StandingWellBack

You can contact me at rogercdavies(atsquiggle)me.com

This blog has evolved into a review of historical and modern explosive devices, and responses to them. Links are drawn between historical activity and similar activity in the world today. Mostly I focus on what are now called IEDs but I have a loose personal definition of that and wilingly stray into discussions of more traditional munitions, the science and technology behind them, tactical employment and EOD responses. Sometimes it's just about interesting people in one form or another. Comment is welcome and encouraged but I do monitor it and reserve the right to delete inappropriate stuff. Guest posts are always welcome. Avoid any stuff that makes the enemy's job easier for them.

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Entries in Sappers (3)

Thursday
Apr272017

Attacking Railway Lines with IEDs - 1870

Readers of this blog will know I have written on a number of occasions about the use of IEDs against railway lines.  In one of the “threads" I have followed, I worked backwards from the use of such devices by Lawrence of Arabia in WW1, established that they had been developed and used in Arabia , by “Bimbashi” Garland, Lawrence’s explosive mentor, a former Ordnance Corps Laboratory technician, and traced the design of these devices back to the Boer War where they were used by Boer guerrillas led by Jack Hindon against the British. Devices under railway lines were also used by Russian Narodnaya Volya terrorists in 1879 and in many attacks since then.    In digging around the provenance of the Boer devices I found a vague reference to the experience of a Boer who had fought in the Franco-Prussian War 30 years earlier, that the Boer's utlised.  Here’s a list of previous posts on the matter in the order I wrote them.
 
 
 
 
 
I have been digging around reports on the Franco-Prussian war for some time, hampered by my sadly limited language skills, looking for something that might indicate where the Boers had gained their experience of blowing up trains using a pressure switch activated by the weight of a train. At last I have found something that fits and it’s pretty interesting. In 1870 a young Royal Engineer officer, Lt Fraser, was observing the events of the Franco-Prussian war, a habit that many armies followed in the 19th century. Lt Fraser wrote a paper, published, in the Professional Papers of the Corps of Royal Engineers, Vol XX in 1872. The paper is entitled  "Account of a Torpedo used for the Destruction of a Railway Train on the 26th of October, 1870.”  As a reminder the word "torpedo" was used at the time to describe a much wider variety of explosive devices and munitions than is applied today.  
 
Here is a brief extract from a third party source, as I await a hard copy of the publication in the post which I hope will contain more detail:
 
Learning that a Prussian troop train was to pass through Lanois (on the line between Reims and Mons) on October 26, 1870, they resolved to effect its destruction. How they operated is told by Lieutenant Fraser, R. E., who arrived on the spot shortly afterwards, and heard the story from some of the men engaged on the work. 
 
Any obstruction placed on the line would have been seen. Hence a different course had to be adopted. Selecting a spot where the line ran along a 12-ft. high embankment, to which a well-wooded slope came down on one side, the franc tireurs took up a pair of rails, removed the sleepers, cut a deep trench across the line, laid some pieces of iron at the bottom of the trench, placed on the iron a box containing thirty kilos (2 qrs. 10 lbs.) of powder, and fixed into the lid of the box a French field shell in such a way that, when the rail was replaced over the box, the head of the fuse would be just below the lower flange of the rail. In restoring the line again in order that there should be nothing to attract attention, the franc tireurs omitted one sleeper so that the weight of the locomotive should in passing press the rail down on to the head of the fuse. The party—some seventy-five strong—then withdrew to the shelter of the woods to await developments.   

In due time the train of forty coaches approached at the ordinary speed, the driver not suspecting any danger. When the engine reached the spot where the "torpedo" had been placed, an explosion occurred which tore up a mass of earth, rails and sleepers, threw the engine and several carriages down the embankment, and wrecked the train. Those of the Prussian troops who got clear from the wreckage were shot down by the franc tireurs under the protection of their cover. The number of the enemy thus disposed of was said to be about 400.
 
 
I think there is a clear link to the device I report in the my previous blogs about the depressing rail activating a pressure sensitive switch albeit in this case an artillery fuse, and not the trigger of a rifle breech as seen in the Boer War and used by Garland and Lawrence in Arabia.  The device too has a link to the earlier pressure sensitive devices, using artillery shells with contact fuses adapted to initiate on pressure used by General Raines in the American civil war in 1862.

 

Thursday
Aug252016

Techniques of Bomb Disposal 1942

Interesting film from 1942 showing Sapper EOD operations against air dropped munitions that end up buried deep. At the six minute point and 11 minute point you will hear the word "Wedges". (hohoho!)  Instructional in nature, but you gotta love the brass band accompaniment at the beginning.   Also, if I'm allowed to make a poor joke, I see that the Royal Engineer Officer's remedy for an unconscious sapper, poisoned by Carbon Monoxide is to turn him on to his front and massage his bottom (24.45).  Good to see that technique existed so long ago... 

BFI Film archive - 1942 Bomb Disposal

 

Monday
Nov262012

Some of my best friends are Sappers… (Sappers, Doctors, explosives and smoking dope)

My last post about the evolution of detonators involved digging around in some interesting history. I came across two fascinating reports about a British military engineering operation on the Hoogly River in Bengal in 1839 and 1840. The crucial piece about this story is that it straddled the invention of sub-aqua electrical initiation of gunpowder charges as used by Pasley with the earlier much less reliable igniferous technique, in this case using tubes of lead filled with gunpowder, soldered together.  The reports are found in the professional papers of the Royal Engineers, 1840 and Volume 8 of the Journal of the Asiatic society of Bengal, 1840. Go google if you want to read the originals.

