KapLt Viktor Dieckmann (1887-1918) was commander of UB 27 in 1916 before he took over U 61 in 1917. On 5 January 1918, he sank the steamship ROSE MARIE in the St George's Channel. Following an attack on the passenger steamer ETONIAN on 23 March 1918, no further contact with U 61 could be established and the submarine vanished with all her crew.

Source:
"Erfolgreiche deutsche U-Boot-Kommandanten." Illustrierte Geschichte des Weltkrieges 1914/15. 8th volume. p. 24.
Oberösterreichische Landesbibliothek. Signatur II-21465/8.