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MT Petali

MT Petali is an Aframax crude oil tanker. Formerly known as Mastera for almost two decades and briefly as Mikines in early 2022 and Alma until September 2023, she and her sister ship Tempera were the first ships to utilize the double acting tanker (DAT) concept in which the vessel is designed to travel ahead in open water and astern in severe ice conditions.[7][15] The icebreaking tanker was built to transport crude oil year-round from the Russian oil terminal in Primorsk to Neste Oil refineries in Porvoo and Naantali.[8]

Petali (as Mastera) outside the Port of Rotterdam
History
Name
  • Mastera (2003–January 2022)
  • Mikines (January–June 2022)
  • Alma (June 2022–2023)
  • Petali (2023–present)[3]
Owner
  • ABB Credit (2003–2006)[1]
  • SEB Leasing (2006–2014)[5]
  • SSC Maslaiva (2014–2019)[1]
  • SEB Leasing (2019–January 2022)[6]
  • Neste Shipping (January 2022)[1]
  • Omega Shipmanagement (January–February 2022)[1]
  • Neptune Seaway (February–June 2022)[1]
  • Zenaida Seaways (June 2022–2023)[3]
  • Lauriane Shipping Corp (2023–present)[3]
Operator
  • Neste Shipping (2003–2014)
  • OSM Ship Management (2014–2015)[1]
  • Neste Shipping (2014–January 2022)[1]
  • Chemikalien Seetransport (January–February 2022)[1]
  • Neptune Seaway (February–June 2022)[1]
  • Zenaida Seaways (June 2022–)[3]
  • Lauriane Shipping Corp (2023–present)[3]
Port of registry
RoutePrimorsk–Porvoo–Naantali (until January 2022)[8]
Ordered2001[7]
BuilderSumitomo Heavy Industries Ltd., Yokosuka, Japan[9]
Cost60–70 million euro (estimate)[10]
Launched30 September 2002[4]
Completed8 January 2003[3]
In service2003–[9]
Identification
StatusIn service[1]
General characteristics [9]
TypeCrude oil tanker
Classification: Lloyd's Register of Shipping
Tonnage
  • 64,259 GT
  • 30,846 NT
  • 106,208 DWT
Length252.0 m (826.77 ft) (overall)
Beam44.0 m (144.4 ft)
Height53.1 m (174 ft)
Draught
  • 15.3 m (50 ft) (summer)
  • 8.6 m (28 ft) (ballast)
Depth22.5 m (74 ft)
Ice class1A Super
Installed power
  • 2 × Wärtsilä 9L38B[5] (2 × 6,0 MW)
  • 2 × Wärtsilä 6L38B[5] (2 × 4.0 MW)
Propulsion
Speed
  • 15.2 knots (28.2 km/h; 17.5 mph) (max)[5]
  • 13.5 knots (25.0 km/h; 15.5 mph) (service)
  • 3 knots (5.6 km/h; 3.5 mph) (1 m (3.3 ft) ice)[14]
Crew15–20[12][13]

Concept edit

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.[16] However, already 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.[17] These findings resulted in the adoption of bow propellers in older icebreakers operating in the Great Lakes and the Baltic Sea, but as forward-facing propellers have a very low propulsion efficiency and the steering ability of a ship is greatly reduced when running astern, it could not be considered a main operating mode for merchant ships.[18][19]

For this reason it was not until the development of electric podded propulsion, ABB's Azipod, that the concept of double acting ships became feasible. The superiority of podded propulsion in icebreaking merchant ships, especially when running astern, was proved when Finnish product tankers Uikku and Lunni were converted to Azipod propulsion in 1993 and 1994, respectively. 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.[18][19]

History edit

Development edit

Following the successful operation of the Azipod-converted tankers Uikku and Lunni in the Northern Sea Route, Kværner Masa-Yards Arctic Research Centre developed the first double acting tanker concept in the early 1990s. The 90,000 DWT tankers were designed to transport oil and gas condensate from the Pechora Sea in the Russian Arctic, where ice conditions during winter can be considered moderate and the ships would operate mainly in astern mode, first to Murmansk and then Rotterdam, where most of the distance can be travelled in open water year round.[18] Other early double acting concepts included a similar ship with an icebreaking bow that would be utilized in summer time when the ship was traveling in areas with low ice concentration but with a risk of colliding with multi-year ice blocks.[19]

In early 2000s Fortum Shipping, the transportation arm of the Finnish energy company Fortum, started a major fleet renewal program to increase the efficiency and reduce the average age of its vessels.[20] The program also included replacing the company's old tankers, such as the 90,000-ton Natura, that were used to transport crude oil to the company's oil refineries in the Gulf of Finland. The old ships had traffic restrictions during the worst part of the winter because of their lower ice class of 1C and could not deliver their cargo all the way to the refineries in Porvoo and Naantali because they were denied 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.[19]

