 The rivers Orwell and Stour - which run between Ipswich and Manningtree, in Suffolk, England - doubled as the Yangtze River during the making of this film.The Chinese PLA gun batteries - depicted by old Royal Navy field guns on land carriages - were deployed on the sloping banks of the Boys' Training Establishment HMS "Ganges" which was sited at Shotley Gate, facing Felixstowe on the Orwell, and Harwich on the Stour, where the rivers converge.During filming, Wilcox's bank told him they would not accept a guarantee of £150,000 from RKO London unless supported by its parent company in New York.