Flotsam - Refers to goods from a sunken vessel that have floated to the surface of the sea, or any floating cargo that is cast overboard.

Jetsam - Designates any cargo that is intentionally discarded from a ship or wreckage. Legally jetsam also floats, although floating is not part of the etymological meaning. Generally, "jettisoning" connotes the action of throwing goods overboard to lighten the load of the ship if it is in danger of sinking.

Lagan - Goods cast overboard and heavy enough to sink to the ocean floor, but linked to a floating marker, such as a buoy or cork, so that they can be found again by the person who marked the item. Lagan can also be large objects trapped within the sinking vessel.

Derelict - Can refer to goods that have sunk to the ocean floor, relinquished willingly or forcefully by its owner, and thus abandoned, but which no one has any hope of reclaiming.

https://en.wikipedia.org/wiki/Flotsam,_jetsam,_lagan_and_derelict