You can contact me at rogercdavies(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.


Entries in 1500-1600 (15)


EOD Equipment 1573 and 1971

I have finally found a picture of a wheeled EOD shield from 1971 - courtesy of RLC Museum. Compare these two largely similar tools, the first from 1573, and the second from 1971 - 402 years apart. I believe the shield was used operationaly in Hong Kong in the sixties, and quickly went out of service after limited use in Ulster in the early seventies.

circa 1573circa 1971

My earlier post on the subject of historical ROV's is here. 




Clocks, locks, energy and initiation

I’ve written before about the evolution of gunlocks, from matchlocks, through wheel-locks to snap-huances and then flintlocks because although these initiation systems were designed to initiate firearms they also enabled initiation mechanisms for explosive devices.  This post returns to that subject to discuss a couple of more elements to that story that I find interesting, namely engineering development and some fundamental issues about “energy” chains that apply both to these firearms systems and explosive devices.  In this post I have made some generalisations and simplifications in my description of the technology - forgive me, but otherwise the post turns into a book and neither you or I have time for that.                                                                      
Firearm initiation systems, and in parallel explosive initiation systems, are about initiating a quantity of explosives at a time that the operator chooses.  Thus, in the simplest of all firearm systems, a burning “match” is placed in contact with a small quantity of blackpowder in a “touch-hole” which then initiates a larger amount of blackpowder in the barrel of a gun.   This system worked for hundreds of years in the cannons you see fired in all the movies.                                                                                                                                                
The gun is aimed and the application of the burning “fuse” simply initiates the blackpowder.  The energy in the arm of the man holding the fuse, and the energy in the already burning fuse is enough to initiate the stored chemical energy in the blackpowder in the barrel.                                                                                                                                                                                                                                                               
But in a small firearm there’s an issue of the man pointing the gun and initiating it at the same time. Generally these firearms were pretty large and required two hands to point at a target.  So quite often the firearm was supported with a crutch allowing the firer to point it with one hand, sight the barrel with an eye at a target and use the “spare hand” to place the burning fuse on the touch hole. 
Firing an early firearm without a trigger and serpentine
But let’s face it, that’s a bit fiddly. The touch hole is small and it might be a bit awkward. The firer is concentrating on doing two things, keeping the target in line and finding a small hole with the burning fuse in one hand.   So, with some very simple engineering the matchlock was developed.    All that happened was that a simple S shaped lever was introduced onto the body of the firearm. One end of the lever held the burning fuse in  a specific position, the centre of the “s" shaped piece of metal was a pivot joint and the bottom end of the s was pulled with one finger.  The placement of the s shaped lever (a “serpentine) ensured that the burning match always found the touchhole or the pan at the entrance to the touch hole, and the firer could use two hands to aim the firearm, concentrate on the target and just use a finger to pull the “s" shaped piece of metal.
A very early, simple matchlock arquebus
 Now , manufacturing such a firearm was pretty simple, and within the engineering skills of the average door-lock manufacturer of the 15th century which simply used levers and pivots.   So matchlock firearms were relatively easy to manufacture and relatively cheap. Matchlocks continued to be produced from the 1400s for about 250 years.  I think this is important to understand - although better technology was invented in a series, starting in the early 1500s, match-locks remained a simple and cheap firearm and so were the most common at least until well in to the 1600s.
A nice image of a Japanese matchlock mechanism showing a pan cover
Now, there are some operational weaknesses with the simple matchlocks.  In the simplest of all matchlocks the pan or the entrance to the touchhole  is permanently exposed to the elements. So in poor weather the firearm simply won’t work.  Also the glowing match gives away both the position of the firer and the nature of their weapon.   Both these weaknesses were partially addressed.  Firstly a mechanism of a sliding or levered cover to the Pan or the entrance to the touchhole was developed, requiring some more intricate engineering so when the serpentine was moved then a cover was moved out of the way allowing the match access to the pan.  A bit complex.  Some attempts, too, were made to hide the burning match in a box, but not very effectively. Burning fuse also, by the way, made the weapon unsuitable for those guarding stores of ammunition.  So in the early 1500s the wheel-lock was developed.                                                                                                                    
In large part the wheel-lock invention was enabled by advances in engineering, and specifically advances in engineering from clock making.  On a fundamental level, the wheel-lock utilises, for the first time in a firearm, “potential energy” in a spring.   A wheel-lock, consists of a steel wheel, which has a small chain wrapped around its axle. The wheel is rotated with a spanner, this wraps the chain around the axle and the other end of the chain is attached to a spring.  Thus when the wheel is rotated it induces a potential energy into the spring. The spring is then held by a trigger. A second spring is then set up to hold the serpentine. In this case the serpentine doesn't hold a burning fuse, but a small lump of iron pyrites.  The spring acting on the serpentine holds the pyrites in contact with the rim of the steel wheel which usually has grooves on its circumference and some small notches to encourage friction.  When the main spring holding the chain attached to the wheel is released by pulling the trigger, the steel wheel rotates and, because it is in contact with the iron pyrites, sparks are formed.  The sparks initiate blackpowder in the pan.
