Why twin 4-inch guns suited sloops better than a 6-inch gun

Why choose twin 4-inch guns instead of a 6-inch gun on a small escort or sloop?

Twin 4-inch guns were easier to stabilize and load, fired faster, and were more likely to hit a surfaced submarine while still delivering enough damage to disable it.

A 6-inch weapon brought greater range and shell weight but was harder to stabilize and load on a small platform. Twin 4-inch guns could be aimed and loaded faster, producing more hits in close combat and against the small silhouette of a surfaced submarine. The Narvik comparison emphasizes volume of fire, contrasting German destroyers with disproportionately heavy weapons against British destroyers able to keep landing rapid hits in a close brawl. A 4-inch shell is given as weighing about 20 pounds, compared with about 112 pounds for a 6-inch shell, making the lighter ammunition easier to load by hand. Since pressure-hull damage could disable a submarine, the practical rate of fire mattered more than additional shell power. Against a small target, a weapon that produces more hits can be more useful than one with greater range and shell weight.