DESCRIPTION:
En route from the Persian Gulf to Rotterdam, Netherlands, via a scheduled stop at Lyme Bay, Great Britain, the ship encountered stormy weather with gale conditions and high seas while in the English Channel. At around 09:45 a.m., a heavy wave hit the ship's rudder and it was found that she was no longer responding to the helm. This was due to the shearing of Whitworth thread studs in the Hastie four ram steering gear, built under licence in Spain, causing a loss of hydraulic fluid. Attempts to repair the damage were made but proved unsuccessful. While the message "no longer manoeuvrable" and asking other vessels to stand by was transmitted at 10:20 a.m., no call for tug assistance was issued until 11:20 a.m.

The German tug Pacific responded and contacted Amoco Cadiz at 11:28 a.m., offering assistance under a Lloyd's Open Form (see below). It arrived on the scene at 12:20 p.m., but because of the stormy sea, a tow line was not in place until 2 p.m. and broke off at 4:15 p.m. Several attempts were made to establish another tow line and Amoco Cadiz dropped its anchor trying to halt its drift. Finally a successful tow line was in place at 8:55 p.m. Yet these measures proved incapable of preventing the supertanker from drifting towards the coast because of its huge mass and the Force 10 storm winds.[3]

At 21:04 p.m., Amoco Cadiz ran aground the first time, flooding its engines, and again at 21:39 p.m., this time ripping the hull and starting the oil spill. Her crew was rescued by French Naval Aviation helicopters at midnight, and her captain and one officer remained aboard until 05:00 the next morning.

At 10:00 a.m., 17 March, the vessel broke in two, releasing its entire cargo of 1.6 million barrels (250,000 m3) of oil, and broke again eleven days later from the buffeting of high stormy seas. The wreckage was later completely destroyed with depth charges by the French Navy.