Standing Well Back
Radio Controlled IED

German WW2 use of ROVs to deliver explosives

In recent years various terrorist groups and others have used land, sea or air ROVs to deliver explosive payloads to targets.  As usual, people view these things as new and innovative threats. But as readers of this blog site will know,  that usually isn’t the case and I have more details here of some interesting early use of such devices from WW2, although they go much further back.  Some of these may be classed as “improvised” but others are clearly formally developed systems – but let’s not get hung up on definitions, because the concept is what is interesting   There are several aspects to this – one is the technology that is used, and another is the tactical employment. Many of the implementations of this concept were unsuccessful but the reasons for this are also interesting and indeed are being repeated in modern terrorist use of ROV technology.  I won’t go into that aspect in too much detail for obvious reasons.   So here goes with a few interesting  German “land based” example ROVs from WW2.

I’ve written before about the WW2 German “Goliath” remote controlled mine, a small tracked vehicle not too different in scale from modern EOD ROVs.   Following the fall of France in WW2, the Germans captured  a prototype French ROVs used for explosive charge delivery which seemed to inspire the development of the Goliath. This vehicle had been “hidden” in the River Seine, but the Germans got to hear of it and salvaged it for technical exploitation and reverse engineering. (Readers may recall a similar reverse engineering operation from a “purchased” French speed boat just before WW1, that I discussed in an earlier post).

 

Captured German Goliath ROVs after D-Day

While there has been some attention on the Goliath tracked vehicle, used to deliver demolition charges to targets, perhaps just as significant for us looking at history was the German Borgward B remote tracked vehicle. A contract was let by the Wehrmacht to the Carl Borgward engineering company in Bremen for 50 tracked vehicles in 1939. It’s not quite clear if the Borgward B was developed originally to deliver demolition charges or for other purposes such as towing mine clearance tools or as an ammunition carriers.  One suggestion is that during the German invasion of France, German engineers found an operational need and had been converting, in an improvised way, standard German tanks to operate remotely for certain tasks. The theory goes that as a result of after-action reports from this campaign the Borgward B was converted to fulfil this role. But it’s war and it’s a little confusing as to which came first, the chicken or the egg.    In any event,  Blaupunkt, the radio manufacturer developed a radio controlled system for the vehicle. These vehicles and their sub-systems were gradually improved in following years resulting in several “versions” as both their use and requirements changed.  A variety of vehicles were used as “control” vehicles as the war progressed. The radio control unit was very “modern” in appearance, using a joystick control and shared many of the features of the Linsen boats control systems.  The key features of the Borgward B was firstly that it could deliver a large charge, (typically 45o – 550kg), and secondly it could drop off the charge and retreat, thus in principle being a re-usable vehicle, unlike the smaller and disposable Goliath.

Here’s a pic of the Borgward B. The driver would drive the vehicle “normally” until it was a “tactical bound” away from the target, then he would get out and the vehicle would then be controlled by radio remotely. It looks like a fun  drive, (unless you are told to drive it to the Eastern Front).

 

The Borgward B wasn’t a huge success. it was unreliable and quite vulnerable to enemy fire.  Some reports suggest that some versions were equipped with smoke units to lay smoke screens or just to hide its own approach, but I’m not sure how it would then be controlled if surrounded by its own smoke screen. Perhaps this version was simply used to lay smoke screen and move laterally across the battlefield.  I have found a report that a single Borgward B was fitted with a TV camera as an observation vehicle during the fall of Berlin, perhaps a prototype but in the main the later use of these vehicles, in theory was to deliver and drop demolition charges.  The explosive charge, when dropped, had a timer initiation system that after a short period caused the charge to detonate.   The charge was released with the help of gravity after explosive retaining bolts were fired by the operator. I’m cautious about this and think it could have been a lever actuator.   It appears that there was an adjustable safety mechanism that armed the charge only after a certain distance (not time) had been covered, so for instance an operator would set the safety distance to 100m as he exited the vehicle, and the charge would only become “armed” after the vehicle had covered that distance. That’s logical, but I’m not sure how it was achieved.  These vehicles were less suited, of course, to defensive operations than offensive, where their utilisation against defended structures was optimised. I’m led to believe that over a thousand Borgward Bs were produced (compared to many thousand Goliath vehicles).

