Shipwreck: Difference between revisions

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{{Short description|Physical remains of a beached or sunk ship}}

[[Image:8 - AmStar 7.JPG|right|thumb|Shipwreck of the [[SS America]]]]

{{other uses}}

A '''shipwreck''' is the remains of a ship after it has sunk or been beached as a result of a '''crisis at sea'''. [[American English|American]] usage of the word may also mean the ''destruction or loss'' of a ship.

[[File:Shipwreck of the SS American Star on the shore of Fuerteventura.jpg|thumb|upright=1.4|The shipwreck of [[SS America (1939)|SS ''American Star'']] on the shore of [[Fuerteventura]] in 2004]]

{{Admiralty law}}

[[File:Miinitraaleri_"Virsaitis"_vrakk.jpg|thumb|right|A [[sonar]] image of the shipwreck of the [[Soviet Navy]] ship ''[[SMS M68|Virsaitis]]'' in [[Estonia]]n waters]]

[[File:Johan Christian Dahl - Shipwreck on the Coast of Norway - Google Art Project.jpg|thumb|right|[[Johan Christian Dahl]]: ''[[Shipwreck on the Norwegian Coast]]'', 1832]]

[[File:Titanic wreck bow.jpg|thumb|upright=1.4|[[Bow (ship)|Bow]] of {{RMS|Titanic}}, first [[Wreck of the Titanic|discovered]] in 1985]]

[[File:Collision of Costa Concordia 24.jpg|thumb|right|upright=1.4|Wreck of ''[[Costa Concordia]]'']]

A '''shipwreck''' is the wreckage of a [[ship]] that is located either beached on land or sunken to the bottom of a body of water. It results from the event of ''[[shipwrecking]]'', which may be intentional or unintentional. There were approximately three million shipwrecks worldwide as of January 1999, according to Angela Croome, a science writer and author who specialized in the history of underwater archaeology <ref>Angela Croome (January 16, 1999). “[https://www.newscientist.com/article/mg16121696-000-sinking-fast/ Sinking fast] {{Webarchive|url=https://web.archive.org/web/20171225203002/https://www.newscientist.com/article/mg16121696-000-sinking-fast/ |date=2017-12-25 }}”, New Scientist, Volume 161, Issue 2169, pp. 49.</ref> (an estimate rapidly endorsed by [[UNESCO]]<ref>“Sinking fast”, [https://open.unido.org/api/documents/4813394/download/MARINE%20INDUSTRIAL%20TECHNOLOGY%201%20AND%202-1999.%20EMERGING%20TECHNOLOGY%20SERIES%20(22293.en) Marine Industrial Technology, 1 and 2/1999] {{Webarchive|url=https://web.archive.org/web/20210224123545/https://open.unido.org/api/documents/4813394/download/MARINE%20INDUSTRIAL%20TECHNOLOGY%201%20AND%202-1999.%20EMERGING%20TECHNOLOGY%20SERIES%20(22293.en) |date=2021-02-24 }}, Emerging Technology Series, United Nations Industrial Development Organization, pp. 58.</ref><ref>Lucia Iglesias Kuntz (June 12, 2002), “[http://portal.unesco.org/en/ev.php-URL_ID=3304&URL_DO=DO_TOPIC&URL_SECTION=201.html UNESCO urges the Americas to join the underwater heritage convention] {{Webarchive|url=https://web.archive.org/web/20171226020827/http://portal.unesco.org/en/ev.php-URL_ID%3D3304%26URL_DO%3DDO_TOPIC%26URL_SECTION%3D201.html |date=2017-12-26 }}”, UNESCO Media Services.</ref> and other organizations<ref>“[https://sha.org/publication-links/newsletter/newsletter-archives/ Lisbon Resolution] {{Webarchive|url=https://web.archive.org/web/20171225203031/https://sha.org/publication-links/newsletter/newsletter-archives/ |date=2017-12-25 }}”, Society for Historical Archaeology Newsletter, Summer 1999, Volume 32, Number 2, pp. 31.</ref>).

== After the shipwreck ==

When a ship's crew has died or abandoned the ship, and the ship has remained adrift but unsunk, they are instead referred to as [[Ghost ship|''ghost ships'']].

Often, attempts are made to [[marine salvage|salvage]] recently wrecked ships to save the whole or part of the ship, its cargo, its equipment or in the worst case, [[steel]] or non-[[ferrous]] metals for [[scrap]]. A good example of this was the salvage of the [[Kaiserliche Marine]] High Seas Fleet at [[Scapa Flow]] in the 1920s. Shipwrecks are attractive to [[Maritime archaeology|maritime archaeologist]]s because they preserve historical information, for example the [[Mary Rose]], which revealed information about seafaring, warfare and life in the 1500s. [[recreational diving|Recreational divers]] enjoy diving shipwrecks because they are often interesting to explore, provide large habitats for many types of marine life and have an interesting history, for example [[SS Thistlegorm]]. Discoveries of treasure ships, often from the period of European [[colonisation]], which sunk in remote places leaving few living witnesses, such as the [[Batavia (ship)|Batavia]], do occur but only very infrequently.

== Types ==

[[Image:Shipwrec-vernet.jpg|thumb|275px|''Shipwreck'' , by [[Claude Joseph Vernet]].]]

[[File:Sparrow Hawk ship.jpg|thumb|right|The 1626 ''Sparrow-Hawk'' wreck is displayed at the [[Pilgrim Hall Museum]] in [[Plymouth, Massachusetts|Plymouth]], [[Massachusetts]]]]

Historic wrecks are attractive to [[maritime archaeology|maritime archaeologist]]s because they preserve historical information: for example, studying the wreck of {{ship||Mary Rose}} revealed information about seafaring, warfare, and life in the 16th century. Military wrecks, caused by a skirmish at sea, are studied to find details about the historic event; they reveal much about the battle that occurred. Discoveries of [[Spanish treasure fleet|treasure ships]], often from the period of European [[colonisation]], which sank in remote locations leaving few living witnesses, such as {{ship||Batavia|1628 ship|2}}, do occur as well.

Some contemporary wrecks, such as the [[Tanker (ship)|oil tanker]] [[Prestige oil spill|''Prestige'']] or {{ship||Erika|tanker|2}}, are of interest primarily because of their potential harm to the environment. Other contemporary wrecks are scuttled in order to spur reef growth, such as {{MV|Adolphus Busch||2}} and ''Ocean Freeze''. Many contemporary and historic wrecks, such as {{SS|Thistlegorm||2}}, are of interest to [[recreational diving|recreational divers]] that dive to shipwrecks because they are interesting to explore, provide large habitats for many types of marine life, and have an interesting history.

