You can contact me at rogercdavies(atsquiggle)  If you have a comment and the system won't let you post it, ping me using the @ for (atsquiggle)

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.

A note on moral perspectives. Throughout this blog there are descriptions of all sorts of people using IEDs, explosives, or suffering the consequences. Some of the people using IEDs are thought of as heroes by some and terrorists by others. One person's good guy fighting for a cause is another person's evil demon.  It's complicated, and history adds another series of filters too. All of us too live in a narrative made up around however we were brought up, what we were taught and what we learned along the way, rightly or wrongly. So if you sense moral ambivalence, one way or the other, well, I'm guilty and I'm not perfect.  By and large though, I have unapologetic sympathy for those dealing with the devices, whether they be soldiers, cops, or whatever, even those who are part of Nazi or other nasty regimes. That's the cool thing about EOD techs - we don't really care who the enemy is.


Entries in 1870-1880 (8)


Attacking the Tsar's train with IEDs, 1879

A shorter gap between blog posts than usual, as I am prompted by responses to the last one about a railway IED in 1880.  This one is about a series of three IEDs all targeting the same train, all carrying Tsar Nicholas II on a journey from the Crimea to St Petersburg in November 1879.   The attack also allows me to explore once again the concepts of tactical or operational design, which describes how, why, what and when an IED plot is developed and instigated and the factors which constrain or provide opportunity to the development of a terrorist plan.. It also allows me to dissect in more detail why railway IED attacks have seemed attractive over the years.
The group concerned was the revolutionary group Narodnaya Volya. Read upon them if you have time, elsewhere.  The sub groups concerned with this “triple” plot are in interesting mix of revolutionaries, peasants and engineer/scientists.  In 1879 Narodnya Volya "passed a death sentence” on the Tsar in August 1879 for all the reasons you can read about elsewhere.  It then came to their attention that the Tsar, who used the railways extensively to travel throughout Russia, would be travelling from the Crimea where he had a “summer residence” at Livadia, all the way North to St Petersburg.  They therefore could predict, somewhat, his route.  Here we come to the issue about railways, that when you look at it, is obvious but needs pointing out. Railways are attractive to terrorists because:
  • The railway provides a location, somewhere on its length, where a target will present itself. The terrorist knows that the target will be at any specific point along its length at some point, between point A and B, at some perhaps unknown time. So it's a location where the target “will” present itself with a degree of certainty, and the manner of that presentation (in a railway carriage) is also known. This is a factor a terrorist can exploit.
  • In many circumstances, trains are scheduled by a time table. so again the terrorist has a factor he can exploit to a greater or lesser extent. This may give him options for detonating the device, either by timer, or by a victim-operated (train operated booby trap) switch, or by command, allowing the terrorist to only be present at a firing point for a limited period of time, enhancing his security.
  • The lengths of railways lines (in this case hundreds of miles) ensures that the terrorist has freedom to lay a device, when no-one else is around, perhaps at night or at distance from people. Security measures cannot cover hundreds of miles of railway. so there is a freedom of action for the terrorist to exploit. In essence every dark night and in every remote location the authorties are forced to relinquish control of the railway.
  • The nature of railway lines provides additional factors that the terrorist can exploit. Firstly it is easy bury and hide a device under a rail. secondly the fact that a train is travelling at speed adds to the effect of an explosion which might, perhaps simply rupture the lines - a train will then be derailed, and thus the explosive effects can be added too if needed, so as well as explosive damage there is the kinetic energy release of a train crash. Trains have a large mass, and a high speed, potentially, and these are again factors for the terrorist to exploit in terms of energy utilisation, especially on a bridge or embankment.
  • Some other factors, which might appear trivial but which can be important. The railway line can usually be found easily by the terrorist -"Go to station A and walk up the line a particular distance." The rail system itself is a mode of transport for the terrorist and the IED. Railways are large constructions and a train can usually be seen approaching from a considerable distance, allowing the terrorist some freedoms, and some warnings which can again alert him and allow him to be in a dangerous firing point for a limited period of time. The noise of a train at night also provides this “signal” to a terrorist, which can help them.
In this case, the Narodnaya Volya, as was sometimes their wont, decided on three separate IED attacks on the train as it carried the Tsar from the Crimea, northwards to Moscow and on to St Petersburg at different points in its journey, providing a degree of built-in redundancy in their plot. Interestingly it was known that there had been a plot ten years earlier in 1869 to attack the Tsar’s train in Elizavetgrad with explosives. so the “concept” of such an attack was known to the revolutionaries. In effect they had a template half formed in their mind already.  
The group had a “man on the inside’, employed as a railway-guard near Odessa who was able to provide a degree of information.  This probably included the fact that actually the Tsar’s train traveled in convoy with at least one other train, one carrying his entourage, with the Tsar in the second train (according to some sources there were three trains and he traveled in the third). This ruled out the sort of attack described in my earlier blog post about the attack in UK, which was designed to be initiated by a train, because that would simply hit the first train.  Thus the attacks on the Tsar in the second or third train had to be by command initiation.   Three subgroups were formed, one for each attack. They were supplied with over 200 pounds of dynamite made by their technical expert Nikolai Kibalchich in his apartment on Nevsky Prospekt in St Petersburg. Kibalchich carefully tested the explosives and the other components, using as a power source a Ruhmkorff induction coil - which produces high voltage pulses from a low voltage battery (plenty of good you-tubes on such things)
  1. At a point on the railway near Odessa, Kilbalchich and four others developed the tunnel or trench to run the wires to an explosive charge under the railway taking two weeks to get it into position. Kibalchich brought the explosives he had made himself in a suitcase.  Then, days before the expected attack they got news from the insider that the Tsar wouldn't be travelling on the stretch of track they had expected. So they packed up, recovered the explosives and abandoned this aspect of the plot. 
  2. At a village called Aleksandrovsk, a village between the Crimea and Kharkhov a second group of five rented a house close to the railway line.  With difficulty they dug a shallow trench all the way to the railway embankment, laying an electrical cable.  It seems the circuit was faulty and when the circuit was closed nothing happened, and the Tsar’s train passed over unharmed.
  3. At the third point, on the approaches to Moscow, the terrorists successfully detonated the device, electrically, under the second train, not knowing that for unknown reasons the order had changed and the Tsar was in the first train which was allowed to pass safely. In this case the device exploded under the baggage train. Interestingly in the “follow up” the police raided the house where the device had been initiated from and remarked how well everything had been "properly camouflaged" to ensure a casual visitor wouldn't deduce what was going on. More evidence of very careful planning.

