 The ship mounted four 45 @-@ calibre 4 @.@ 7 @-@ inch ( 120 mm ) Mark IX guns in single mounts . For anti @-@ aircraft defence Hostile had two quadruple Mark I mounts for the 0 @.@ 5 inch Vickers Mark III machine gun . 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 . 