To solve these problems Kværner Masa-Yards Arctic Research Centre developed a new 100,000 DWT Aframax tanker concept together with Fortum Shipping, which ordered two vessels from Sumitomo Heavy Industries in 2001. The new ships were designed to the highest Finnish-Swedish ice class, 1A Super, and to be capable of operating in all ice conditions encountered in the Baltic Sea. The possibility to operate in the Pechora Sea was also taken into account in the design process. Extensive ice model tests confirmed the vessel's operational capability in level ice, rubble fields, ice channels and ridges.[19]

The world's first double acting tanker and the largest 1A Super class oil tanker at that time, Tempera, was delivered from Yokosuka shipyard in late August 2002.[21][22] She was awarded the Ship Of The Year 2002 award by the Society of Naval Architects of Japan (SNAJ).[23] The second ship, Mastera, was delivered in the following year.[7][9] Both ships were named after the company's oil products.[24] While the price of the contract was not made public, the company later admitted that the 60–70 million euro estimate was "quite close to the truth". The ships were owned by ABB Credit, which leased them to Fortum for ten years.[10] The leasing business was later sold to SEB Leasing.

Career edit

 
MT Mastera in 2020 near Primorsk

Since the beginning, Tempera and Mastera were used mainly for year-round transportation of crude oil from the Russian oil terminal of Primorsk to company's own oil terminals in Porvoo and Naantali,[8] where they were the only ships capable of operating without delays or problems during the harshest winters.[25] Occasionally they also carried cargoes in the Gulf of Bothnia and even outside the Baltic Sea depending on the amount of oil in the refineries' storage tanks.[13][26] However, due to draft restrictions the ships could not carry a full cargo of 100,000 tons to the port of Naantali until April 2010 — they had to stop at Porvoo on the way and unload 20,000 tons of oil to reduce the draft of the vessel.[27]

In 2005 Fortum's oil division was transferred to the re-established Neste Oil and the management of the ships, including the double acting tankers, was handed over to a subsidiary company Neste Shipping. On 19 September 2013, Neste Oil announced that it would sell its shipping business and the majority of its ships, including Mastera, to a new company owned by the Finnish insurance company Ilmarinen and the National Emergency Supply Agency.[28] In 2019, Mastera was resold back to SEB Leasing.[6]

Since 2017, Mastera was the only double acting tanker operating in the Baltic Sea after Tempera was sold overseas.[29] While other double acting ships have been built, the tankers operated by Neste Shipping were the only ones equipped with a bulbous bow designed primarily with open water performance in mind — the tankers and container ships built for the Russian Arctic have a more traditional icebreaking bow due to the more severe ice conditions.[30]

In September 2021, Mastera was transferred to the Norwegian International Ship Register.[2] In January 2022, she was renamed Mikines and reflagged to Liberia.[1] In March 2022, the 19-year-old Mikines appeared on list of tonnage sold for demolition,[31] but has since resumed trading and was renamed Alma in June 2022.[3]

In May 2023, Alma was recognized as one of the oil tankers transmitting a falsified automatic identification system (AIS) to circumvent the 2022 Russian crude oil price cap sanctions.[32]

In September 2023, the ship was renamed Petali.[3]

Design edit

General characteristics edit

The double acting Aframax tanker is 252.0 metres (826.8 ft) long overall and 237.59 metres (779.5 ft) between perpendiculars. The moulded breadth and depth of her hull are 44.0 metres (144.4 ft) and 22.5 metres (74 ft), respectively, and from keel to mast she measures 53.1 metres (174 ft). Her gross tonnage is 64,259 and net tonnage 30,846, and the deadweight tonnage corresponding to the draft at summer freeboard, 15.3 metres (50 ft), is 106,208 tons, slightly more than that of her sister ship. In ballast, the ship draws only 8.6 metres (28 ft) of water.[9]

The foreship of the tanker is designed for open water performance with a bulbous bow to maximize the hydrodynamic efficiency. The ship is, just like any other ice-strengthened vessel, also capable of running ahead in light ice conditions. The stern is, however, shaped like an icebreaker's bow, and the vessel is designed to operate independently in the most severe ice conditions of the Baltic Sea.[7] For this purpose the ship is also equipped with two bridges for navigating in both directions.[9] The ship is served by a crew of 15 to 20 depending on operating conditions during winter and maintenance work during summer.[12][13]

The ship is classified by Lloyd's Register of Shipping.[9]