Here’s a great pic of the explosive charge after being “dropped off” by the vehicle. You can see it slides off the front plate where it is held in a “shoe”.

I think it’s worth thinking about the relative strengths and weaknesses of the Borgward B and the Goliath.  The Borgward B could be moved into its tactical launch position by one man, but the Goliath needed a small team of men.  Perhaps that’s why the Goliath was used in defensive positions like the beaches of Normandy, where it was prepositioned in shrapnel proof hides, (but it wasn’t particularly effective). The Borgward B was larger and therefore more vulnerable, but delivered a much bigger charge than the Goliath more suitable to taking on defensive positions. The Borgward B was more expensive but in theory was reusable. In the main the Borgward B was radio controlled and this offered some flexibility but also posed some reliability problems with the technology of the day. The cable system principally used by the Goliath was more reliable but vulnerable to shrapnel damage.

There was an attempt at a “middle ground” the NSU “Springer” ROV developed in 1943/1944. This was smaller than the Borgward B, bigger than the Goliath, but was driven into launch position by a driver. About 50 were made, I think. Here’s a picture showing its scale and size. They seem to have limited operational use. I don’t have a handle on their control system.

 

I think it’s fascinating that the Germans also used vehicles captured  from the British and French and convert to ROVs. It seems that the German engineers saw potential in particular from the British Bren Gun carrier and the Belgian “utility tractor” (a British built tracked vehicle made by Vickers, who also made a proportion of the British Bren carriers).

Here’s a pic of both in “normal use”

A Belgian Vickers Utility tractor

Bren Carrier

A number of both these vehicles were converted to be cable-controlled demolition vehicles, each with a 1.2 km cable.  That’s quite a distance, and one imagines that control of vehicle at such range was tricky, based on distant observation.  A total of 60 were sent to the Crimea in 1941.  The German Crimean campaign of 1941 is interesting because I think it was used as a testing ground for range of innovative German technologies.  I’m currently exploring the use of an advanced prototype German fuel air explosive weapon in this campaign, to clear bunkers and defence structures, and it appears that these converted Belgian and British ROVs were used against the same targets to deliver relatively large explosive charges. I have also seen reports of Borgward B vehicles used in the Crimea at this time.  It appears that the majority of the 60 vehicles were deployed with mixed results – some destroyed by mines before they reached the targets, some destroyed by enemy fire, some failed and some functioned as intended destroying Russian defensive positions.  I can find no specifics over the amount of explosives carried by either vehicle, nor any specifics on the control mechanisms fitted.   It appears that the ROVs were “controlled” from a “mother” command tank.  The Germans complained that there were no spare parts for the captured ROVs and recommended development of indigenous vehicles accordingly.  Other feedback included the suggestion that they would be better employed in flatter, desert conditions, such as North Africa, rather than the complex urban defence environments of Sebastopol, and indeed at least one Bren carrier, captured at El Alamein was so converted.   While this effort to convert enemy tracked vehicles to wire guided demolition use wasn’t really repeated , it’s clear it had some success and more importantly allowed the Germans to develop tactics and concepts of operation. . I think too, given the large amounts of “enemy” vehicles abandoned in Europe at Dunkirk and elsewhere, it made economic sense to utilise them, and the Germans had no qualms about recovering, and using, where possible, quite a range of enemy equipment.

This picture is, it is claimed, a captured Bren carrier (complete with German Cross) fitted with explosives being deployed on the Eastern front. The vehicle in the distance is Borgward B, I think, so it seems very likely.

I think it’s fair to say that the Goliath and the Borgward B ROVs were less effective than the Germans had hoped in normal operations on the Eastern and Western fronts. But it’s worth looking more closely at their deployment in the tight urban environments of cities. There are notable reports of Goliaths being deployed into the Warsaw Ghetto in responding to the Warsaw uprising in 1943.  If ever there was a historic precedent to the urban destruction seen in modern day Syria, the destruction of the ghetto by the German in 1943 is it.    Goliath were used to target buildings, and of course with only small arms the defenders had little defence against these ROVs, unlike formal military units.  I also see parallels with modern anti-tank missiles being used against defensive positions in Syria, of which we are seeing many. Yes these aren’t as fast as those missiles but the targets and tactics are quite similar.

