Standing Well Back
20th Century

Chemical render-safe techniques for explosives -1926

I’m deep into research into Soviet explosive activity in the first half of the twentieth century but in doing so came across a very interesting Russian technical EOD procedure from 1926, developed at an incident that’s worth discussing.

In many parts of the world in the late 19th and 20th century, bridges were built with special shafts, or alcoves, designed to take explosive charges to destroy the bridge in the event of a foreign invasion as part of defensive blocking operations.  At one point in about 1926, a bridge in the Ukraine was being inspected, and engineers found a forgotten series of explosive charges in a bridge, left over from a previous conflict. It is likely that in preparation for defensive operations that never subsequently occurred, the bridge was prepared for demolition by placing large quantities of explosives in the shafts, and then for whatever reason this was forgotten.

The large charges were of dynamite and had been placed in shafts built into a bridge then covered in a thick protective layer of grease.  Because of their age, and environmental heat cycling over the years, the dynamite was exuding nitroglycerine, and was assessed as very unstable.  The engineers were tasked with removing the dynamite without detonating it.

The innovative render-safe technique developed at the scene, if I’m honest, isn’t quite 100% clear because I’m dealing with a non-technical translation, but it’s interesting for a few reasons and was apparently successful.  It went like this, or something like this, from what I can glean.

  1. Oil (I think engine oil) was slowly poured onto the protective grease, dissolving it, but leaving behind the dynamite.
  2. The engine oil was then treated with sawdust, to soak it up from the bottom of the shaft and carefully removed. My guess is that such a shaft would have a drain hole, and this may have been plugged.
  3. A warm water-based alkaline solution was then poured onto the unstable dynamite.  This isn’t a technique I’m familiar with, but the engineer responsible claims the alkaline solution in contact with nitroglycerine results in a more stable material, which was then decanted from the bottom of each bridge shaft. I don’t know volumes or timescales but the whole operation dealing with several shafts, presumably one after another, took several days. It could be that the warm alkaline solution simply washed the remaining oil from the dynamite, as the engineer seems to be concerned with the grease interacting with the exuding nitroglycerine.
  4. Finally the remaining dynamite could be removed.

Have any readers come across any elements of this render safe procedure before? Any chemists out there able to comment on the nitroglycerine / alkaline effects and products? I’m assuming that some form of hydrolysis reaction takes place but my chemistry knowledge isn’t quite strong enough in this specific case… comments very welcome. Or was something lost in translation?

There is much more fascinating Russian stuff coming soon. The explosives specialist who came up with the procedure went on to be responsible for more explosive devices than any other person in history, and I’ll be posting more stuff on him soon. In the history of IED campaigns, and associated activity I don’t think there is a more important person.

Update:

Thanks to Matyas Koszik for this comment suggesting that chemically a hydrolysis of NG makes sense:

Re:alkaline hydrolysis of nitroglycerine:
https://onlinelibrary.wiley.com/doi/pdf/10.1002/kin.550160808
Seems to work similarly to other ester hydrolysis reactions.

 

20th Century

IEDs in Belfast – 1922

Ian Jones has passed me details of IEDs in Ulster in 1922. Ian is a real EOD history guru and I recommend his excellent books.

In 1922 Ireland was still being fought over and Irish republican bomb attacks were still relatively frequent (see my earlier posts such as this.)

Belfast was no different and a range of IEDs were encountered. There are details below of some interesting devices.  But note that the military response to these was by the Royal Engineers, not the RAOC who later became responsible in the province for such activity.  In a report published in the Royal Engineer Journal, which I cannot reproduce here for copyright reasons,  Captain EW T Graham-Carter reports a series of incidents that his Unit responded to.

1. An attempted bombing of a telephone junction box in Arthur Square in the centre of Belfast, two IRA men disguised and equipped as telephone repair men opened a manhole cover and left a times device behind. A Sapper Unit was requested to deal with the device. The manhole was filled with water by the Fire Brigade (!) and after three hours the package was removed. The device, wrapped in sacking, consisted of a wooden box with a slider switch on the outside. The timing device was an adapted alarm clock. (There are pictures in the journal). The device failed because the alarm clock had not been wound up. The main charge was an unidentified home made explosive or incendiary material (possibly sodium chlorate and sulphur). The initiators were interesting – two glass tubes sealed with insulating tape with two copper electrodes immersed in magnesium flash powder. Subsequent experiments were able to cause the main charge mix to explode.

