 U @-@ 3 was 138 feet 9 inches ( 42 m ) long by 14 feet ( 4 @.@ 3 m ) abeam and had a draft of 12 feet 6 inches ( 3 @.@ 81 m ) . She displaced 240 tonnes ( 260 short tons ) surfaced and 300 tonnes ( 330 short tons ) submerged . She was armed with two bow 45 @-@ centimeter ( 17 @.@ 7 in ) torpedo tubes , and was designed to carry up to three torpedoes . 