So we have the potential energy in the spring, making kinetic energy in the wheel , which initiates chemical energy in contact with the pyrites, which initiates the chemical energy in the blackpowder, which converts to kinetic energy in the projectile, and that kinetic energy is transfered t o the target t cause damage.  A nice little chain, but one which requires a significantly more detailed engineering capability than a match-lock.                                                                                                         
The wheel-lock however has several advantages.   It is safer, in that safety catches can be applied to both the serpentine and the wheel.  The presence of a firearm is not given away by the burning fuse.  It can be prepared well in advance of use (if the springs don’t deform as some where liable to)  The firearm can be concealed. Since it is possible to conceal, the firearm was then made smaller, and so the pistol appeared for the first time, able to be held about a person, and the same person could indeed carry two or three wheel lock pistols. Since this is a blog about explosive devices, then of course the wheel-lock became a potential initiator for IEDs - the device could be hidden and initiated at a point of the firers choosing, perhaps say with a string to the trigger or a potential booby trap switch. IEDs are more suited to initiation by potential energy.
But now we have economics at play. The high level of engineering and therefore cost required for a wheel-lock would make it usually unsuitable for a one-time-use in an IED, although possible.   Only the rich could afford wheel-locks.  So wheel-locks and match-locks existed side by side for decades and indeed for at least 150 years. The economics of the engineering had some other interesting implications.  Matchlocks are simple utilitarian devices usually without decoration through the 16th century. Wheel-locks however, bought by the rich became covered in ornate art, and became models of fine engineering and artistic excellence.  Here’s some images of highly decorative wheel locks.
The fact that wheel-locks were used by the rich also had an effect on the manner in which warfare was conducted.   Ordinary infantrymen could not afford wheel-locks but the aristocratic and rich cavalry could. Cavalry tactics then evolved to make benefit of the capabilities that two or three wheel locks could provide. The cavalry galloped forward to a point within range of their wheel-locks, fired, and galloped back.   The tactics of cavalry using wheel-locks then had an impact on the types of horses and armour being used by the military. The huge horses required for armour encumbered cavalry with lances were replaced with smaller, quicker more agile horses. This perhaps lead, by connection, to the evolution of horse racing and blood stock management.   The armour, designed to to defeat the weapons of the medieval horseman was discarded - armour could be produced to protect against the bullets fired from wheel-locks but frankly it was too heavy.  So the nature of warfare rapidly evolved.  One could say that the nature of warfare evolved over the period of between 1500 and 1620 entirely because of the initiation system moving to a potential energy storage device (a spring) for the initiator rather than a chemical energy storage initiator (the burning match).                                                              
Subsequent evolutions of the gun-lock technology brought together the principle of a potential energy store (from the springs in the wheel-lock), with simpler engineering requirements.   I think that the spring-held serpentine of the wheel-lock got people thinking. Firstly pyrites wasn't always a solid enough material to hold reliably in the jaws of the serpentine, and indeed the spring holding the pyrites wasn’t designed to cause the pyrites to impact with the steel wheel, just hold it against it.  I think that the metallurgy of springs improved throughout out the 16th century.  A powerful spring could cause a flint to strike a steel firmly and reliably enough to set a spark - earlier technology wouldn't allow that - the springs would break or the springs would deform very quickly. But the evolution of clocks and associated engineering developed through the 16th century so that steel suitable for using in springs evolved.  All of a sudden there was a metal available that could be used in a  spring that could force a serpentine holding a flint hard enough to cause sparks. The “snaplock” then developed in about 1540 utilised the same serpentine used in the match-lock and wheel-lock, but this time powered by a strong spring to strike a “steel” to cause sparks - subsequent developments of the snap-huance and then the flintlock were simply improvements on that design, improving its reliability and weather protection.  Essentially then in energy terms, the potential energy inherent in the spring that powered the wheel in the wheel-lock was changed to potential energy in the main-spring of the flintlock. Crucially though the engineering required of the flintlock was still considerably simpler than the technology used in the wheel-lock. Flintlocks could be pretty much mass produced while wheel-locks remained the product of a highly skilled craftsmen. As an aside, the engineering tolerances required of the wheel of the wheel-lock needed to be much tighter than the engineering tolerances in a flintlock. In a wheel-lock the wheel rotates through a slot in the “pan” and if the slot is too big then the gunpowder falls through it.   The fact that flintlocks used potential energy , but were also cheap and able to be mass produced means that they became attractive to use in “one time use” IEDs such as this device . The first mine , Samual Zimmerman's "fladdermine" also use a flintlock mechanism.                                                                                                                                              
It is clear from reading up about the history of clock development that many of the principles of engineering in clocks developed during the period of about 1550 - 1750 were subsequently applied to the production of munitions fuses. There’s probably another blog (or book!) to be written about that. 



