Standing Well Back
19th Century

Update – Majendie and the “Crime of the Century” bomb

A few years ago I wrote a blog post about an IED that exploded prematurely at Bremerhaven docks on 11 December 1875. That post is at this link here – Crime of the Century.  Please re-read that report before reading on here.   At the time I had somewhat incomplete information but now I have found more material including a report, written soon after the incident by Col (then Major) Majendie that has come into my hands and adds some fascinating detail.  This is good Weapons Technical Intelligence from our esteemed Colonel Majendie. Majendie was the lead explosive expert in the Home Office and the father of modern British EOD and IED incident investigation. He had access to German police reports suggesting the following:

  1. The explosive used was a Nitro-glycerine based dynamite, called “Lithofracteur” – nitro-glycerine mixed into kieselguhr, sawdust, charcoal and bran . This, Thomas (aka, Keith, aka Garcie) had purchased in March 1875 .
  2. Keith had actually attempted to blow up cargo ships on one or two previous translatlantic crossings, but the initiation mechanism had failed. It seems likely that the Bremerhaven incident was the second or third attempt.
  3. The large crate that the device was hidden in was dropped but it probably wasn’t the impact of the drop on the sensitive dynamite to explode that caused the explosion.
  4. The complex timing and initiation contraption, designed by Keith but manufactured by German clock engineers , was not quite manufactured as per the instructions – because Keith’s “cover story” to the manufacturers provided a set of circumstances that didn’t quite make sense. Part of the contraption had levers which caused the action on the detonator at the right time.  These levers were held in place with springs.  The design included a spring detent to hold the levers in place but because Keith had told the  manufacturers that the levers were to cut silk threads while fitted to a bench in a factory, the manufacturers saw no need for this detent and left the spring out.
  5. Thus, the levers were able to move under external force on the whole mechanism. The force of the crate dropping on the stone dockside was not enough to cause the explosive to function – this form of dynamite is not that sensitive in most cases. But the assessment is that the force was enough to overcome the striker springs in the timed initiation mechanism even though it wasn’t  technically  “armed” at that point.
  6. So the premature explosion of the IED occurred because the perpetrator was so secretive about the use of the mechanism that the efficient German engineers manufacturing it thought it was a redundant part so omitted it without telling Keith.

Majendie also reports on the complex insurance negotiations that Keith engaged in with the insurers Baring Brothers and others regarding the insurance of the box, which was his ultimate purpose to defraud.  The report by Majendie then suggests a deeper engagement in the investigation. Separate from the German police reports furnished by the British consul in Bremherhaven, it appears that Majendie and his scientific adviser Dr Dupre obtained a diagram based on a drawing by the clockwork engineer Fuchs of the timing and initiation mechanism.   I think this was a copy of the diagram shown in this excellent report. This report even includes a picture of replica of the mechanism made by the original maker.  Fuchs, the clock engineer made a bit of hay after the explosion and made duplicates of his clockwork mechanism and sold them to a number of museums. There is a vagueness about the source of this diagram in Majendie’s report which I find suspicious and deliberate.   Furthermore it is clear that there was some form of very rapid international investigation which Majendie refers to obliquely. Although Majendie doesn’t mention it, I think this will have been an international investigation undertaken by the famous Pinkerton’s agency, probably at the behest of the insurance companies involved.  Majendie’s report also suggests to me that Dr Dupre, the scientist, was working perhaps secretly on a mission Germany to gather more intelligence on the operation. It certainly appears he met Fuchs, the clockmaker. A secret IED intelligence operation, no less. Certainly Majendie seems to have full details of negotiations the perpetrator had with insurers so I suspect he was provided with a copy of the Pinkerton report on their investigation.

It is suggested that Thomas/Keith may have had a role in other curious incidents and missing ships, perhaps in a series of insurance frauds.  This appears to have worried Majendie who undertook investigations of other cargoes that may have been sent by “Keith” including the investigation of the cargo on the ship “Salier” docked in Southampton.  Majendie also conducted quite a range of experiments on the sensitivity of lithofracteur – but also complains of the salacious reports in the press which exaggerate the threats from explosives- comments from public figures who should know better, exacerbating his challenges in an unwanted manner and misunderstanding, misrepresenting or having no bearing on the technical issues. Plus ca change as Dr Dupre would say.

