The Argo Merchant, a 644-foot, 18,743-ton Liberian-flagged oil tanker, ran aground Dec. 15, 1976 southeast of Nantucket Island, Mass. Six days later, on Dec. 21, the ship carrying 7.3 million gallons of heavy industrial oil, broke apart, causing one of the largest oil spills in history.
An investigation established that the ship carried two unqualified crew as helmsmen, a broken gyrocompass, inadequate charts and an inaccurate radio direction finder.
In high winds and 10-foot seas, the tanker ran aground on Middle Rip Shoal about 25 nautical miles southeast of Nantucket and more than 24 miles off her intended course. The 38 members of the crew were evacuated, but the shallow waters and weather conditions made it impossible to offload the oil or salvage the ship.