Here’s the remains of a burnt out Borgward B vehicle, I think destroyed by fire after it had dropped off its charge in Kilińskiego Street in Warsaw in August 1944. The explosion reportedly killed 200 residents. The story of this attack is dramatic and a desperately sad tragedy. Essentially the vehicle had been captured by Polish troops as the Germans attempted to deploy it towards a road block and was being paraded around Warsaw by cheering locals. Someone pulled a lever which caused the deployable explosive charge to slide off, and as we know there was a timer started by this activation which the crowds did not understand.  The charge detonated shortly after.  There is more detail here if you are interested. It is possible of course that this was a “Trojan horse” attack, and a number of sources claim this but I suspect that it was just accidental.

Here’s some pics of the Goliath systems being deployed in Warsaw.

This is the effect of a Goliath on a building in Warsaw

I think the German forces of WW2 had, in their ROVs, some interesting tools for offensive operations, and for the built up environments of  Warsaw and heavily prepared defensive environments off Sebastopol they were of some use.  But for German defensive operations, they were less suited. Fundamental unreliability was a major issue, it seems, with all the systems they used, and that’s both in terms of motive power and in terms of the control systems. Modern technology perhaps allows for more reliance on the systems used by terrorists and others. In a battle there is perhaps more of an issue of unit cost – whereas modern ROVs are cheaper, and not being deployed, in general, in battle conditions are doubly attractive. Modern ROVs have more precise controls including reliable and usable video components that makes control easier and more attractive. More accurate control also leads to the potential to reduce charge size and so allow the vehicle to be smaller. I think this aspect of modern ROV weapons is not yet widely understood.  Improved batteries for electric vehicles also increases range.  The issue of logistic support is somewhat useful in understanding use of ROVs for delivering explosives and again modern terrorist use changes the impact of that logistic support and is maybe less crucial in terms of systems.  What is inescapable now and in the past is that ROVs offer an aggressor a safe way of delivering explosives, with the size of the explosive charge required having, of course, an impact on the vehicles that might be suitable.  The key difference today is that technology has improved reliability of control systems, and also that technology is broadly available.  However it is susceptible to technical counter-measures.  In particular radio control systems are now consumer items and not limited to government enterprises.  There are also some other parallels in terms of utilisation of captured weapons systems – and here I’m thinking of the way some Syrian jihadists have adapted captured armoured vehicles for suicide VBIEDS.

I recommend thinking in terms of tactical design – the systems outlined above all approached the target to a “control” point. From there the mode of control switches – and remote control takes over.  It’s worth, as with any attack system, particularly terrorist attack using radio or other command systems, having a hard think about what defines that “control point”.  What are the characteristics of that change over point that are needed, are chosen and utilised? Understanding those will help you develop some counter-measures. Modern day control points are perhaps less clearly defined than these WW2 examples, but the principle remains. Another thought that comes to mind is the importance of Technical Intelligence to the EOD operator. Put yourself on the shoes of an EOD tech 75 years ago – what would you want to know about the command and initiation system before you dealt with such an object? It may have no relevance today but as a “process” it’s useful to think through how you, a modern EOD operator, would deal with such things in a variety of situations – it’ll get your brain thinking, and that’s the best use for a brain.

Most of you will be aware of the command driven vehicles used by modern terrorist groups – various Jihadi ones, ETA, FARC and the IRA have all use such systems and others too are in the back pages of this blog site. But most importantly don’t be then thinking remotely driven vehicles delivering explosives are anything new – they are more than a century old and there are lessons to be learned still. From a historical perspective I’m intrigued by the German campaign in Crimea and the manner in which they used innovative weapons systems there – I’ll be digging further as it’s not a part of WW2 that I’m all that familiar with and instinct is telling there’s some interesting history. I have one wild reference to an ROV being used underground there which I’m trying to track down, and of course Russian defence of Sebastopol in the century before has been a subject of previous blogs. It’s strange how the patterns of explosive use over the centuries return to the same places. Sebastopol, Antwerp, London…

 

20th Century

The IED that sank a US Aircraft Carrier

Ships in ports are potentially vulnerable to terrorist attack. Their size and value make them attractive to insurgents, and while ships are at sea they are probably relatively invulnerable. But tied up in a busy port with small boats in large numbers and with the difficulty of establishing secure perimeters around them, they become a real target. Most people remember the USS Cole attack in October 2000, but few remember the successful IED attack on  a US aircraft carrier in May 1964.

