SM UB-121

SM UB-121 was a German Type UB III submarine or U-boat in the German Imperial Navy (Kaiserliche Marine) during World War I. She was commissioned into the German Imperial Navy on 10 February 1918 as SM UB-121.

UB-121 was surrendered to France on 20 November 1918 in accordance with the requirements of the Armistice with Germany. She was broken up in Toulon in July 1921 after being used for underwater demolition training.

Construction
She was built by AG Weser of Bremen and following just under a year of construction, launched at Bremen on 6 January 1918. UB-121 was commissioned later the same year. Like all Type UB III submarines, UB-121 carried 10 torpedoes and was armed with a 8.8 cm deck gun. UB-121 would carry a crew of up to 3 officer and 31 men and had a cruising range of 7280 nmi. UB-121 had a displacement of 512 t while surfaced and 643 t when submerged. Her engines enabled her to travel at 13.9 kn when surfaced and 7.6 kn when submerged.