Cargo tanks and handling edit

The ship has six pairs of heated, partially epoxy-coated cargo tanks and one pair of fully coated slop tanks, all divided by a longitudinal center bulkhead and protected by double hull, with a combined capacity of 121,158.2 cubic metres (4,278,660 cu ft) at 98% filling. For cargo handling she has three electrically driven cargo oil pumps with a capacity of 3,500 m3/h × 130 m and one cargo oil stripping pump rated for 300 m3/h × 130 m. The cargo can be loaded in 10 hours and discharged in 12 hours. Each cargo tank has two and both slop tanks one automated tank cleaning machines as well as holes for portable tank cleaning machines.[9]

The ship's ballast water capacity of 46,922.4 cubic metres (1,657,050 cu ft) is divided into sixteen segregated ballast tanks, six pairs in the double hull around the cargo tanks, two fore peak tanks and two aft peak tanks.[21] She has two electrically driven ballast pumps rated at 2,500 m3/h × 35 m and 3,000 m3/h × 70 m.[9] The ballast capacity is needed to maintain correct trim especially during drydocking — the empty ship has an aft trim of 3 metres (9.8 ft) and an uneven weight distribution may damage the hull girder.[12]

Power and propulsion edit

The ship has diesel-electric powertrain with four main generating sets, two nine-cylinder Wärtsilä 9L38B and two six-cylinder 6L38B four-stroke medium-speed diesel engines, with a combined output of 20 MW (27,000 hp). The main engines are equipped with exhaust gas economizers. In addition Mastera has one auxiliary diesel generator that can be used when the ship is at port. The auxiliary generator, six-cylinder Wärtsilä 6L26A, has an output of 1.7 MW (2,300 hp). While underway at 13.5 knots (25.0 km/h; 15.5 mph), the fuel consumption of the ship's main engines is 56 tons of heavy fuel oil per day when loaded and 40 tons per day in ballast. Her tanks can store 2,890.1 cubic metres (102,060 cu ft) of heavy fuel oil for the main engines, 308.2 cubic metres (10,880 cu ft) of diesel oil for the auxiliary generator, steam boilers and inert gas system, and 63.2 cubic metres (2,230 cu ft) of lubrication oil.[9]

When built, Mastera and her sister ship were the first tankers propelled by ABB Azipod electric azimuth thrusters capable of rotating 360 degrees around the vertical axis. The pulling-type VI2500 pods in these two ships, with a nominal output of 16 MW and 7.8-metre (26 ft) fixed-pitch propellers turning at 86 rpm, are the most powerful ice-strengthened Azipod units ABB has ever produced.[10][33] The forward-facing propeller increases the propulsion efficiency due to optimal water flow to the propeller and thus improves fuel efficiency. In addition an azimuthing thruster's ability to direct thrust to any direction also results in excellent manoeuvrability characteristics that exceeds those of ships utilizing traditional mechanical shaftlines and rudders.[34] The turning circle of the Azipod-equipped double acting ships is only half a kilometer at full speed, half of that of a traditional oil tanker of the same size. This is a significant safety factor as the stopping distance of a traditional tanker can be up to 2.5 kilometres (1.6 mi).[15]

For maneuvering at low speeds in harbours, the ship is also equipped with two 1,750 kW bow thrusters.[11]

Icebreaking capability edit

The icebreaking capability of the double acting tankers proved to be superior to other ships since the beginning — in shuttle service between Primorsk, Russia, and the Finnish refineries the tankers require no icebreaker assistance and have even acted as an icebreaker for other merchant ships that have utilized the wide channel opened by the Aframax tanker.[10][30] However, this has not been intentional — when the world's largest 1A Super class ice tanker Stena Arctica, also owned by Neste Shipping, became stuck in ice outside the port of Primorsk during the winter of 2009–2010, a decision was made to leave the assisting to Russian icebreakers.[12]

The ships have performed beyond expectations in both level ice up to 1 metre (3.3 ft) thick, which can be broken in continuous motion at 3 knots (5.6 km/h; 3.5 mph),[14] and ridges up to 13 metres (43 ft) deep, which can be penetrated by either allowing the forward-facing propeller to mill (crush) the ice or breaking the ridge apart with the propeller wash.[19][35] While the vessels have been immobilized occasionally by pack ice, they have been able to free themselves by using the rotating propeller pod to clear the ice around the hull.[36]

