The River class was larger and had two shafts unlike the Flower-class corvette, yet it was not built to the full naval standards expected of a sloop or escort destroyer. Because the design fit none of those existing categories, the Royal Navy revived frigate. Its wartime success and large postwar inventory tied the name to lower-cost ASW escorts. Treasury assumptions that frigates were cheaper then encouraged the label to spread while naval requirements pulled their construction and capability back toward sloop standards. The result was frigate by name and sloop by nature: frigates became ASW-focused escorts while destroyers retained a broader fleet-fighting role.
Chapter · 33:14-35:30
The River class revived frigate as an ASW escort name
A two-shaft escort larger than a corvette but cheaper than a full naval-standard sloop gave frigate its modern ASW association.