Well-known shipwrecks include the catastrophic ''[[Titanic]]'', [[MV Doña Paz]], {{ship|HMHS|Britannic||2}}, {{RMS|Lusitania||2}}, {{MS|Estonia||2}}, {{RMS|Empress of Ireland||2}}, {{SS|Andrea Doria||2}}, {{ship||Endurance|1912 ship|2}}, {{ship||Costa Concordia}}, and {{ship||SS Waratah||2}}. There are also thousands of wrecks that were not lost at sea but have been abandoned or sunk. These abandoned, or derelict ships are typically smaller craft, such as fishing vessels. They may pose a hazard to navigation<ref>{{cite web|title=Wrecks and Obstructions Database|url=https://www.nauticalcharts.noaa.gov/data/wrecks-and-obstructions.html|website=NOAA|access-date=2018-04-26|archive-date=2018-04-05|archive-url=https://web.archive.org/web/20180405024308/https://www.nauticalcharts.noaa.gov/data/wrecks-and-obstructions.html|url-status=live}}</ref> and may be removed by [[port authority|port authorities]].<ref name="ScurvyDeath2007">{{cite video | title = Scurvy, Death and Cannibalism | medium = internet video | publisher = Shipwreck Central | date = 2007 | url = http://www.webcastr.com/videos/informational/scurvy-death-and-cannibalism.html | url-status = dead | archive-url = https://web.archive.org/web/20080306183447/http://www.webcastr.com/videos/informational/scurvy-death-and-cannibalism.html | archive-date = 2008-03-06 }}</ref>

== Causes ==

{{main|Shipwrecking}}

[[File:Vista Sur.jpg|thumb|right|{{ship||County of Peebles|ship|2}}, used as breakwater in [[Punta Arenas]] at the [[Strait of Magellan]]]]

Poor design, improperly stowed [[cargo]], navigation and other human errors leading to collisions (with another ship, the shoreline, an iceberg, etc.), inadequate maintenance, bad weather, [[fire]], and other causes can lead to accidental sinking. Intentional reasons for sinking a ship include: intending to form an [[artificial reef]]; destruction due to [[war]]fare, [[piracy]], [[mutiny]] or [[sabotage]]; using the vessel for [[target practice]]; or removing a [[hazard to navigation]]. A scuttled ship can be also used as [[Breakwater (structure)|breakwater structure]] or to deny or restrict access to an area to other shipping.

==Distribution==

Ships are lost for many reasons, including:

{{main|Lists of shipwrecks}}

Shipwrecks are widely distributed, but are concentrated where there is more shipping and more [[navigational hazard]]s.

Some shipwrecks have been recorded and the circumstances of loss may be known. other ships have [[List of missing ships|disappeared without trace]] and are assumed to have been wrecked.

== State of preservation ==

* failure of the ship's equipment

[[File:The Wasa from the stern.jpg|thumb|{{ship||Vasa|ship|2}} is one of the oldest and best-preserved ships salvaged in the world, owing to the cool temperatures and low salinity of the [[Baltic Sea]]]]

* instability

* [[navigation]] errors and other human errors, leading to collisions or running aground

* bad [[weather]]

* [[warfare]], [[piracy]], [[mutiny]], or [[sabotage]]

* [[fire]]

Many factors determine the state of preservation of a wreck:

* the ship's construction materials

* the wreck becoming covered in sand or silt

* the [[salinity]] of the water the wreck is in

* the level of destruction involved in the ship's loss

* whether the components or [[cargo]] of the wreck were [[marine salvage|salvage]]d

* whether the wreck was demolished to clear a navigable channel

* the depth of water at the wreck site

* the strength of [[tide|tidal]] currents or [[wave action]] at the wreck site

* the exposure to surface weather conditions at the wreck site

* the presence of [[marine life]] that consume the ship's fabric

* temperature

* the acidity (or [[pH]]), and other chemical characteristics of the water at the site

The above - especially the stratification (silt/sand sediments piled up on the shipwrecks) and the damages caused by marine creatures - is better described as "stratification and contamination" of shipwrecks. The stratification not only creates another challenge for marine archaeology, but also a challenge to determine its primary state, i.e. the state that it was in when it sank.

=== Equipment failure ===

Stratification includes several different types of sand and silt, as well as tumulus and encrustations. These "sediments" are tightly linked to the type of currents, depth, and the type of water (salinity, pH, etc.), which implies any chemical reactions that would affect potential cargo (such as wine, olive oil, spices, etc.).

Failure or leaking of the [[hull (watercraft)|hull]] is a serious problem that can lead to the loss of [[buoyancy]] and the sinking of the vessel. Even the hulls of large modern ships have cracked in heavy [[storm]]s. Leaks between the hull planks of wooden vessels was a particular problem.

Besides this geological phenomenon, wrecks also face the damage of marine creatures that create a home out of them, primarily octopuses and crustaceans. These creatures affect the primary state because they move, or break, any parts of the shipwreck that are in their way, thereby affecting the original condition of [[amphorae]], for example, or any other hollow places. Finally, in addition to the slight or severe destruction marine animals can create, there are also "external" contaminants, such as the artifacts on and around the wreck at [[Pickles Reef]] and the over-lapping wrecks at the [[Molasses Reef Wreck]], or contemporary pollution in bodies of water, that severely affect shipwrecks by changing the chemical structures, or further damaging what is left of a specific ship.

Failure of the means of propulsion, such as [[engine]]s, [[sail]]s or [[rigging]], can lead to the loss of a ship. When the ship's movement is determined only by currents or the [[wind]] and particularly by [[storm]]s, a common result is that the ship is unable to avoid natural hazards like [[rock (geology)|rocks]], shallow water or [[tidal race]]s.

Despite these challenges, if the information retrieved does not appear to be sufficient,{{explain|sufficient for what?|date=January 2019}} or a poor preservation is achieved, authors like J.A. Parker claim that it is the historical value of the shipwreck{{explain|date=January 2019}} that counts as well as any slight piece of information or evidence that is acquired.<ref>{{cite journal| last=Parker| first=A.J.| title=Stratification and contamination in ancient Mediterranean shipwrecks.| journal=The International Journal of Nautical Archaeology and Underwater Exploration| volume=10| year=1981| issue=4| pages=309–335| doi=10.1111/j.1095-9270.1981.tb00045.x}}</ref>

=== Instability ===

=== Construction materials ===

Instability is caused by the center of [[mass]] or other [[force]]s acting on the ship rising above the center of buoyancy resulting in the ship tipping on its side or [[capsize|capsizing]].

[[File:The Wreck, by Knud-Andreassen Baade c.1835.JPG|thumb|upright=1.3|The Wreck, by Knud-Andreassen Baade {{Circa|1835}}]]

Exposed [[wood]]en components decay quickly. Often the only wooden parts of ships that remain after a century are those that were buried in [[silt]] or [[sand]] soon after the sinking. An example of this is ''Mary Rose''.

[[Steel]] and [[iron]], depending on their thickness, may retain the ship's structure for decades. As [[corrosion]] takes place, sometimes helped by tides and weather, the structure collapses. Thick ferrous objects such as [[cannon]]s, [[steam]] [[boiler]]s or the [[pressure vessel]] of a [[submarine]] often survive well underwater in spite of corrosion.

This can lead to a sinking if the openings on the upper side of the side are not watertight at the time of the capsize. To remain buoyant, the hull of a vessel must prevent water entering the large air spaces of the vessel. Clearly for the ship to float, the submerged parts of the hull will be waterlogged, but the upper parts of the hull must have openings to allow the crew to work and to load and unload cargo.

[[Propeller]]s, [[condenser (heat transfer)|condenser]]s, [[hinge]]s and port holes were often made from non-ferrous metals such as [[brass]] and [[phosphor bronze]], which do not corrode easily.