Historical ROVs

Recently I had a dialogue with some colleagues as I researched modern versions of this very early piece of EOD equipment from 1573.
A remarkably similar piece of equipment was in operational use only 45 years ago and I was seeking a photo of the equipment in use in the 1960's/1970s. I'm still digging on that. 
Anyway the dialogue with a few modest practitioners of the art of EOD in the 1970s took me in an interesting direction, and I’ve turned up some interesting stuff from much earlier on the subject of ROVs.  The general perception of the world we live in is that the tracked ROV as used in EOD is a very modern invention. Manufacturers produce glitzy videos showing these twin-tracked vehicles performing tricks as the operator remains a safe distance behind, secure from the hazards that their robotic buddy faces. All very High-Tech.  I used to work for one such manufacturer, and we have all seen the videos showing the technological prowess of a wide range of differing modern ROVs.   Like many, I assumed that the tracked ROV was essentially invented for the purpose of EOD in the dark days of the early 1970s.  But it appears that ROVs were around for a considerable time before the 1970s.  This does not to lessen in any way the significant innovative effort that went into the development of the “wheelbarrow” series of ROVs and all subsequent EOD “robotics”, but there are some fascinating precedents.
I began by searching for images of the first ROVs in Northern Ireland in about 1972, in the hope that they might also show images of the protective screen I was looking for so I could do a visual comparison. Suddenly I came across a picture in some archives that made me sit up.  You should understand that my operational experience was largely in the 1990s so I’m most familiar with Mk8 “wheelbarrow” ROV.  But I came across the image which at first glance appeared to show a number of Mk 8 Chassis…. but from WW2… How could that be?
British soldiers with captured Goliaths
US Navy examine captured Goliaths on Utah Beach 11 June 1944
For comparison here’s  a picture of a Mk 8 wheelbarrow - note that the main body of the Mk 8 is remarkably similar to the images above in terms of shape and scale.
The WW2 item turns out to be of a system called Goliath. It's not an EOD ROV, but rather its a remotely controlled demolition vehicle. 
When you think that probably there were only a couple of hundred Mk 8 wheelbarrows produced in the 1980s and 1990s, but there were many thousand “Goliath” ROVs produced.  The Goliath ROVs were initially electrically powered but later used a small two cylinder engine.  Here's a great shot from the top, showing the engine and the wire spooling from the rear. 
I also found reference to a Japanese tracked ROV, also used a a remote demolition tool - called the "I-GO” developed in 1937. How strange that the nomenclature predates the “I-Robot"
Japanese I-GO ROV from 1937
Now in the early 1990s some of the Northern Ireland EOD units developed a deployment technique called the “Rapid Deployment Trolley”.  This was a cobbled together wheeled trolley on which we placed the Mk 8 wheelbarrow ROV to transport it rapidly to and from a small helicopter in emergency situations where a full deployment requiring a large helicopter wasn’t possible. So it was with delight I saw that Germans in WW2 also had such a “trolley” for the Goliath - and actually theirs looked much better engineered!. Vorsprung Durch Technic.
Wheeled Trolley for moving Goliath ROVsA Goliath being moved on its wheeled Trolley, Warsaw
Then as I was researching the provenance of the German Goliath I came across reference to the genesis of this equipment… It turns out that the German Goliath was based on an ROV developed by the French in the years running up to WW2….  Supposedly, as the Germans advanced on Paris the inventor, Adolphe Kegresse threw the prototype into the Seine, but somehow the Nazis got wind of this, reverse-engineered it, and ended up building the Goliath.  I have also found reference to the Germans recovering , later, Kegresse’s blueprints for the ROV and reverse engineering their ROV from that. 
The French Kegresse ROV, 1940
I then found details of  British tracked ROV, developed in 1940 by Metropolitan Vickers, again as a remote demolition tool. Here’s an image - note the interesting inwardly facing track extensions.
Vickers MLM ROV, 1940
50 of these Vickers MLMs were built before the project was suspended in 1944.  I have a copy of a Canadian officer’s trial report if anyone is interested.  The ROV had a range of 1100 yards and could carry 120lbs of Ammonal. Initiation was either by a command signal or a contact switch (which had a command safety override). 
I then found a reference to an American ROV from WW1. This is the Wickersham Land Torpedo, built in 1918, possibly 1917 but patented in 1922. Here's the link to the patent. They were manufactured by the Caterpillar company, I think.  
Wickerhsam Land Torpedo
This ROV looks similar in size shape and design to a modern day Talon EOD ROV, or a Dragon Runner. The Wickersham and the Kegresse ROVs look pretty similar.
I kept digging and encountered 2 more tracked ROvs that predates the American one - both French.
The first of these was the “torpille terrestre electrique”  (electrical land torpedo), developed by M. Gabet and M. Aubriot in 1915. It could carry 200kgs of explosive and was wire guided of course.  I’m intrigued that the single lever track at the rear looks a little like the lever track on some modern robots.
The second of these was the “Schnieder Crocodile” also developed in 1915 and trialled by many Allied nations, including the British, Belgian, Italian and Russians.
"Crocodiles" Schneider type B.
It could carry 40kg of explosives and looks similar in size, shape and scale to the Allen-Vanguard ROV
So it seems that next year will be the centenary of the tracked ROV...