2. A series of other devices are interesting because like many modern devices in the Middle East they utilised artillery shells, in this case 18pdr, but filled with home-made explosive. These were left in a number of “picture-houses” (cinemas), but on a number of occasions failed to function and were recovered by the Royal Engineers.

3. Other devices were designed to be hidden by or in roads. One found near Armagh consisted of hollow concrete blocks, 9in X 9in X 9in, with the addition of scrap metal as improvised shrapnel. It held 5lbs of explosive and was initiated electrically by a command wire of 300 yards in length.

Plus ca change, plus c’est la meme chose. Apart from the Sappers that is.

19th Century

The Horse’s Head and the Horse’s Hoof – VBIED Investigation in 1800 and 1920

I have posted before about the vehicle bomb attack in the failed attempt to assassinate Napoleon Bonaparte in Paris in 1800, details here.  I have now uncovered some fascinating details about the subsequent investigation. This was an extremely high profile incident and initially focus was placed on “The Jacobins”, a political opposition to Bonaparte, or indeed the British. But I have found in the memoirs of a French dignitary details of a more thorough investigation headed by Fouche (who I have written about elsewhere).

The device used was in a container placed on a horse-drawn cart in the Rue St Nicaise.  The horse that was harnessed to the bomb vehicle had been killed on the spot, but apparently was “not in the least disfigured”. Fouche, the Prefect of Police, ordered that parts of the dead horse including its head be taken to all the horse dealers in Paris to see if they recognised it.  One of them indeed recognised the horse, and was able to direct the police to a specific house.  The woman who “kept the door” identified the occupants who were affiliated within a particular group  (the “Chouans” – a group of “Royalists” and not the Jacobins).  She was also able to detail how the leader of the group had worked on something placed in a “water-carrier’s barrel” over a period of six weeks.

The leader of the group, a man called St Regent, was still in the vicinity of the bomb when it detonated, and was thrown against a post, breaking his ribs. He “was obliged to resort to a surgeon”, and the surgeon betrayed him to the police.  He and an accomplice were guillotined.

In one of those fascinating parallels that I encounter occasionally on standingwellback, the VBIED attack on Wall St, New York City, in September 1920 also featured the remains of a horse as part of the investigation.

In this attack, 120 years after the Paris attack, outside the bank of JP Morgan, a horse drawn cart also exploded. In this explosion, however, the horse wasn’t left intact and was blown to bits, not least because the device contained dynamite rather than the gunpowder used in the 1800 device. The investigators were able to recover one of the hooves and took it to blacksmiths across the city.  The blacksmith was eventually identified a month later but by then the investigative trail had run dry.

We sometimes assume that modern day bomb investigators are a new breed of professionals in a new industry. while me way not see many horse drawn vehicle bombs these days, the modes of investigation go an awful long way back.

Technology Development

Irish Republican Improvised Mortar Design – 1920

In a previous blog post 18 months ago I described how the IRA in 1920 designed and used an improvised mortar.  I’ve now found some context for that development and found out where a damaged mortar tube from 1920 exists today. Some of the below is a repeat of the earlier post and some is new information.

A number of IRA members had fought in the British Army in WW1 and had experienced trench mortars, either as a user or recipient.   The IRA funded a secret delegation to visit Germany and buy arms on the black market , including a German trench mortar but this mission was unsuccessful.  As a fall-back they asked their engineers to develop a home made mortar based on the British “Stokes” trench mortar.  I’m not sure how closely they followed the design, but the IRA version appears to have been of same calibre as the Mk 1 Stokes mortar (3 inch) and projected an 11lb mortar bomb, again the same as a Mk 1 Stokes mortar.  It appears that the IRA was able to obtain British Army manual for the Stokes mortar.   The tube was made by Matt Furlong’s brother, Joe, at a railway workshop, and Matt (who later died testing a version of the mortar) made the bombs for it at 198 Parnell St, Dublin.

Some early Stokes mortar bombs are “armed” on launch by use of a grenade lever spring which is released when the lever arm is free to fly off as it leaves the barrel.  I can’t be certain but i suspect the 1920 IRA mortar bombs used this principle too, and not the more sophisticated fuze design used in later WW1 Stokes mortars. Here’s a British Stokes mortar handbook from 1919 showing the later fuze types. Here’s an image of a Stokes mortar with a fuse fitted with a fly off lever.

The propellant charge was a 12 bore shotgun cartridge with shot removed and more propellant (black powder) added.  The impact fuze was adapted from a grenade fuze, (as was the early Stokes mortar bomb fuze). The mortar bomb weighed 11lbs.  I don’t have exact details but have a pretty good idea and those of you with an EOD background can probably make the same assumptions about arming on launch as I have.  For the rest of you, tough.                                 

