ned to be passing by. Nowadays, most salvage is carried out by specialist salvage firms with dedicated crew and equipment. The legal significance of salvage is that a successful salvor is entitled to a reward, which is a proportion of the total value of the ship and its cargo. The amount of the award is determined subsequently at a "hearing on the merits" by a maritime court in accordance with Articles 13 and 14 of the International Salvage Convention of 1989. The common law concept of salvage was established by the English Admiralty Court, and is defined as "a voluntary successful service provided in order to save maritime property in danger at sea, entitling the salvor to a reed collection of buildings used as a military garrison, and is the equivalent of the Roman castellum or English fortress. These constructions mainly served the purpose of a watch tower, to guard certain roads, passes, and lands that might threaten the kingdom. Though smaller than a real fortress, they acted as a border guard rather than a real strongpoint to watch and maintain the border. The art of setting out a military camp or constructing a fortification traditionally has been called "castrametation" since the time of the Roman legions. Fortification is usually divided into two branches: permanent fortification and field fortification. There is also an intermediate branch known as semi-permanent fortification. Castles are fortifications which are regarded as being distinct from the generic fort or fortress in that they are a residence of a monarch or noble and command a specific defensive territory. Roman forts and hill forts were the main antecedents of castles in Europe, which emerged in the 9th century in the Carolingian Empire. The Early Middle Ages saw the creation of some towns built around castles. Medieval-style fortifications were largely made obsolete by the arrival of cannons in the 14th centward"; and this definition has been further refined by the 1989 Convention. Originally, a "successful" salvage was one where at least some of the ship or cargo was saved, otherwise the principle of "No Cure, No Pay" meant that the salvor would get nothing. In the 1970s, a number of marine casualties of single-skin-hull tankers led to serious oil spills. Such casualties were unattractive to salvors, so the Lloyd's Open Form (LOF) made provision that a salvor who acts to try to prevent environmental damage will be paid, even if unsuccessful. This Lloyd's initiative proved so advantageous that it was incorporated into the 1989 Convention. All vessels have an international duty to give reasonable assistance to other ships in distress in order to save life, but there is no obligation to try to salve the vessel. Any offer of salvage assistance may be refused; but if it is accepted a contract automatically arises to give the successful salvor the right to a reward under the 1989 Convention. Typically, the ship and the salvor will sign up to an LOF agreement so that the terms of salvage are clear. Since 2000, it has become standard to append a SCOPIC ("Special Compe
