The mystery ship is the Royal Mail liner Atlantis (15,363grt), built as Andes by Harland & Wolff, Belfast and completed in September 1913. During World War I she served as an Armed Merchant Cruiser and then operated on the route for which she was built, UK to South America east coast, for ten years.

In 1929 she was withdrawn from this service and refitted as a cruise ship, given an all-white hull (previously black) and renamed Atlantis. The Government took her over in 1939 and she served as a hospital ship throughout World War II. In 1948 she became an immigrant carrier to Australia and New Zealand and was sold for breaking at Faslane in 1952.

She was one of nine very similar ships. In fact, five of them were almost identical, so I may not be quite right, but Atlantic outlived all the others by many years.

Peter Sommerville, Greenock