The Black Swan's value as an upgradeable escort

Would Black Swan sloops still be useful against more advanced submarines?

They would remain useful for convoy escort after upgrades, even though later submarines would be more demanding opponents.

Faster postwar submarines would challenge an older escort, especially in a high-end contest. Convoy protection is a narrower mission, however, and the Black Swan's basic seakeeping and escort qualities would remain useful. Improved ahead-throwing weapons or later anti-submarine systems could be added as technology advanced. The class's real strength was adaptability: ships entering service in 1939 differed substantially from their late-war configuration.