[1] The vessel must be in peril, either immediate or forthcoming; the "salvor" must be acting voluntarily and under no pre-existing contract; and some life or property must be successfully saved.
With its origins in antiquity, the basis of salvage is that a person helping another at sea is putting himself and his vessel at risk and should be appropriately rewarded.
A related consideration was to prevent piracy, since any vessel in peril might well be abandoned to pirates if the owner did not reward an honest salvor.
The assumption here is that when faced with the loss of his vessel and cargo, a reasonable prudent owner would have accepted salvage terms offered, even if time did not permit such negotiations.
Even so, the shipowner is entitled to reject any offer of help, and would do so if the shipping line had already made arrangements with a professional salvor of their choice.
[3] There is no equivalent to salvage when ashore: a person who assists another on land has no entitlement unless a court deems that an implied contract had arisen, whether objectively or subjectively.
If the salvor prevents oil pollution from happening, he indeed performs a valuable service to the community as mentioned by (1997) 1 Lloyd's Rep 323 (HL), pp.
Voluntary means that the services are not rendered under a pre-existing contract agreement or under official duty or purely for the self-preservation interests of the salvor.
The case of the Sandefjord (1953 2 Lloyd's Rep. 557) held that the pilot brought his personal knowledge of the local conditions and his seafaring skills to bear when faced with a grounding.
Crewmen cannot claim themselves as individual salvors unless their employment contract has been actually or constructively terminated before the salvage service commenced.
Additionally, hostile capture of the crew effectively causes the dissolution of the sailors' employment contract, as the general and expected duties for the seamen no longer exist.
However, there are vessels standing by, crewed by professional salvors under a salvage agreement in Lloyd's Open Form (LOF).
Special compensation is paid, however, as a reward for efforts to prevent or minimize damage to the environment even if no property is saved under the convention.
While the general principle of salvage law has been no cure; no pay, special consideration had to be given as more vessels were propelled by internal combustion engines, with the related environmental hazards that were possible if one were to sink.
Under Article 14(1) the salvor is entitled to special compensation if he has carried out salvage operation on a vessel which by itself or its cargo threatens damage to the environment.
The salvor does not necessarily have to achieve success in preventing and minimizing damage to the environment in obtaining special compensation.
The possibility exists that an arbitrator may increase the special compensation to 100 percent of the expenses incurred, if warranted by circumstances.
Article 23 of the 1989 Convention provides for a two-year limit to commence judicial or arbitration proceedings arising from a salvage claim.