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.


Spanish naval troopship destroyed by an IED?

The Brod Martolisi was a high sided, commercial trading ship, of 800 tons, probably built in Dubrovnik some time before 1585.  It was a little under 100ft long.  It was owned by Petrov Jug and Jaketa Martolosic, traders operating from an Adriatic base. “Brod Martolisi” means "Martoli’s ship”, probably referring to the latter of the two owners. The ship served a wide range of trading in the Mediterranean and beyond. In 1586 it was returning from a long voyage to England, with a cargo of wool, due to be delivered to somewhere in the Eastern Mediterranean.

The ship called in to the port of Termini in Sicily, then under the control of the Spanish.   There, the Spanish viceroy was having trouble mounting support to a military operation in Cartagena. So he simply requisitioned the vessel and crew, offloaded the wool, and put aboard 300 Sicilian mercenaries.  The captain at that time was Luka Ivanov Kinkovic. 

By 1588, the ship was still being used by the Spanish as a troop transport as preparations for the the invasion of England began and the Spanish naval fleet prepared itself. The ship was one of the bigger vessels in the fleet, essentially a large troop transport.  A Spaniard, Don Diego Tellez Enriquez,was put aboard as the nominal commander, but it is thought the original captain (referred to in Spanish as Luca de Juan) remained skipper. The ship, by then renamed formally Santa Maria de Gracia y san Juan Bautista, but referred to as San Juan de Sicilia underwent minor adaptations for the joining the Armada, including fitting 12 guns.  The ship was part of the "Levant squadron" of the Armada. The squadron consisted of 10 ships, with 767 seamen and 2780 soldiers. Aboard the ship when it set sail for England were 3 contingents of troops, - Sicilians, Flemings and Spaniards. The senior officer of the troops was Don Diego Tellez Enríquez.
In the battles with the English along the Channel, as the desperate attempts of the English Navy kept the Armada at bay, initially the ship played only a small part, but later near Calais, it was at the heart of the sea battle. One story recounts how the sea was stained red with blood in its wake, so much damage and injury was caused aboard. It is also suggested that the ship might have been lost to English boarders, had it not been the deterrent of the high sides of the ship.  The Spanish fleet decided to retreat, by sailing north around Scotland.  The San Juan lagged behind, its masts and rigging severely damaged.  The English fleet in the main did not chase the Armada because they were concerned with other Spanish forces holed up in Holland and they had, by and large, run out of ammunition anyway, and the fleet was suffering from an outbreak of typhus.
On 20th September 1588 as the remaining ships of the Armada were off the west coast of Ireland there was a huge storm.  It wrecked many Spanish ships on the Irish coast. Lagging behind because of damage to its sails, the San Juan was hit off the Western Isles of Scotland, suffered more damage and sought refuge there. It was spotted off Islay on the 23rd September and a few days later it put into the small bay at Tobermory on the Isle of Mull, north of Islay.  Negotiations were opened with the local clan leader of the Clan McLean, and for some weeks the ship was repaired, and the troops aboard acted as mercenaries for the McLeans in a local dispute with rival Clan MacDonald.
Finally, repaired, re-victualled and re-supplied, the ship was about to set sail and still within the bay when a massive explosion occurred and the ship was destroyed. The entire ship forward of the mizzen mast and above water was blown apart and the ship sank immediately. Only two people survived, both occupants of a cabin that was completely blown the hundred yards to shore, where, shaken and injured they emerged. (This latter story may not be true).
Now the question is, what caused this explosion?  There are a number of possibilities - accident, sabotage by the local McLean clan when by some reports they fell out with the Spanish who had been supporting them, or could it have been another unseen hand initiating the sabotage?  I want to explore the latter, and look at the role of Sir Francis Walsingham, the English spymaster and and true master of intrigue.
