Video shows an 8,000-container ship scraping along the side of another, sending multiple crushed and torn containers into the water.
South Korean authorities believed the vessel made a ship-to-ship transfer of 600 tons of oil products to a North Korean tanker.
The ship can run for 50 miles at a speed of eight miles an hour.
The man was dehydrated and suffering from hypothermia when he was rescued.
Rolls-Royce are developing unmanned ships - but are they the future or just an easy catch for pirates?