 Erich Koellner carried five 12 @.@ 7 cm SK C / 34 guns in single mounts with gun shields , two each superimposed , fore and aft . The fifth gun was carried on top of the rear deckhouse . Her anti @-@ aircraft armament consisted of four 3 @.@ 7 cm SK C / 30 guns in two twin mounts abreast the rear funnel and six 2 cm C / 30 guns in single mounts . The ship carried eight above @-@ water 53 @.@ 3 @-@ centimeter ( 21 @.@ 0 in ) torpedo tubes in two power @-@ operated mounts . A pair of reload torpedoes were provided for each mount . Four depth charge throwers were mounted on the sides of the rear deckhouse and they were supplemented by six racks for individual depth charges on the sides of the stern . Enough depth charges were carried for either two or four patterns of 16 charges each . Mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines . ' GHG ' ( Gruppenhorchgerät ) passive hydrophones were fitted to detect submarines . 