References edit

  1. ^ a b c d e f g h i j k l m n "Mikines (9235892)". Equasis. French Ministry for Transport. Retrieved 19 March 2022.
  2. ^ a b "Fartøyet LAOI8 MASTERA". Norwegian Maritime Authority. Retrieved 21 September 2021.
  3. ^ a b c d e f g h "Alma (9235892)". Sea-web. Retrieved 26 June 2022.
  4. ^ "Mastera (9235892)". Miramar Ship Index. Retrieved 13 March 2020.
  5. ^ a b c d Vapalahti, H: Finnish illustrated List of Ships 2007. Judicor Oy, 2008.
  6. ^ a b "Suomen suurin öljytankkeri ruotsalaisomistukseen: "Merimiehet huutavat liikenneministeri Sanna Marinin ja pääministeri Antti Rinteen perään"". Iltalehti (in Finnish). Alma Media Suomi Oy. 5 August 2019. Retrieved 6 August 2019.
  7. ^ a b c d The development of the new double acting ships for ice operation 2012-03-03 at the Wayback Machine. Aker Arctic, 2001.
  8. ^ a b c Remmiä kaulan ympärillä kiristetään jatkuvasti. Merimies - Sjömannen, 3/10[permanent dead link]. Suomen Merimies-Unioni. Retrieved 2011-09-20.
  9. ^ a b c d e f g h i j . Neste Oil. 2004. Archived from the original on 29 September 2011. Retrieved 20 September 2011.
  10. ^ a b c d Potkurikeksintö herätti kilpailijat 2012-04-01 at the Wayback Machine. Tekniikka & Talous, 9 October 2003. Retrieved 2011-09-19.
  11. ^ a b MASTERA: double-acting tanker for Arctic routes. Significant Ships 2003, page 66.
  12. ^ a b c d Tempera telakalla. Vapaavahti 4/2010 2012-04-02 at the Wayback Machine, pages 4-7. Merimiespalvelutoimisto, 2010.
  13. ^ a b c Varmoilla jäillä. Refine 1/07 2012-04-02 at the Wayback Machine, pages 25-27. Neste oil, 2007.
  14. ^ a b Fortum ́s Double Acting Tankers. ABB. Retrieved 2014-04-03.
  15. ^ a b Fortum toi Itämerelle ketterän öljytankkerin, Tekniikka & Talous, 2002-11-14
  16. ^ Kujala, P and Riska, K: Talvimerenkulku (TKK-AM-13). Department of Applied Mechanics, Helsinki University of Technology, 2010.
  17. ^ Aker Arctic Technology Inc.: Icebreaking Supply Vessels Arcticaborg and Antarcticaborg 2011-07-18 at the Wayback Machine. Retrieved 2010-02-08.
  18. ^ a b c Juurmaa, K et al.: New ice breaking tanker concept for the arctic (DAT) 2012-03-03 at the Wayback Machine. Kvaerner Masa-Yards Arctic Technology, 1995.
  19. ^ a b c d e f Juurmaa, K et al.: The development of the new double acting ships for ice operation. Kvaerner Masa-Yards Arctic Technology, 2001 2012-03-03 at the Wayback Machine and 2002 2012-09-04 at the Wayback Machine.
  20. ^ NextStop - Merten valtiaat. Refine 2/06 2013-08-14 at the Wayback Machine, page 24. Neste Oil, 2006.
  21. ^ a b TEMPERA Tanker double act 2012-03-31 at the Wayback Machine. The Motor Ship, 1 October 2002. Retrieved 2011-09-26.
  22. ^ Ice-class tankers 2014-07-16 at the Wayback Machine. Lloyd's Register, 16 April 2004. Retrieved 2011-09-26.
  23. ^ The Ship of The Year 2002 Award goes to the Tempera 2005-02-14 at the Wayback Machine. SEA Japan No. 300, August–September 2003.
  24. ^ Refine 1/08, page 23. Neste Oil, 2008.
  25. ^ Opening up Arctic oil resources. High Technology Finland 2006. Retrieved 2011-09-26.
  26. ^ Ahteri edellä Primorskiin. Rannikkoseutu, 13 April 2011. Retrieved 2011-09-26.
  27. ^ Neste Oilin tankkialus ajoi ensimmäisenä uutta syväväylää Naantaliin. Helsingin Sanomat, 25 April 2010. Retrieved 2011-09-26.
  28. ^ Ilmarinen varustamobisneksestä: Riskit minimoitu. Taloussanomat, 19 September 2013. Retrieved 2013-09-19.
  29. ^ A passion for ice. High Tech Finland 2011. Retrieved 2011-09-26.
  30. ^ a b Anatoly Gorshkovskij & Göran Wilkman: "Norilskiy Nickel" a Breakthrough in Cost Efficient Arctic Transports 2007-10-10 at the Wayback Machine. Aker Arctic Technology Inc, 2007. Retrieved 2010-06-07.
  31. ^ "Weekly S&P market report" (PDF). 11 March 2022. Retrieved 19 March 2022.
  32. ^ "Fake Signals and American Insurance: How a Dark Fleet Moves Russian Oil". New York Times. 30 May 2023. Retrieved 26 June 2023.
  33. ^ References - Propulsion Products. ABB. Retrieved 2015-05-28.
  34. ^ Azipod Propulsion, ABB
  35. ^ Opening up the Arctic. High Technology Finland 2005. Retrieved 2010-09-26.
  36. ^ Oil Tanker Maestra cuts backward course through solid ice 2012-03-29 at the Wayback Machine. Helsingin Sanomat International Edition, 1 April 2003. Retrieved 2011-09-26.