So the attacks all failed in their stated intent. But nonetheless Narodnaya Volya claimed a degree of success in terms of derailing the Tsar’s baggage train, and notably announced their pride in planning such a complex operation with care and great diligence. The group saw the attack as a “modern” attack better than confronting the target with a revolver and little chance of escape. Interestingly not long after in 1881 they succeeded in assassinating the Tsar, in St Petersburg, but not by “sophisticated” command devices, allowing their escape but with a bomb simply thrown at the feet of the Tsar, in effect a suicide bomb. 
There has been some discussion about how the Narodnaya Volya attacks may have ben a preliminary inspiration for other railway attacks that occurred in subsequent decades.  But while it may have been something of an inspiration I think that the experience of the US Civil war, where there were a number of IED attacks on railways, and indeed the IED incident I reported on previously in 1870 as art of the Franco-Prussion war, showed the world the potential vulnerabilities of railways to IEDs, well before the Russian events detailed here. 
To return to the tactical and operational design concept. I think it's useful to look in detail at this triple plot, (which failed) compared to the assassination of of the Tsar two years later, which succeeded. An understanding of the design of these plots, and indeed any plot is best elicited (I propose) by asking the following questions of each incident:
  1.  Why did the attack occur here, at this point?   The answer is rarely simple, and indeed some of the factors may not even be recognised by the terrorist perpetrator themselves. A few years ago doing a study of roadside bombs in Iraq, an activity I was associated with established 27 different factors which affected the choice of firing point , route of command wire and initiation point. 
  2. Why did the attack occur at this time?  Again think beyond just time of day.
  3. Why was this target attacked?
  4. Why was this particular device used? Not just the actual device but why this means of initiation, this size, in this container , etc. sometimes an IED is presented to a perpertrator and they have to use it somehow, at other times the device is designed or at least adapted for a particular mission. Understanding which of these options occurred is a useful insight.  Sometimes it is driven by some of the other factors.
Answering as many of those questions as you can will give insights into the expertise, resources and skills of the perpertrator, and also provide other valuable information or suggest other leads for the investigator.  for the historian too these leads may become fruitful as a result. Comparing the answers regarding these attacks in 1879 and the subsequent successful assassination two years later in intriguing - very different operations, yet counter-intuitively the mission with less detailed planning succeeded. How Narodnaya Volya got from planning meticulously three electrically initiated command devices, over the length of the country (all of which failed in one sense) to a much more ad hoc but successful suicide bombing gives insights that are valuable today, I submit.