Here’s a pic of the bodies being removed from the dockside in Bremerhaven after the explosion:

The lessons from this incident, still today, after over 150 years are:

a. International cooperation on IED investigation is not new, and pays dividends.
b. The implicit secrecy of planning and preparing IEDs leads to unexpected pressures. These pressures often cause the operation to fail, or provide the perpetrator with unwanted or unexpected changes to the operation. A careful WTI investigator will consider these pressures in his analysis.
c. The obvious cause of an explosion isn’t always the case. Only careful examination of the components, or in this case the component diagram revealed the full nature of why it occurred when it occurred.
d. Close partnership between lead investigators and scientific advisers is essential as is the ability to carry out experiments to test theories.
e. IED incident investigations were pretty good 150 years ago.

Accidental Explosions

Echoes of the Past – Beirut Explosion and Erith, 1864

I am fortunate to have “inherited” an archive of historical material from “IJ” which I am slowly cataloguing. I can’t help but to dive in on some of the historical documents which although perhaps not connected with IEDs and EOD have a broader historical interest in those interested in explosives.  One particular set of documents relate to the latter part of the 1800s when the UK was undergoing a period of regulatory development of controls on the production and storage of explosives. Until then it appears that safety and good practice were unregulated and the industrial expansion of the explosives industry  was little constrained, and as a result a number of accidents occurred.  This led to investigations by military officers (first Lt Col Boxer RE in 1864, and later by 1874, Major (later Colonel) Majendie RA.  I have often mentioned Colonel Majendie in earlier posts as he was really the first “formal” practitioner of both Improvised Explosive Device Disposal and what is now called Weapons Technical intelligence in relation to IEDs.

As I looked at the early reports by Col Boxer and Maj Majendie I was struck by some similarities in a major explosion that occurred in Erith and the recent explosion in Beirut.  I propose no particular comment here on the Beirut explosion other to say that I was disappointed at the volume of technically illiterate comments in the news media.  But it is interesting to see how two events in 1864 caused the establishment of suitable regulatory control. The two events, which I’ll discuss below, and a number of other explosions in the latter part of the 1800s heightened public and government awareness of the safety issues in the manufacture and storage of explosives, and the appointment of Majendie as the lead government authority on the matter of explosives also provided him, inadvertently but happily, with the powers to investigate IEDs.

The first incident in 1864 was the explosion of the “Lottie Sleigh” a sailing barque carrying 11 tonnes of gunpowder on the River Mersey on 15 January 1864. A sailor aboard knocked over a lamp causing a fire. All the crew “baled out” and were picked up by a ferry. Shortly afterwards the unmanned vessel exploded. No-one was killed but the damage on both sides of the Mersey was significant. Thousands of windows were broken and doors were blown open in both Birkenhead and Liverpool and most of the gas lamps in the streets of Liverpool were “blown out”.  The explosion was heard 40 miles away.  Subsequently insurance companies were involved in complex process to assess liability.  Here’s a pic of the vessel exploding:

Later that year, on October 1st two storage warehouses containing a total of 50 tonnes of gunpowder exploded at Erith on the Southern Bank of the Thames, not far from Woolwich. No cause of the explosion has ever been established.  The explosion was felt 50 miles away. The store was adjacent, like in Beirut, to some docks,

This quote helps us understand the significant devastation:

Everything within its reach was annihilated. Man and matter perished together, shivered into a thousand fragments and whirled into space. People know there used to be a magazine in the Erith marshes, but there is now only a yawning crater there. The very ruins are lost. A visitor to the spot went to look for a cottage which he
remembered ; it had been ” swept entirely away, as with a broom.” Every witness whose evidence could have thrown light on the catastrophe has been hurried out of the world by that tremendous thunder- clap. Those immediately concerned can hardly be returned as killed-they are “missing”-that is to say, their very bodies have disappeared.

Property was damaged 20 miles away but only 10 people died.

These two explosions caught the imagination of the public and communities adjunct to “powder stores” up and down the country. There seems to have been a campaign by many of them to write to the Home Secretary to request oversight of the storage of explosives, and so Lt Col Boxer RE was tasked with inspecting many of these sites up and down the country. In effect this became the first Report of the Chief Inspector of Explosives, a report which became annual under Major Majendie 10 years later and which provide today a treasure trove of historical research. I have copies now from 1864 and then from 1874 till recent reports.

