Black Swan sloops as a submarine-threat reserve

Were the Black Swan sloops designed to prevent a repeat of the First World War submarine crisis?

They gave the Royal Navy a reliable force to attack concentrated submarines when keeping a major port or route open justified accepting losses.

Black Swan sloops gave the Royal Navy a force it could commit when concentrated submarines threatened an indispensable route or port. The example imagines German wolf packs outside Liverpool attempting to close the harbor. The sloops would be sent to fight through that concentration even with casualties expected. Their specialization offered the prospect of achieving the mission with fewer losses than other available units. The comparison with the destroyer force protecting D-Day reinforces that an essential operation could justify accepting losses.