Kvaerner Masa-Yards' Arctic Research Center (MARC) in Helsinki has developed a new type of oil tanker that can cope with even thick ice cover without the help of traditional ice breakers. In open waters the ship looks like a regular oil tanker. Upon reaching the edge of ice cover, this Double Acting tanker turns around and breaks ice using its special-design stern and Azipod propellers. Two tankers are currently under construction at a Japanese shipyard.

In the early 1990s, a MARC research team begun to investigate how to make oil shipping more efficient in the arctic seas, particularly in Russia. After departing Russia, oil tankers must travel through ice that is both thick and difficult to traverse. At the Kola Peninsula tankers reach the edge of the ice cover and the rest of their route to Europe, some 90 percent of the total distance, passes through open sea.

Three alternatives have been available for the transportation of oil under these variable conditions, all of which add to the price of oil or are harmful to the environment. With the most common approach, tankers are assisted by ice breakers. The second option is to use an ice-breaking tanker for the early part of the voyage, and to transfer the entire oil cargo into a regular tanker upon reaching open waters. The transfer of oil from one ship to another is very hazardous for the environment, however. The newest alternative is to equip tankers with a so-called compromise bow, a hybrid ice breaker-tanker bow.

Bow first in open waters, stern first in ice

Many vessels built by Kvaerner Masa-Yards are powered by Azipod propulsion systems developed by ABB that enable even the largest ships to turn around without moving forward. As this system was being tested, it became clear that the Azipod-equipped test vessel was able to move through ice most effectively stern first. Its stern-mounted propellers pull the vessel as it backs up and push it more effectively into the ice cover. The mating of Azipod propulsion with an ice-breaking bow produced a Double Acting tanker, a vessel with a regular bow but an ice-breaking stern.

As a Double Acting tanker reaches the edge of ice cover it turns around, reverses the rotation of its propellers, and starts to break ice using its stern. It does not need any help from an ice breaker, and it travels through warmer waters with the same ease as a regular oil tanker.

The Kvaerner Masa-Yards Arctic Research Center has over 30 years of experience at designing vessels for arctic conditions. Related research is particularly important for Finland, as all Finnish ports freeze over during the winter months and the local ice breaker fleet is in heavy use. This latest innovation will guarantee that Finnish foreign trade will continue to flow in future winters as well.

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Ice breakers are crucial to Finland: 80% of foreign trade is sea-borne, and a normal winter freezes all ports