Marine salvage is the process of rescuing a ship, its cargo and sometimes the crew from peril. Salvage encompasses rescue towing, refloating a grounded ship or patching or repairing a ship. Today the protection of the environment from cargoes such as oil is often considered a higher priority than saving the ship or cargo.
"Salvors" are seamen and engineers who carry out salvage to vessels that are not owned by themselves. When salvaging large ships, they may use caranes, floating dry docks and divers to lift and repair ships for short journeys to safety towed by a tugboat. The aim of the salvage may be to repair the vessel at a harbour or dry dock, or to clear a channel for navigation. Another reason for salvage may be to prevent pollution or damage to the marine environment. Alternatively the vessel or valuable parts of the vessel or its cargo may be recovered for its resale value, or for scrap.