=== Navigation errors ===

=== Salinity of water ===

Many shipwrecks have occurred when the crew of the ship allowed the ship to collide with rocks, [[reef]]s, [[iceberg]]s, or other ships. Accurate navigation is made more difficult by poor visibility in bad weather. Also, many losses happened before modern navigation aids such as [[GPS]], [[radar]] and [[sonar]] were available. Until the twentieth century, the most sophisticated navigational tools and techniques available, [[dead reckoning]] using the [[magnetic compass]], [[chronometer]] and [[sextant]] were rather inaccurate.

====Freshwater and low saline====

Even today, when highly accurate navigational equipment is readily available and universally used, there is still scope for error. Using the incorrect horizontal [[datum]] for the [[chart]] of an area may mislead the navigator, especially as many charts have not been updated to use modern datums. It is also important for the navigator to appreciate that charts may be significantly in error, especially on less frequented coasts. For example, a recent revision of the map of [[South_Georgia_and_the_South_Sandwich_Islands|South Georgia]] in the [[South Atlantic]] showed that previous maps were in some places in error by several kilometres!

Shipwrecks in some [[freshwater]] lakes, such as the [[Great Lakes]] of North America, have remained intact with little degradation. In some sea areas, most notably in [[Gulf of Bothnia]] and [[Gulf of Finland]], salinity is very low, and centuries-old wrecks have been preserved in reasonable condition. However, [[bacteria]] found in fresh water cause the wood on ships to rot more quickly than in seawater unless it is deprived of oxygen.<ref>{{cite web|title=Final Management Plan|url=http://thunderbay.noaa.gov/pdfs/management%20plan_final.pdf#page=20|website=Thunder Bay National Marine Sanctuary|publisher=NOAA|access-date=11 August 2015|archive-date=12 November 2015|archive-url=https://web.archive.org/web/20151112194943/http://thunderbay.noaa.gov/pdfs/management%20plan_final.pdf#page=20|url-status=live}}</ref> Two shipwrecks, {{USS|Hamilton|1809|6}} and {{USS|Scourge|1812|6}}, have been at the bottom of [[Lake Ontario]] since they sunk during a violent storm on August 8, 1813, during the [[War of 1812]]. They are in "remarkably good" condition.<ref>{{cite news|title=Hamilton's War of 1812 shipwrecks 'an archeologist's dream'|url=http://www.cbc.ca/news/canada/hamilton/hamilton-s-war-of-1812-shipwrecks-an-archeologist-s-dream-1.1284755|website=cbc.ca|publisher=CBC News|access-date=11 August 2015|archive-date=24 September 2015|archive-url=https://web.archive.org/web/20150924163740/http://www.cbc.ca/news/canada/hamilton/hamilton-s-war-of-1812-shipwrecks-an-archeologist-s-dream-1.1284755|url-status=live}}</ref>

=== Bad weather =Seawater====

Wrecks typically decay rapidly when in [[seawater]]. There are several reasons for this:

* [[Iron]]-based metals [[corrosion|corrode]] much more quickly in seawater because of the dissolved [[salt]] present; the sodium and chloride [[ion]]s chemically accelerate the process of metal oxidation which, in the case of ferrous metals, leads to [[rust]]. Such cases are prominent on deep-water shipwrecks, such as [[RMS Titanic|RMS ''Titanic'']] (sank 1912), {{RMS|Lusitania}} (sank 1915), and {{ship|German battleship|Bismarck}} (sank 1941). However, there are some exceptions; ''[[RMS Empress of Ireland]]'' (sank 1914) lies in the saltwater portion of the [[St. Lawrence River]], but is still in remarkably good condition.<ref>{{cite web |url=http://www.tekdiv.com/index.php?option=com_content&view=article&id=6&Itemid=56&lang=en |title=Empress of Ireland (Canada) |author=Dominique |year=2010 |access-date=16 March 2019 |work=Tekdiv Exploration |archive-date=18 July 2014 |archive-url=https://web.archive.org/web/20140718180718/http://www.tekdiv.com/index.php?option=com_content&view=article&id=6&Itemid=56&lang=en |url-status=live }}</ref>

* Unprotected wood in seawater is rapidly consumed by [[shipworm]]s and small wood-boring sea creatures. Shipworms found in higher salinity waters, such as the [[Caribbean]], are notorious for boring into wooden structures that are immersed in sea water and can completely destroy the hull of a wooden shipwreck.<ref>{{cite news |last=Gilman |first=Sarah |title=How a Ship-Sinking Clam Conquered the Ocean |url=http://www.smithsonianmag.com/science-nature/tunneling-clam-bedeviled-humans-sank-ships-conquered-oceans-180961288/ |magazine=[[Smithsonian Mag]] |date=December 5, 2016 |access-date=16 March 2019 |archive-date=9 July 2019 |archive-url=https://web.archive.org/web/20190709052941/https://www.smithsonianmag.com/science-nature/tunneling-clam-bedeviled-humans-sank-ships-conquered-oceans-180961288/ |url-status=live }}</ref>

=== Loss, salvage, and demolition ===

Poor weather can cause several problems:

{{Unreferenced section|date=May 2013}}

* wind

* low visibility

* cold

[[File:SS Austria shipwreck.jpg|thumb|The shipwreck of {{SS|Austria}} on 13 September 1858]]

[[Wind]] causes [[wave]]s which result in other difficulties. Waves make navigation difficult and dangerous near shallow water. Also, waves create buoyancy stresses on the structure of a hull. The weight of breaking waves on the fabric of the ship force the crew to reduce [[speed]] or even travel in the same direction as the waves to prevent damage. Also, wind stresses the rigging of sailing ships.

An important factor in the condition of the wreck is the level of destruction at the time of the loss or shortly afterwards due to the nature of the loss, salvage or later demolition.

Examples of severe destruction at the time of loss are:

The force of the wind pushes ships in the direction of the wind. Vessels with large [[windage]] suffer most. Although powered ships are able to resist the force of the wind, sailing vessels have few defences against strong wind. When strong winds are imminent, sailing vessels typically have several choices:

* Being blown onto a beach, reef, or rocks during a storm, termed "grounding" (e.g., {{ship||Royal Adelaide|1865|2}})

* try to position themselves so that they cannot be blown into danger

* Collision with another ship (e.g., {{SS|Andrea Doria||2}})

* shelter in a [[harbour]]

* Catastrophic explosion (e.g., {{HMS|Hood|51|6}}), steamship boilers often explode when water covers them during the process of sinking

* [[anchor]] behind a sheltering [[landform]]

* Fire that burns for a long time before the ship sinks (e.g., {{MS|Achille Lauro||2}})

* Foundering, i.e., taking in so much water that buoyancy is lost and the ship sinks (e.g., RMS ''Titanic'' and HMHS ''Britannic''); some ships with a dense cargo (e.g., iron ore) may break up when sinking quickly and hitting a rocky seabed

* Enemy action from [[aerial bomb]]s or [[torpedo]]es that may cause destruction before sinking (e.g., the {{ship|Italian battleship|Roma|1940|6}} and {{HMS|Barham|04|6}})

After the loss, the vessel's owners may attempt to [[marine salvage|salvage]] valuable parts of the ship and its cargo. This operation can cause further damage.

