KapLt Otto Hersing (1885-1960) was the commander of U 21 and during the First World War. He sank 40 ships and damaged another two.

During his command of U 21, he sank three ships in Welsh waters, the LINDA BLANCHE, BEN CRUACHAN and KILCOAN on 30 January 1915.

In 1924, he left naval service and became a farmer.

Source:
Langsdorff, Werner von, editor. U-Boote am Feind: 45 deutsche U-Boot-Fahrer erzählen. Gütersloh: C. Bertelsmann, [1937].