answer:Check this article out on Wikipedia. Excerpt: “Salvage law has as a basis that a salvor should be rewarded for risking his life and property to rescue the property of another from peril. Salvage law is in some ways similar to the wartime law of prize, the capture, condemnation and sale of a vessel and its cargo as a spoil of war, insofar as both compensate the salvor/captors for risking life and property.[3] The two areas of law may dovetail. For instance, a vessel taken as a prize, then recaptured by friendly forces on its way to the prize adjudication, is not deemed a prize of the rescuers (title merely reverts to the original owner). But the rescuing vessel is entitled to a claim for salvage.[4] Likewise a vessel found badly damaged, abandoned and adrift after enemy fire disabled her does not become a prize of a rescuing friendly vessel, but the rescuers may claim salvage.[5] A vessel is considered in peril if it is in danger or could become in danger. Examples of a vessel in peril are when it is aground or in danger of going aground. Prior to a salvage attempt the salvor receives permission from the owner or the master to assist the vessel. If the vessel is abandoned no permission is needed.”