MS Herald of Free Enterprise was a roll-on roll-off (RORO) ferry which capsized moments after leaving the Belgian port of Zeebrugge on the night of 6 March 1987, killing 193 passengers and crew.

The modern 8-deck car and passenger ferry, owned by P&O, had been designed for rapid loading and unloading on the competitive cross-channel route, and there were no watertight compartments. When the ship left harbour with her bow-door open, the sea immediately flooded the decks, and within minutes she was lying on her side in shallow water.

The immediate cause of the sinking was found to be negligence by the assistant boatswain, asleep in his cabin when he should have been closing the bow-door. But the official inquiry placed more blame on his supervisors and a general culture of poor communication in the ferry company P&O European Ferries.

The ship left its berth in Zeebrugge inner harbour at 18:05 (GMT) with a crew of 80 and carrying 459 passengers, 81 cars, 3 buses and 47 trucks. She passed the outer mole at 18:24 and capsized about four minutes later.

When the ferry reached 18.9 knots (35.0 km/h; 21.7 mph) 90 seconds after leaving the harbour, water began to enter the car deck in large quantities. The resulting free surface effect destroyed her stability.

In a matter of seconds, the ship began to list 30 degrees to port. The ship briefly righted herself before listing to port once more, this time capsizing. The entire event took place within 90 seconds.[8] The water quickly reached the ship's electrical systems, destroying both main and emergency power and leaving the ship in darkness.

Although the vessel was salvaged and put up for sale, there were no takers, and she ended her days in a scrapyard in Taiwan.