Many losses of sailing ships were caused by sailing, with a following wind, so far into a [[bay]] that the ship became trapped upwind of a [[lee shore]], being unable to sail into the wind to leave the bay.

Shipwrecks in shallow water near busy shipping lanes are often demolished or removed to reduce the danger to other vessels. On charts, some wreck symbols have a line under the symbol with a depth mark, which indicates the water depth above the wreck.

Low visibility caused by [[fog]], [[mist]] and heavy [[rain]] increase the navigator's problems.

=== Depth, tide and weather ===

Cold can cause metal to become [[brittle]] and fail more easily. A build-up of [[ice]] high on the ship can cause instability.

On the seabed, wrecks are slowly broken up by the forces of [[wave action]] caused by the weather and currents caused by [[tide]]s. Also, more highly oxygenated water, which promotes [[corrosion]], reduces the strength of ferrous structural materials of the ship. Deeper wrecks are likely to be protected by less exposure to water movement and by lower levels of oxygen in water.

=== ViolenceTemperature ===

Extreme cold (such as in a [[glacier|glacial-fed]] lake, [[Arctic]] waters, the [[Great Lakes]], etc.) slows the degradation of organic ship materials. Decay, corrosion and marine encrustation are inhibited or largely absent in cold waters.<ref>{{cite news |last=Steere |first=Mike |title=Superior keeps its shipwrecks fresh Preservation: In the cold, almost sterile water at the bottom of the Great Lake, divers find the remains of marine disasters. |url=https://www.baltimoresun.com/1996/05/12/superior-keeps-its-shipwrecks-fresh-preservation-in-the-cold-almost-sterile-water-at-the-bottom-of-the-great-lake-divers-find-the-remains-of-marine-disasters/ |newspaper=[[Baltimore Sun]] |access-date=29 August 2015 |archive-url=https://web.archive.org/web/20181116061613/http://articles.baltimoresun.com/1996-05-12/features/1996133022_1_lake-superior-great-lakes-lakes-shipping |archive-date=16 November 2018 |url-status=live |date=12 May 1996}}</ref>

==Marine pollution==

[[Warfare]], [[pirate|piracy]] and [[mutiny]] have also led to the loss of many ships.

Many modern shipwrecks contribute to [[marine pollution]], mainly as sources of significant [[oil spill]]s.<ref name="Smithsonian Ocean"/> A 2005 survey of shipwrecks since 1890 found that over 8,500 of the submerged wrecks may still contain oil.<ref>{{cite journal |last1=Michel |first1=Jacqueline |last2=Schmidt Etkin |first2=Dagmar |last3=Gilbert |first3=Trevor |last4=Urban |first4=Robert |last5=Waldron |first5=Jon |last6=Blocksidge |first6=Charles T. |title=Potentially Polluting Wrecks in Marine Waters: An Issue Paper Prepared for the 2005 International Oil Spill Conference |date=2005 |pages=8, 11 |url=https://portal.helcom.fi/meetings/SUBMERGED%205-2016-377/Related%20Information/Potentially%20Polluting%20Wrecks%20in%20Marine%20Water_Michel_etal_2005.pdf |journal=Helcom |archive-date=2022-10-06 |access-date=2022-10-26 |archive-url=https://web.archive.org/web/20221006045726/http://portal.helcom.fi/meetings/SUBMERGED%205-2016-377/Related%20Information/Potentially%20Polluting%20Wrecks%20in%20Marine%20Water_Michel_etal_2005.pdf |url-status=dead }}</ref> Oil spills can have devastating effects on marine and coastal environments as well as fisheries. In addition to being toxic to marine life, [[polycyclic aromatic hydrocarbon]]s (PAHs), found in [[crude oil]], are very difficult to clean up, and last for years in the [[sediment]] and marine environment.<ref name="Panetta">{{Cite book |author=Panetta, L.E. (Chair) |year=2003 |title=America's living oceans: charting a course for sea change |url=https://nauticalcharts.noaa.gov/hsrp/admin/nov2004/oceans_report.pdf |publisher=Pew Oceans Commission |page=64 |archive-date=2024-03-17 |access-date=2022-10-26 |archive-url=https://web.archive.org/web/20240317004850/https://nauticalcharts.noaa.gov/hsrp/admin/nov2004/oceans_report.pdf |url-status=live }}</ref><ref name="VanLanduyt2022">{{Cite journal |last1=Van Landuyt |first1=Josefien |last2=Kundu |first2=Kankana |last3=Van Haelst |first3=Sven |last4=Neyts |first4=Marijke |last5=Parmentier |first5=Koen |last6=De Rijcke |first6=Maarten |last7=Boon |first7=Nico |date=2022-10-18 |title=80 years later: Marine sediments still influenced by an old war ship |journal=Frontiers in Marine Science |volume=9 |pages=1017136 |doi=10.3389/fmars.2022.1017136 |issn=2296-7745|doi-access=free |hdl=1854/LU-01GKS4PJA2JJ06GXN0FQHFMB4D |hdl-access=free }}</ref>

Shipwreck pollution may also originate with a ship's cargo or munitions,<ref name="Smithsonian Ocean">{{cite web |last1=Spalding |first1=Mark J. |title=Underwater WWII Wrecks – Pollution or Cultural Heritage? {{!}} Smithsonian Ocean |url=https://ocean.si.edu/conservation/pollution/underwater-wwii-wrecks-pollution-or-cultural-heritage |publisher=Smithsonian Institution |language=en |date=January 2013 |access-date=2022-10-26 |archive-date=2024-07-23 |archive-url=https://web.archive.org/web/20240723134206/https://ocean.si.edu/conservation/pollution/underwater-wwii-wrecks-pollution-or-cultural-heritage |url-status=live }}</ref> such as [[unexploded ordnance]] or [[chemical weapon]]s canisters.<ref>{{cite journal |last1=Brown |first1=Valerie J. |title=Warfare: Iraq's Toxic Shipwrecks |journal=Environmental Health Perspectives |date=April 2005 |volume=113 |issue=4 |pages=A230 |doi=10.1289/ehp.113-a230 |pmid=15811816 |pmc=1278500 |language=en |issn=0091-6765}}</ref> German trawler [[German trawler V 1302 John Mahn|V 1302 ''John Mahn'']], sunk in the [[North Sea]] in 1942,<ref name="Sven 2020">{{Cite journal |last=Sven |first=Van Haelst |date=2020 |editor-last=Mees |editor-first=Jan |editor2-last=Seys |editor2-first=Jan |title=North Sea Wrecks: A future decision support tool for blue growth activities |url=https://www.researchgate.net/publication/342657720 |journal=Vlaams Instituut voor de Zee – Flanders Marine Institute (VLIZ) |volume=84 |pages=83 |via=ResearchGate}}</ref><ref name="Termote 2009">{{Cite book |last1=Termote |first1=Tomas |title=Schatten en Scheepswrakken: boeiende onderwaterarcheologie in de Noordzee |last2=Termote |first2=Dirk |publisher=Davidsfonds Leuven |year=2009 |language=nl}}</ref> has multiple unexploded [[depth charges]] on board which render the wreck hazardous.<ref name="Sven 2020"/> Samples taken from the wreck and nearby sediment show the presence of [[heavy metals]] like nickel and copper, [[Polycyclic aromatic hydrocarbon|polycyclic aromatic hydrocarbons]], [[arsenic]] and explosive compounds into surrounding waters, which have changed the local microbial ecology.<ref name="VanLanduyt2022"/>

Typical weapons used to sink ships include: [[gun]]s, [[fire]], [[torpedo]]es, [[depth charge]]s, [[naval mine|mine]]s and [[bomb]]s.

