Nice post on the lex Rhodia. The assimilation into Roman law is interesting: the duty to contribute was interpreted by the jurists as an aspect of good faith in the contract of carriage, entered into by merchants with the ship's business manager (magister navis)...
When a ship is at risk, it's sometimes necessary to throw some of its cargo overboard to save it.
But who decides whose cargo is thrown?
To avoid counterproductive bickering in times of danger, the ancient Greeks widely adopted a law from Rhodes: "Lex Rhodia de iactu," which states that financial losses for thrown cargo are equally shared among all cargo owners on the ship.
So ,since losses are shared, the owners of heavy, cheap items didn't fight to stop the crew from dumping their property, because they knew they would be compensated by the owners of lightweight luxury goods.
This Rhodian law was later adopted by the Romans and, through transmission, became the basis of modern maritime law regarding jettisoned cargo.