Editing Rogue wave (section)

==Quantifying the impact of rogue waves on ships==

The loss of the {{MS|München}} in 1978 provided some of the first physical evidence of the existence of rogue waves. ''München'' was a state-of-the-art cargo ship with multiple water-tight compartments and an expert crew. She was lost with all crew, and the wreck has never been found. The only evidence found was the starboard lifeboat recovered from floating wreckage sometime later. The lifeboats hung from forward and aft blocks {{convert|20|m|ft|abbr=on}} above the waterline. The pins had been bent back from forward to aft, indicating the lifeboat hanging below it had been struck by a wave that had run from fore to aft of the ship and had torn the lifeboat from the ship. To exert such force, the wave must have been considerably higher than {{convert|20|m|ft|abbr=on}}. At the time of the inquiry, the existence of rogue waves was considered so statistically unlikely as to be near impossible. Consequently, the Maritime Court investigation concluded that the severe weather had somehow created an "unusual event" that had led to the sinking of the ''München''.<ref name="BBCFreak">{{cite web
 | url        = http://www.bbc.co.uk/science/horizon/2002/freakwave.shtml
 | title      = Freak Wave – programme summary
 | date       = 14 November 2002
 | website    = www.bbc.co.uk/
 | publisher  = BBC
 | access-date= 15 January 2016
 }}</ref><ref name="McCloskey2014">{{cite book
 | author     = Keith McCloskey
 | title      = The Lighthouse: The Mystery of the Eilean Mor Lighthouse Keepers
 | url        = https://books.google.com/books?id=cOn3AwAAQBAJ
 | date       = 2014
 | publisher  = History Press Limited
 | isbn       = 978-0-7509-5741-0}}</ref>

In 1980, the [[MV Derbyshire|MV ''Derbyshire'']] was lost during [[Typhoon Orchid (1980)|Typhoon Orchid]] south of Japan, along with all of her crew. The ''Derbyshire'' was an ore-bulk oil combination carrier built in 1976. At 91,655 gross register tons, she remains the largest British ship ever lost at sea. The wreck was found in June 1994. The survey team deployed a remotely operated vehicle to photograph the wreck. A private report published in 1998 prompted the British government to reopen a formal investigation into the sinking. The investigation included a comprehensive survey by the [[Woods Hole Oceanographic Institution]], which took 135,774 pictures of the wreck during two surveys. The formal forensic investigation concluded that the ship sank because of structural failure and absolved the crew of any responsibility. Most notably, the report determined the detailed sequence of events that led to the structural failure of the vessel. A third comprehensive analysis was subsequently done by Douglas Faulkner, professor of marine architecture and ocean engineering at the [[University of Glasgow]]. His 2001 report linked the loss of the ''Derbyshire'' with the emerging science on freak waves, concluding that the ''Derbyshire'' was almost certainly destroyed by a rogue wave.<ref name="FaulknerD"/><ref name="FaulknerConference">{{cite conference
 |url          = http://www.ifremer.fr/web-com/molagnon/bv/Faulkner_w.pdf
 |title        = Rogue Waves – Defining Their Characteristics for Marine Design
 |first        = Douglas
 |last         = Faulkner
 |year         = 2000
 |conference   = Rogue Waves 2000 Workshop
 |publisher    = French Research Institute for Exploitation of the Sea
 |location     = Brest
 |pages        = 16
 |access-date  = 15 January 2016
 |quote        = This paper introduces the need for a paradigm shift in thinking for the design of ships and offshore installations to include a Survival Design approach additional to current design requirements.
 |archive-date = 15 February 2018
 |archive-url  = https://web.archive.org/web/20180215024344/http://www.ifremer.fr/web-com/molagnon/bv/Faulkner_w.pdf
 |url-status   = dead
}}</ref><ref name = EuropeanUnionSurvey >{{cite web
 | url        = http://www.worldnavalships.com/forums/showthread.php?t=13867
 | title      = The Loss of the 'DERBYSHIRE'
 | last1      = Brown
 | first1     = David
 | year       = 1998
 | publisher  = Crown
 | archive-url = https://web.archive.org/web/20130322054007/http://www.worldnavalships.com/forums/showthread.php?t=13867
 | archive-date = 2013-03-22
 | type       = Technical Report }}</ref><ref name = HansardJune2002>
{{Cite Hansard
 | house      = House of Commons
 | title      = Ships and Seafarers (Safety)
 | url        = https://www.theyworkforyou.com/whall/?id=2002-06-25.193.1
 | date       = 25 June 2002
 | column_start= 193WH
 | column_end = 215WH
 | quote      = The MV ''Derbyshire'' was registered at Liverpool and, at the time, was the largest ship ever built; it was twice the size of the ''Titanic''. }}</ref><ref name = WoodsHoleNavigation>{{cite web
 | url        = https://apps.dtic.mil/sti/pdfs/ADA370001.pdf
 | archive-url = https://web.archive.org/web/20170204151313/http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA370001
 | url-status = live
 | archive-date = February 4, 2017
 | title      = Navigation for the ''Derbyshire'' Phase2 Survey
 | last1      = Lerner
 | first1     = S.
 | last2      = Yoerger
 | first2     = D.
 | last3      = Crook
 | first3     = T.
 | date       = May 1999
 | publisher  = Woods Hole Oceanographic Institution MA
 | pages      = 28
 | type       = Technical Report
 | id         = WHOI-99-11
 | quote =In 1997, the Deep Submergence Operations Group of the Woods Hole Oceanographic Institution conducted an underwater forensic survey of the UK bulk carrier MV ''Derbyshire'' with a suite of underwater vehicles. This report describes the navigation systems and methodologies used to position the vessel and vehicles precisely. Precise navigation permits the survey team to control the path of the subsea vehicle to execute the survey plan, provides the ability to return to specific targets, and allows the assessment team to correlate observations made at different times from different vehicles. This report summarizes the techniques used to locate Argo and the repeatability of those navigation fixes. To determine repeatability, we selected a number of instances where the vehicle lines crossed. We can determine the true position offset by registering two images from overlapping areas on different track lines. We can determine the navigation error by comparing the position offset derived from the images to the offsets obtained from navigation. The average error for 123 points across a single tie line was 3.1 meters, the average error for a more scattered selection of 18 points was 1.9 meters.
 | ref        = WHOI-99-11}}</ref>

