JF Ptak Science Books Post 2430
In August 1940 Popular Mechanics reported on another example of cloudy thinking on the coming world of warfare--the "Floating Wall of Fire" of Romanian defensive consideration. The article tells the story of how Romania "girdled itself, like a medieval castle, with avast moat stretching for 750 miles....which, at the moment of invasion, can be turned into a river of flaming oil". The canals which make up this open-pit Maginot line were 50' wide and 12' deep, the longest of them running some 400 miles, the combined efforts of the big dig meant top protect the country from invasion from Hungary, Poland, the Soviet Union, Yuoslavia, and Bulgaria--and of course from Germany which at the time could advance from a number of different positions. There were also hundreds of gun emplacements facing the pit, I guess to fire on whomever if they decided to try and break through/over the moat, which would have been flooded with crude oil and set ablaze when invasion occurred.
The problem of course was that even a year after the Blitzkrieg in Poland with the combined assault by land/air forces the lesson had not been learned here--unless of course the flames were 20,000' high. And obviously the river of fire would last only so long--depending on available amounts of crude oil I wonder how long they determined the wall of fire could be maintained? A day? A week? (I know that from controlled burns of oil spills that in one case some 16,000 barrels of floating oil was burned off in a controlled burn in about four hours--it seems to me that if there was an invasion front that was miles wide and striking at numerous point along a 100-mile front that...well, the problems are obvious.)
Could anyone have expected an invasion force to arrive and then once confronted by a burning moat turn back and retreat?
In spite of fulfilling expectations during a "rehearsal of a large-scale invasion", it seems very highly dubious that anyone could really have been comfortable with the first line of national defense being fire in a long hole.
[It should be mentioned that after the once-neutral-ish Romania settled into its relationship with the Axis that the worst single-mission air losses for the U.S. Army Air Force occurred in the bombing of petroleum facilities in the area of Ploiesti, Romania, on 1 August 1943. In an unsuccessful attempt to damage the flow of petroleum to Axis forces, Operation Tidal Wave targeted this location but with devastatingly bad consequences, with 53 aircraft and 660 servicemen lost in the action.]