The Erith explosion has a number parallels with the Beirut explosion. Lessons can still be learned 150 years later.  Alas, this was not the last explosion in this vicinity. There was an explosion at Woolwich in 1883, and another in 1907. In World War One (1917) there was a massive explosion of 50 tons of TNT in Silvertown docks on the North bank of the Thames nearby.  Weirdly there was another explosion at a factory in Erith 4 months ago.

I have somewhere a catalogue of such accidental explosions in history, a remarkable number, which perhaps I’ll pull together in blog post – going back hundreds of years.  Bottom line – every explosive store should be sited and managed on the presumption that it will explode.  Major Majendie’s report of 1874 is a fantastic “tour de force” of the explosives industry of the time and the needs of detailed explosive regulations – I’d recommend it to anyone with an interest in explosive storage.

 

20th Century

Starinov, Krushchev and the radio-controlled explosive device

In my last post I promised a little more on Ilya Starinov, the Russian explosives expert and the godfather/grandfather of sabotage explosive attacks.  In the blog post on the F-10 explosive device I recounted how Starinov himself was directly involved in planting the F-10 radio controlled device that killed German General Braun in Kharkov in 1941, and this story relates to that incident directly.

The Russian retreat from Kharkhov was carefully planned. Hundreds of “stay-behind” explosive devices were left and Starinov was directly involved. Some of the explosive devices were on timers, some of them with victim-operated switches, and a good handful of F-10 radio controlled devices, these usually with very large charges associated with them. Furthermore there were large numbers of deliberate indications  left behind that the Russians created to give the impression of yet more devices to further slow the German progress into the region – holes in the ground, disturbed earth, and hoax devices where no device was actually planted, and sometimes devices laid on top of other hidden devices.  According to Soviet sources, 30,000 anti-tank mines were laid in and around Kharkov, about 1000 victim operated devices, and 2000 timed devices.

This anecdote relates to Starinov’s role in this and I cannot be certain it is true, but it is a story worth telling anyway.  A key individual in the Soviet forces in the region was Nikita Khrushchev, who apparently worked closely with Starinov. It is clear, with our view of history, that the Russians expected a significant German EOD effort – by November 1941 the pattern of “stay-behind” devices had been set, including the use of F-10 devices hidden in likely headquarter buildings to be occupied by advancing German forces  in Odessa and Kiev in previous months.

Here’s a pic of an F-10 device being removed from the Opera House in Kiev in October 1941, by a German EOD team. The distinctive construct of the F10 receiver is clear.

-and below is a fascinating Nazi propaganda film showing towards the end the explosive charges and German EOD team’s removal and inspection of the F-10 device itself recovered from the Kiev Opera House. Quite remarkable footage.

So Starinov was instrumental in the dummy devices, and the efforts to overwhelm, fool, distract and out-think the Wehrmacht engineers.   In the run up to the German advance, Krushchev’s headquarters was in a building in Dzerzhinskiy Street on Kharkov, in a building identified by Starinov as likely to be soon used as a German headquarters. Learning the lessons from Kiev, according to this story, two F-10 devices were planted, one hidden carefully below the other in the basement.  Interestingly Krushchev did not move out from the headquarters immediately, as he felt this might give an indication to the advancing Germans that the building was prepared with F-10 devices.  So clearly Krushchev and Starinov met and there was a degree of trust between the two. But remember, the political atmosphere within Soviet forces was febrile and senior officers were frequently “purged”, accused by Beria’s secret police. In some ways Starinov had been lucky to escape, but here we see perhaps a clue giving one reason he had evaded the purges.

As the Germans entered Kharkov, they did indeed , as Starinov expected, have some success at finding and rendering safe quite a number of explosive devices. Nazi propaganda was quick to trumpet these successes and their success against the “dastardly Bolshevik devices”. This apparent success was noticed by Beria’s secret police, who saw, perhaps, that the devices were being found too easily, giving the German’s success and suggested that something had been so planned by Starinov. The Nazi propaganda from the previous month of the device being found in Kiev would perhaps have added to their suspicions. Then General Braun’s staff made an announcement that they had “easily cleared the major part of the mines”.  The secret police prepared a case against Starinov, but Krushchev got to hear of it. He advised Starinov to detonate the two devices in the Dzerzinskiy Street Headquarters now, as predicted, occupied by General Braun.

