Double acting ship
Encyclopedia
Double acting ship is a type of icebreaking
merchant ship designed to run ahead in open water and astern (in layman's terms, backwards) in ice. Such ships 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
(DAT). In the early 1990s Kværner Masa-Yards Arctic Technology Centre (MARC) 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. The concept has been patented by Aker Arctic, the successor company of MARC, although some ships with similar characteristics have been designed by other companies.
to Europe the ship's open water efficiency is as important factor as its ability to operate in difficult ice conditions as on a direct route 90% of the time will be spent in open water. Direct independent transportation with a vessel capable of navigating in both ice and open water was also found out to be the most economical alternative in comparison with transshipment
, i.e. the use of different vessels for different parts of the journey, or normal ships relying on icebreaker assistance.
Although icebreaking cargo ships had been built in the past, their hull forms were always compromises between open water performance and icebreaking capability. A good icebreaking bow, designed to break the ice by bending it under the ship's weight, has very poor open water characteristics and is subjected to slamming
in heavy weather while a hydrodynamically efficient bulbous bow greatly increases the ice resistance. The total efficiency of icebreaking ships is 20-40% less than that of good open water vessels of similar size mainly due to the bow form.
In the late 1800s captains operating ships in icebound waters discovered that sometimes it was easier to break through ice by running their vessels astern. This was because the forward-facing propellers generated a water flow that lowered the resistance by reducing friction between the ship's hull and ice. These findings resulted in the adoption of bow propellers in older icebreakers operating in the Great Lakes
and the Baltic Sea
, but in the more severe Arctic ice conditions they could not be used because the risk of bow propellers being damaged is too great. Forward-facing propellers have also a very low propulsion efficiency and the steering ability of a ship is greatly reduced when running astern, so it could not be considered a main operating mode for merchant ships.
in the early 1990s. It combines the advantages of the diesel-electric powertrain, already widely used in icebreakers, with the excellent manoeuvrability of azimuth thrusters
.
The superiority of Azipod
propulsion in icebreaking ships, especially when running astern, was proved when the first propulsion pod was installed on fairway maintenance vessel Seili, owned by the Finnish Maritime Administration, in 1990. Before the conversion the ship could not break ice astern at all, but after the propeller and rudder were replaced with an 1.5 MW Azipod unit she could run astern in level ice as thick as 0.60 meters. The vessel could also easily be steered when running astern in ice. When product tankers Uikku
and Lunni
were converted to Azipod propulsion in 1993 and 1994, respectively, the result was similar increase in manoeuvrability and icebreaking capability. Even though the ships were originally designed with icebreaking capability in mind, after the conversion ice resistance in level ice when running astern was only 40% of that when breaking ice ahead despite the ships being equipped with an icebreaking bow and not designed to break ice astern.
Model tests conducted by MARC in 1994 showed that a double acting ship equipped with an Azipod
propulsion unit could break through ice ridges in continuous motion instead of ramming like conventional icebreakers. It also required less power for running in level ice than traditional designs, resulting in 40-50% reduction in ice resistance due to lubricating effect of propeller-induced water flow, more open stern design and the propellers being allowed to mill (crush) the ice. The icebreaking capability of an Azipod-equipped icebreaker operating astern in level ice was also found out to be superior to traditional icebreakers regardless of propulsion arrangement.
when moving astern. It was followed by icebreaking supply ships Arcticaborg and Antarcticaborg, delivered in 1998, that were the first vessels to fully utilize the double acting ship concept by having the bow designed for operation in open water and light ice conditions, but being capable of breaking level ice up to one meter in thickness when running astern. With the help of two Azipod units the ships can also penetrate ice ridges that in the Caspian Sea
sometimes reach to the seabed
.
The Norwegian Coast Guard
operates a double acting offshore patrol vessel KV Svalbard
, built in 2002 and equipped with two 5 MW Azipod propulsors. On 9 July 2007 the Canadian Broadcasting Corporation
reported that Canadian
Prime Minister
Stephen Harper
had announced that Canada
would be building six to eight corvettes
based on the Svalbard.
Icebreaking supply and standby vessel SCF Sakhalin, delivered in 2005 as FESCO Sakhalin, was the first large-scale double acting icebreaker. The 99 metres (325 ft) vessel has two Azipods with a total output of 13 MW. The ship, designed to break level ice up to 1.5 metres (5 ft) thick and 20 metres (66 ft) ice ridges with a 4 metres (13 ft) consolidated layer, has performed beyond expectation in the harsh ice conditions of the Sea of Okhotsk
. Two sister ships of slightly different design were ordered by Sovcomflot in 2010 and will be delivered in 2013.
