While modern language casually lumps lost sea debris under the phrase 'flotsam and jetsam,' historic English Admiralty law established strict, separate legal definitions for four distinct types of marine goods: flotsam, jetsam, lagan, and derelict. These classifications determined who had the right to salvage abandoned oceanic property and who ultimately owned it. Flotsam refers to goods floating on the surface of the water after a vessel has sunk or been destroyed by the sea.
Because the crew had no agency in casting these items overboard, flotsam remained the property of the original owner if claimed within a year and a day. In contrast, jetsam describes cargo intentionally thrown overboard by a ship's crew in an attempt to lighten a distressed vessel and prevent shipwreck. Under maritime law, jetting cargo was an intentional sacrifice, creating unique general average salvage rights among surviving cargo owners.
Lagan, sometimes spelled ligan, refers to heavy goods cast overboard that were attached to a buoy or floating marker so the owners could locate and recover them later. The marker signified an ongoing claim of ownership, preventing scavengers from legally claiming the goods as abandoned. Finally, derelict refers to any vessel or cargo completely abandoned at sea by its crew without hope of recovery or intention of returning.
Under traditional English common law, rights to unclaimed marine property were split between the High Court of Admiralty and the Crown under the royal prerogative of 'wreck of the sea.' Mastering these precise nuances allowed salvors, merchants, and monarchical tax collectors to navigate complex legal disputes across centuries of maritime trade.