Shipwreck
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 [1] (an estimate rapidly endorsed by UNESCO[2][3] and other organizations[4]).
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 treasure ships, often from the period of European colonisation, which sank in remote locations leaving few living witnesses, such as Batavia, do occur as well.
Well-known shipwrecks include the catastrophic Titanic, MV Doña Paz, Britannic, Lusitania, Estonia, Empress of Ireland, Andrea Doria, Endurance or Costa Concordia.
[6] Poor design, improperly stowed cargo, navigation and other human errors leading to collisions (with another ship, the shoreline, an iceberg, etc.
Intentional reasons for sinking a ship include: intending to form an artificial reef; destruction due to warfare, piracy, mutiny or sabotage; using the vessel for target practice; or removing a menace to navigation.
Besides this geological phenomenon, wrecks also face the damage of marine creatures that create a home out of them, primarily octopuses and crustaceans.
Parker claim that it is the historical value of the shipwreck[further explanation needed] that counts as well as any slight piece of information or evidence that is acquired.
Thick ferrous objects such as cannons, steam boilers or the pressure vessel of a submarine often survive well underwater in spite of corrosion.
Propellers, condensers, hinges and port holes were often made from non-ferrous metals such as brass and phosphor bronze, which do not corrode easily.
However, bacteria found in fresh water cause the wood on ships to rot more quickly than in seawater unless it is deprived of oxygen.
Shipwrecks in shallow water near busy shipping lanes are often demolished or removed to reduce the danger to other vessels.
Also, more highly oxygenated water, which promotes corrosion, reduces the strength of ferrous structural materials of the ship.
[15][16] Shipwreck pollution may also originate with a ship's cargo or munitions,[13] such as unexploded ordnance or chemical weapons canisters.
[17] German trawler V 1302 John Mahn, sunk in the North Sea in 1942,[18][19] has multiple unexploded depth charges on board which render the wreck hazardous.
[18] Samples taken from the wreck and nearby sediment show the presence of heavy metals like nickel and copper, polycyclic aromatic hydrocarbons, arsenic and explosive compounds into surrounding waters, which have changed the local microbial ecology.
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.
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.
For example, in the British case of 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.
[30] After several days, the police and Receiver of Wreck, in conjunction with the landowner and the contracted salvors, established a cordon to prevent access to the beach.
One such example is Queen Anne's Revenge[33] which is undergoing archaeological recovery by the North Carolina Department of Cultural Resources near Beaufort Inlet, NC.
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.
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.