The IRA conducted some extensive trials, under Matt Furlong of this improvised mortar system in October 1920 in County Meath. First a number of dummy mortar bombs with propellant only were fired, to establish ranges and calculate the propellant charge needed for a range of 100 yards.  Then three bombs were fired without a main charge but with an impact fuze fitted to test initiation.   The trials established that the bomb tumbled through the air, but despite that, the fuze appeared to work however it struck the ground.  One of the engineers believed that the impact fuze was being initiated on “set back” within the mortar tube and not on impact at the target. This is an important assessment ignored by Matt Furlong.  Attempts to fire a “live” mortar failed as the bomb got stuck in the tube.  Probably fortunately.

The engineers involved were concerned about the impact fuze functioning on “set back” within the mortar tube, so they added an additional safety mechanism (which I won’t describe here) and this was was built in to the fuze for subsequent trials. The second set of trials took place near Kells in County Meath.  After firing a live shell with the new safety feature which then failed to function on impact, an argument ensued between Furlong and McHugh, an assistant who was present.  Matt Furlong insisted on removing the additional safety feature and firing the mortar as originally designed. McHugh, nervous, stepped a few yards away.   The others retreated. As the mortar bomb was launched it did indeed explode in the tube, severely injuring Matt Furlong, who later died in hospital after losing a limb.

The loss of the mortar was seen as a significant blow to the IRA in Dublin who had expected to be able to mortar barracks with impunity mounting the mortar on the back of a vehicle, a tactic that they applied successfully 60 years later in the North.  

The mortar tube that exploded, eventually killing Matt Furlong, was hidden in the River Tolka for some years before being recovered.  In 1937 it was given to the National Museum of Ireland (NMI) where it exists today.  There’s some pictures at this link here – it has been mounted at an incorrect angle, but that doesn’t matter.
(Note the damaged base of the mortar tube some way down the page)

On occasion the arming system also failed in later IRA mortars, as I can vouch for personally.  To me there is a clear technological development route from the Stokes mortar of WW1, to the IRA’s improvised Mk 10 and Mk 11 mortars of the late 1980s and early 1990s.  I think there is a distinct possibility that the PIRA designer of the Mk 10 mortar and bomb based the designs in part on the 1920 Joe Furlong designed mortar and bomb which in itself was based on early WW1 Stokes Mortar designs.

Additional research leads me to believe that the additional safety feature in the mortar fuze that Matt Furlong removed before his accident was remarkably similar to a fuze safety feature I saw in on operations in 1991 – on another IRA mortar.  That’s seventy years apart, and essentially the same safety feature being used on an improvised mortar.  I won’t post details here, of course. The British Army EOD techs of the time were certainly not aware of that provenance. More fool us.

1920-1930

History lessons

Some earlier posts discussed the home made explosives and IEDs manufactured by Irish republicans shortly after WW1 (around 1920), and I’ve returned to the trove of information I have discovered on this subject. One of the themes of this blog has become the way in which today’s counter-terrorist operatives can learn lessons from the past, and this is a particularly good example.   During the 1980s one of a number of explosive devices designed by the Provisional IRA was a “drogue bomb”.  This basically consisted of a tin full of explosives, with a striker fuze behind it, and it was lobbed at vehicles with plastic strips trailing behind it to ensure it hit the target nose first so activating the striker by momentum.  To the EOD operator this was simple but “new” device.

What is interesting is that it wasn’t new at all. In about 1920 the IRA had previously developed what they called then a “drogue bomb”, and the diagram is shown below.  For obvious reasons I’ve left off some of the technical detail – if you are an appropriately accredited EOD operator contact me and I’ll give you the full diagram.   There are of course some differences between this 1920 design and the one from 60 years later in the 1980s… the striker mechanism has switched from the front to the back, and the steel case in the earlier device is thicker.  Those of you knowledgeable of other IRA mortars from the 70’s, 80’s and 90’s will also recognise certain aspects of the fusing from this earlier device.  I can tell you that EOD operators of my generation had no knowledge of the history of Irish republican device design from earlier campaigns. More fool us. As I’ve shown in earlier blog posts, improvised munition design used by Irish republicans goes back not only to this post-Easter Rising period, but to much earlier back to almost 1800.   Previous blogs to have highlighted the similarity between an IRA mortar of this 1920 period and the British Stokes Mortar of WW1.

 

 

Of course there are similarities to this device and Russian grenades, and I believe also to WW1 German trench grenades which I suspect this device is derived from.

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