Walsingham maintained a spy network, of course, in Scotland, then not part of the Union. One of his Scottish spy networks was conbtrolled by the “Head of Station”, William Ashby, who worked within the English Embassy in Edinburgh. Walsingham had other agents throughout Scotland, included John Smollett, a merchant in Dunbarton.   Walsingham put out a request for intelligence about any sightings of the Armada’s ships in Scotland and in Sepetmber, Ashby started to report the sightings of large ship, variously in Islay and then Tobermory. Here is Ashby’s first report (ignore the wrong date and the over estimate of the tonnage).
‘As I had writ this letter Sir William Kith send me wourd that Mack Cleiden an Irishe Lord in the isles wrot to the K. that on Fridai the 13 of September there arrived a greate ship of Spaigne of 1400 tons, having 800 soldiours and there commanders; at an Iland caulled Ila (Islay) on the west part of Scotland; thether driven by weather, thei thinke that thei rest of the Fleat is driven on the north part of Ireland; I will make further inquirie and presentlie certifie your honour with sped: thei report this ship to be fournished with 80 brass peces, She beaten with shote and wether
The difference in the date can be ascribed to the ten day difference in calendars used by England and the rest of the world at the time. 13th September in Spanish and Scottish calendars was the equivalent of 23rd September in the English calendar. The assessment of the tonnage of the ship is not relevant and perhaps a typical exaggeration. Ashby clearly has interesting intelligence sources within the royal court in Scotland (“K" being the King James VI)
It would appear too, that John Smollett played a key role in re-victualling and re-supplying the ship in Tobermory bay.  Much more interestingly, in another secret letter to Walsingham on 26 November, Ashby writes:
the partie that laid the traine (fuse)...the man knowen to your honour and called Smallet’
As to the technical aspects of the intrigue, it remains possible the explosion was caused by the drying of gunpowder in the open air on the deck and that was the cause that a later Spanish inquiry came to conclude, albeit I think based on speculation themselves.  Procedures at the time for drying powder are not known but it is hard to imagine that it would be done with anything other than small quantities at a time. It’s also hard to imagine that it was dry and sunny enough in Tobermory in November! But the explosion must have been of the entire magazine and I think that is hard to ascribe to drying explosives on deck.
That leaves us with the saboteur theory.  I think that the saboteur theory has some speculative merit because:
  1. The ship had been resupplied and re-victualled, providing an opportunity for a saboteur to get aboard or have a device put aboard. The several weeks the ship had spent in Tobermory allowed times for the sabotage operation to be put in place. The supplier, Smollett, was an agent of Walsingham.
  2. Ashby specifically uses the phrase ”laid the train”, which is clearly, I think, a reference to an explosive train in an IED.  A similar set of words is used , just a few years later to describe the actions of Guy Fawkes.
  3. The indications are that the whole magazine exploded, if there was a fire first, some of the crew would maybe have been expected to have abandoned ship as the fire got close to the magazine. An accidental fire of powder drying on deck would not necessarily cause the magazine to detonate.
  4. Walsingham had the best motivation, and everything we learn about him suggests a willingness to use these tactics, and he had a demonstrated a direct intelligence interest in the Spanish ships in the Western Isles.
  5. Walsingham had the technology because not least he had hired Giambelli three years earlier. Even if the device was a simple IED , then that would of course not have been a problem for Walsingham's resources. The actual technique for initiating the device would have perhaps have been a burning fuze, similar to the “match” of a matchlock - a slow burning igniferous fuse. The magazine would have contained slow fuses for initiating cannon, of course.  But a clockwork timing mechanism was within the technical capability of the English secret service at the time, and arguably more easily to conceal inside a barrel of gunpowder than a burning fuse which would protrude. A booby trap using a wheel-lock mechanism is also theoretically possible. 
Warships in foreign ports have been and always will be potential targets for attack by IEDs.