==Natural deterioration process==

Examples of the use of violence to sink civilian ships include the [[commerce raiding]], [[unrestricted submarine warfare]] and [[tonnage war]].

[[File:Quartette 03 noaa casserley.jpg|thumb|Propeller amongst corals]]

Iron and steel wrecks are subject to corrosion, which is most rapid in shallow sea water where the salinity induces galvanic corrosion, oxygen content is high and water movement replenishes the oxygen rapidly. In deeper water and in still water the corrosion rates can be greatly reduced. Corrosion rates of iron and steel are also reduced when concretions, solid layers of rust, or layers of marine organisms separate the metal from the ambient water, and encourage the development of a layer of relatively stable black oxide in the hypoxic layers.<ref name="Edney 2006" />

Ships that sink onto a [[sediment]]ary bottom tend to settle into the sediment to a level determined by the density and penetration resistance ([[bearing capacity]]) of the sediment, and is also affected by [[hydrodynamic scour]]. Dynamic conditions can also bury wreckage under sediment. The thinner materials of the upper works tend to break up first, followed by the decks and deck beams, and the hull sides unsupported by bulkheads. The bow and stern may remain relatively intact for longer as they are usually more heavily constructed. Heavy machinery like boilers, engines, pumps, winches, propellers, propeller shafts, steering gear, anchors and other heavy fittings also last longer and can provide support to the remaining hull, or cause it to collapse more rapidly. Vessels that come to rest upside down on a yielding seabed can be relatively stable, although the upper decks usually collapse under the load and machinery and fittings fall. Wrecks that rest on their side tend to deteriorate quickly, as the loads are not what they were designed to support, and poorly supported hull sides give way fairly soon and the wreckage collapses. Wrecks supported by a rocky seabed tend to collapse over and around the rocks relatively rapidly. Submarines tend to last longer as they are built much more strongly to withstand the working loads of external pressure, and may last for centuries.<ref name="Edney 2006" />

===Fire===

Fire can cause the loss of ships in many ways. The most obvious way would be the loss of a wooden ship which is burned until watertight integrity is compromised. The detonation of cargo or ammunition can cause the breach of a steel hull. Often a large fire causes a ship to be abandoned and left to drift. Should it run aground beyond economic salvage, it becomes a wreck. In certain cases, the use of seawater to extinguish a fire results in loss of buoyancy as was the case of the liner [[SS Normandie]].

{{expand section|<ref name="Edney 2006" />|date=March 2020}}

==Prevention of shipwrecks==

==Value==

Over the centuries, many technological and organisational developments have been used to reduce accidents at sea including:

A shipwreck may have value in several forms:<ref name="Edney 2006" >{{cite journal |url=<!--http://www.nla.gov.au/nla.arc-65664-->https://www.researchgate.net/publication/242540533_Impacts_of_recreational_scuba_diving_on_shipwrecks_in_Australia_and_the_Pacific_A_review |title=Impacts of Recreational Scuba Diving on Shipwrecks in Australia and the Pacific - A Review |journal=Micronesian Journal of the Humanities and Social Sciences |publisher=Heritage Futures International |___location=Albury NSW, Australia |issn=1449-7336 |first=Joanne |last=Edney |volume=5 |issue=1/2 Combined |date=November 2006 |archive-date=2021-02-25 |access-date=2020-03-16 |archive-url=https://web.archive.org/web/20210225221039/https://webarchive.nla.gov.au/tep/65664 |url-status=dead }}</ref>

* [[pilotage]] aids including [[lighthouse]]s and [[sea mark]]s

*Cultural heritage,

* basic [[navigation]] tools such as the [[magnetic compass]], [[nautical chart]], [[chronometer]], [[sextant]], [[log (speed)|log]]

*Recreational diving and other tourism attraction

* advanced navigation tools such as the [[radio]] communication, [[gyrocompass]], [[sonar]], hyperbolic [[radio navigation]] and [[satellite navigation]]

*Scientific, educational and monetary values

* inspection of [[shipbuilding]] quality and maintenance of seaworthiness of the ship such as "[[A1 at Lloyd's]]"

**Artificial reefs

* better defences to protect the ship from acts of violence, war and piracy

**Monetary value of salvageable cargo and components

*use of fireproof/unflamable materials to prevent fires from spreading rapildly

{{expand section|<ref name="Edney 2006" />|date=March 2020}}

== Salvage ==

==State of preservation==

{{Main|Marine salvage}}

[[Image:HMS Perseus Wreck - Mediterranean.jpg|thumb|right|300px|The well-preserved wreck of the submarine ''[[HMS Perseus (1929)|HMS Perseus]]'', sunk in the Mediterranean in 1941. The picture was taken in 1996 and shows the well preserved condition of the wreck.]]

Often, attempts are made to salvage shipwrecks, particularly those recently wrecked, to recover the whole or part of the ship, its cargo, or its equipment. An example was the salvage of the [[scuttling of the German fleet at Scapa Flow|scuttled German High Seas Fleet at Scapa Flow]] in the 1920s and 1930s. The unauthorized salvage of wrecks is called [[wrecking (shipwreck)|wrecking]].

=== Legal aspects ===

Many factors determine the state of preservation of a wreck:

{{main|Law of salvage}}

* the ship's construction materials

Shipwreck law determines important legal questions regarding wrecks, perhaps the most important question being the question of ownership. Legally wrecks are divided into ''wreccum maris'' (material washed ashore after a shipwreck) and ''adventurae maris'' (material still at sea),<ref>For example, under English law the former were dealt with under rules relating to things found on land, the latter were dealt with under Admiralty jurisdiction.</ref> which are treated differently by some, but not all, legal systems.

* the level of destruction involved in the ship's loss

[[File:Nanking Cargo kijkdag (1986).jpg|thumb|Viewing at [[Christie's]] auction in Amsterdam for the cargo of the [[Dutch East India Company]] (VOC) ship ''Geldermalsen'' (1747)]]

* whether the components or [[cargo]] of the wreck were [[marine salvage|salvage]]d

Wrecks are often considered separately from their cargo. For example, in the British case of ''[[RMS Lusitania#1984 British legal action|Lusitania]]'' [1986] QB 384 it was accepted that the remains of the vessel itself were owned by the insurance underwriters who had paid out on the vessel as a total loss by virtue of the law of [[subrogation]] (who subsequently sold their rights), but that the property aboard the wreck still belonged to its original owners or their heirs.

