 UB @-@ 42 was ordered in July 1915 and was laid down at the AG Weser shipyard in Bremen in September . UB @-@ 42 was 36 @.@ 90 m ( 121 ft 1 in ) in length and displaced between 270 and 305 tonnes ( 266 and 300 long tons ) , depending on whether surfaced or submerged . She was equipped to carry a complement of four torpedoes for her two bow torpedo tubes and had an 5 cm ( 1 @.@ 97 in ) deck gun . As part of a group of six submarines selected for Mediterranean service , UB @-@ 42 was broken into railcar sized components and shipped to Pola where she was assembled , launched and commissioned in March 1916 . 