There are a number of reasons why this attack is no widely known:

  • The story was “sat” on by the US Defense Department at the time, who only announced that the ship had been damaged.
  • The Aircraft Carrier the “Card” was a WW2 aircraft carrier and wasn’t performing as an aircraft carrier at the time. It was shuttling military equipment as a ferry/transport ship from Japan to Vietnam. It had been redesignated from the USS Card to the USNS Card accordingly.

USNS Card, a WW2 aircraft carrier

  • Although technically it sank , it settled in shallow water in the port and was repaired, and refloated relatively quickly.

Because the story was squashed not much attention has been paid to the attackers and the IED they used. The attack was made by insurgents from the 65th Special Operations Group. The USNS Card had been shuttling heavy equipment into Saigon Harbour for three years – aircraft, armoured vehicles and the like. it and a sister ship, the USNS Core had attracted the attention of local insurgents.

There had been an earlier attempted attack on the Core, in late 1963, which had failed but the IEDs had actually been recovered by the same terrorist that had laid them, without detection. It was assessed that the battery power source had failed. I find it interesting that the attack in 2000 on the USS Cole had been preceded by a a failed attack (that similarly was not detected) on the USS The Sullivans earlier in the year.

For the attack on the Crd the battery power was replaced, and two devices were made, each weighing about 40kg.  Some of the explosive was probably a US military C4 demolition charge stolen or trafficked by the Viet Cong from the South Vietnamese Navy, and the remainder was some other type of explosive, possibly TNT. The devices were transported by a  small boat and then carried through a sewer to the vicinity of the docked USNS Card. A port security boat had stopped the small boat but had been bribed to let the men pass. From the sewer the two insurgents swam to the Card. Their devices must have had some sort of flotation.  One they attached to the ship near the bilges, and the other by the engine compartment.

One report suggests that the power supply, a battery was stuck on a pole sticking out of the water. A timer was then set – I cant identify from reports the specific nature of the timer, but I’m going to guess an adapted watch. I can’t be sure if there was a single initiator system or two seperate ones.

After the explosion the aircraft settled on the bottom of the 48ft deep port, its superstructure remaining above the water. In less than a month it was refloated and taken to Subic Bay in the Philippines for repairs. although the US Defence Department played down the attack, the North Vietnamese made a thing of it and even issued a stamp commemorating the attack. There are strangely conflicting reports about deaths caused by the attack.

You can find an interesting interview with one of the perpertators here.

 

1910-1920

More “Stay behind” devices

In a couple of posts over the last few months I’ve discussed “stay behind” devices.

In this post I discussed Russian stay-behind devices in the Crimean War in the 1850s .  The Russians, in ceding Sebastopol to the French and British, were able to predict where attacking troops would be – whether that be to seize high profile buildings or munition dumps, and lay “booby-traps” which caused significant problems.

In this post I discussed Russian stay-behind explosive devices in WW2, used to attack the invading Nazi army. In particular the Russians in many instances were able to predict the sort of buildings that the Wehrmacht would be attracted to use as headquarter buildings – typically large imposing buildings with large rooms suitable for converting into the various facilities needed by a military headquarters. Using both long delay mechanical timers and radio-controlled F-10 devices they had considerable success in Kharkov, Kiev and Odessa, targeting incoming headquarter units , in many cases several days or weeks after losing the territory.  In many cases, including a device personally emplaced by Ilya Starinov,  deliberately “poorly concealed devices” were laid “on top” of the deeply buried device. EOD troops inspected the proposed building, and cleared the obvious device in the cellar  (not realising another much larger device was hidden under it). Three weeks later the massive device was detonated, successfully taking out an entire headquarter staff.