* whether the wreck was demolished to clear a navigable channel

* the depth of water at the wreck site

* the strength of [[tide|tidal]] currents at the wreck site

* the exposure to surface weather conditions at the wreck site

* the presence of marine animals that consume the ship's fabric

* the [[salinity]] of the water the wreck is in

* extreme cold (such as a [[glacier|glacial-fed]] lake) can slow degradation of organic ship materials

Military wrecks, however, remain under the jurisdiction{{snd}}and hence protection{{snd}}of the government that lost the ship, or that government's successor. Hence, a German [[U-boat]] from World War II still technically belongs to the German government, although [[Nazi Germany]] (the government at the time) is long-defunct. Many military wrecks are also protected by virtue of being [[war grave]]s.

=== Construction materials ===

However, many legal systems allow the rights of salvors to override the rights of the original owners of a wreck or its cargo. As a general rule, non-historic civilian shipwrecks are considered fair game for salvage. Under international [[maritime law]], for shipwrecks of a certain age, the original owner may have lost all claim to the cargo. Anyone who finds the wreck can then file a salvage claim on it and place a lien on the vessel, and subsequently mount a salvage operation (see [[Finders, keepers]]).<ref>{{cite web |title=Treasure Salvage: Finders Keepers?|url=http://www.wcslaw.com/news/2001/10/05/treasure-salvage-finders-keepers/ |work=wcslaw.com |archive-url=https://web.archive.org/web/20150917131032/http://www.wcslaw.com/news/2001/10/05/treasure-salvage-finders-keepers/ |archive-date=17 September 2015 |access-date=16 March 2019 |date=5 October 2001 |first=Stephen F. |last=White}}</ref> The State of North Carolina questionably claims "all photographs, video recordings, or other documentary materials of a derelict vessel or shipwreck or its contents, relics, artifacts, or historic materials in the custody of any agency of North Carolina government or its subdivisions" to be its property.<ref>{{cite web |title=HB 184 |url=http://www.ncleg.net/Sessions/2015/Bills/House/PDF/H184v7.pdf |work=[[General Assembly of North Carolina]] |date=18 August 2015 |access-date=16 March 2019 |pages=6 |first1=Philip E. |last1=Berger |first2=Tim |last2=Moore |first3=Pat |last3=McCrory |archive-date=28 September 2015 |archive-url=https://web.archive.org/web/20150928013307/http://www.ncleg.net/Sessions/2015/Bills/House/PDF/H184v7.pdf |url-status=live }}</ref>

Exposed [[wood]]en components decay quickly. Often the only wooden parts of wooden ships that remain after a [[century]] are those that were buried in [[silt]] or [[sand]] soon after the sinking. An example of this is the [[Mary Rose]].

Some countries assert claims to all wrecks within their territorial waters, irrespective of the interest of the original owner or the salvor.<ref>For example, the US [[Abandoned Shipwrecks Act]] 1987 and the Spanish Estatuto No 60/62, 24 December 1962</ref>

[[Steel]] and [[iron]], depending on its thickness, may retain the ship's structure for decades. As [[corrosion]] takes place, sometimes helped by tides and weather, the structure collapses. Thick ferrous objects like [[cannon]]s, [[steam]] [[boiler]]s or the [[pressure vessel]] of a [[submarine]] often survive well underwater in spite of corrosion.

[[File:Napolibeached.jpg|thumb|{{ship||MSC Napoli}} beached off Branscombe]]

[[Propeller]]s, [[condenser]]s, [[hinge]]s and port holes were often made from non-ferrous metals such as [[brass]] and [[phosphor bronze]], which do not corrode easily in water.

Some legal systems regard a wreck and its cargo to be abandoned if no attempt is made to salvage them within a certain period of time. English law has usually resisted this notion (encouraged by an extremely large maritime insurance industry, which asserts claims in respect of shipwrecks which it has paid claims on), but it has been accepted to a greater or lesser degree in an Australian case<ref>''Robinson v Western Australian Museum'' (1977) 51 ALJR 806 at 820-821, although significantly the court held that it had not been abandoned despite the fact the ship, the ''Gilt Dragon'', was lost in 1656.</ref> and in a Norwegian case.<ref>N. Rt. 346 (1970 N.D. 107), per Eckhoff J. ([[Supreme Court of Norway]]), "It is possible that an owner's inactivity over a long period of time, taking into account the circumstances, can be sufficient reason for considering that the proprietary right to the wrecked vessel has been relinquished. ... [But] inactivity over a certain number of years cannot in itself be conclusive."</ref>

The American courts have been inconsistent between states and at federal level.<ref>In ''Treasure Salvors Inc. v Unidentified Wreck'' [1978] AMC 1404, [1981] AMC 1857 relating to [[Spanish ship Nuestra Señora de Atocha (1620)|the ''Atocha'']] the courts treated the wreck and cargo as abandoned, arguing it would be an "absurd fiction" to regard a centuries-old shipwreck as still owned by the original owner. But in ''Columbus America Discovery Groupo v Unidentified Wreck'' [1990] AMC 2409, (1992) 337 LMNL 1 the courts were prepared to uphold the claims of the original insurers to the cargo subject to their providing the necessary proof, which they were unable to do.</ref> Under Danish law, all shipwrecks over 150 years old belong to the state if no owner can be found.{{Citation needed|date=October 2018}} In Spain, wrecks vest in the state if not salvaged within 3 years.{{Citation needed|date=October 2018}} In Finland, all property on board shipwrecks over 100 years old vests in the state.{{Citation needed|date=October 2018}}

=== Salinity of water ===

The British [[Protection of Wrecks Act 1973|Protection of Wrecks Act]], enacted to protect historic wrecks, controls access to wrecks such as [[Cattewater Wreck]] which can only be visited or investigated under licence. The British [[Protection of Military Remains Act 1986]] also restricts access to wrecks which are sensitive as [[war grave]]s. The Protection of Military Remains Act in some cases creates a blanket ban on all diving; for other wrecks divers may visit provided they do not touch, interfere with or penetrate the wreck. In the United States, shipwrecks in state waters are regulated by the [[Abandoned Shipwrecks Act]] of 1987. This act is much more lenient in allowing more open access to the shipwrecks.

Shipwrecks typically decay rapidly when in [[sea water]]; however shipwrecks in some [[fresh water]] lakes, such as the [[Great Lakes]] of [[North America]], have remained intact with little degradation. There are two reasons for this. [[Iron]]-based metals [[corrosion|corrode]] much more quickly in sea water due to the dissolved [[salt]] present; the sodium and chloride [[ion]]s chemically accelerate the process of metal oxidation which, in the case of ferrous metals, leads to [[rust]]. [[Bacteria]] found in sea water cause the [[wood]] on ships to rot more quickly than in fresh water. In some sea areas, most notably in [[Gulf of Bothnia]] and [[Gulf of Finland]], salinity is very low, and centuries old wrecks have been preserved in reasonable condition.