Work by sailor and author Craig B. Smith in 2007 confirmed prior forensic work by Faulkner in 1998 and determined that the ''Derbyshire'' was exposed to a [[hydrostatic pressure]] of a "static head" of water of about {{convert|20|m|ft|abbr=on}} with a resultant [[static pressure]] of {{convert|201|kPa|bar psi}}.{{efn|Equivalent to {{nowrap|20,500 kgf/m<sup>2</sup>}} or {{nowrap|20.5 t/m<sup>2</sup>}}.}} This is in effect {{convert|20|m|abbr=on}} of seawater (possibly a super rogue wave){{efn|The term "super rogue wave" had not yet been coined by ANU researchers at that time.}} flowing over the vessel. The deck cargo hatches on the ''Derbyshire'' were determined to be the key point of failure when the rogue wave washed over the ship. The design of the hatches only allowed for a static pressure less than {{convert|2|m|ft|abbr=on}} of water or {{convert|17.1|kPa|bar psi |abbr=on}},{{efn|Equivalent to {{nowrap|1,744 kgf/m<sup>2</sup>}} or {{nowrap|1.7 t/m<sup>2</sup>}}.}} meaning that the typhoon load on the hatches was more than 10 times the design load. The forensic structural analysis of the wreck of the ''Derbyshire'' is now widely regarded as irrefutable.<ref name="SmithConference"/>

In addition, fast-moving waves are now known to also exert extremely high dynamic pressure. Plunging or breaking waves are known to cause short-lived impulse pressure spikes called [[Gifle peaks]]. These can reach pressures of {{convert|200|kPa|bar psi|abbr=on}} (or more) for milliseconds, which is sufficient pressure to lead to brittle fracture of mild steel. Evidence of failure by this mechanism was also found on the ''Derbyshire''.<ref name="FaulknerD">{{cite book
 |last      = Faulkner
 |first     = Douglas
 |date      = 1998
 |title     = An Independent Assessment of the Sinking of the M.V. ''Derbyshire''
 |url       = http://www.sname.org/HigherLogic/System/DownloadDocumentFile.ashx?DocumentFileKey=df0dc59b-5d4e-43a2-9c97-f2a031de8ca6
 |archive-url = https://web.archive.org/web/20160418161247/http://www.sname.org/HigherLogic/System/DownloadDocumentFile.ashx?DocumentFileKey=df0dc59b-5d4e-43a2-9c97-f2a031de8ca6
 |url-status  = dead
 |archive-date = 2016-04-18
 |publisher = SNAME Transactions, Royal Institution of Naval Architects
 |pages     = 59–103
 |quote     = The author's starting point, therefore, was to look for an extraordinary cause. He reasoned that nothing could be more extraordinary than the violence of a fully arisen and chaotic storm-tossed sea. He therefore studied the meteorology of revolving tropical storms and freak waves and found that steep elevated waves of 25 to 30 m or more were quite likely to have occurred during Typhoon Orchid.
}}</ref> Smith documented scenarios where hydrodynamic pressure up to {{convert|5650|kPa|bar psi |abbr=on}} or over 500&nbsp;metric tonnes/m<sup>2</sup> could occur.{{efn|Equivalent to {{nowrap|576,100 kgf/m<sup>2</sup>}} or {{nowrap|576.1 t/m<sup>2</sup>}}.}}<ref name="SmithConference"/>

In 2004, an extreme wave was recorded impacting the Alderney Breakwater, [[Alderney]], in the [[Channel Islands]]. This [[Breakwater (structure)|breakwater]] is exposed to the Atlantic Ocean. The peak pressure recorded by a shore-mounted transducer was {{Convert|745|kPa|bar psi |abbr=on}}. This pressure far exceeds almost any design criteria for modern ships, and this wave would have destroyed almost any merchant vessel.<ref name="MyUser_Soest.hawaii.edu_April_16_2016c">{{cite web
 | url        = http://www.soest.hawaii.edu/PubServices/Muller_Rogue_Wave.pdf
 | title      = Rogue Waves: The Fourteenth 'Aha Huliko'A Hawaiian Winter Workshop
 | newspaper  = Soest.hawaii.edu
 | date       = 3 September 2005
 | publisher  = Oceanography
 | volume     = 18
 | issue      = 3
 | pages      = 66–70
 | access-date = April 16, 2016}}</ref>