With all that in mind, I have found another use of a very similar tactics, but used by the Germans against the Allies, in WW1. Booby trapped explosive devices were used extensively by the Germans in WW1. In this example, the tactic used by the Russians, against the Germans seems to be identical.

On about the 18 March 1917 Bapaume, a small but strategic town was captured from the Germans. After taking the town, an EOD unit found a mine of some sort in the cellar under the Town Hall, a prominent building – whose cellars were deep enough to provide shell shelter – so an attractive structure for forces “moving in”.  It is believed that the Germans may have expected or hoped that a Divisional Headquarters may have decided to use the place.  I think that in an earlier part of the war the Town Hall had been  indeed previously used by a British or French headquarters.  As it happens that did not occur but about 30 Australians had “moved in” along with a tea stall from the “Australian Comforts Fund”. On the night of 26 March, so about 8 days later, a timer, set before the Germans retreated, caused a massive device to explode, killing most of the occupants.  I have found reports that the charge could have been as large as 10,000lbs, (but I think that unlikely, more likely maybe a couple of hundred lbs) and had two independent “time pencils”, of the type where the delay is provided by acid eating through a steel thread holding a striker under spring tension.  Interestingly there is a suggestion that the German Pioneers who laid the devices defecated on the ground above it, to dissuade careful inspection.  I also understand that the German withdrawal from Bapaume was part of a carefully planned operation to fall back to the Siegfried Line, which will have given time for the preparatory effort.

UPDATE:  I have learned from Ian Jones that the details of the incident aren’t quite as I described. A large, easily found device was discovered and made safe in the cellar. a somewhat smaller device carefully hidden in the tower of the Town Hall was the device that exploded, collapsing the cellar trapping people in there.

Shortly later a German was captured nearby and interrogation of him suggested there were other devices in the area.  Before this warning could be circulated, at 12.37 p.m. On March 26th, the luxurious dugout system on the edge of Bapaume, in which a headquarters had been set up was entirely destroyed by a similar mine. Several other similar devices appear to have been used in the area.

Here’s a diagram of a German delay switch. I think the Germans also had mechanical clockwork delay switches.

German WW1 Boob-traps are very well explained in Ian Jones’s excellent book “Malice Aforethought”   Anyway, I think its interesting that a tactic perfected by the Germans in WW1 was used by Russians against the Germans in WW2.  There are lessons here too about “predictability” of the target’s behaviour in terms of choice of location for an explosive device, and also in terms of disguising stay-behind devices. Of course, booby traps were used by the British, French and Australians too.

Uncategorised

Tremble! – The Answer to the Mystery Device

A couple of weeks ago I set blog readers a challenge regarding this device, who made it, what the mystery component in the bottom right corner was, and who rendered it safe.

Well done to KH for his (close, but not perfect) answer. I’ll be buying him lunch soon.  It’s actually a pretty interesting story.  The device was found placed next to a telephone junction box under a manhole cover in a street in Arthur Square, Belfast, Northern Ireland, laid by the IRA , in 1922.  The fuel can “Pratts Perfection Spirit” contained a home made mix and two improvised igniters (not a detonators) in parallel. The EOD team (about more of which shortly) recovered a wooden box with a single slider switch on the outside. Inside was the timing circuit, which had failed. There was a 4 volt “Ever-Ready” battery, an American made clock with a soldered wire switch connection.  The improvised igniter design is quite intricate with a thin copper wire running through magnesium flash powder held in a glass tube, but with a spark gap. The can contained about 20lbs of home made incendiary mix, based on sodium chlorate, some scrap metal and  handful of bullets.  When testing the explosive, it burnt with an intense heat, but interestingly also proved in some circumstances to be “detonable”. I’m leaving out details of the mix for obvious reasons.

Here’s a circuit diagram , done in follow up investigation and analysis.

(This device did not work)

The mystery component is, I think, very interesting, but received scant attention at the time. It is described as a “trembler” but it would be wrong to think of it as an anti-handling trembler switch.  It is in fact an induction coil device for upping the voltage from the 4v Ever-Ready to sufficient voltage to cause the igniters to act as designed. It is actually a car component from a Ford Model T.  This component was known as a “trembler” or “buzzer coil”, and provided sufficient voltage for a car’s ignition system (several thousand volts).  Here’s a video explaining this component.

