The Type 1934 and 1934A destroyers carried five single 5-inch guns. Type 1936A ships increased the calibre to 5.9 inches, with either four single mounts or a twin and three singles, to threaten cruisers. That choice aggravated the slower practical rate of fire already identified in German 5-inch weapons. At Narvik, a Tribal-class destroyer approaching bow-on could bring four 4.7-inch guns to bear against a German opponent with only two forward guns. The lighter British shell also made handling easier in rough conditions. A 5.9-inch shell remained within human handling limits, but the ship's motion and the heavier ammunition reduced the rate at which crews could serve the guns. The later Type 1936B returned to 5-inch armament.
Notable Point · 1:59:24-2:05:13
Why heavier German destroyer guns reduced practical firepower
The Type 1936A's 5.9-inch guns promised a threat to cruisers but made rapid firing harder on a maneuvering destroyer.