Aker Arctic Technology (AARC) and its predecessors have been responsible for the design of well over half of the world’s icebreakers, numerous Arctic and Antarctic research vessels, and a large number of cargo vessels and offshore structures designed to operate in some of the harshest climates anywhere.
Aker Arctic Technology’s decades of experience and state-of-the art, third-generation testing facilities give the company an unrivalled insight into the challenges involved in designing ships capable of navigating effectively in ice. Its unique technologies, such as double-acting (Aker Arctic DAS™) vessels and other breakthrough vessels, lead the field; and its extensive cooperation with oil companies, shipowners, and shipbuilders worldwide mean that it can constantly update its expertise with new field data from areas such as Sakhalin, the Kara sea, and the Beaufort Sea.
AARC’s experts were the first ship designers to bring electric azimuthing thrusters (Azipods) to ice-going vessels, for example. Used in combination with modern hull forms optimised for ice conditions, these have brought a revolution in energy saving and overall ship design, overcoming the shortcomings associated with conventional shafts and propellers.
Azipods played a key role in the development of AARC’s revolutionary DAS™ principle, which allows vessels to proceed ahead in thinner ice and astern in heavier ice using 40% less fuel than traditional technologies.
|The Mangystau-1 is one of five shallow-draught icebreakers fitted with three Schottel pulling thrusters intended for use in the Caspian Sea, designed by Aker Arctic and built by STX in Romania.
When double-acting vessels operate astern, the milling action of the propeller helps cut a path for the ship through the ice from below; the water flow automatically flushes the hull, easing progress. Until this type of operation became possible, ice-going ships needed to be designed with an ice bow, which is much less hydrodynamically beneficial than an open-water bow and inevitably results in higher fuel consumption.
The first ships to incorporate the DAS™ principle have operated successfully in the Caspian Sea for over 10 years. Two 1AS ice-classified Aframax-class tankers, Neste Oil’s Tempera and Mastera, have been operating without icebreaker assistance in the Gulf of Finland between the Russian terminal at Primorsk and Neste Oil’s refineries for close to a decade.
The SCF Sakhalin – an ice-breaking platform support and standby vessel based on an Aker Arctic DAS™ design for Exxon Neftegaz’ Sakhalin 1 project in the Sea of Okhotsk – was a breakthrough for the arctic offshore market. The ship has proved very capable of dealing with conditions there, where 1.5 metre-thick ice can create rubble formations 20 metres deep. Two more vessels of this type are under construction at Archtech Helsinki Shipyard for completion in spring 2013.
In the far north, Norilsk Nickel’s fleet of five modern vessels, which has been fully operational since January 2007, has ushered in a completely new logistics system capable of operating independently of high-cost icebreaker assistance through the Kara Sea and the River Yenisei. Norilsk Nickel is now building a similar tanker for its gas condensate exports.
These ships are able to break ice up to 1.5 metres thick covered by 0.2 metres of snow at approximately 3 knots moving either forward or astern. Powered by twin pods and featuring a hull that has been ice-strengthened in accordance with RMRS Ice Class ARC 7, these ships are fully winterised to cope with temperatures down to -45 °C.
A fleet of three 70,000-dwt shuttle tankers featuring the Aker Arctic DAS™ design, built by Samsung, is operating in the Pechora Sea. These ships, which serve the Varandey terminal there, are capable of handling ice up to 1.7 metres thick without icebreaker assistance, thanks to their unique hull form and two 10 MW Azipods.
Two similar-sized shuttle tankers built at the Admiralty Shipyard in St. Petersburg – the Mikhail Ulyanov and the Kirill Lavrov – entered service in 2010 and will handle shipments from the Prirazlomnoye oil field, south of Novaya Zemlya, when it comes on stream in 2011. Outside temperatures here can go as low as -46 °C, winds can reach 36 m/s, and average ice cover typically lasts over 210 days a year.
AARC provided the complete basic design of the ships, which include bow loading and dynamic positioning systems, one of the first times these technologies have been used in vessels designed for arctic waters.
|Aker Arctic is developing new types of floating platforms and ships to help open up high Arctic areas to oil and gas exploration. Modelling the ice loads likely to be imposed on these Arctic floaters and developing the propulsion and mooring systems needed is extremely challenging.
Designs for a wide range of conditions and needs
Recent design and development work at AARC has focused on Arctic floaters and new multipurpose and ice management icebreakers. Work includes an oblique icebreaker for use in dealing with oil spills and a trimaran icebreaker for ice management and marine research purposes.
Ice management is very useful in exploration drilling in harsh arctic environments, where dedicated icebreakers can break up heavy ice as it approaches a drilling site, ensuring that ice loads on other vessels and structures are kept to an acceptable level and that vessels can be kept on location at all times to guarantee safe production operations.
As part of its R&D work, AARC has also developed the Hybrid DAS™ system, which combines Azimuthing thrusters with conventional propulsion to provide the high output called for in the most challenging ice and sea conditions and give greater flexibility in different types of ice management scenarios. The system is currently being developed for large Arctic LNG carriers for carrying output from the huge Yamal natural gas fields.
The system has also been selected for Russia’s new-generation, diesel-electric polar icebreakers, which will have a total propulsion power of 25 MW and be capable of operating in very difficult ice conditions.
“AARC’s expertise in designing ships capable of
operating in extreme cold and ice is unique.”