These trembler switches were popular with ham radio enthusiasts and early electronics hobbyists as an easily available and reliable component.

Finally we come to who rendered it safe. For many recent decades, the lead military agency for EOD in Northern ireland was the Royal Army Ordnance Corps who morphed in the 1990s to the Royal Logistic Corps. And very proud of it we were too!  But in the 1920s, it was the Royal Engineers who provided their expertise to deal with the device and many others.  I can hear my spiritual foundations shaking…

Other devices dealt by the Sappers near Armagh that year were cast into concrete to look like kerb-stones, a technique used more recently in Iraq. They were initiated by command-wire.

Update: Render Safe Procedure used in 1922

I have been asked about the Render Safe Procedure (RSP) used by the Royal Engineer EOD personnel  on this device in 1922. I don’t often discuss these things for obvious reasons but I think I’m OK with this one and its quite interesting.  Here’s what they did:

  1. Filled the manhole with water from a fire hose, submerging the device. Gave it a three hour “soak”.
  2. Removed the wooden box (which was in a sack) from the manhole, cut open the sack. There was a concern over a possible booby trap switch attached to the sacking but none was
  3. The external slider switch was cut off manually, leaving an open circuit
  4. The wooden box was pried open, and components separated after photographing
  5. The cap of the fuel can was removed manually  and the “sand like” HME observed, with the leads leading in.
  6. There was a small 1″ diameter hole in the base of the can covered with some sort of cover.  Apparently this concerned the operator as it may have indicated something clever included in the devices construction. Rather than pull the leads out through the cap, or open the tin with a tin opener or hammer and chisel, the explosive was carefully removed, through the bottom 1″ hole, bit by bit with a a long gouge to eventually reveal the igniters (at this stage assumed to be detonators/blasting caps). These were then cut out.
  7. A series of tests were conducted on the components, quite thoroughly.

 

Uncategorised

Stealthy Explosive Attacks at Sea – 1805

Given recent explosive attacks in the Gulf, it’s worth remembering that stealthy attacks on maritime vessels with explosive devices isn’t exactly new.  In 1804 and 1805 Robert Fulton designed some IEDs for the British Navy. Fulton was something of a peripatetic bomb maker and inventor – making devices for the French, for the British and then for his home nation the USA. In 1805, his devices were used in a small number of British attacks against the French in the Channel ports.  Most of these attacks were failures or had limited effect.  However the French authorities recovered the devices, and examined them in detail.  So this is a lovely early example of Technical Intelligence and Weapons Technical intelligence regarding IEDs.  The French artist was fantastic and his diagrams of the devices have survived. Frankly they put many modern IED intelligence reports to shame. Here are the diagrams with some annotations (in red) by me.

The first diagram is a clockwork timer initiation device, used to detonate a floating explosive charge. The clockwork timer is connected to an adapted firearm lock, a flintlock in this case. You should recognise the flintlock mechanism in the device below:

This clockwork initiation mechanism was attached to a main explosive charge. The main charge was a large sealed canoe shaped pontoon, described as a coffer. Two of these were attached to make a barely buoyant twin raft with a rowing position in the middle.

Here’s the charge:

The coffer was filled with gunpowder and also, in effect, sub-munitions, described as “combustible balls” and other, larger “hogshead” explosive charges were , I think towed behind, but the initiation mechanism for these hogsheads I can’t quite make head or tail of.

Finally here

Finally, here’s a diagram of the “catamaran”. It was rowed into place not far from the French Imperial Fleet. The rowers then pulled a lever to start the timer, slipped into the water and swam to accompanying boats. The tide then took the just-floating catamarans (I think there were at least two) towards the anchored fleet, with the barrels designed to foul the ships and swing the larger charges alongside the ship. As you can see they were pretty large contrivances.

So… Here we have, 214 years ago, a stealthy IED attack on French Navy vessels, by the British, designed by an American, and with a superb Technical Intelligence report on the failed devices by the French. This stuff ain’t new.  I hope to have more (new) detail on Fulton’s explosive device design in coming months.

Close Me
Looking for Something?
Search:
Post Categories: