page_title: Double acting ship
section_title: Tankers
hierarchical_section_title: Double acting ship / Double acting ships / Cargo ships / Tankers
caption_attribution_description: English: MT Mastera in Rotterdam harbour. IMO Number: 9235892 MMSI Number: 230945000 Callsign: OJKE Length: 252 m Beam: 44 m Deutsch: Der dieselelektrisch angetriebene Tanker MASTERA, in Japan 2003 gebaut, hat einen Tiefgang von 15,30 m. Es ist mit 64259 BRZ; Tragfähigkeit: 106206 tdw vermessen und besitzt eine Doppelhülle. Für die Eisfahrt hat das Schiff auch eine Brücke nach achtern.
context_page_description: Double acting ship is a type of icebreaking ship designed to run ahead in open water and thin ice, but turn around and proceed astern in heavy ice conditions. In this way, the ship can operate independently in severe ice conditions without icebreaker assistance but retain better open water performance than traditional icebreaking vessels.
  Double acting ships carrying liquid cargo are generally referred as double acting tankers. In the early 1990s Kværner Masa-Yards Arctic Technology Centre developed the concept for oil transportation between the Russian Arctic and Europe and the first double acting tanker, Finnish crude oil tanker Tempera, was delivered in 2002.
context_section_description: In 2001 Fortum ordered two 106,000 DWT double acting Aframax tankers from Sumitomo Heavy Industries Ltd., Japan, to replace the company's older tankers that, because of their lower ice class, had traffic restrictions during the worst part of the winter and could not deliver their cargo all the way to the refineries in Porvoo and Naantali because they were not given icebreaker assistance. When this happened, the oil had to be transported to smaller ships of higher ice class at the edge of the ice — a practice that was both uneconomical and hazardous. The new ships are equipped with one pulling-type 16 MW Azipod unit and have the highest Finnish-Swedish ice class, 1A Super. They are designed to be capable of independent navigation and icebreaking in Baltic ice conditions with a possibility to operate also in the Pechora Sea. The ships follow the double acting principle with a bulbous bow for open water performance and stern designed with icebreaking performance in mind. The first double acting tanker, Tempera, was delivered in 2002 and its sister ship, Mastera, in 2003. The icebreaking capability of the vessels proved to be superior to other ships — in shuttle service between Primorsk, Russia, and the Finnish refineries the tankers required no icebreaker assistance and even acted as icebreakers for other merchant ships. The ships can break level ice up to 1 metre (3.3 ft) thick at 3 knots (5.6 km/h; 3.5 mph) when operating astern.
  The Swedish shipping company Donsötank operates four small product tankers that the company refers to as double acting ships. Prospero and Bro Sincero are 18,119 DWT product tankers built in 2000 and 2002, respectively, and equipped with one Siemens Schottel azimuth thruster each. Evinco and Excello are slightly larger at 19,999 DWT. Evinco, built in 2005, is equipped with one Schottel unit and the 2008-built Excello with two smaller Azipod units.
  In 2007, the Russian state-owned shipping company Sovcomflot ordered three 70,000 DWT double acting Arctic shuttle tankers from Samsung Heavy Industries, South Korea, to transport oil from the Varandey oil terminal and two similarly-sized ships of slightly different design from Admiralty Shipyard in St. Petersburg, Russia, for the Prirazlomnoye field. The first ship, Vasily Dinkov, was delivered in 2007 and its two sister ships, Kapitan Gotsky and Timofey Guzhenko in 2008 and 2009, respectively. Kirill Lavrov, the first double acting tanker built in a Russian shipyard, was delivered in 2009 and the last of the series, Mikhail Ulyanov, in 2010. The tankers, equipped with two Azipod units, are capable of bow loading and independent operation in level ice up to 1.2 meters in thickness.
  In March 2010 Norilsk Nickel placed an order for an Arc7 ice class oil tanker derivate of its double acting arctic cargo ships at Nordic Yards in Wismar. The 18,500 DWT vessel, referred to as the "Nordic AT 19" design, has similar main dimensions, characteristics and capabilities as the company's five icebreaking container vessels. The tanker, named Enisey, was delivered in the end of September 2011.
  The double acting ship concept has been selected as the main transportation concept for the Yamal LNG project. In July 2013, Daewoo Shipbuilding & Marine Engineering (DSME) won the tender for the construction of sixteen Arc7 ice class LNG carriers and the contract for the first vessel, worth 339.3 billion won ($316.4 million), was signed in March 2014. The Arctic LNG carriers, fitted with three 15 MW ABB Azipod propulsion units, are the largest icebreaking vessels in the world with an independent ice-going capability in level ice up to 2.1 metres (6.9 ft) in thickness. The first vessel, Christophe de Margerie, was launched in January 2016.
  In July 2014, Samsung Heavy Industries received a $440 million order for three ice class Arc7 shuttle tankers for the Russian shipping company Sovcomflot. A follow-up order for the construction of three more tankers of similar design to an unnamed European shipping company at the same price was announced in October 2014. The 42,000 DWT tankers
caption: Mastera, one of the first double acting tankers.
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