The steel steamship Manchester Mariner was built by Furness Withy and Co Ltd., West Hartlepool for Manchester Lines Ltd and launched on 19th December 1903. She measured 360.0′ x 48.0′ x 20.2′ and weighed 4,506 gross tons, 2,569 net tons. She was powered by a triple expansion steam engine by Richardson, Westgarth and Co Ltd., Hartlepool delivering 403 net horse power. After a successful career for Manchester Lines she was sold in 1925 to Finska Angfartygs A/B (Finland – America Line ), registered in Helsingfors and renamed Mercator.
At the outbreak of World War Two Finland’s position in the conflict was complicated by Soviet Union incursions into their territory and, although the Finns were no supporters of Hitler a pact was agreed between Nazi Germany and Finland in an effort to keep the Russians out of the country which resulted in German troops stationed on the ground in Finland. Despite this agreement Finnish shipping still had to run the gauntlet of German U-boats in the Atlantic and North Sea and the Mercator was to be one of the Finnish ships lost as a result.
In November 1939 the Mercator steamed out of Buenos Aires bound for Europe with a cargo of coffee, wheat, maize and linseed. In command was Captain Gunnar Nilsson-Ollandt and she had a crew of thirty five men. The voyage across the Atlantic was uneventful and she reached Leith on the Firth of Forth near the end of the month. At this stage in the war, the final leg of her journey back to the Baltic and Helsinki was the most hazardous but the ship set off from Leith late on 30th November unescorted hoping perhaps her Finnish nationality would protect her from the patrolling German U-boats. However, as the Mercator steamed past Cruden Bay she was spotted by U-21 and her commander Fritz Frauenheim ordered the attack. A single torpedo was enough to sink the ship. Fired without warning, the explosion killed one of the crew but the rest of the crew managed to abandon ship in two lifeboats and a life raft. One lifeboat with nineteen men aboard and the life raft with a further four crewmen were picked up by the Peterhead lifeboat which has launched when the explosion of the torpedo was heard from the shore. The second lifeboat with a further twelve crewmen aboard safely reached the shore at Boddam.
The wreck of the Mercator lies some ten miles off Cruden Bay in position 57°23.586’N, 001°41.583’N (WGS84). She was located and dived by Buchan Divers in 2007 and positively identified by the discovery of crockery bearing the Finska Angfartgys logo. The ship sits on an even keel in 82 metres oriented 125°/305° and rises 10 metres from the seabed. The wreck is well preserved and more or less intact with stern section totally preserved and mid section superstructure still place. Forward of the engine room area towards the bridge and accommodation areas the ship has been torn apart by the impact of the torpedo. The bow section is also intact undamaged by the explosion which sank the ship.