Following the beaching of {{ship||MSC Napoli}}, as a result of severe damage incurred during European storm [[Kyrill (storm)|Kyrill]], there was confusion in the press and by the authorities about whether people could be prevented from helping themselves to the [[flotsam]] which was washed up on the beaches at [[Branscombe]]. Many people took advantage of the confusion and helped themselves to the cargo. This included many [[BMW]] motorbikes and empty wine casks as well as bags of disposable nappies ([[diapers]]).<ref>{{cite news |url=http://news.bbc.co.uk/1/hi/england/devon/6450219.stm |title=Napoli 'scavenging' beach to open |work=[[BBC News]] |date=14 March 2007 |access-date=19 September 2009 |publisher=[[BBC]] |archive-url=https://web.archive.org/web/20070317035032/http://news.bbc.co.uk/1/hi/england/devon/6450219.stm |archive-date=17 March 2007}}</ref> The legal position under the [[Merchant Shipping Act 1995]] is that any such finds and recovery must be reported within 28 days to the [[Receiver of Wreck]].<ref>{{cite web |url=http://www.mcga.gov.uk/c4mca/mcga-environmental/mcga-dops_row_receiver_of_wreck/mcga-dops_row_report.htm |title=ROW- The reporting process |work=[[Maritime and Coastguard Agency]] |access-date=18 May 2013 |archive-url=https://web.archive.org/web/20080225222905/http://www.mcga.gov.uk/c4mca/mcga-environmental/mcga-dops_row_receiver_of_wreck/mcga-dops_row_report.htm |archive-date=25 February 2008}}</ref> Failure to do so is an offence under the Merchant Shipping Act and can result in a criminal record for [[theft by finding]].<ref>{{cite web |url=http://www.mcga.gov.uk/c4mca/mcga-environmental/mcga-dops_row_receiver_of_wreck/mcga-dops_row_penalties.htm |title=Wreck and salvage law - Detailed guidance |work=[[Maritime and Coastguard Agency]] |date=14 September 2012 |access-date=17 September 2015 |archive-url=https://web.archive.org/web/20110128191037/http://www.mcga.gov.uk/c4mca/mcga-environmental/mcga-dops_row_receiver_of_wreck/mcga-dops_row_penalties.htm |archive-date=28 January 2011}}</ref> After several days, the police and Receiver of Wreck, in conjunction with the landowner and the contracted [[marine salvage|salvors]], established a cordon to prevent access to the beach.<ref>{{cite web |url=http://www.mcga.gov.uk/c4mca/mcga-newsroom/incident/dops_-_hq-napoli_15_february_.htm |title=Structural failure of container vessel MSC Napoli and subsequent beaching Marine Accident Investigation Branch report |work=[[Maritime and Coastguard Agency]] |date=18 January 2007 |access-date=17 September 2015 |archive-url=https://web.archive.org/web/20071018170141/http://mcga.gov.uk/c4mca/mcga-newsroom/incident/dops_-_hq-napoli_15_february_.htm |archive-date=18 October 2007}}</ref> A similar situation occurred after the wreck of {{MV|Cita||2}} in 1997.

=== Loss, [[marine salvage|salvage]] and demolition===

Historic wrecks (often but not always defined as being more than 50 years of age) are often protected from pillaging and looting through national laws protecting cultural heritage.<ref>{{cite news |url=http://www.bbc.co.uk/worldservice/documentaries/2008/08/080821_what_lies_beneath.shtml |work=[[BBC Radio World Service]] Broadcast |title=What Lies Beneath |date=22 August 2008 |publisher=[[Bbc.co.uk]] |access-date=19 September 2009 |archive-date=6 January 2017 |archive-url=https://web.archive.org/web/20170106092046/http://www.bbc.co.uk/worldservice/documentaries/2008/08/080821_what_lies_beneath.shtml |url-status=live }}</ref> Internationally they may be protected by a State ratifying the [[Underwater cultural heritage|Unesco Convention on the Protection of the Underwater Cultural Heritage]]. In this case pillaging is not allowed. One such example is {{ship||Queen Anne's Revenge}}<ref>{{cite journal |url=http://archive.archaeology.org/9705/newsbriefs/blackbeard.html |title=Blackbeard's Flagship |journal=Archaeology Magazine Archive |date=May–June 1979 |access-date=17 September 2015 |first=Angela M.H. |last=Schuster |publisher=[[Archaeological Institute of America]] |archive-date=27 August 2015 |archive-url=https://web.archive.org/web/20150827035802/http://archive.archaeology.org/9705/newsbriefs/blackbeard.html |url-status=live }}</ref> which is undergoing archaeological recovery by the North Carolina Department of Cultural Resources near Beaufort Inlet, NC.

An important factor in the condition of the wreck is the level of destruction at the time of the loss or shortly afterwards due to the nature of the loss, salvage or later demolition.

An important international convention aiming at the protection of underwater cultural heritage (including shipwrecks) is the '''Convention on the Protection of the Underwater Cultural Heritage.'''<ref>{{cite web |url=http://portal.unesco.org/culture/en/ev.php-URL_ID=34114&URL_DO=DO_TOPIC&URL_SECTION=201.html |archive-url=https://wayback.archive-it.org/all/20080815180246/http://portal.unesco.org/culture/en/ev.php-URL_ID=34114&URL_DO=DO_TOPIC&URL_SECTION=201.html |archive-date=15 August 2008 |work=[[UNESCO]] |year=2001 |title=Convention on the Protection of the Underwater Cultural Heritage |access-date=19 September 2009}}</ref>

Examples of severe destruction at the time of loss are:

The 2001 UNESCO Convention on the Protection of the Underwater Cultural Heritage represents the international community's response to the increasing looting and destruction of underwater cultural heritage. It forms part of a group of UNESCO standard setting instruments regarding the ___domain of cultural heritage, encompassing seven conventions adopted by UNESCO Member States, which constitute a coherent and complementary body guaranteeing a complete protection of all forms of cultural heritage.

* being blown onto a beach, reef or rocks during a storm

* collision with another ship

* destruction in warfare

The UNESCO 2001 Convention is an international treaty aimed exclusively at the protection of underwater cultural heritage and the facilitation of international cooperation in this regard. It does not change sovereignty rights of States or regulate the ownership of wrecks or submerged ruins.<ref>{{Cite journal|last=Roberts|first=Hayley|title=The British Ratification of the Underwater Heritage Convention: Problems and Prospects|date=2018|journal=International & Comparative Law Quarterly|language=en|volume=67|issue=4|pages=833–865|doi=10.1017/S0020589318000210|s2cid=149780539|issn=0020-5893|url=https://research.bangor.ac.uk/portal/en/researchoutputs/the-british-ratification-of-the-underwater-heritage-convention-problems-and-prospects(5d0f3e40-6d37-42bb-805c-8de96b82dbae).html|archive-date=2020-06-10|access-date=2020-05-23|archive-url=https://web.archive.org/web/20200610223253/https://research.bangor.ac.uk/portal/en/researchoutputs/the-british-ratification-of-the-underwater-heritage-convention-problems-and-prospects(5d0f3e40-6d37-42bb-805c-8de96b82dbae).html|url-status=live}}</ref>

After the loss the owners of the ship may attempt to recover valuable parts of the ship or its cargo. This can cause damage.

=== Notable salvages ===

Shipwrecks in shallow water near busy shipping lanes are often demolished to reduce the danger to other vessels.

