The CU series of convoy ran initially from Curacao but later, and mainly, from New York to Liverpool carrying much needed fuel supplies. Since the tankers that were involved in this series were capable of sustaining 14 knots, the series also became popular for the transport of other fast vessels. The protection of this series was under USN control. The series began in March 1943 and continued until the end of the war.

There were no cancelled convoys.