HMS Cam, HMS Chelmer, HMS Ettrick, HMS Helmsdale and HMS Tweed 2 shaft Geared Turbines 

HMS Cam, HMS Chelmer, HMS Ettrick, HMS Helmsdale and HMS Tweed S.H.P. 6.500 

Commonwealth frigates were specifically designed as anti-submarine escorts for trans-Atlantic convoys. River class frigates offered the size, speed, and endurance of escort sloops using inexpensive reciprocating machinery of corvettes. River class were designed for North Atlantic weather conditions and included the most effective anti-submarine sensors and weapons.

HMS Rother and HMS Spey were launched in late 1941, and Canadian and Australian construction continued through 1944. Early River class units were available for the turning point convoy battles of the winter of 1942-43. River class frigates generally replaced the old Town and V&W class destroyers which had been assigned to ocean escort groups.

Ten River class frigates were built for the United States in Canada. Two were commissioned in 1942 as USS Asheville (PF-1) and USS Natchez (PF-2), they were armed with U.S.N. pattern 3"/50 AA guns. The other eight were released under lend-lease for use by Commonwealth forces.