Jettison has a long and significant history. In the Old Testament stow of Jonah, it will be recalled, the sailors threw cargo overboard to lighten the ship. Jonah's exit overboard shortly afterwards did not constitute jettison—as it was to appease the Lord—although it certainly appears to have been efficacious in saving the ship!
Mercantile law followed the practice when in 900 B.C. the laws of the island of Rhodes prescribed the law of jettison whereby, if cargo was thrown overboard to lighten a ship for the general safety, that which was thrown away would be made good by general contribution or, as it later became known, by General Average.
Another Biblical hero, Paul, witnessed jettison firsthand near the island of Crete on his voyage from Caesarea to Rome. You may recall the vessel was making very heavy weather and they began to lighten the ship and, on the third day, they jettisoned the ship's gear with their own hands. Presumably General Average was not declared because, despite the jettison, the ship subsequently went aground and was pounded to pieces.
Rhodian law on jettison was incorporated into the Digest of Justinian (Emperor Justinian—A.D. 500) and later into the laws of Oleron in the twelfth century. Those were attributed to the English king, Richard I, or his mother, Eleanor of Aquitaine. Article 8 of the Sea Laws of Oleron provided for General Average when cargo was jettisoned to save ship and cargo. Three thousand years on from the laws of Rhodes, and even longer from the days of Jonah, the current rules of General Average—the York/Antwerp Rules 1974—provide that the sacrifice of cargo by jettison for the common safety shall be made good in General Average.
Lloyd's Open Form 1990 (LOF 90), the most frequently used salvage contract, (although it is little used in the United States) permits the salvor to jettison cargo within reason to salve the ship, although that is not something which any salvor does lightly in practice.
Jettison therefore has a long history and encapsulates the rule which applies in many walks of life—that at times it is necessary to make a small sacrifice in order to avert a greater loss.
Groundings were much more common 100 years ago than they are today. Ships still depended to a degree on sail, propulsion machinery was not always reliable, and navigational aids were primitive. The Salvage Associations' records for 1892 and 1893 show its surveyors attending many groundings. Often, the ship had to be lightened, and it is fair to say that in most instances the cargo was lightened rather