In 2011, the most valuable cargo of a sunken shipwreck was identified near the western edge of the [[Celtic Sea]]. This World War II era sinking of {{SS|Gairsoppa||2}} led to a treasure almost {{convert|3|mi|ft m|spell=in|}} deep.<ref>{{cite encyclopedia |first=C.Michael |last=Hogan |date=27 September 2011 |url=http://www.eoearth.org/article/SS_Gairsoppa_recovery?topic=49523 |title=SS Gairsoppa recovery |editor-first=Peter |editor-last=Saundry |editor2-first=C.J. |editor2-last=Cleveland |encyclopedia=[[Encyclopedia of Earth]] |publisher=[[National Council for Science and the Environment]] |___location=Washington DC |archive-url=https://web.archive.org/web/20130604011024/http://www.eoearth.org/article/SS_Gairsoppa_recovery?topic=49523 |archive-date=4 June 2013 |access-date=16 March 2019}}</ref>

A U.S. federal court and a panel from the United States Court of Appeals for the Eleventh Circuit have upheld the Spanish claim to the contents of the ship {{ship||Nuestra Señora de las Mercedes}}; Spain took control of the treasure in February 2012. A very small number of coins and effects recovered from the ship were deposited in Gibraltar, because they showed clear signs coherent with an internal explosion on the ship and thus confirmed Spanish claims to the wreck being that of the ''Nuestra Señora de las Mercedes''. They were not returned to Spain until 2013, when a court finally ordered Odyssey Marine to return the missing pieces.

=== Depth, tide and weather ===

Archaeologist [[Valerios Stais]] discovered one of the most notable instruments of time keeping and prediction of celestial events off the coast of the Greek island Antikythera on May 17, 1902. The device, known as the [[Antikythera Mechanism]], is perhaps the earliest example of what would be known as today as an [[analog computer]], and the technology it encompasses predates any other recorded description by hundreds or thousands of years.

==Gallery==

<gallery>

Shipwreck sis.png|Shipwreck on a shore near [[Gytheio]], [[Greece]]

Wrecked fishing boats, Finnmark.jpg|Wrecked fishing boats in [[Finnmark]], North [[Norway]]

Assalama.jpg|The ferry ''Assalama'' wrecked off of [[Tarfaya]], [[Morocco]]

ShipWreckMahenoFraserIsland.jpg|Ship wreck of {{SS|Maheno||2}}, [[Fraser Island]], Australia

FrotamericaShipWreck.jpg|Shipwreck of ''Frotamerica'' at the west coast of [[Namibia]]

File:A piece of Shipwreck.jpg|A piece of Shipwreck of Portuguese stranded deep sea-takers 1975 Luanda

File:A Piece of history.jpg|A Shipwreck in Luanda

</gallery>

== See also ==

* {{annotated link|Lists of shipwrecks}}

* {{annotated link|Abandoned Shipwrecks Act}}

* {{annotated link|Australasian Underwater Cultural Heritage Database}}

* {{annotated link|The captain goes down with the ship}}

* [[Conservation and restoration of shipwreck artifacts]]

* {{annotated link|Flotsam, jetsam, lagan and derelict}}

* {{annotated link|Historic Shipwrecks Act 1976}} (Superseded by the ''[[Underwater Cultural Heritage Act 2018]]'')

* {{annotated link|Hulk (ship type)}}

* {{annotated link|Nairobi International Convention on the Removal of Wrecks}}

* {{annotated link|Ship graveyard}}

* {{annotated link|Shipwrecking}}

* {{annotated link|Second Geneva Convention}}

* {{annotated link|Sinking ships for wreck diving sites}}

* {{annotated link|Underwater archaeology}}

* {{annotated link|Wreck diving}}

== References ==

{{Reflist}}

==Further reading==

Wrecks are slowly broken up by exposure to breaking waves, the weather and the tides.

* Jamieson, Alan G. (2022), ''Out of the Depths: A History of Shipwrecks'', Reaktion Books, {{ISBN|9781789146196}}

===Marine animals===

* {{Citation | author1=Larn, Richard | author2=Larn, Bridget | author3=Lloyd's Register of Shipping | title=Shipwreck index of the British Isles | date=1995 | publisher=Lloyd's Register of Shipping }}; Vol.1 - The South West {{ISBN|0-900528-88-5}}; Vol.2 - The South Coast,{{ISBN|0-900528-99-0}}; Vol.3 - The East Coast,{{ISBN|1-900839-10-5}}; Vol.4 - Scotland, {{ISBN|1-900839-01-6}}; Vol.5 - West Coast & Wales, {{ISBN|1-900839-61-X}}; Vol. 6- Ireland (all) {{ISBN|1-900839-03-2}}

Some [[species]] of marine [[worm]]s eat wood.

* {{Citation | author1=Muckenhaupt, P. G.| title=Treasure Pirates Shipwrecks Gold and Silver| date=2018 | publisher=Amazon Digital Services LLC}} {{ISBN|9781729469668}}

==See alsoExternal links ==

{{Commons category|Shipwrecks}}

*[[List of shipwrecks]]

* [https://wayback.archive-it.org/all/20080815180246/http://portal.unesco.org/culture/en/ev.php-URL_ID=34114&URL_DO=DO_TOPIC&URL_SECTION=201.html UNESCO 2001 Convention on the Protection of the Underwater Cultural Heritage]

*[[List of disasters#Ship and ferry disasters|List of ship and ferry disasters]]

* [http://www.wrecksite.eu/ WreckSite.eu], worldwide database of + 105,000 wrecks with history, maritime charts and GPS positions (subscription required) {{in lang|nl|en|fr|de|es}}

*[[Receiver of Wreck]]

* [http://www.nauticalcharts.noaa.gov/hsd/wrecks_and_obstructions.html NOAA Wrecks and Obstructions Database] {{Webarchive|url=https://web.archive.org/web/20210723033310/https://www.nauticalcharts.noaa.gov/hsd/wrecks_and_obstructions.html |date=2021-07-23 }}

*[[Alain Bombard]]

* [http://www.nc-wreckdiving.com/ Wreck Diving in the Graveyard of the Atlantic]

*[[Banco Chinchorro]]

* [http://thunderbay.noaa.gov/welcome.html Thunder Bay National Marine Sanctuary]

* [https://web.archive.org/web/20150816004056/http://www.courthousenews.com/2015/08/12/battle-over-shipwreck-photos-brews-in-n-c.htm Battle Over Shipwreck Photos Brews in N.C.], Courthouse News

*[https://www.fayobserver.com/news/20191111/nc-supreme-court-revives-lawsuit-over-blackbeards-ship-and-lost-spanish-treasure-ship N.C Supreme Court revives lawsuit over Blackbeard’s ship and lost Spanish treasure ship], Fayetteville Observer

{{Authority control}}

==External links==

{{commonscat|Shipwrecks}}

*[http://www.NorthernMaritimeResearch.com Database of 100,000+ North American shipwrecks from 25 years of documenting wrecks]

*[http://chartmaker.ncd.noaa.gov/hsd/hsd-3.html Database of 10,000 submerged wrecks and obstructions in the coastal waters of the United States]

*[http://www.numa.net/index.html| National Underwater and Marine Agency]

*[http://ehlt.flinders.edu.au/archaeology/welcome/maritime.php Flinders University Maritime Archaeology Program]

*[http://www.maritimequest.com/database.htm Maritimequest Shipwreck Database (Downloadable Excel file)]

*[http://www.thesextant.org The Sextant], Online community of Underwater Archaeology and Maritime History

[[Category:Shipwrecks|*]]

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