 U @-@ 20 was just over 127 feet ( 39 m ) long and was armed with two bow torpedo tubes , a deck gun , and a machine gun . U @-@ 20 had no wartime successes and was sunk in early July 1918 by the Italian submarine F @-@ 12 . The wreck of U @-@ 20 was located in 1962 and salvaged . A portion of her conning tower is on display in a military museum in Vienna . 
