 By October 1940 , the ship 's AA armament was increased when the rear set of torpedo tubes was replaced by a 3 @-@ inch ( 76 @.@ 2 mm ) ( 12 @-@ pounder ) AA gun and ' Y ' gun was removed to compensate for the additional depth charges added . Boreas was converted to an escort destroyer in late 1943 with the replacement of the 12 @-@ pounder high @-@ angle gun with additional depth charge stowage . The 2 @-@ pounder mounts were replaced during the war by 20 @-@ millimetre ( 0 @.@ 8 in ) Oerlikon autocannon . Four additional Oerlikon guns were added in the forward superstructure for a total of six guns . 
 By October 1940 , the ship <a href='null_genetive' title='1'><mark>'s</mark></a>AA armament was increased when the rear set of torpedo tubes was replaced by a 3 @-@ inch ( 76 @.@ 2 mm ) ( 12 @-@ pounder ) AA gun and ' Y ' gun was removed to compensate for the additional depth charges added . Boreas was converted to an escort destroyer in late 1943 with the replacement of the 12 @-@ pounder high @-@ angle gun with additional depth charge stowage . The 2 @-@ pounder mounts <a href='uninflect' title='2'><mark>were</mark></a> replaced during the war by 20 @-@ millimetre ( 0 @.@ 8 in ) Oerlikon autocannon . Four additional Oerlikon guns <a href='uninflect' title='3'><mark>were</mark></a> added in the forward superstructure for a total of six guns . 
By October 1940 , da ship  AA armament was increased when tdarear set of torpedo tubes was replaced by a 3 @-@ inch ( 76 @.@ 2 mm ) ( 12 @-@ pounder ) AA gun and ' Y ' gun was removed to compensate for thdadditional depth charges added . Boreas was converted to an escort destroyer in late 1943 w/ the replacement of the 12 @-@ pounder high @-@ angle gun wiwiddditional depth charge stowage . Theda@-@ pounder mounts was replaced during the da by 20 @-@ millimetre ( 0 @.@ 8 in ) Oerlikon autocannon . 4 additional Oerlikon guns was added in the forward superstructure fir a total of six guns .