Three icebreaking platform supply vessels, Pacific Endeavour, Pacific Enterprise and Pacific Endurance, were delivered for Swire Pacific Offshore
in 2006. The ships are equipped with two 7,000 kW Aquamaster ARC 1.0 azimuth thrusters and are capable of breaking first year ice up to 1.5 metres (5 ft) thick and multi-year ridges with a thickness of 4 metres (13 ft).
The 3,500-ton United States Coast Guard
multipurpose icebreaker and buoy tender
USCGC Mackinaw
, delivered in 2005, also incorporates some of the features typical for double acting icebreakers, such as podded propulsion and astern icebreaking capability.
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 — the most powerful ice-strengthened pod ABB has ever produced — 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 in the Pechora Sea
as well. 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 metres (3.3 ft) thick at 3 knots (1.6 m/s) 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 thrusters each. Evinco and Excello are slightly larger at 19,999 DWT. The Evinco, built in 2005, is equipped with one Schottel unit and the 2008-built Excello with two smaller Azipods.
In 2007 the Russian state-owned shipping company Sovcomflot ordered three 70,000 DWT double acting Arctic shuttle tankers from Samsung Heavy Industries
in South Korea
and two from Admiralty Shipyard
in St. Petersburg, Russia. The first ship, Vasily Dinkov, was delivered in 2007 and its two sister ships, Kapitan Gotskiy 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.
that were built in Finland in the 1980s. Unlike the tankers, the ARC-7 ice class ship was designed to have excellent icebreaking capability, 2 knots in level ice with a thickness of 1.5 meters, both ahead and astern. The ship, Norilskiy Nickel, was delivered from Hietalahti shipyard
in 2006 and performed beyond expectations during ice trials in the Yenisei Gulf
. Four additional ships, with an option for fifth, were ordered in 2007 from Aker Yards's shipyards in Germany, with deliveries in the second half of 2008 (Monchegorsk, Zapolyarny and Talnakh) and early 2009 (Nadezdha). Later an oil tanker derivative of the same design was constructed by Nordic Yards.
On 22 March 2011 Gaiamare, a subsidiary of Meriaura, ordered a 115 metres (377.3 ft) double acting multipurpose cargo ship from STX Finland. The new vessel, designed especially for demanding projects such as transporting wind turbines to offshore installations, will be constructed in Turku in 2011. In addition the environmentally friendly ship, designed to run on biofuel
, can be used in oil spill combating — the vessel can be equipped with skimmers and has 2,700 m3 of tanks for recovered oil. The diesel-electric propulsion with two electric azimuth thrusters and two bow thrusters allows the ship to maneuver and even move sideways at low speeds, considerably increasing the oil recovery rate.
Icebreaker
An icebreaker is a special-purpose ship or boat designed to move and navigate through ice-covered waters. Although the term usually refers to ice-breaking ships, it may also refer to smaller vessels .For a ship to be considered an icebreaker, it requires three traits most...
merchant ship designed to run ahead in open water and astern (in layman's terms, backwards) in ice. Such ships 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
Tanker (ship)
A tanker is a ship designed to transport liquids in bulk. Major types of tankship include the oil tanker, the chemical tanker, and the liquefied natural gas carrier.-Background:...
(DAT). In the early 1990s Kværner Masa-Yards Arctic Technology Centre (MARC) developed the concept for oil transportation between the Russian Arctic and Europe and the first double acting tanker, Finnish
Finland
Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...
crude oil tanker Tempera
MT Tempera
MT Tempera is a Finnish Aframax crude oil tanker operated by Neste Shipping. She was the first ship to utilize the double acting tanker concept, developed by Aker Arctic, in which the vessel is designed to travel ahead in open water and astern in severe ice conditions...
, was delivered in 2002. The concept has been patented by Aker Arctic, the successor company of MARC, although some ships with similar characteristics have been designed by other companies.
History
In the early 1990s studies conducted by Kvaerner Masa-Yards showed that in oil transportation from the Russian ArcticArctic
The Arctic is a region located at the northern-most part of the Earth. The Arctic consists of the Arctic Ocean and parts of Canada, Russia, Greenland, the United States, Norway, Sweden, Finland, and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost...
to Europe the ship's open water efficiency is as important factor as its ability to operate in difficult ice conditions as on a direct route 90% of the time will be spent in open water. Direct independent transportation with a vessel capable of navigating in both ice and open water was also found out to be the most economical alternative in comparison with transshipment
Transshipment
Transshipment or Transhipment is the shipment of goods or containers to an intermediate destination, and then from there to yet another destination....
, i.e. the use of different vessels for different parts of the journey, or normal ships relying on icebreaker assistance.
Although icebreaking cargo ships had been built in the past, their hull forms were always compromises between open water performance and icebreaking capability. A good icebreaking bow, designed to break the ice by bending it under the ship's weight, has very poor open water characteristics and is subjected to slamming
Slamming
Slamming is the impact of the bottom structure of a ship onto the sea surface. It is mainly observed while sailing in waves, when the bow raises from the water and subsequently impacts on it. Slamming induces extremely high loads to ship structures and is taken under consideration when designing...
in heavy weather while a hydrodynamically efficient bulbous bow greatly increases the ice resistance. The total efficiency of icebreaking ships is 20-40% less than that of good open water vessels of similar size mainly due to the bow form.
In the late 1800s captains operating ships in icebound waters discovered that sometimes it was easier to break through ice by running their vessels astern. This was because the forward-facing propellers generated a water flow that lowered the resistance by reducing friction between the ship's hull and ice. These findings resulted in the adoption of bow propellers in older icebreakers operating in the Great Lakes
Great Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...
and the Baltic Sea
Baltic Sea
The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...
, but in the more severe Arctic ice conditions they could not be used because the risk of bow propellers being damaged is too great. Forward-facing propellers have also a very low propulsion efficiency and the steering ability of a ship is greatly reduced when running astern, so it could not be considered a main operating mode for merchant ships.
Development
Because of the limitations of traditional propulsion systems the development of double acting ships wasn't seriously considered until the development of electric podded propulsionAzipod
Azipod is the registered brand name of the ABB Group for their azimuth thruster. Originally developed in Finland jointly by Kvaerner Masa-Yards dockyards and ABB, these are marine propulsion units consisting of electrically driven propellers mounted on a steerable pod.The pod's propeller usually...
in the early 1990s. It combines the advantages of the diesel-electric powertrain, already widely used in icebreakers, with the excellent manoeuvrability of azimuth thrusters
Azimuth thruster
An azimuth thruster is a configuration of ship propellers placed in pods that can be rotated in any horizontal direction, making a rudder unnecessary...
.
The superiority of Azipod
Azipod
Azipod is the registered brand name of the ABB Group for their azimuth thruster. Originally developed in Finland jointly by Kvaerner Masa-Yards dockyards and ABB, these are marine propulsion units consisting of electrically driven propellers mounted on a steerable pod.The pod's propeller usually...
propulsion in icebreaking ships, especially when running astern, was proved when the first propulsion pod was installed on fairway maintenance vessel Seili, owned by the Finnish Maritime Administration, in 1990. Before the conversion the ship could not break ice astern at all, but after the propeller and rudder were replaced with an 1.5 MW Azipod unit she could run astern in level ice as thick as 0.60 meters. The vessel could also easily be steered when running astern in ice. When product tankers Uikku
MT Varzuga
MT Varzuga is a Russian product tanker operated by Murmansk Shipping Company. After her modernization in 1993 she became the first merchant ship to be equipped with an electric azimuth thruster, Azipod.-History:...
and Lunni
MT Indiga
MT Indiga is a Russian product tanker operated by Murmansk Shipping Company. After her modernization in 1994 she became the second merchant ship, after her sister ship Varzuga, to be equipped with an electric azimuth thruster, Azipod....
were converted to Azipod propulsion in 1993 and 1994, respectively, the result was similar increase in manoeuvrability and icebreaking capability. Even though the ships were originally designed with icebreaking capability in mind, after the conversion ice resistance in level ice when running astern was only 40% of that when breaking ice ahead despite the ships being equipped with an icebreaking bow and not designed to break ice astern.
