u-31

The U-28, which had done such effective work for the Germans during the month of March, 1915, was relieved of duty near the British Isles during the first week of April by the U-31, which sank the Russian bark Hermes and the British steamship Olivine off the coast of Wales on April 5, 1915.

- The Story of the Great War, Volume V (of 12): Neuve Chapelle, Battle of Ypres, Przemysl, Mazurian Lakes