The U.S. Coast Guard has a long history in participating in COMINT. In the 1920’s and early 1930’s, during the liquor prohibition era, the Coast Guard had responsibility for interdicting the movement of illegal liquor into the United States.
One of the main targets was the Consolidated Exporters Company. This firm used rum runner ships which typically would load with illegal liquor in Bermuda, the Bahamas, or Cuba. They would remain outside the three mile limit where they would rendezvous with fast speedboats. The speedboats would load from the mother ship and attempt a fast run to some secluded harbor, usually within 25-50 miles distance. These speedboats were almost always faster than the fastest Coast Guard ships. The many coves and small harbors along the coast line made it difficult, if not impossible, for the Coast Guard to anticipate the actions of the mother ship and the speedboats. The mother ships communicated with their masters, the supply points, and the speedboats, by radio and that lead to the introduction of COMINT as a means of discovering rendezvous points, and other vital information.
Mrs. Elizabeth Friedman, wife of William F. Friedman, worked first in cryptology for the War Department and the U.S. Navy from 1921 to 1923, then later for the Treasury Department where she was employed as Head of that Department’s cryptographic unit. However, her unit was physically located with the Coast Guard which was under the Treasury Department as that time. Mrs. Friedman was successful in her work against the cryptographic systems of Consolidated Exporters Co. as well as other liquor and drug dealers. The Coast Guard was shifted to the U.S. Navy during World War II and Mrs. Friedman continued her work with the Coast Guard during that period. There is some indication that Coast Guard intercept operator personnel were assigned to U.S. Embassies during the above mentioned period. There they could copy traffic involved with activities of the illegal liquor and drug trade.
There was an Army-Navy -FBI COMINT agreement of 1942 which delineated responsibility in the areas of foreign intelligence. As a result the Coast Guard COMINT efforts were targeted against German and Japanese efforts to penetrate the North American continent, and to assist ships and aircraft in distress. In these endeavors they worked closely with the Federal Communications Commission (FCC) and Federal Bureau of Investigation (FBI). A Coast Guard officer was station at OP-20-G to coordinate clandestine intercept operations.