Model tests conducted by MARC in 1994 showed that a double acting ship equipped with an Azipod
Azipod
Azipod is the registered brand name of the ABB Group for their azimuth thruster. Originally developed in Finland jointly by Kvaerner Masa-Yards dockyards and ABB, these are marine propulsion units consisting of electrically driven propellers mounted on a steerable pod.The pod's propeller usually...
propulsion unit could break through ice ridges in continuous motion instead of ramming like conventional icebreakers. It also required less power for running in level ice than traditional designs, resulting in 40-50% reduction in ice resistance due to lubricating effect of propeller-induced water flow, more open stern design and the propellers being allowed to mill (crush) the ice. The icebreaking capability of an Azipod-equipped icebreaker operating astern in level ice was also found out to be superior to traditional icebreakers regardless of propulsion arrangement.
Icebreakers and other special vessels
The first double acting icebreaker, Azipod-equipped river icebreaker Röthelstein, was delivered in 1995. The vessel was designed to break apart ice ridges deeper than the vessel's draftDraft (hull)
The draft of a ship's hull is the vertical distance between the waterline and the bottom of the hull , with the thickness of the hull included; in the case of not being included the draft outline would be obtained...
when moving astern. It was followed by icebreaking supply ships Arcticaborg and Antarcticaborg, delivered in 1998, that were the first vessels to fully utilize the double acting ship concept by having the bow designed for operation in open water and light ice conditions, but being capable of breaking level ice up to one meter in thickness when running astern. With the help of two Azipod units the ships can also penetrate ice ridges that in the Caspian Sea
Caspian Sea
The Caspian Sea is the largest enclosed body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea. The sea has a surface area of and a volume of...
sometimes reach to the seabed
Seabed
The seabed is the bottom of the ocean.- Ocean structure :Most of the oceans have a common structure, created by common physical phenomena, mainly from tectonic movement, and sediment from various sources...
.
The Norwegian Coast Guard
Norwegian Coast Guard
The Norwegian Coast Guard, or Kystvakten in Norwegian, is a military force and part of the Royal Norwegian Navy, but has separate vessels, many of which are purpose-built. All coast guard vessels have the prefix KV. Four of these vessels are capable of embarking one or more helicopters...
operates a double acting offshore patrol vessel KV Svalbard
NoCGV Svalbard
|...
, built in 2002 and equipped with two 5 MW Azipod propulsors. On 9 July 2007 the Canadian Broadcasting Corporation
Canadian Broadcasting Corporation
The Canadian Broadcasting Corporation, commonly known as CBC and officially as CBC/Radio-Canada, is a Canadian crown corporation that serves as the national public radio and television broadcaster...
reported that Canadian
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
Prime Minister
Prime minister
A prime minister is the most senior minister of cabinet in the executive branch of government in a parliamentary system. In many systems, the prime minister selects and may dismiss other members of the cabinet, and allocates posts to members within the government. In most systems, the prime...
Stephen Harper
Stephen Harper
Stephen Joseph Harper is the 22nd and current Prime Minister of Canada and leader of the Conservative Party. Harper became prime minister when his party formed a minority government after the 2006 federal election...
had announced that Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
would be building six to eight corvettes
Arctic Patrol Ship Project
In July 2007 The Government of Canada announced plans for the Arctic Patrol Ship Project which will see the construction of 6-8 vessels for the Royal Canadian Navy....
based on the Svalbard.
Icebreaking supply and standby vessel SCF Sakhalin, delivered in 2005 as FESCO Sakhalin, was the first large-scale double acting icebreaker. The 99 metres (325 ft) vessel has two Azipods with a total output of 13 MW. The ship, designed to break level ice up to 1.5 metres (5 ft) thick and 20 metres (66 ft) ice ridges with a 4 metres (13 ft) consolidated layer, has performed beyond expectation in the harsh ice conditions of the Sea of Okhotsk
Sea of Okhotsk
The Sea of Okhotsk is a marginal sea of the western Pacific Ocean, lying between the Kamchatka Peninsula on the east, the Kuril Islands on the southeast, the island of Hokkaidō to the far south, the island of Sakhalin along the west, and a long stretch of eastern Siberian coast along the west and...
. Two sister ships of slightly different design were ordered by Sovcomflot in 2010 and will be delivered in 2013.
Three icebreaking platform supply vessels, Pacific Endeavour, Pacific Enterprise and Pacific Endurance, were delivered for Swire Pacific Offshore
Swire Group
The Swire Group is a transnational corporation headquartered in the Swire House in the City of Westminster, London, England. It controls a range of wholly owned businesses, including deep-sea shipping, cold storage, road transport, and agricultural activities. The current chairman is James...
in 2006. The ships are equipped with two 7,000 kW Aquamaster ARC 1.0 azimuth thrusters and are capable of breaking first year ice up to 1.5 metres (5 ft) thick and multi-year ridges with a thickness of 4 metres (13 ft).
The 3,500-ton United States Coast Guard
United States Coast Guard
The United States Coast Guard is a branch of the United States Armed Forces and one of the seven U.S. uniformed services. The Coast Guard is a maritime, military, multi-mission service unique among the military branches for having a maritime law enforcement mission and a federal regulatory agency...
multipurpose icebreaker and buoy tender
Buoy tender
A buoy tender is a type of vessel used to maintain and replace navigational buoys. The name is also used for someone who works on such a vessel and maintains buoys....
USCGC Mackinaw
USCGC Mackinaw (WLBB-30)
USCGC Mackinaw is a vessel built as a heavy icebreaker for operations on the North American Great Lakes for the United States Coast Guard. IMO number: 9271054...
, delivered in 2005, also incorporates some of the features typical for double acting icebreakers, such as podded propulsion and astern icebreaking capability.
Tankers
In 2001 FortumFortum
Fortum Oyj is a Finnish publicly listed energy company, which focuses on the Nordic and Baltic countries, Poland and the north-west of Russia. After acquisition of Russian energy company TGC-10 in year 2008, Western Siberia has become an important operating area for Fortum. The head of the company...
ordered two 106,000 DWT double acting Aframax
Aframax
An ' ship is an oil tanker smaller than and with a breadth above 32.31 m. The term is based on the Average Freight Rate Assessment tanker rate system. class tankers are largely used in the basins of the Black Sea, the North Sea, the Caribbean Sea, the China Sea and the Mediterranean...
tankers from Sumitomo Heavy Industries
Sumitomo Heavy Industries
Sumitomo Heavy Industries, Ltd. is an integrated manufacturer of industrial machinery, automatic weaponry, ships, bridges and steel structure, equipment for environmental protection, including recycling, power transmission equipment, plastic molding machines, laser processing systems, particle...
Ltd., Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, to replace the company's older tankers that, because of their lower ice class
Ice class
Ships with an Ice Class have a strengthened hull to enable them to navigate through sea ice.-History:The first requirements for merchant ships to be escorted by icebreakers were set in Finland in 1890, after winter traffic to the port of Hanko was started. In the past, different classification...
, had traffic restrictions during the worst part of the winter and could not deliver their cargo all the way to the refineries in Porvoo
Porvoo
Porvoo is a city and a municipality situated on the southern coast of Finland approximately east of Helsinki. Porvoo is one of the six medieval towns in Finland, first mentioned as a city in texts from 14th century...
and Naantali
Naantali
Naantali is a city in south-western Finland, known as one of the most important tourist centres of the country. The municipality has a population of , and is located in the region of Finland Proper, west of Turku....
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 — the most powerful ice-strengthened pod ABB has ever produced — and have the highest Finnish-Swedish ice class
Finnish-Swedish ice class
The Finnish-Swedish ice class is an ice class assigned to a vessel operating in first-year ice in the Baltic Sea and calling Finnish or Swedish ports...
, 1A Super. They are designed to be capable of independent navigation and icebreaking in Baltic
Baltic Sea
The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...
ice conditions with a possibility to operate in the Pechora Sea
Pechora Sea
Pechora Sea , is a sea at the northwest of Russia, the southeastern part of the Barents Sea. The western border of the sea is off Kolguyev Island, while the eastern border is the western coasts of Vaygach Island and the Yugorsky Peninsula, and the northern border the southern end of Novaya...
as well. 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
MT Mastera
MT Mastera is a Finnish Aframax crude oil tanker operated by Neste Shipping. She and her sister ship, Tempera, are the first ships to utilize the double acting tanker concept, developed by Aker Arctic, in which the vessel is designed to travel ahead in open water and astern in severe ice conditions...
, in 2003. The icebreaking capability of the vessels proved to be superior to other ships — in shuttle service between Primorsk
Primorsk, Leningrad Oblast
Primorsk is a coastal town in Vyborgsky District of Leningrad Oblast, Russia, and the largest Russian port on the Baltic. It is located on the Karelian Isthmus, west of St. Petersburg, at the northern coast of the Gulf of Finland, near Birch Islands, protected as a sea bird sanctuary...
, Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
, 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 metres (3.3 ft) thick at 3 knots (1.6 m/s) when operating astern.
The Swedish
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
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
Siemens AG
Siemens AG is a German multinational conglomerate company headquartered in Munich, Germany. It is the largest Europe-based electronics and electrical engineering company....
Schottel azimuth thrusters each. Evinco and Excello are slightly larger at 19,999 DWT. The Evinco, built in 2005, is equipped with one Schottel unit and the 2008-built Excello with two smaller Azipods.
In 2007 the Russian state-owned shipping company Sovcomflot ordered three 70,000 DWT double acting Arctic shuttle tankers from Samsung Heavy Industries
Samsung Heavy Industries
Samsung Heavy Industries or SHI is one of the largest shipbuilders in the world and one of the "Big Three" shipbuilders of South Korea...
in South Korea
South Korea
The Republic of Korea , , is a sovereign state in East Asia, located on the southern portion of the Korean Peninsula. It is neighbored by the People's Republic of China to the west, Japan to the east, North Korea to the north, and the East China Sea and Republic of China to the south...
and two from Admiralty Shipyard
Admiralty Shipyard
The Admiralty Shipyard is one of the oldest and largest shipyards in Russia, located in Saint Petersburg. The shipyard's building ways can accommodate ships of up to , 250 meters in length and 35 meters in width...
in St. Petersburg, Russia. The first ship, Vasily Dinkov, was delivered in 2007 and its two sister ships, Kapitan Gotskiy 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
Wismar
Wismar , is a small port and Hanseatic League town in northern Germany on the Baltic Sea, in the state of Mecklenburg-Vorpommern,about 45 km due east of Lübeck, and 30 km due north of Schwerin. Its natural harbour, located in the Bay of Wismar is well-protected by a promontory. The...
. 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.
Freighters
The next generation of double acting ships emerged when the Russian mining company Norilsk Nickel ordered a prototype of a series of 14,500 DWT arctic general cargo/container ships intended to replace its ageing fleet of SA-15 class cargo shipsSA-15 (ship)
SA-15 is the project name for a series of icebreaking multipurpose cargo ships built in Finland for the Soviet Union in the 1980s. The ships, capable of independent operation in all prevailing arctic ice conditions, were the first merchant vessels designed for year-round operations in the Northern...
that were built in Finland in the 1980s. Unlike the tankers, the ARC-7 ice class ship was designed to have excellent icebreaking capability, 2 knots in level ice with a thickness of 1.5 meters, both ahead and astern. The ship, Norilskiy Nickel, was delivered from Hietalahti shipyard
Hietalahti shipyard
Hietalahti shipyard is a shipyard in Hietalahti, in downtown Helsinki, Finland. It is operated by Arctech Helsinki Shipyard, a joint venture between STX Finland Cruise Oy and United Shipbuilding Corporation....
in 2006 and performed beyond expectations during ice trials in the Yenisei Gulf
Yenisei Gulf
The Yenisei Gulf is a large and long estuary through which the lower Yenisei River flows into the Kara Sea.The Yenisei Gulf is formed by the river widening to an average of 50 km for up to 250 km in a roughly north-south direction, between a latitude of 70° 30' N in the area around...
. Four additional ships, with an option for fifth, were ordered in 2007 from Aker Yards's shipyards in Germany, with deliveries in the second half of 2008 (Monchegorsk, Zapolyarny and Talnakh) and early 2009 (Nadezdha). Later an oil tanker derivative of the same design was constructed by Nordic Yards.
On 22 March 2011 Gaiamare, a subsidiary of Meriaura, ordered a 115 metres (377.3 ft) double acting multipurpose cargo ship from STX Finland. The new vessel, designed especially for demanding projects such as transporting wind turbines to offshore installations, will be constructed in Turku in 2011. In addition the environmentally friendly ship, designed to run on biofuel
Biofuel
Biofuel is a type of fuel whose energy is derived from biological carbon fixation. Biofuels include fuels derived from biomass conversion, as well as solid biomass, liquid fuels and various biogases...
, can be used in oil spill combating — the vessel can be equipped with skimmers and has 2,700 m3 of tanks for recovered oil. The diesel-electric propulsion with two electric azimuth thrusters and two bow thrusters allows the ship to maneuver and even move sideways at low speeds, considerably increasing the oil recovery rate.