petali, aframax, crude, tanker, formerly, known, mastera, almost, decades, briefly, mikines, early, 2022, alma, until, september, 2023, sister, ship, tempera, were, first, ships, utilize, double, acting, tanker, concept, which, vessel, designed, travel, ahead,. MT Petali is an Aframax crude oil tanker Formerly known as Mastera for almost two decades and briefly as Mikines in early 2022 and Alma until September 2023 she and her sister ship Tempera were the first ships to utilize the double acting tanker DAT concept in which the vessel is designed to travel ahead in open water and astern in severe ice conditions 7 15 The icebreaking tanker was built to transport crude oil year round from the Russian oil terminal in Primorsk to Neste Oil refineries in Porvoo and Naantali 8 Petali as Mastera outside the Port of RotterdamHistoryNameMastera 2003 January 2022 Mikines January June 2022 Alma June 2022 2023 Petali 2023 present 3 OwnerABB Credit 2003 2006 1 SEB Leasing 2006 2014 5 SSC Maslaiva 2014 2019 1 SEB Leasing 2019 January 2022 6 Neste Shipping January 2022 1 Omega Shipmanagement January February 2022 1 Neptune Seaway February June 2022 1 Zenaida Seaways June 2022 2023 3 Lauriane Shipping Corp 2023 present 3 OperatorNeste Shipping 2003 2014 OSM Ship Management 2014 2015 1 Neste Shipping 2014 January 2022 1 Chemikalien Seetransport January February 2022 1 Neptune Seaway February June 2022 1 Zenaida Seaways June 2022 3 Lauriane Shipping Corp 2023 present 3 Port of registryPorvoo Finland 2002 2021 Arendal Norway 2021 2022 2 Monrovia Liberia 2022 RoutePrimorsk Porvoo Naantali until January 2022 8 Ordered2001 7 BuilderSumitomo Heavy Industries Ltd Yokosuka Japan 9 Cost60 70 million euro estimate 10 Launched30 September 2002 4 Completed8 January 2003 3 In service2003 9 IdentificationCall sign 5LEL4 1 IMO number 9235892 1 MMSI number 636021543 1 StatusIn service 1 General characteristics 9 TypeCrude oil tankerClassification Lloyd s Register of ShippingTonnage64 259 GT 30 846 NT 106 208 DWTLength252 0 m 826 77 ft overall Beam44 0 m 144 4 ft Height53 1 m 174 ft Draught15 3 m 50 ft summer 8 6 m 28 ft ballast Depth22 5 m 74 ft Ice class1A SuperInstalled power2 Wartsila 9L38B 5 2 6 0 MW 2 Wartsila 6L38B 5 2 4 0 MW PropulsionABB Azipod 16 MW Two bow thrusters 2 1 750 kW 11 Speed15 2 knots 28 2 km h 17 5 mph max 5 13 5 knots 25 0 km h 15 5 mph service 3 knots 5 6 km h 3 5 mph 1 m 3 3 ft ice 14 Crew15 20 12 13 Contents 1 Concept 2 History 2 1 Development 2 2 Career 3 Design 3 1 General characteristics 3 2 Cargo tanks and handling 3 3 Power and propulsion 3 4 Icebreaking capability 4 ReferencesConcept editMain article Double acting ship 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 16 However already 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 17 These findings resulted in the adoption of bow propellers in older icebreakers operating in the Great Lakes and the Baltic Sea but as forward facing propellers have a very low propulsion efficiency and the steering ability of a ship is greatly reduced when running astern it could not be considered a main operating mode for merchant ships 18 19 For this reason it was not until the development of electric podded propulsion ABB s Azipod that the concept of double acting ships became feasible The superiority of podded propulsion in icebreaking merchant ships especially when running astern was proved when Finnish product tankers Uikku and Lunni were converted to Azipod propulsion in 1993 and 1994 respectively 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 18 19 History editDevelopment edit Following the successful operation of the Azipod converted tankers Uikku and Lunni in the Northern Sea Route Kvaerner Masa Yards Arctic Research Centre developed the first double acting tanker concept in the early 1990s The 90 000 DWT tankers were designed to transport oil and gas condensate from the Pechora Sea in the Russian Arctic where ice conditions during winter can be considered moderate and the ships would operate mainly in astern mode first to Murmansk and then Rotterdam where most of the distance can be travelled in open water year round 18 Other early double acting concepts included a similar ship with an icebreaking bow that would be utilized in summer time when the ship was traveling in areas with low ice concentration but with a risk of colliding with multi year ice blocks 19 In early 2000s Fortum Shipping the transportation arm of the Finnish energy company Fortum started a major fleet renewal program to increase the efficiency and reduce the