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Marine salvage is the process of recovering a ship, its cargo, or other property after a shipwreck or other maritime casualty. Salvage may encompass towing, re-floating a sunken or grounded vessel, or patching or repairing a ship. Today, protecting the environment from cargoes such as oil or other contaminants is often considered a high priority. "Salvors" are seamen and engineers who carry out salvage to vessels that they do not own, and who are not members of the vessel's original crew. When salving large ships, they may use cranes, floating dry docks and divers to lift and repair submerged or grounded ships, preparing them to be towed by a tugboat. The goal of the salvage may be to repair the vessel at a harbour or dry dock, or to clear a channel for navigation. Salvage operations may also aim to prevent pollution or damage to the marine environment. Additionally, the vessel or valuable parts of the vessel or its cargo may be recovered for resale, or for scrap. ==History== In the Early Modern Period, diving bells were often used for salvage work. In 1658, Albrecht von Treileben was contracted by King Gustavus Adolphus of Sweden to salvage the warship ''Vasa'', which sank in Stockholm harbor on its maiden voyage in 1628. Between 1663-1665 von Treileben's divers were successful in raising most of the cannon, working from a diving bell.〔Vasa Museet. http://www.vasamuseet.se/en/The-Ship/Important-dates/〕 In 1687, Sir William Phipps used an inverted container to recover £200,000-worth of treasure from a Spanish ship sunk off the coast of San Domingo. The era of modern salvage operations was inaugurated with the development of the first surface supplied diving helmets by the inventors, Charles and John Deane and Augustus Siebe, in the 1830s. The , a 100-gun first-rate ship of the line of the Royal Navy, sank undergoing routine maintenance work in 1782, and the Deane brothers were commissioned to perform salvage work on the wreck. Using their new air-pumped diving helmets, they managed to recover about two dozen cannons. Following on from this success, Colonel of the Royal Engineers Charles Pasley commenced the first large scale salvage operation in 1839. His plan was to break up the wreck of ''Royal George'' with gunpowder charges and then salvage as much as possible using divers. Pasley's diving salvage operation set many diving milestones, including the first recorded use of the buddy system in diving, when he ordered that his divers operate in pairs. In addition, the first emergency swimming ascent was made by a diver after his air line became tangled and he had to cut it free. A less fortunate milestone was the first medical account of a diver squeeze suffered by a Private Williams: the early diving helmets used had no non-return valves; this meant that if a hose became severed, the high-pressure air around the diver's head rapidly evacuated the helmet causing tremendous negative pressure that caused extreme and sometimes life-threatening effects. At the British Association for the Advancement of Science meeting in 1842, Sir John Richardson described the diving apparatus and treatment of diver Roderick Cameron following an injury that occurred on 14 October 1841 during the salvage operations. Pasley recovered 12 more guns in 1839, 11 more in 1840, and 6 in 1841. In 1842 he recovered only one iron 12-pounder because he ordered the divers to concentrate on removing the hull timbers rather than search for guns. Other items recovered, in 1840, included the surgeon's brass instruments, silk garments of satin weave 'of which the silk was perfect', and pieces of leather; but no woollen clothing.〔The Times, London, article CS117993292 dated 12 Oct 1840, retrieved 30 Apr 2004.〕 By 1843 the whole of the keel and the bottom timbers had been raised and the site was declared clear. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Marine salvage」の詳細全文を読む スポンサード リンク
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