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.



Mechanical Sabotage Devices

This is an interesting news report I found.  It discusses some clever mechanical devices used to sabotage ships. The devices are secreted inside the ship, against the hull, and utilise the movement of a ship through the waves to steadily and slowly bore or cut a hole in the hull. This report from about 1876 was repeated in some other newspapers at the time, in identical reports referring to the Bremerhaven attack  and provided as context for other types of attacks on ships.  However, I have dug away and not found any other details of such devices. Really this single report. Intruiging. The explanations are not entirely clear, I'm afraid.



18th Century TPU, 19th Century Grave Robbers

I've blogged before about the use of flintlocks and other gun-lock mechanisms used as initiators in IEDs between the end of the 16th century and the middle of the 19th century.   Some recent digging has made me think that the integration of a timing mechanism with a flintlock mechanism was a widely used system, perhaps not regularly within an IED but widely enough that it's use must have been well known, even if only as a potential initiation system.  Here's some images of a couple of peculiar alarm clocks which I think make the point well. The operator sets a time on the clock which when reached released a spring loaded trigger on a flintlock.  A small amount of powder is then initiated which also ignite the wick of a candle which then by a linked spiring stands up in the box. These are I think from the period 1715- 1740 or thereabouts. Nowadays we'd call these a Time and Power Unit (TPU)

 I have also found a "set gun" which attached a flintlock to a tripwire, used as a deterrent for both for both poachers and grave robbers. Here's an image of one of these.  

To be clear I'm not suggesting any of these are IEDs, just that such a mechanism could have been used at the tme to initiate explosive devices.  The set guns were outlawed eventually but in 1878 an inventor, Mr Clover of Columbus, Ohio then came up with a "coffin torpedo" to deter grave robbers who opened a coffin with something like a shotgun cartridge, initiated by the opening lid.  "Torpedo" was the name given to IEDs at that time.   

In 1881 a Mr Howell invented two "Grave Torpedos", much more like IEDs and images from the patent application is shown below. These were much more like an American Civil War land mine, placed on top of a coffin with a plate above it, designed to be initiated when the grave robbers dug down.

These were effective - a grave robber was killed by the device and an accomplice wounded: 



How gun locks were used in IEDs for over 250 years

When I started my research into historical IEDs a few years ago, I came across references to “gun locks” used as initiation mechanisms. The “gun locks” are from firearms such as wheel-locks or flintlocks repurposed to initiate a larger explosive charge.

