Decades of experience and state-of-the art test facilities give Aker Arctic Technology (AARC) an unrivalled insight into the challenges involved in designing ships capable of navigating effectively in ice. No wonder then that Canada and China recently turned to AARC to carry out key design work for their new icebreakers.
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.
AARC’s unique technologies, such as double- acting (Aker Arctic DAS™) vessels and other breakthrough vessels, lead the field. AARC’s experts were also the first to bring electric azimuthing thrusters (Azipods) to ice-going vessels. Used in combination with modern hull forms optimised for ice conditions, these have brought a revolution in reduced energy usage and overall ship design, overcoming the shortcomings associated with conventional shafts and propellers.
|AARC’s unique technologies, such as double-acting (Aker Arctic DAS™) vessels and other breakthrough vessels, lead the field.
Aker Arctic DAS™ technology enables vessels to proceed ahead in thinner ice and astern in heavier ice using 40% less fuel than traditional technologies. When operating astern, the milling action of the propeller helps cut a path for the ship through the ice from below. Until this 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 15 years. Two 1AS ice-classified Aframax-class tankers owned and operated by Neste Oil have been carrying crude in the Baltic without icebreaker assistance for around 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.
A fleet of five modern vessels operated successfully by Norilsk Nickel since April 2006 has ushered in a completely new logistics system capable of operating independently of high-cost icebreaker assistance in the far north, through the Kara Sea and the River Yenisei. Norilsk Nickel took delivery of a similar tanker for its gas condensate exports – the MT Enisey – last year.
All of 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 and have demonstrated average winter transit speeds of close to 10 knots in the Kara Sea without the need for any icebreaker assistance.
Three 70,000-dwt shuttle tankers featuring the Aker Arctic DAS™ design, built by Samsung, serve the Varandey terminal in the Pechora Sea and are capable of handling ice up to 1.7 metres thick without icebreaker assistance.
AARC also provided the complete basic design for two similar-sized shuttle tankers built at the Admiralty Shipyard in St. Petersburg – the Mikhail Ulyanov and the Kirill Lavrov. These entered service in 2010 and handle shipments from the Prirazlomnoye oil field, south of Novaya Zemlya, where average ice cover typically lasts over 210 days a year.
Now that the new IMO-regulated EEDI requirements are coming into force, AARC’s solutions can help owners meet the new emission standards – and helps explain why AARC has been chosen to design Finland’s new flagship icebreaker for the next 50 years, which is schedule to enter service in 2016.
Pushing technology even further
|A triple pod design based on the Aker Arctic Multi-Screw DAS™ concept.
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. The first Oblique Icebreaker ARC 100 is already under construction for Russia’s Ministry of Transport and will enter service in early 2014.
AARC has also developed the Multi-Screw DAS™ system, which combines three azimuthing thrusters or two 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 ice management scenarios. The system is currently being developed for large Arctic LNG carriers to carry output from the huge Yamal natural gas fields; and 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 polar ice conditions. The first reference application, however, will be a new Finnish coastguard cutter to be completed towards the end of 2013.