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Overcoming the ice challenge

Advanced ice model testing facilities and decades of experience give Aker Arctic Technology a very good understanding of the problems involved in designing ships capable of navigating in ice and breaking through it. Unique technologies developed by the company, such as double-acting vessels, lead the field.
Aker Arctic Technology Inc.

Aker Arctic Technology (AARC ) has over 50 years of experience in developing ships for efficient operation in ice, and has been involved in work on over 60% of all the icebreakers built to date.

AARC was the first to bring electric azimuthing thrusters (Azipods) to ice-going ships. Used in combination with modern hull forms optimised for ice conditions, these units have revolutionised vessel operations in ice, overcoming the shortcomings associated with conventional shafts and propellers that limit steering in ice dramatically.

Azipods were central to the development of the double-acting principle that allows vessels to proceed ahead in thinner ice and astern in heavier ice. The first of these vessels, the Arcticaborg and the Antarcticaborg, two supply vessels based in the Caspian Sea, have operated successfully for more than 10 years. The 1AS ice-classified Tempera and Mastera Aframax-class tankers, delivered by Sumitomo Heavy Industries to Neste Oil in 2002 and 2003, feature pod drives and a double-acting design.

When double-acting vessels operate astern, the milling action of the propeller helps cut a path for the ship through the ice, and the water flow automatically flushes the hull, easing the ship’s progress. Until this type of operation became possible, icegoing ships needed to have an ice-going bow, totally different from an open-water bow and much less hydrodynamic, leading to higher fuel consumption.

The Vasily Dinkov is one of a trio of tankers designed to transport crude from Varandey in the new oilfields of the Pechora Sea to Murmansk without icebreaker assistance.

World’s first Arctic oil export system

Vladivostok-based FESCO , with design expertise and support from Aker Arctic, won a contract from Exxon Neftegaz in 2003 to deliver and operate an icebreaking platform support and standby vessel for the Sakhalin 1 project in the Sea of Okhotsk. Based on a double-acting design, the 13 MW Fesco Sakhalin has proved very capable of dealing with conditions there, where 1.5 meter-thick ice can create rubble formations 20 meters deep.

Following the delivery of the Norilskiy Nickel Arctic container vessel, with a 13 MW electric pod and built to the highest ARC 7 Arctic ice class so far, Norilsk Nickel now has a series of four more similar vessels in service – forming a totally new logistic system able to operate independently of high-cost icebreaker assistance through the Kara Sea and the River Yenisei.

Transporting oil by tanker in the Arctic used to be handled by fleets of nuclear icebreakers and relatively small oil tankers. After electric pod propulsion was tested in the region through retrofits of the Uikku and the Lunni. Naryanmarneftegaz – a joint venture between LUKoil and ConocoPhillips – launched a project to develop a direct marine export system for onshore oil production in the Timan Pechora region together with Aker Arctic. This system is now in its first winter of operations.

This work led to a pioneering trio of Arctic icebreaking shuttle tankers built by Samsung Heavy Industries for Sovcomflot under a cooperation agreement on the double-acting concept with AARC signed in 2004.

The third vessel of the trio, the Timofei Guzhenko, was delivered in March 2009, and will transport crude from Varandey in the new oilfields of the Pechora Sea to Murmansk without icebreaker assistance – the first time such a journey has been handled in this way.

These new designs will be able to break ice up to 1.5m thick with a 0.2m snow covering at a speed of approximately 3 knots either forward or astern. The ships are powered by twin pods (2 x 10 MW) and feature a hull that has been ice-strengthened in accordance with RMRS Ice Class ARC 6, and are fully winterised to cope with temperatures down to -45 °C. Their bow loading system, capable of loading/unloading 10,000m3/h, will ensure no spills at sea, protecting the sensitive Arctic environment.

Two vessels of the same size and completely designed by AARC are being built at the OAO Admiralty Shipyards in St. Petersburg.

The design of AARC’s new generation of multipurpose icebreakers.
AARC is also working on innovative drillship designs.

Meeting new challenges

The latest fruits of AARC ’s intensive product development programme have been reflected in a number of contracts for the design of a new generation of multipurpose icebreakers. Work includes the development of the conceptual and basic designs and preparation of the tender documents needed for yard contracts, together with construction supervision in some cases.

The vessels will have a beam of up to 28 metres and be capable of breaking through level ice 1.2 to 1.8 metres thick ahead and astern at a continuous speed of 3 knots, as well as moving smoothly through heavy polar ice ridges astern. The vessels will feature twin azimuthing drives or a combination of pods and traditional shafts of up to 25 MW, and be fitted with equipment for oil spill, fire fighting, towing, and offshore duties outside the winter season.

AARC is also working on innovative drillship designs that could open up new opportunities at even higher latitudes, such as the Beaufort Sea, by offering new solutions based on dynamic positioning, reducing ice loads, and transfer operations.

> Mikko Niini
(Published in HighTech Finland 2009)