 UB @-@ 50 was ordered by the German Imperial Navy on 20 May 1916 . She was built by Blohm & Voss , Hamburg and following just under a year of construction , launched at Hamburg on 6 January 1917 . UB @-@ 50 was commissioned later that same year under the command of Kapitänleutnant ( Kptlt . ) Franz Becker . Like all Type UB III submarines , UB @-@ 50 carried 10 torpedoes and was armed with an 8 @.@ 8 cm ( 3 @.@ 5 in ) deck gun . UB @-@ 50 could carry a crew of up to 34 men and had a cruising range of 9 @,@ 040 nautical miles ( 16 @,@ 740 km ; 10 @,@ 400 mi ) . UB @-@ 50 had a displacement of 516 t ( 508 long tons ) while surfaced and 651 t ( 641 long tons ) when submerged . Her engines enabled her to travel at 13 @.@ 6 knots ( 25 @.@ 2 km / h ; 15 @.@ 7 mph ) when surfaced and 8 knots ( 15 km / h ; 9 @.@ 2 mph ) when submerged . 
