On Christmas Eve 1789, HMS Guardian found itself in the shadow of two great icebergs some 1,300 miles southeast of the Cape of Good Hope. The ship’s captain, 27-year-old Edward Riou, ordered a double watch to be kept, but, engulfed in fog and with darkness falling, the Guardian struck one all the same. The collision tore a hole in the ship’s hull beneath the waterline and destroyed its rudder.

Riou set all hands to man the ship’s four pumps and ordered much of its cargo to be thrown overboard. By 8.15pm, there were two feet of water in the hold. By 10pm, with two pumps broken, it was at five feet. At times over the next thirty-six hours it seemed as though the crew was winning. On Christmas morning, they ‘fothered’ the hull, wrapping two oakum-lined sails underneath the ship to stem the flow of water. But the water carried on rising. By Boxing Day, it was at seven feet.

At 9pm that evening around thirty-six men left the ship in five small boats. Most were never seen again. Riou remained on board with some thirty crew. He did not expect to live. But, remarkably, he did. On 21 February, Riou brought his ship in sight of Table Bay, having