According to the source I have found the “top” F-10 explosive device planted in the cellar had, as expected, been found, made safe and the initiation mechanism presented to General Braun, showing the headquarters was made safe. The now safe initiator sat on a desk in a main room. Accordingly Starinov, warned of the expected investigation by the secret police, ordered the first device initiated – and in the main hall of the German headquarters the receiver “clicked”, to the delight of the Wehrmacht.  Five minutes later the second device, still hidden deep under the building and with a massive charge attached to it received the necessary transmission… and General Braun and many of his staff perished in the explosion. Thus , Starinov’s investigation was dropped by the secret police, and he continued his career.

I should state that other sources slightly contradict this story – saying the “top device” designed to be found was a time delay device. But perhaps the story as detailed above makes a better story – I found it in a 1963 edition of Izvestiya, and it too may well be propaganda. The best stories often are. I do note that the Izvestiya report gets the wrong date attributing it to 1942 and not November 1941.

Here’s a picture of Starinov I have found. I’m not sure when this was taken but I suspect it was some years after the war. Starinov is the older man in civilian clothes pictured with serving Russian soldiers, perhaps those he was training in the late 1960s or 1970s.

Here’s another picture of Starinov taken, I think in the late 1980s.

 

And here, as young man being introduced to Marshal Klim Voroshilov.

The efforts of the German Wehrmacht EOD/Engineer units in dealing with the significant explosive threat in places like Kiev and Kharkov in 1941 probably deserve some attention.

 

 

1940-1950

The Russian IED connection

Last year I wrote two important blog pieces. The first was about the Russian IED expert Ilya Starinov – certainly the most important person in the history of explosive sabotage.  The second post was about the Russian F-10 radio controlled demolition device, used successfully by Starinov in WW2.

Since than I have been digging to find more details of Starinov’s devices, which I have finally successfully done, and there are some very interesting findings.    I’ve also uncovered other anecdotal stuff about Starinov and indeed about the broader history of IEDs which I’ll post in coming days and weeks.  I also have more technical detail on the F-10 to discuss in future posts.

Now, firstly, a caution. Some of the material I have found regarding the construction and design of certain IEDs could be abused by people with ill-intent. All the material I am going to post is unclassified, but I’m going to obscure parts of it and discuss things in some vague terms  to make it much less useful to those with criminal intent.  If you want to know the source and you know me or can prove you have a legitimate need to see the sources I am using, then get in touch. Otherwise I make no apology for being deliberately non-specific about some of this material. Now, I found the source of this material on line, and others may be able too, but I am going to limit my helpfulness towards those who shouldn’t have this detail.  If you want to challenge my assessments and why I draw the conclusions I reach below, I’m very happy to do this off-line.  This means, perhaps, you are going to have to trust me on some of my assessments. Or not!  Finally I should also point out, sadly, that there is no shortage of detailed technical instructions for miscreants to find how to make bigger and better IEDs then these here discussed in an openly available 70-year-old document, discussing devices from the Eastern Front in 1942.  The horse of IED knowledge bolted a long time ago.  Close the stable door if you can – I can’t.

The document I found was developed not from Russian sources, but from US sources, who clearly in the immediate post-war period of 1945-1950 had access to German Wehrmacht engineers reports. These engineers had conducted thousands of successful EOD operations. By gleaning reports of Soviet demolition activity, dealt with by the German engineers in WW2, the US military tried to gain a greater understanding of Soviet capabilities in the 1950s. So this was real technical intelligence on Soviet explosive technology, and explosive sabotage tactics, as the Cold War span up.  So here we have, in 2020, the opportunity to examine 1950s US military technical intelligence, derived from Nazi German technical intelligence from the period 1940-1945, about Russian explosive devices.  So this isn’t exactly a primary source.  But some of the detail I’m going to show you makes me convinced this is worthwhile, valuable historical material, and there are certain aspects which surprised me.

