 The ship mounted four 45 @-@ calibre quick @-@ firing ( QF ) 4 @.@ 7 @-@ inch Mk IX guns in single mounts , designated ' A ' , ' B ' , ' X ' , and ' Y ' from front to rear . For anti @-@ aircraft ( AA ) defence , Boreas had two 40 @-@ millimetre ( 1 @.@ 6 in ) QF 2 @-@ pounder Mk II AA guns mounted on a platform between her funnels . She was fitted with two above @-@ water quadruple torpedo tube mounts for 21 @-@ inch ( 533 mm ) torpedoes . One depth charge rail and two throwers were fitted ; 20 depth charges were originally carried , but this increased to 35 shortly after the war began . The ship was fitted with a Type 119 ASDIC set to detect submarines through sound waves beamed into the water that would reflect off the submarine . 
 The ship mounted four 45 @-@ calibre quick @-@ firing ( QF ) 4 @.@ 7 @-@ inch Mk IX guns in single mounts , designated ' A ' , ' B ' , ' X ' , and ' Y ' from front to rear . For anti @-@ aircraft ( AA ) defence , Boreas had two 40 @-@ millimetre ( 1 @.@ 6 in ) QF 2 @-@ pounder Mk II AA guns mounted on a platform between her funnels . She was fitted with two above @-@ water quadruple torpedo tube mounts for 21 @-@ inch ( 533 mm ) torpedoes . One depth charge rail and two throwers <a href='uninflect' title='1'><mark>were</mark></a> fitted ; 20 depth charges <a href='uninflect' title='2'><mark>were</mark></a> originally carried , but this increased to 35 shortly after the war began . The ship was fitted with a Type 119 ASDIC set to detect submarines through sound waves beamed into the water <a href='null_relcl' title='3'><mark>that</mark></a>would reflect off the submarine . 
The ship mounted four 45 @-@ calibre quick @-@ firing ( QF ) 4 @.@ 7 @-@ inch Mk IX guns in single mounts , designated ' A ' , ' B ' , ' X ' , and ' Y ' from front to rear . fa anti @-@ aircraft ( AA ) defence , Boreas had two 40 @-@ millimetre ( 1 @.@ 6 in ) QF 2 @-@ pounder Mk II AA guns mounted on a platform between her funnels . She was fitted with two above @-@ water quadruple torpedo tube mounts for 21 @-@ inch ( 533 mm ) torpedoes . One depth charge rail and two throwers was fitted ; 20 depth charges was originally carried , but dis increased to 35 shortly after the war began . da ship was fitted w/ a Type 119 ASDIC set to detect submarines through sound waves beamed into the water would reflect off the submarine .