The National Oceanic and Atmospheric Administration has some choice words for those of you who think flotsam and jetsam are just synonyms for odds and ends:
Flotsam and jetsam are terms that describe two types of marine debris associated with vessels. Flotsam is defined as debris in the water that was not deliberately thrown overboard, often as a result from a shipwreck or accident. Jetsam describes debris that was deliberately thrown overboard by a crew of a ship in distress, most often to lighten the ship’s load.
Does it really matter, though? Glad you asked.
Under maritime law the distinction is important. Flotsam may be claimed by the original owner, whereas jetsam may be claimed as property of whoever discovers it. If the jetsam is valuable, the discoverer may collect proceeds received though the sale of the salvaged objects.
Pays to be precise, I reckon.