average age of its vessels 20 The program also included replacing the company s old tankers such as the 90 000 ton Natura that were used to transport crude oil to the company s oil refineries in the Gulf of Finland The old ships had traffic restrictions during the worst part of the winter because of their lower ice class of 1C and could not deliver their cargo all the way to the refineries in Porvoo and Naantali because they were denied 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 19 To solve these problems Kvaerner Masa Yards Arctic Research Centre developed a new 100 000 DWT Aframax tanker concept together with Fortum Shipping which ordered two vessels from Sumitomo Heavy Industries in 2001 The new ships were designed to the highest Finnish Swedish ice class 1A Super and to be capable of operating in all ice conditions encountered in the Baltic Sea The possibility to operate in the Pechora Sea was also taken into account in the design process Extensive ice model tests confirmed the vessel s operational capability in level ice rubble fields ice channels and ridges 19 The world s first double acting tanker and the largest 1A Super class oil tanker at that time Tempera was delivered from Yokosuka shipyard in late August 2002 21 22 She was awarded the Ship Of The Year 2002 award by the Society of Naval Architects of Japan SNAJ 23 The second ship Mastera was delivered in the following year 7 9 Both ships were named after the company s oil products 24 While the price of the contract was not made public the company later admitted that the 60 70 million euro estimate was quite close to the truth The ships were owned by ABB Credit which leased them to Fortum for ten years 10 The leasing business was later sold to SEB Leasing Career edit nbsp MT Mastera in 2020 near PrimorskSince the beginning Tempera and Mastera were used mainly for year round transportation of crude oil from the Russian oil terminal of Primorsk to company s own oil terminals in Porvoo and Naantali 8 where they were the only ships capable of operating without delays or problems during the harshest winters 25 Occasionally they also carried cargoes in the Gulf of Bothnia and even outside the Baltic Sea depending on the amount of oil in the refineries storage tanks 13 26 However due to draft restrictions the ships could not carry a full cargo of 100 000 tons to the port of Naantali until April 2010 they had to stop at Porvoo on the way and unload 20 000 tons of oil to reduce the draft of the vessel 27 In 2005 Fortum s oil division was transferred to the re established Neste Oil and the management of the ships including the double acting tankers was handed over to a subsidiary company Neste Shipping On 19 September 2013 Neste Oil announced that it would sell its shipping business and the majority of its ships including Mastera to a new company owned by the Finnish insurance company Ilmarinen and the National Emergency Supply Agency 28 In 2019 Mastera was resold back to SEB Leasing 6 Since 2017 Mastera was the only double acting tanker operating in the Baltic Sea after Tempera was sold overseas 29 While other double acting ships have been built the tankers operated by Neste Shipping were the only ones equipped with a bulbous bow designed primarily with open water performance in mind the tankers and container ships built for the Russian Arctic have a more traditional icebreaking bow due to the more severe ice conditions 30 In September 2021 Mastera was transferred to the Norwegian International Ship Register 2 In January 2022 she was renamed Mikines and reflagged to Liberia 1 In March 2022 the 19 year old Mikines appeared on list of tonnage sold for demolition 31 but has since resumed trading and was renamed Alma in June 2022 3 In May 2023 Alma was recognized as one of the oil tankers transmitting a falsified automatic identification system AIS to circumvent the 2022 Russian crude oil price cap sanctions 32 In September 2023 the ship was renamed Petali 3 Design editGeneral characteristics edit The double acting Aframax tanker is 252 0 metres 826 8 ft long overall and 237 59 metres 779 5 ft between perpendiculars The moulded breadth and depth of her hull are 44 0 metres 144 4 ft and 22 5 metres 74 ft respectively and from keel to mast she measures 53 1 metres 174 ft Her gross tonnage is 64 259 and net tonnage 30 846 and the deadweight tonnage corresponding to the draft at summer freeboard 15 3 metres 50 ft is 106 208 tons slightly more than that of her sister ship In ballast the ship draws only 8 6 metres 28 ft of water 9 The foreship