The projected escorts need more than ASDIC and depth charges because cruiser submarines can initiate surface gun actions. A plausible battery is four 4.7-inch guns using weapons already available for destroyers. Slightly larger hulls would improve both stability as gun platforms and the ability to absorb damage. Formal armor may remain treaty-sensitive, but subdivision and the Royal Navy's use of water or coal as protective material offer indirect ways to improve survival.
Notable Point · 38:18-39:12
Fighting cruiser submarines changes sloop protection and gun power
Larger sloops with four 4.7-inch guns, better stability, and protective subdivision are more likely to survive a surfaced gun duel.