However I have continued to encounter these mechanisms at every turn of my research. The deeper I dive into historical documents the more I think they were much more common than I had realised. In fact I think they were a usual way of initiating IEDs for about 250 and even for as long as 330 years. I think that’s surprising and worthy of explanation   The wheel-lock and its successors, the snap lock, the snap-haunce and the flintlock are essentially spring loaded levers operating around an axis which contrives to place a spark ignition system in direct proximity to gunpowder. In a firearm the “trigger” is pulled by the person aiming the firearm - the pull of the trigger releases the spring-loaded mechanism. In general terms in an IED the trigger is pulled or released by another mechanism such as a lever or a cord. But it is the same mechanism.

The developments of gun locks for firearms were paralleled and linked inextricably with the development of household locks for doors and chests, and the same people made both.  There is also a distinct parallel in technological development terms with clock making which saw some significant developments in about 1580 with the development of spring driven rather than pendulum driven mechanisms, and one sees this being a mechanism that enables mechanical timing mechanisms in IEDs for the first time at around this date.  But the clock is only a component to release a spring loaded lever, allowing the flint, for example, to strike and cause sparks.   One can still see the influence of clock making in fairly modern fuzes, and I think that’s an area for future research, to explore the early parallels of lock mechanics with fuze mechanics. Indeed the language of clocks and explosive fuzes is very similar in describing components - ”fuzes" and “trains".

I’ve discussed before some of this , in relation to the invention of detonating systems,  but here I want to concentrate on the locks and the derived implications to IED design. 

Here’s an outline of the technology:

Prior to 1500 firearms were fired with "match locks". Pulling a trigger caused a slow burning cord, (a "match")  held on an "s" shaped lever to be pushed into contact with the gunpowder charge. In about 1500 the wheel lock was developed as a sophisticated mechanism to initiate a firearm without a pre-lit match.  The wheel lock is a spring loaded steel wheel which acts with friction against a piece fo pyrite to produce sparks, pushed against it by a spring loaded lever or "dog".   The resultant sparks land upon the beginning of the gunpowder train. (think of a Bic cigarette lighter, yet the thumb which turns the steel is replaced by a spring).  A simple "detent” safety catch is easy to include which prevents the spring loaded mechanism being moved until the device is set up in place.  Thus the wheel lock is:

  1. Safer than using a matchlock where a slow burning fuse ("match”) is introduced to the gunpowder train (not a good idea with a large charge of gunpowder immediately adjacent)
  2. Able to be left in place for as long as the gunpowder doesn't deteriorate
  3. Able to facilitate its containment and concealment (partly due to its small size) within an enclosure, which again a matchlock is not suited to.
  4. Able to prevent the give-away smell of  a burning match and the sight of a glow.

So in IED terms the wheel lock and its sucessors enable ease of use, concelament and safety, all key asopects for someone wanting to use an IED.

Pyrite is used in wheel-locks rather than flint because flint is too hard and the wheel would wear away rapidly. The wheel-lock is quite a complex piece of engineering and therefore expensive, which would have been a discouragement for the “one time use” within an explosive device.  

The snap lock was introduced in the late 1540s. The key to its design is that it is simpler, with less moving parts - simply a spring loaded lever holding a flint that falls on a steel or “frizzen". There is no wheel to wear out, and much less complexity, meaning that it is cheaper and therefore more likely to be “thrown away” in an IED.

The snaphaunce LINK developed in the 1550s and the flintlock LINK developed in 1620, were basically improvements on the snaplock design , allowing the pan to be covered for safety and to keep out the weather - the essential difference between these latter two is the mechanism by which the pan of gunpowder was uncovered.

So, between 1500 there is a period of 120 years of technological development to get from the original matchlock to the safe, flexible, cheap, easy to operate flintlock. Here's a video showing in a bit more detail how a flintlock on a firearm works.

From about the 1540s it may have become an economic option to use a gun lock in a “one time use” IED - perhaps from a broken firearm.

