 After U @-@ 3 's arrival at Pola in January 1909 , she was commissioned into the Austro @-@ Hungarian Navy on 12 September 1909 as SM U @-@ 3 . During the evaluation of the U @-@ 3 class conducted by the Navy , the class ' poor diving and handling characteristics were noted . To alleviate the diving problems , U @-@ 3 's fins were changed in size and shape several times , and eventually , the front diving planes were removed and a stationary stern flap was affixed to the hull . U @-@ 3 served as a training boat between 1910 and 1914 and made as many as ten cruises per month in that capacity . 