The circumstances were that a ship, the Equitable, had sunk on a sandbank and was posing a hazard to shipping. So a young British military engineer, Captain Fitzgerald serving in the Bengal Engineers and some colleagues decided to blow it up, as is the wont of young Engineer officers.  In this case (and not for the last time), they were accompanied, encouraged and assisted by a young medical officer

So, this was a complex operation in a fast flowing and murky river. The Equitable had sunk in October 1839 in the middle of the shipping channel.  It was decided to use large gunpowder charges to break up the vessel.

 Attempt 1, Igniferous - Failed.

The first attempt used a large waterproof cylinder full of gunpowder, ignited by means of a linen hose protected by lead piping.  The charge was an enormous 2400 pounds of powder.  The cylinder was an oak cask, bound with iron hoops, and plates of lead were carefully soldered onto it to seal it. The lead pipe protecting the powder train in the hose was made from four 15 feet lengths, soldered carefully together. The hose, 1inch in diameter and containing gunpowder was then inserted into the pipe.  I have a description of the explosive chain between the main charge and the gunpowder hose, but have not yet found an associated diagram. so I can’t yet make head or tail of it.  The characteristics of a loose filled gunpowder hose clearly gave rise to challenges, in terms of transmission of the igniferous process in a vertical pipe. To manage this the hose was knotted every 6 inches, and held in place by fastening to a pewter wire inserted down the length of the pipe.

The seal between the powder hose in the pipe and the “primer cylinder” appears to have been achieved with brass fittings and leather gaskets.

The first attempt took place on December 6 1839, and the charge was lowered from a boat onto the deck of the sunken ship.  A “portfire” with an estimated burning time of 10 minutes fastened to the top of the gunpowder filled pipe, and the boat rowed away.  However the portfire failed to ignite the gunpowder train. A second portfire was set, and after a few minutes a muffled small explosion was heard, which was assessed as being the pipe rupturing. The main charge failed to ignite, and the pewter wire was ejected from the lead pipe. The pipe was raised and the rupture found at 25 feet from the top.

Attempt 2. Timed, electrical, using a watch - Successful

For the second attempt the Egineer team, encouraged by a medical doctor William O’Shaugnessy, and no doubt hearing of the success of Pasley, used an electrical initiation method.  O’Shaugnessy “read up” on electrical theory and designed and built his own galvanic battery, a description of which can be found in the reference. O'Shaugnessy conducted several experiments with his battery and platinum wire or platinum foil filaments, making the foil white heat with its electrcial resistance.  Working the physics, O’Shaughnessy established that with some careful design he could initiate the platinum filaments through bare un-insulated wire, under water, provided he kept the “legs” sufficiently far apart and the battery powerful enough.  He also designed a highly ingenious system for holding the filament in a sealed container using a breech of a gun.  Furthermore O’Shaugnessy then designed a remarkable timing initiation using a simple watch, copper “arms” and mercury filled tubes that the copper arms of the watch swept through that automatically “made safe” the firing circuit four minutes after initiation, so it would be safe to recover if the initiation failed.  It is clear from O’Shaugnessy’s report that he had no actual reports of Pasley’s successes other than newspaper reports, and so was working on first principles.

The second attempt took place on 14 December 1839, using this electrical mechanism, the battery and timer being in a small fishing boat above the charge. After setting charge, the demolition party consisting of Capts Fitzgerald and Debude, and Lieutenant Smith, accompanied by O’Shaughnessy and his assistant Mr Siddons, rowed quickly away.  Here’s O’Shaugnessy’s description of the subsequent explosion:

At the thirteenth minute a slight concussion was was felt in our boat, a sound like that of a very distant and heavy gun at sea was heard, and a huge hemispherical mass of discoloured water was thrown to the height of about 30 feet. From the centre of this mass there then rose slowly a and majestically a pillar of water, intermingled with foam and fragments of wreck , and preserving a cylindrical form till it reached an elevation of at least 150 feet. The column then subsided slowly, a wreath of foam and sparking jets of water following its descent, and rendering the spectacle one of indescribable beauty.

O’Shaughnessy later also significantly improved the manner in which the heated platinum filament ignites the charge. Previously the heated filament was embedded directly into gunpowder but O’Shaughnessy found that by embedding the filament in cotton which had been soaked in a solution of “purest saltpeter” effectively lowered the temperature that the filament was required to reach to cause ignition.

Attempt 3, Electrical using an improvised timing mechanism involving portfires and "string" - Failed

A third operation occurred a month later to remove a large part of the sunken wreck still remaining, and this too used a timing mechanism and electrical initiation, however the system failed to initiate due to damage to the priming charge where it was fastened to the main charge.  The sapper officers revised the mechanical timing mechanism of an adapted watch used by O’Shaughnessy and used portfires burning string at timed intervals to make and then break a circuit if detonation had not occurred – I see in the different reports of Capt Fitzgerald and Dr O’Shaughnessy a little irritation from the good doctor as to the contrived nature of this measure, which he regards as crude an unreliable, but which the sapper officers are very proud of (it saved the expense of a watch).

Attempt 4. Electrical using an improvised timing mechanism involving portfires and "string" - Successful

A fourth operation took place on 28th January 1840.  A successful explosion took place, breaking up the remaining part of the wreck and also killing two porpoises.

O’Shaughnessy went on to an interesting career where he was involved in pharmacology, the electric telegraph, encryption and most famously the introduction of cannabis to the UK for “therapeutic use”.