The next issue to address is how the trigger is pulled or released to allow the gun lock to fire.  There are essentially three principle modes of initiation for IEDs, all based around the fundamental idea that the perpertrator does not want to be near when the device explodes -  and the firing lock can enable each one of these three:

  • By command from a distance.  Simply by tying a cord to the trigger of a gun lock a device can be initiated from a safe distance.
  • By a victim’s action.  By tying a cord to the trigger and attaching the end of the cord to an attractive object or some other thing likely to be moved, the perpetrator can cause the initiation by a victim.
  • By timer. if the firing lock trigger is attached in some appropriate way to a clockwork mechanism, then after a set time, the trigger will be pulled.   

The following examples detail use of these three technique from the period between 1585 to 1918 - a significant period of history

In the 1570s the somewhat exotic inventor Ralph Rabbards describes contrivances that require some sort of spring loaded mechanisms to initiate explosives, and at the same time Samuel Zimmerman of Augsberg described explosive devices set off with hidden springs and string.    Zimmermann discusses “booby trapping” a chair that will initiate a device when sat on, and booby trapping a “purse of gold” left lying in the street.    I’m pretty certain that these devices would have used a gun lock initiator - how else would they have been initiated?  The technology was there and there are no other apparent mechanisms available to the bomb designer of the time. 

In 1581, the Polish besiegers of the City of Pskov sent a jewelled casket to the occupants of the city of Pskov. The device exploded when it was opened by the Russian defenders.   This booby trap mechanisms must have been initiated by a gun lock , adapted and contained in the casket.

This link here, tentatively dated to the 1580s shows 4 command initiated devices, initiated by operators pulling a cord from a distance. One has to assume that the cord was attached to the trigger of a firing lock buried in the barrels on the route of the target convoys. Not much changes does it?

In 1585, Giambelli’s clockwork Hellburner was triggered by a clock provided by Antwerp clock maker Jean Bovy.  Now techncialy, that could have been a lever, activated by the clock, which moved a burning match.  But I think a gun lock is more likely.

In 1628 Cornelius Drebbell (the inventor of an early submarine) developed floating devices used (unsuccessfully) by the English Navy against the French in La Rochelle. I have found this description of Drebbels explosive devices, written by Carles Bernard in 1628 in the Mercure Francois:

`During the night between Sunday (Oct. 1st.) and Monday, the English shot ten or twelve floating petards for the purpose of setting fire to the royal French fleet. The body of these petards is of white iron filled with gun-powder and floats on a piece willow wood, through which a spring is made, which when it encountered the bows of one of the royal ships, took effect, which consisted simply in this, that it threw water into the ship with much power; all the others were captured as they floated on the water and did no harm.’

So, my assessment is this - the iron cased charge is mounted on the floating wood platform, some form of spring powered lever acts on the device when it comes into contact with the enemy ships.  I think the most likely technology of the time which could have utilised that spring action is to release the trigger of a gun lock. I’m happy to consider other solutions but to me I’m now fairly certain.  One historian has suggested that Drebbell, who was known to have dabbled in alchemy, may have used the first ever high explosive, the primary explosive Gold Fulminate (discovered in 1602) – but I remain unconvinced. Occams Razor suggests to me a gun lock.

This diagram below from about 1630, shows a clear representation of a booby trap with a basket of attractive objects , within which is a firing lock tied to one of the top objects - lift the attractive object, pull the cord and the firing lock will cause the device to explode. Look carefully and you'll see the lock at the bottom.

In 1645 we have this description of two IEDs, each clearly using a firearm lock attached to clocks.

In 1650 we have this device, using a pistol firearm lock, initiated by the pull of a string. 

In 1764 we have a postal device that utilised a booby trap using a firearm lock. 

In 1776 and 1777 The American revolutionaries used systems that instinct suggests to me were similar to Drebbel’s devices of 1628, but develped by David Bushnell. Buchnell also followed Drebbels lead in submarine vessel ideas.

