 "R1" through "R4" were ordered from Chatham, "R5" and "R6" from Devonport (later changed to Pembroke), "R7" and "R8" from Vickers, "R9" and "R10" from Armstrong, and "R11" and "R12" from Cammell Laird.In August 1919, with World War I over, "R5" and "R6" were cancelled, the rest being completed.To save time, they used H-class components.