View source for Engineering:Oblique icebreaker

{{short description|Asymmetric icebreaker that can break ice sideways to open a wide channel}}
[[File:Oblique Icebreaker Arctech NB508.jpg|thumb|right|A rendering of the icebreaking multipurpose emergency and rescue vessel ordered by the Russian Ministry of Transport, showing the unconventional operating mode of an oblique icebreaker.]]

An '''oblique icebreaker''' is a special type of [[Engineering:Icebreaker|icebreaker]] designed to operate not only ahead and astern, but also obliquely (sideways) with a large [[Physics:Angle of attack|angle of attack]]. In this way, a relatively small icebreaker is capable of opening a wide channel in ice for large merchant ships.

The oblique icebreaker concept was developed in the late 1990s by Kværner Masa-Yards Arctic Technology Centre (MARC), the Finnish engineering company also responsible for the development of the [[Engineering:Double acting ship|double acting ship]]s. The first vessel of this kind was ordered by the Russian Ministry of Transport on 8 December 2011 and was completed in 2014.

== Development ==

The development of the oblique icebreaker concept began in 1997, when Kværner Masa-Yards Arctic Technology Centre (MARC) established a project to develop new ways of assisting large tankers in ice conditions. Traditionally, escorting large ships up to {{convert|40|m|ft}} wide required two conventional icebreakers with a [[Engineering:Beam (nautical)|beam]] of {{convert|23|-|25|m|ft}}, a practice that was not very efficient and economical. Analysis of Finnish harbour statistics and icebreaker logbooks showed that with a beam of {{convert|20|m|ft}}, the icebreaker would be wide enough to provide assistance to most merchant ships in need of towing. The larger ships, fewer in number, could then be assisted with an unconventional method. The result was an asymmetrical, triangle-shaped vessel with three [[Engineering:Azimuth thruster|azimuth thruster]]s in the "corners" pushing the icebreaker with a 50-degree angle of attack—almost sideways—in ice. [[Ship model basin|Model tests]] in an [[Ice tank|ice tank]] showed that the proposed concept was viable and that the resistance of a large cargo ship was considerably reduced in both level ice as well as frozen brash ice when operating behind the oblique icebreaker.<ref name="poac99">{{cite conference | first1=M. |last1=Arpiainen | first2=M. |last2=Bäckström | first3=R.-A. | last3=Suojanen | title=Revolutionary Oblique Icebreaker | conference=15th International Conference on Port and Ocean Engineering under Arctic Conditions, 1999 (POAC'99). Espoo, Finland |year=1999 |url=http://poac.com/Papers/POAC99_V2.zip |pages=552–560}}</ref><ref name="abs">[http://www.eagle.org/eagleExternalPortalWEB/ShowProperty/BEA%20Repository/News%20&%20Events/Publications/Quarterly/Surveyor/2005/Surveyor_Summer05 The Oblique Icebreaker]. ABS Surveyor Summer 2005, page 15. {{retrieved |accessdate=2012-10-04}}</ref> The concept has been patented.<ref name="patent">Arpiainen, M. et al. (1999): [http://www.google.fi/patents/US5996520?printsec=abstract Icebreaking method and icebreaker]. United States Patent no. 5,996,520. {{retrieved |accessdate=2012-10-04}}</ref>

Over the years, the concept was further developed by MARC and its successor, Aker Arctic, together with [[Company:ABB Group|ABB]] and the Finnish Funding Agency for Technology and Innovation (Tekes). In addition to icebreaking, the oblique vessel could also be utilized for oil spill response operations in both open and ice-infested waters by using the flat side to guide the oil to a recovery unit.<ref name="abs" /><ref name="tt">[http://www.tekniikkatalous.fi/rakennus/vino+jaanmurtaja+kulkee+kylki+edella/a30550 Vino jäänmurtaja kulkee kylki edellä]. Tekniikka & Talous, 30 October 2003. {{retrieved |accessdate=2012-10-04}}</ref> However, there have also been doubts about the ability of the relatively small vessel to break a wide channel in ice without the much greater displacement and shaft power of a traditional icebreaker.<ref name="tiede">Kauhanen, E. (2003): [http://www.tiede.fi/artikkeli/447/jaat_pareiksi_sitten_kesatoihin Jäät päreiksi, sitten kesätöihin] {{webarchive|url=https://web.archive.org/web/20120511022204/http://www.tiede.fi/artikkeli/447/jaat_pareiksi_sitten_kesatoihin |date=2012-05-11 }}. Tiede 7/2003. {{retrieved |accessdate=2012-10-04}}</ref>