Here's part of the timing mechanism that Bushnells famous "Turtle" submarine was meant to fasten to the bottom of HMS Eagle. The timing mechanism's gears ultimately tripped a flintlock mechanism to fire a gunpwder charge. (Photo John Wideman)

Bushnell also used floating explosive charges with levers on the outside designed to be pulled when they came into contact with ships, very much like Drebbels devices of 1628. 

This image is a replica of a Bushnell IED that was floated down a river towards the Britsh ships. The lever on the outside causes a flintlock on the inside lid of the barel to be activated when the external lever comes into contact with the side of a ship, or a cable is pulled in some manner.

This image below is of an original revolutionary IED, the inside of the lid of the barrel, showing the flint lock mechanism held in place, to be activated by the lever on the outside. The flinlock shown appears to be from a British made "Brown Bess".

 (My thanks to John Wideman for allowing me to reproduce these images from his book “Civil War Torpedoes” where these pictures provide context for his very detailed and excellent work of later devices.)  

In 1805 Robert Fulton, an American working for the British Navy, (after being rejected by the French) designed a range of explosive devices using gun lock initiators. This diagram, produced by French technical investigators who captured and defused at least one of the devices following an attack on St Malo, shows clearly the firing lock mechanism adapted by Fulton as the explosive initiator. This diagram is one of my best finds.  This is a very sophisticated device and a very sophisticated techncial exploitation of the device by the French. The red annotations are mine, part of a lecture I give on historical technical exploitation.

In 1812, during the war with the British, Robert Fulton (who switched sides again, back to his mother country) used gun locks in a number of attacks using explosive devices on the British.  This attack on HMS Ramillies which was blockading American ports, used a very simple device, and nbot one of Fulton's designs, but nonetheless used firing lock.  It is described by Benjamin Lossing (thanks again to John Wideman for finding this)

In the hold of the schooner Eagle, John Scudder, junior, the originator of the plot placed ten kegs of gunpowder , with a quantity of sulphur mixed with it, in a strong cask, and surrounded it with huge stones and other missiles, which in the event of an explosion might inflict great injury.  At the head of the casks, on the inside, were fixed two gun locks with cords fastened to their triggers at one end and two barrels of flour at the other end, s that when the flour should be removed the locks would be sprung, the powder ignited and the terrible mine exploded. Thus prepared, with a cargo of flour and naval stores over the concealed mine, the Eagle sailed … . she was captured as expected and desired by armed men sent out on boats from the Ramillies.  The crew of the Eagle escaped to the shore at Millstone Point, and anxiously awaited the result. The wind had fallen and for two hours unavailing efforts were made to get the Eagle alongside the Ramillies for the purposes of transferring the cargo to that vessel. Finally boats were sent out as lighters, the hatches of the Eagle were opened and when the first barrel of flour was removed the explosion took place.  A column of fire shot up into the air a full nine hundred feet  and a shower of pitch and tar fell upon the deck of the Ramillies . The schooner, and the first Lieutenant and ten men from the flag-ship on board of her , were blown into atoms and most of those in the boats outside were seriously and some fatally wounded.

Although not involving flintlocks I have details of Fenian IEDs using high explosive initiated by pistols connected to timers in the 1870s, and Lawrence of Arabia’s railway IEDs in WW1 were initiated by adapted martini rifles firing mechanisms - which themselves were an idea copied from the Boers in South Africa in the Boer war.  However all these latter devices were in one sense different – they each actually fired a bullet into high explosive rather than igniting low explosive gunpowder.

I am by no means saying that every IED between 1540 and WW1 used gun locks - but gun locks enabled a simple and reliable way of initiating explosive charges and were used frequently and quite widely during the period.  A gunlock could be used easily to initiate a device, by those three key ways - by command, by the victim or by timer. A gunlock enables concelament and surprise.  I think these facts are crucial to an understanding of how IEDs were used in history.