Designing for the Arctic: why less ice won’t mean easier ships

Sea ice is retreating and traffic is rising, but designers and classification experts say vessels still have to be built for the worst conditions they might meet. Open water, shifting ice, and extreme cold all pull a design in different directions.

In the face of climate change, the Arctic is one of the fastest changing regions on Earth. In particular, the decline of sea ice extent is seeing more vessels in the region – a 40% increase since 2013 according to data collected by the Arctic Council Working Group on the Protection of the Arctic Marine Environment (PAME).

While climate change is likely to make the region more accessible in the future, it does not necessarily mean that vessels operating in the Arctic will look hugely different to today.

A highly dynamic region

“There is a very common misconception of having single Arctic conditions and climate change is changing the conditions everywhere the same,” says Arto Uuskallio, Head of Sales & Marketing at Railotech, formerly Aker Arctic, the Finnish icebreaking specialists.

Even without climate change, Arctic conditions vary considerably across the region and between seasons. Ice can be level, ridged, drifting or compressed, shaped by different winds, different temperatures, and local geography.

When it comes to designing a vessel for the Arctic conditions, “there’s an infinite number of variables, so you’re not designing for one gross condition, but for the operational conditions of the vessel,” Uuskallio explains.

Those include where and when a vessel is supposed to operate, what its operational or mission purpose is, and how far it may need to travel through the sea. Vessel designers are not, however, making assumptions about the future climate.

“We have to assume that the vessel will meet difficult conditions, even if in its lifetime it may not. It might make the ship more expensive [than it would otherwise need to be] but we cannot compromise on safety,” says Uuskallio.

That principle also underpins how vessels are classified. “Lloyd’s Register's approach is based on assessing a vessel against its intended operating envelope rather than assuming Arctic routes are becoming progressively less demanding,” says Andrew Bennett, Machinery Survey Policy Manager in the Technical Directorate at Lloyd's Register.

Sea ice will remain a challenge

While sea ice is predicted to decline across the region, it will not completely disappear – at least before 2050. These changing dynamics bring about new challenges. More open water can mean greater exposure to waves and storms, while changing temperatures and winds can alter how ice forms, moves and packs together.

“You're going to operate in open waters, you're going to operate in ice channels, and you're going to break ice,” says Göran Grunditz, Director of Hydrodynamics at Kongsberg Maritime. “So, you need efficiency when you're operating in open waters, but you also need high bollard pulls for pushing through ice, for example, and you need high manoeuvrability to be able to manoeuvre around the ice and keep your position.”

Those demands can pull a vessel design in different directions. An icebreaking hull, for example, is built to break ice rather than minimise resistance and fuel use in open water, notes Erik Leenders, Chief Designer – Ship Design Solutions at Kongsberg Maritime.

Trond Arvid Rolstad Paulsen, Global Segment Lead for Icebreaker and Research Vessels at Kongsberg Maritime, likens the process to pulling a piece of rubber in different directions. “You can pull it towards polar capability, you can pull it towards efficiency, or you can pull it towards the silent notations. But going in one direction will always make this rubber tighter and more difficult pull to another.”

That trade-off does not necessarily mean every vessel heading north needs to be a powerful icebreaker. Icebreakers can instead provide support to other ships, opening or widening channels through difficult areas. By angling azimuth thrusters outwards, for example, an icebreaker can push water and broken ice to the sides, producing a channel wider than the vessel itself.

Designing for other extremes

While sea ice is an important consideration for Arctic vessels, it is not the only one. Bennett highlights topside icing – when freezing ocean spray, rain, or fog can lead to heavy ice buildup on a ship's decks, masts, and superstructure - “which can affect vessel stability and the performance of critical equipment”, and low temperatures, as just a few of the issues that need to be considered.

“The more you can move [equipment] away from exposed areas, like the deck, the better it is” says Leenders. Invariably, some equipment like radars and sensors need to stay outdoors. “When you have these extreme temperatures, any kind of sea that comes in freezes very, very quickly. We spend quite a lot of time finding good solutions for that.”

Those solutions are often a combination of using equipment that is more tolerant of extreme cold, providing heating and/or insulation, and operational procedures. “For instance, if it's getting colder and colder, you need to start up the radars and keep them spinning, because the problem comes when it stops or when it stops emitting heat themselves” Leenders explains.

More vessels, evolving designs

Interest in Arctic-capable vessels is already growing. “For us, this has been an industry which for the last ten years typically produced one to three vessels a year. Now there are twenty being built more or less at the same time,” says Paulsen.
Greater access does not mean owners are looking for less capable vessels. “The conversation is less about reducing capability because sea ice may be changing and more about defining a credible operating profile and designing a vessel accordingly,” says Bennett.

Instead, changes may come in vessel efficiency as technology advances with improvements in how to break through ice and designing for Arctic operations.

Propulsion systems may also become more flexible, combining different technologies to perform efficiently in both ice and open water. Grunditz of Kongsberg Maritime points to configurations with “a centre propeller with wing thrusters or wing pods that gives you the combination of good pull output, good efficiency, and still good manoeuvrability”.

At least for the near future, “less ice just means that new areas are opening for exploration or new opportunities to explore,” says Paulsen. “It doesn't change so much about what the vessel itself will have to do.”

Tell us what you think about this article by joining the discussion on IMarEST Connect.

Main image: Icebreaker in the Arctic ice floe zone

Credit: Shutterstock