i got a plan from the past lol
The Petroleum Warfare Department concentrated initially on static and mobile flame traps to defend, for example, the defiles from likely invasion beaches. It was slightly later, in July 1940, that it turned its attention to setting the sea on fire.
There was a precedent. The British had been contemplating the use of burning oil on the sea well before the war, and in May 1939, in an Admiralty experiment at Shoeburyness, 17 tons of petrol, spread over an area of 1,100 square yards, burnt for five minutes. Maurice Hankey (google is your friend) himself had long been gripped by the idea of deterring the invader by creating a vast flame barrage on the surface of the water, having been inspired by his reading of ancient Roman and Greek history. He wrote in 1940: ‘It is described in Gibbon’s “Rise and Fall of the Roman Empire” and Greek Fire, which was only an application of the same principle, was used by the Byzantine Emperors for years and years to maintain their sea power and defend Constantinople itself against their enemies.’ Hankey’s own early experiments of Dungeness and Dumpton in July 1940 were promising, but not very successful. They certainly did not match the descriptions of the Ancients.
The Royal Navy was interested in using petroleum warfare offensively, rather like the old fireships, but the practicality of transporting and then deploying many tons of oil at German ports put an end to such ambitions.
Another champion was found at the RAF in the person of Arthur Harris, a man who would subsequently command Bomber Command. He would write.
‘We should investigate the possibility of releasing quantities of petrol in the sea and setting it alight as the tows come in. It is obviously impracticable when considering the length of the coastline that we have to protect in this country. At the same time, however, the human inability to face flame being what it is, I think that there may be something in the idea and I have suggested to my own Commander-in-Chief an experiment of dropping light containers of petrol (such as the ordinary four-gallon petrol tin) in quantity to see if we can put up a concentration on the surface of the water which would present an effective barrier to small craft coming in to beach.’
Bomber Command’s more pressing engagements, particularly the plan to deploy gas from the air against any invasion meant that this initiative came to nothing.
On 24 August 1940, the biggest test yet with burning oil at sea was conducted on the northern shore of the Solent estuary near Titchfield, in front of a large gathering of spectators and experts. Ten Scammel petrol tankers gathered at the top of a cliff 30 feet high and then 160-foot-long pipes from each of them were taken down into the water, well below the high-water mark. The ten valves on the tankers were turned on, immediately delivering oil into the sea at a rate of about 12 tons per hour. What happened next impressed all who saw it, according to the account by Donald Banks (again, google is your friend):
‘Admiralty flares and a system of sodium and petrol pellets were used for ignition and within a few seconds of the pumps being started a wall of flame of such intensity raged up from the sea surface that it was impossible to remain on the edge of the cliff and the sea itself began to boil.’
I suspect that this test is the subject of the film linked by Dave Hopkin.
The burning sea seemed a reality. Harold Simpson, the commanding officer of the Admiralty’s Fuel Experimental Station at Haslar, wrote that
‘with all the waggons discharging, the fire produced was definitely man and boat-stopping, being a continuous bank of smoke and flame fully 30 yards in width.’
However, conditions were ideal for this test and some doubted that such a good effect could be achieved on the more exposed coasts of East Anglia. Nonetheless, following further experiments at Studland bay in Dorset (another contender for the linked film), the use of such a defence was approved. The right mixture for the oil and petrol was perfected and different types of pipes were trialled and approved.
It was not until February 1941 that the Chiefs of Staff approved the installation of 50 miles of piping, made up of 25 miles in South-Eastern Command, 15 in Eastern and 10 in Southern. In the end, however, as the invasion threat lifted and Hitler turned his gaze eastwards, only a small fraction of the barrage was installed, most of it in east Kent.
Not only were there plans to set the sea on fire, these plans came to fruition. It was only the lifting of the invasion threat, as the Germans turned their attention to the Soviet Union, that caused the plans not to be more widely implemented.