of the tanker is designed for open water performance with a bulbous bow to maximize the hydrodynamic efficiency The ship is just like any other ice strengthened vessel also capable of running ahead in light ice conditions The stern is however shaped like an icebreaker s bow and the vessel is designed to operate independently in the most severe ice conditions of the Baltic Sea 7 For this purpose the ship is also equipped with two bridges for navigating in both directions 9 The ship is served by a crew of 15 to 20 depending on operating conditions during winter and maintenance work during summer 12 13 The ship is classified by Lloyd s Register of Shipping 9 Cargo tanks and handling edit The ship has six pairs of heated partially epoxy coated cargo tanks and one pair of fully coated slop tanks all divided by a longitudinal center bulkhead and protected by double hull with a combined capacity of 121 158 2 cubic metres 4 278 660 cu ft at 98 filling For cargo handling she has three electrically driven cargo oil pumps with a capacity of 3 500 m3 h 130 m and one cargo oil stripping pump rated for 300 m3 h 130 m The cargo can be loaded in 10 hours and discharged in 12 hours Each cargo tank has two and both slop tanks one automated tank cleaning machines as well as holes for portable tank cleaning machines 9 The ship s ballast water capacity of 46 922 4 cubic metres 1 657 050 cu ft is divided into sixteen segregated ballast tanks six pairs in the double hull around the cargo tanks two fore peak tanks and two aft peak tanks 21 She has two electrically driven ballast pumps rated at 2 500 m3 h 35 m and 3 000 m3 h 70 m 9 The ballast capacity is needed to maintain correct trim especially during drydocking the empty ship has an aft trim of 3 metres 9 8 ft and an uneven weight distribution may damage the hull girder 12 Power and propulsion edit The ship has diesel electric powertrain with four main generating sets two nine cylinder Wartsila 9L38B and two six cylinder 6L38B four stroke medium speed diesel engines with a combined output of 20 MW 27 000 hp The main engines are equipped with exhaust gas economizers In addition Mastera has one auxiliary diesel generator that can be used when the ship is at port The auxiliary generator six cylinder Wartsila 6L26A has an output of 1 7 MW 2 300 hp While underway at 13 5 knots 25 0 km h 15 5 mph the fuel consumption of the ship s main engines is 56 tons of heavy fuel oil per day when loaded and 40 tons per day in ballast Her tanks can store 2 890 1 cubic metres 102 060 cu ft of heavy fuel oil for the main engines 308 2 cubic metres 10 880 cu ft of diesel oil for the auxiliary generator steam boilers and inert gas system and 63 2 cubic metres 2 230 cu ft of lubrication oil 9 When built Mastera and her sister ship were the first tankers propelled by ABB Azipod electric azimuth thrusters capable of rotating 360 degrees around the vertical axis The pulling type VI2500 pods in these two ships with a nominal output of 16 MW and 7 8 metre 26 ft fixed pitch propellers turning at 86 rpm are the most powerful ice strengthened Azipod units ABB has ever produced 10 33 The forward facing propeller increases the propulsion efficiency due to optimal water flow to the propeller and thus improves fuel efficiency In addition an azimuthing thruster s ability to direct thrust to any direction also results in excellent manoeuvrability characteristics that exceeds those of ships utilizing traditional mechanical shaftlines and rudders 34 The turning circle of the Azipod equipped double acting ships is only half a kilometer at full speed half of that of a traditional oil tanker of the same size This is a significant safety factor as the stopping distance of a traditional tanker can be up to 2 5 kilometres 1 6 mi 15 For maneuvering at low speeds in harbours the ship is also equipped with two 1 750 kW bow thrusters 11 Icebreaking capability edit The icebreaking capability of the double acting tankers proved to be superior to other ships since the beginning in shuttle service between Primorsk Russia and the Finnish refineries the tankers require no icebreaker assistance and have even acted as an icebreaker for other merchant ships that have utilized the wide channel opened by the Aframax tanker 10 30 However this has not been intentional when the world s largest 1A Super class ice tanker Stena Arctica also owned by Neste Shipping became stuck in ice outside the port of Primorsk during the winter of 2009 2010 a decision was made to leave the assisting to Russian icebreakers 12 The ships