79th USN Construction Battalion

Operation Fog Intensity; Dispersal Of (F.I.D.O.) at Amchitka:

During the reunion of the 79th Battalion veterans held in Biloxi, MS on 27-30 October 2003, it was brought to attention by one of the veterans that a detachment of the 79th NCB was sent to Amchitka to participate in the construction of Fog Intensity; Dispersal Of (F.I.D.O.) at Amchitka in the Aleutians during World War II.  According to the Officer in Charge of this Detachment, F.I.D.O. was an experimental project in which gasoline was used to burn up the fog in order for the bombers to use the runways at Amchitka.

Last island in a string of islands known as the Rat Islands in the Aleutian Chain, 2,900 miles off the coast of Alaska and often hampered by dense fog up to 4,000 feet thick and winds up to 35 miles per hour, Amchitka was scheduled in March 1944 to become the first F.I.D.O. installation in the United States in order to conduct wartime air operations.  

In April, 1944 the Seabees built a FIDO installation on Amchitka in the Aleutians which necessitated the removal of tremendous amounts of tundra, draining and filling of small lakes, the rescue and reservicing of muskeg, and numerous other obstacles to overcome. A U.S. Navy publication, 1947, states "Work stated on the project in April, 1944, with Seabee personnel installing the equipment, a tough job because of the nature of the terrain.  Enormous amounts of tundra had to be moved to provide a firm and level foundation for burners.  Special supports driven through the tundra to rock strata were necessary to carry the burners over small ponds and uneven ground.  The burners, based primarily on British design, were constructed right at the sight.  100 of them being produced in a five-day period."  A Haigill-type burner was constructed at Amchitka, consisting of miles of burner and preheated pipe, supply lines to a new fuel storage area and pumping station.  The Haigill burner burns vaporized gasoline through a vaporizer which is a supply tube suspended with and above the burner tube, connecting at the end of the burner unit.  Thermal output of these burners varied from 15 to 50 therms per yard hour. 

In July, 1944, the Seabees completed the Amchitka FIDO and the installation was tested.  Despite heavy fog, six aircraft were launched in August, 1944 and FIDO was used tactically for the first time.  The 1947 U.S. Navy publication records:   "On July 25, 1944, just before dawn, the burners were ignited, and the fog lifted from zero-zero weather conditions so that the sky became visible. A Navy PBY-5A took off and disappeared into the fog. The plane then made a normal instrument approach and broke into the clear at 150 feet over the runway. After this successful take-off and landing, the Army C-47 made two take-offs and landings with FIDO.  Again in August of the same year, when President Roosevelt was visiting the Aleutian area, all stations with patrol planes were fogbound. FIDO was lighted and six PBY-5A's took off to fly anti-submarine patrol."  Amchitka FIDO was eventually turned over to the Army Air Forces.

Any information on participation of the 79th Naval Construction Battalion or other Seabee Battalions in the construction of Fog Intensity Dispersal Of (F.I.D.O.) at Amchitka in the Aleutians during World War II will be greatly appreciated. Please contact:

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Email:  JWinter588@aol.com

References to the Seabees in the F.I.D.O.operation:

  • LANDING AIDS FOR ALL-WEATHER FLYING, by Vance Gudmundsen, Reports Analyst, Landing Aids Experiment Station, James E. Davis, January 31, 1947 Dows Prairie, California
  • Thermal Fog-Dispersal, High Pressure System by Dave Zebo, Director, Department of Aviation, Humboldt County, August 16, 1957


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