaker
Once considered inaccessible, the Arctic is now being opened up by icebreakers; a little-known class of advanced ships that are shaping the region’s geographical and geopolitical landscape
The diamond-hard, glittering Baltic Sea stretches for hundreds of thousands of kilometres, with a 1.5m thick layer of ice across its surface. A testing ground for Arctic icebreakers, it’s a vast, dangerous and seemingly impenetrable environment, and for most sea vessels it is.
However, as commercial shipping, geological research and even tourism in the Arctic region increases, navigating these previously impassable routes is made possible thanks to icebreakers: a class of specially reinforced steel ships designed to cut through the dense sheet ice.
The technique of ice breaking is a fairly rudimentary one. The smooth, curved underside of the vessel is made of reinforced steel, a high-performing, tough material that has been integral to the icebreaking industry since its inception. The hull glides over the top of the ice and crushes it beneath a colossal, armour-plated belly.
Breaking the highly pressured frozen surface requires a strengthened-steel hull around 48mm thick, with a 5-7mm stainless steel belt to protect it from rust and abrasion. More sophisticated models have built-in systems that fire bubble jets over the surface to help reduce drag and friction.
The majority of icebreakers are tested off the western coast of Finland, in the Bay of Bothnia – which is mostly composed of flat sheet ice for six months of the year. The bay is used due to its suitability for measurement and testing, but most modern models are designed to cut through much tougher ridge ice – essentially frozen clusters the size of small hills.
If a boat becomes stranded in an ice field, razor-sharp ridges will begin to drive into the hull of a vessel. If a ship gets stuck here for too long these extreme conditions can create compression stresses, meaning reinforced steel has become essential.
“The ice-belt covering the hull is made of a combination of high-strength steel and acid-resistant clad steel, which requires less maintenance than regular ice-belts”
Out of the global fleet of around 110 vessels, newer models can assist with search and rescue, scientific and oil research, oil spill response and emergency towing, along with their chief function. Russia’s quest for oil means it is one of the biggest manufacturers of icebreakers.
Finland is another prolific producer. Its fleet has garnered recent public attention after the unveiling of the world’s first eco-friendly icebreaker, the Polaris. At 110 metres long, weighing in at 9,300 tonnes and with a maximum speed of 17 knots, Arctia’s €145m, cutting-edge Polaris is also the first icebreaker to run on liquefied natural gas (LNG), and represents the industry’s change in attitude towards the use of heavy fuels in the Arctic.
Tero Vauraste, President and CEO of Arctia said: “Polaris represents a new generation of icebreakers, which supports the proposed ban on heavy fuel in the Arctic.” Polaris complies with International Maritime Organization Tier 3 emission limits and Vauraste believes that vessels powered by ‘green energy’ will eventually become an industry standard. “We’re proud to be the owner of the world’s most environmentally friendly icebreaker. I think the use of LNG and the built-in 1,300m2 oil recovery system are the cost-effective future for our industry.”
Polaris’ dual engine can run for 10 days on LNG before a low-sulphur diesel engine kicks in for a further 20 days, after which it returns to shore for its monthly refuelling. While this is a comparatively unimpressive record compared to fossil fuel-powered icebreakers’ stamina of three to four months, the vessel is the perfect test bed for developing onboard renewable technology for the shipping industry in general, as no extra space is given over to cargo.
Polaris, the highest-spec icebreaker in the world, relies on advanced steel to power it through the unpredictable Arctic waters. “The ice-belt covering the hull is made of a combination of high-strength steel and acid-resistant clad steel, which requires less maintenance than regular ice-belts,” explained Mika Willberg, Project Manager at Arctech Helsinki Shipyard, where the Polaris was constructed.
The Polaris is also extremely agile thanks to a set of three powerful Azipod propellers. Each features four large multidirectional stainless steel blades that allow the vessel to turn deftly at 200° in different directions through the water. These powerful steel propellers and the curved steel hull, combined with a sophisticated control system and renewable capacity, represent the future of the gentle giants of icebreaking. The perfect blend of hi-tech, cutting-edge technology and the best steel engineering can offer is a testament to the enduring power of this robust material.