have performed beyond expectations in both level ice up to 1 metre 3 3 ft thick which can be broken in continuous motion at 3 knots 5 6 km h 3 5 mph 14 and ridges up to 13 metres 43 ft deep which can be penetrated by either allowing the forward facing propeller to mill crush the ice or breaking the ridge apart with the propeller wash 19 35 While the vessels have been immobilized occasionally by pack ice they have been able to free themselves by using the rotating propeller pod to clear the ice around the hull 36 References edit nbsp Wikimedia Commons has media related to Mastera a b c d e f g h i j k l m n Mikines 9235892 Equasis French Ministry for Transport Retrieved 19 March 2022 a b Fartoyet LAOI8 MASTERA Norwegian Maritime Authority Retrieved 21 September 2021 a b c d e f g h Alma 9235892 Sea web Retrieved 26 June 2022 Mastera 9235892 Miramar Ship Index Retrieved 13 March 2020 a b c d Vapalahti H Finnish illustrated List of Ships 2007 Judicor Oy 2008 a b Suomen suurin oljytankkeri ruotsalaisomistukseen Merimiehet huutavat liikenneministeri Sanna Marinin ja paaministeri Antti Rinteen peraan Iltalehti in Finnish Alma Media Suomi Oy 5 August 2019 Retrieved 6 August 2019 a b c d The development of the new double acting ships for ice operation Archived 2012 03 03 at the Wayback Machine Aker Arctic 2001 a b c Remmia kaulan ymparilla kiristetaan jatkuvasti Merimies Sjomannen 3 10 permanent dead link Suomen Merimies Unioni Retrieved 2011 09 20 a b c d e f g h i j Mastera Tempera Neste Oil 2004 Archived from the original on 29 September 2011 Retrieved 20 September 2011 a b c d Potkurikeksinto heratti kilpailijat Archived 2012 04 01 at the Wayback Machine Tekniikka amp Talous 9 October 2003 Retrieved 2011 09 19 a b MASTERA double acting tanker for Arctic routes Significant Ships 2003 page 66 a b c d Tempera telakalla Vapaavahti 4 2010 Archived 2012 04 02 at the Wayback Machine pages 4 7 Merimiespalvelutoimisto 2010 a b c Varmoilla jailla Refine 1 07 Archived 2012 04 02 at the Wayback Machine pages 25 27 Neste oil 2007 a b Fortum s Double Acting Tankers ABB Retrieved 2014 04 03 a b Fortum toi Itamerelle ketteran oljytankkerin Tekniikka amp Talous 2002 11 14 Kujala P and Riska K Talvimerenkulku TKK AM 13 Department of Applied Mechanics Helsinki University of Technology 2010 Aker Arctic Technology Inc Icebreaking Supply Vessels Arcticaborg and Antarcticaborg Archived 2011 07 18 at the Wayback Machine Retrieved 2010 02 08 a b c Juurmaa K et al New ice breaking tanker concept for the arctic DAT Archived 2012 03 03 at the Wayback Machine Kvaerner Masa Yards Arctic Technology 1995 a b c d e f Juurmaa K et al The development of the new double acting ships for ice operation Kvaerner Masa Yards Arctic Technology 2001 Archived 2012 03 03 at the Wayback Machine and 2002 Archived 2012 09 04 at the Wayback Machine NextStop Merten valtiaat Refine 2 06 Archived 2013 08 14 at the Wayback Machine page 24 Neste Oil 2006 a b TEMPERA Tanker double act Archived 2012 03 31 at the Wayback Machine The Motor Ship 1 October 2002 Retrieved 2011 09 26 Ice class tankers Archived 2014 07 16 at the Wayback Machine Lloyd s Register 16 April 2004 Retrieved 2011 09 26 The Ship of The Year 2002 Award goes to the Tempera Archived 2005 02 14 at the Wayback Machine SEA Japan No 300 August September 2003 Refine 1 08 page 23 Neste Oil 2008 Opening up Arctic oil resources High Technology Finland 2006 Retrieved 2011 09 26 Ahteri edella Primorskiin Rannikkoseutu 13 April 2011 Retrieved 2011 09 26 Neste Oilin tankkialus ajoi ensimmaisena uutta syvavaylaa Naantaliin Helsingin Sanomat 25 April 2010 Retrieved 2011 09 26 Ilmarinen varustamobisneksesta Riskit minimoitu Taloussanomat 19 September 2013 Retrieved 2013 09 19 A passion for ice High Tech Finland 2011 Retrieved 2011 09 26 a b Anatoly Gorshkovskij amp Goran Wilkman Norilskiy Nickel a Breakthrough in Cost Efficient Arctic Transports Archived 2007 10 10 at the Wayback Machine Aker Arctic Technology Inc 2007 Retrieved 2010 06 07 Weekly S amp P market report PDF 11 March 2022 Retrieved 19 March 2022 Fake Signals and American Insurance How a Dark Fleet Moves Russian Oil New York Times 30 May 2023 Retrieved 26 June 2023 References Propulsion Products ABB Retrieved 2015 05 28 Azipod Propulsion ABB Opening up the Arctic High Technology Finland 2005 Retrieved 2010 09 26 Oil Tanker Maestra cuts backward course through solid ice Archived 2012 03 29 at the Wayback Machine Helsingin Sanomat International Edition 1 April 2003 Retrieved 2011 09 26 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