== Construction ==

On 8 December 2011, the Russian Ministry of Transport ordered an icebreaking multipurpose emergency and rescue vessel from Arctech Helsinki Shipyard (AHS), then a joint venture between the Finnish STX Finland Cruise Oy and the Russian United Shipbuilding Corporation. The 76 million [[Finance:Euro|euro]] vessel, based on Aker Arctic's ''Aker ARC 100'' oblique icebreaker concept developed for AHS,<ref>[http://akerarctic.fi/sites/default/files/reference/fields/field_attachments/aker_arc_100_0.pdf Aker ARC 100] {{Webarchive|url=https://web.archive.org/web/20160818181217/http://akerarctic.fi/sites/default/files/reference/fields/field_attachments/aker_arc_100_0.pdf |date=2016-08-18 }}. Aker Arctic. {{retrieved|accessdate=2016-07-21}}</ref> was designed to be capable of breaking level ice up to {{convert|1|m|ft}} thick both ahead and astern, and generate a {{convert|50|m|yd|adj=on}} channel in {{convert|0.6|m|ft|adj=on}} ice when moving sideways using three [[Engineering:Z-drive|Z-drive]] thrusters with a combined output of 7,500{{nbsp}}kW.<ref name="workboat">[http://www.workboat.com/newsdetail.aspx?id=17596 Oblique Icebreaker for Russia]. WorkBoat.com, 8 July 2012. {{retrieved | accessdate=2012-10-04}}</ref> Initially, the hull of the {{convert|76.4|m|ft|adj=on}} vessel referred to as "NB508" was to be built by Shipyard Yantar JSC in Yantar, Kaliningrad, where production began on 24 April 2012<ref name="arctech2">[http://arctech.fi/wp-content/uploads/PRESS-RELEASE-24042012-NB-508-Start-of-Production.pdf The Production of Icebreaking Multipurpose Emergency and Rescue Vessel Was Started]. Arctech Helsinki Shipyard, 24 April 2012. {{retrieved | accessdate=2012-10-04}}</ref> and keel was laid on 6 July.<ref name="arctech3">[http://arctech.fi/wp-content/uploads/PRESS-RELEASE-06072012-NB-508-Keel-Laying.pdf The Hull Assembly of Icebreaking Emergency and Rescue Vessel started in Kaliningrad]. Arctech Helsinki Shipyard, 6 July 2012. {{retrieved | accessdate=2012-10-04}}</ref> However, instead of launching the unfinished hull in Kaliningrad and towing it to Helsinki for outfitting, the blocks were transported to Helsinki and the hull was assembled in Finland.<ref>[http://arctech.fi/the-hull-assembly-of-an-icebreaking-multipurpose-emergency-and-rescue-vessel-started-at-arctech-helsinki-shipyard/ The Hull Assembly of an Icebreaking Multipurpose Emergency and Rescue Vessel started at Arctech Helsinki Shipyard]. Arctech Helsinki Shipyard, 28 June 2013. {{retrieved|accessdate=2013-07-26}}</ref><ref>[http://www.cb-smartcomp.eu/download.php/dms/smartcomp/meetings and events/Roundtable_May2013/Mustamaki.pdf Shipbuilding cooperation with Russia]. Esko Mustamäki, Arctech Helsinki Shipyard. {{retrieved|accessdate=2013-06-12}}</ref> The first blocks arrived on a barge on 9 April 2013 and the vessel, which was given the name ''Baltika'', was completed in 2014.<ref>[http://jks.1g.fi/kuvat/Laivakuvia/2013-04-09+Arctech+NB-508/ 2013-04-09 Arctech NB-508]. {{retrieved|accessdate=2013-11-10}}</ref> In 2015, the oblique icebreaker carried out ice trials in the Gulf of Ob where the sideways icebreaking was successfully demonstrated for the first time.<ref name="fullscale">[http://akerarctic.fi/en/news/press-release-baltika-revolutionary-oblique-icebreaker-demonstrates-its-operational-capability Baltika revolutionary oblique icebreaker demonstrates its operational capability]. Aker Arctic, 14 April 2015. {{retrieved|accessdate=2015-04-14}}</ref>
{{-}}

== See also ==
* {{annotated link|Engineering:Double acting ship}}

== References ==
{{reflist|30em}}

[[Category:Ship types]]

{{Sourceattribution|Oblique icebreaker}}