SM UB-9
SM UB-9 was a German Type UB I submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. UB-9 was ordered in October 1914 and was laid down at the AG Weser shipyard in Bremen in November. UB-9 was a little under 92 feet (28 m) in length and displaced between 127 and 141 metric tons (140 and 155 short tons), depending on whether surfaced or submerged. She carried two torpedoes for her two bow torpedo tubes and was also armed with a deck-mounted machine gun. She was launched and commissioned as SM UB-9 in February 1915.
UB-9's commanding officer at commissioning only remained in charge of the ship for a week. Sources do not report any more commanding officers assigned through the end of the war, so it's not clear if the submarine remained in commission. UB-9 was reported in use as a training vessel at Kiel in September 1915. The U-boat made no war patrols and sank no ships during the war, which may indicate that the vessel remained in a training role. At the end of the war, UB-9 was deemed unseaworthy and unable to surrender at Harwich with the rest of Germany's U-boat fleet. She remained in Germany where she was broken up by Dräger at Lübeck in 1919.
Read more about SM UB-9: Design and Construction, Career