Page 77 - Ranger Demo

Flash, Sound and Air Photos at El Alamein 1942
Mike Nolan
The following notes on Flash Spotting, Sound Ranging and Air Photos at the Battle of Alamein came to light recently, after the article on Block Plots had been submitted to the Editor. They are included as a short supplement to that article. Some abbreviations have been transcribed in full, but some have been left as written in 1942: CBO = counter battery office, FS = flash-spotting and SR = sound- ranging.
In the desert of North Africa, the block plot gave a co-ordinate which hopefully was reasonably accurate. A photo-interpreter trying to do the same by eyeballing from a featureless flattish desert photo to a British 100K map copied from pre-war Italian 100k map may have had doubtful
results. Similarly, later, in Sicily and Italy, where there was more map detail at 50K and 25K, rugged relief became a factor. In very rugged terrain, a P.I. would have had to contend with height displacements on the photos.
Flash Spotting
The Composite Survey Battery under Eighth Army having been captured in Tobruk, there was no Survey assistance available at the commencement of operations at El Alamein. About the middle of July, the Flash Spotting Troop of No. 1 Composite Survey Battery arrived and was deployed on the 30 Corps front. As was expected in the desert, the Flash Spotters found visibility by day from ground Ops to be so limited as to be almost useless.
Towers were accordingly demanded from the RE. There was some delay in obtaining these owing to difficulty of getting material. In time, however, a line of towers varying from 30 to 80 ft high was erected from the coastal ridge to the Ruweisat Ridge. The southernmost towers were not manned before the offensive but were built so that the FS base could be moved southwards across the front to meet an enemy threat to our centre, as at one time appeared possible.
Some Flash Spotting was carried out on the 13 Corps front by the NZ Survey Troop which had been trained in this work. It was more often out of action than in, owing to lack of personnel to maintain lines. Signal Sections from AA Regiments were borrowed from time to time but could not be retained for very long. When it was known that a Flash Spotting Troop was shortly arriving in 13 Corps, towers were asked for, and half the number required were erected before the Troop arrived. Towers for the whole base were eventually erected. The results obtained from FS were as expected – very quick and accurate locations at night and also by day as far as visibility permitted. It frequently happened that only the most forward posts could see far enough to get flashes, but these single bearings in conjunction with air photo locations frequently identified the battery firing. Better results could have been achieved of these towers had they been further forward, but there was a marked aversion on everybody’s part to having towers in their area as being likely to attract shelling. Few of our towers were ever shot at, and then only slightly. It is considered that towers would keep more shelling off the forward areas than they would bring down on it. One of the most important effects flash spotting had on the enemy was to stop night firing almost entirely. The enemy started night firing seriously at about the same time as the flash spotting Troop came into action on the 30 Corps front. The resulting counter-bombardment not only stopped night firing in this front but on the whole Army front. The enemy seem very quick to pass this sort of information along the front as was seen later when the Sound Ranging came into action.
Sound Ranging
The Sound Ranging Troop of No. 1 Composite Survey Battery did not arrive until 1st September. It was hoped to carry out Sound Ranging Shoots on to hostile guns firing by day from roving positions. The enemy were very quiet at this period, however, and after only four days in action, the Troop was moved to the 13 Corps area, where it carried out many successful sound ranging shoots. After about a week the enemy appeared to realise what was happening and took evasive measures, chiefly by firing about six troops simultaneously and ranging with one gun out to flank.
Although these single guns were often located and shot up, the number of locations obtained on
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