One of the most notorious regions for rogue or freak waves is the southern coast of South Africa where the five-knot west-going Agulhas Current meets strong westerlies from the Southern Ocean.
On 31 December 1970 the Smit-Lloyd 102 was on its way to Port Elisabeth with a load of casing (220 tons) when it was hit by two consecutive freak waves. During the night the weather deteriorated to force 9 - 10 and seas 20 - 30 feet, both from the west. These came in from behind and passed the ship. Quartering seas are notoriously dangerous especially for a ship with a ‘bathtub’ aft with a length of about 37 meters.
Around 06.30 a high sea, about 15 meters, came on deck, causing the ship to list heavily, followed very soon after by a second even higher one, on which the ship capsized and later sunk at position 34.07 East 24.09 West. The wheelhouse was forcibly torn from the ship! One of the sailors came to his senses in the water, luckily close to a dinghy he could climb into. Moments later, the helmsman was forcibly blown out of the ship and pulled into the dinghy by the sailor.
The two crew members managed to get free of the ship and were able to get to safety by means of a dinghy. With the help of a floating anchor they stayed at the location for 1 hour, then they were driven by the current to the rocky coast, which came into view after 12 hours. The last mile was done by swimming to a small stretch of beach near Humansdorp (Wreck point). The night was spent in a cabin, the next day they met vacationers who took the two men to hospital.
In fact this was the only major incident in all those years with the Smit-Lloyd ships that I know of. And that in a rough and dangerous working environment. It says something about the reliability and safety of these new type of vessels and of course the seamanship of the crews.
This safety record is remarkable if compared with the situation in the GOM where eight offshore supply vessels capsized and sank between 1956 and 1963. Interesting in this respect is this gCaptain thread. One of the causes of the losses was that the mud tank was mounted on the deck which caused loss of stability and capsizing. They were later mounted below decks.