SS Mercian was a steamer of 6,305 GR tons. Built 1908 by Harland & Wolff, Ltd., Belfast and operated by Wilsons & Furness-Leyland Line, Ltd., Liverpool. She is described as a cargo vessel with passenger accomodation. Titled transferred at some point in 1915 to Fred. Leyland & Co., Ltd., Liverpool.
15 March 1915. 1 officer and 70 other ranks from 1st Royal Dublin Fusiliers with regimental horses and mules embarked on HMT Mercian. Destination Alexandria
8th - 25th April 1915. Men and horses from 1st Battalion, The Border Regiment sailed from Alexandria to Gallipoli via Lemnos
November 1915 Lincolnshire Yeomanry embarked in the S.S. Mercian at Southampton.for Salonica as infantry. The ship endured rough seas following her departure and had to put in at Gibraltar, although the troops weren't allowed ashore. She put to sea again and, on 3 November 1915, she was attacked in the Mediterranean by a German submarine U38 using 21-pound canon. After more than an hour being bombarded, the Mercian escaped. However, in that time 78 men were wounded, 23 were dead, 22 troops and eight crew members were missing. Later 13 of the Lincolnshire Yeomanry and five crew members were rescued. MOD reports at the time state that 23 men were killed, thirty were missing and 50 were wounded.
The story of the incident in the Mediterannean Sea is fairly well-known in Grimsby. The Mercian had no guns, and some of the troops, under Major J. W. Wintringham, M.C., brought up their machine guns, but were outranged. Still the men made a fight for it. The captain handled his vessel with skill. Private Thompson, a Lincolnshire man, taking the wheel under his direction and men of the Yeomanry going down in the stokehold and keeping up steam after the crew had left the vessel. The vessel was hit several times, and the casualties numbered about a hundred, Capt. Lord Kesteven being among the killed, but the Mercian eventually got clear and made for Oran, in Algeria, where the French treated them very kindly. Lord Kesteven and about 30 N.C.O.'s and men who were killed were buried at sea or at Oran, and five days later the troops again set sail, calling at Malta, and then proceeding to Alexandria.