Firstly to remind you of the context. It is apparent that the Soviet soldier of WW2 was pretty familiar with improvising explosives charges, either using his own munitions or captured German munitions. The Germans state that the Russian soldier is “particularly ingenious in installing improvised mines and booby traps“. During the latter part of WW2, the Russian use of sabotage explosive devices went way beyond anything seen before or since. Furthermore partisans in Eastern European countries were trained to improvise yet further. Thousands of railway lines, trains and vehicles were attacked explosively by Russians or Russian sponsored partisans in eastern Europe. Much of this was coordinated by Ilya Starinov, who also designed explosive devices , trained the perpetrators and on many occasions planted key devices himself. Starinov survived numerous purges, and went on to develop spetzntaz units and tactics, and taught revolutionaries around the world in the 1950s and 1960s.

In this first post, I’m going to highlight some very interesting similarities between Soviet sabotage devices from WW2 and (get this) IRA devices of the 1970’s, 1980’s and even 1990’s.  These similarities go beyond just application of general explosive/sabitage principles – there are significant design similarities in aspects of the devices.  Here’s some examples, and a final, highly technical device that I won’t comment on too deeply.

  1. Firstly there is the use of specific component items.  In the 1970s and into the 1990s, many PIRA devices encountered in the UK had firing or arming switches as part of the circuitry. In the vast majority of cases, in what was termed “Time and Power Units” (TPUs) this switch consisted of an adapted wooden springed clothes peg help open with a wooden dowel. Here’s a demonstration circuit showing the “IRA technique”.
  2. The clothes peg was wired so that a switch closed when an insulator was removed from the jaws of the peg, arming this device. In the 1950 document I have found. German engineers describe this exact concept being found in Russian devices in the early 1940s. Here’s a pic:  

3. In the late 1980s, PIRA developed the “Mk 12” mortar as British Forces called it. This was followed in 1993 by the smaller “Mk16” Mortar. These were missiles that had a shaped charge in its front end, a hollow pipe behind it containing a fuze and tail fins to stabilise in flight.  This wasn’t really a mortar but a horizontally fired missile typically fired at vehicles. It had a shaped charge warhead and a fuze set in the hollow tube behind, with simple fns to stabilise  it in its short flight.  Here’s  a picture of a PIRA Mk 12 Mortar. disassembled:

4. In WW2 Russian partisans developed a device that is remarkably similar. Not tube-launched but built for a similar purpose and with almost identical design principles. Here’s the pic from the 1950 report:

5.  The Russians also concentrated significantly on additional circuits or mechanisms to booby trap charges. By introducing anti-handling and anti-lift charges, several of the devices used by the Soviets appear remarkably similar to what the British EOD community of the 1970’s refer to as “Castlerobin” devices. I’m not going to discuss this further here. But clearly there is a thought-process going on to prevent the render safe of devices, and target the EOD operator. The parallels in design are clear.

6. The creation of devices which target EOD activities went a step further with the introduction of a RF sensitive switch designed to initiate an explosive device when certain mine detection equipment was used. This was fielded in December 1943.  Some of this equipment was captured by the Wehrmacht in January 1944, and rapidly exploited.  70 years later , technology which is triggered by the RF signature of certain EOD equipments would be regarded as a very high threat indeed – yet, here the Russians were in the early 1940s developing such technology. The device responded to a frequency of 800-2000Hz at short range, emitted by German EOD equipment. What is more, the Germans recognised the importance of such an advance, examined the Russian technology, identified some flaws, and developed their own version of the equipment. They also developed technical solutions to the threat.   I find that remarkable, and some of you will share my surprise for reasons we won’t go into. Here’s an excerpt from the report showing the circuit to prove it is what I say it is – (I have obscured part of it for reasons explained earlier).

To be clear in my assessments: I’m not saying that the IRA devices of the late twentieth century were designed by the Russians – just that there are some odd parallels, that may be coincidences. Direct influence is possible but so, theoretically, is the potential for the IRA to have got hold of the American report written in the 1950s. It’s not secret.  But we shouldn’t underestimate the fact that Starinov was training revolutionaries from around the world. I do think that these parallels once again highlight the importance of understanding the history of IEDs.  The fact that Russian devices were so focused on countering EOD action is interesting and significant and deserves wider understanding.  The general under-appreciation of the extensive, WW2 Russian sabotage campaigns using improvised explosive devices is barely recognised and deserves a much greater level of attention. Frankly it makes the efforts of the British SOE or American OSS look very paltry in comparison.

In future blogs related to all this I will address the following:

  1. Some Russian devices designed specifically for targeting railways – further to my series in the subject. Some were designed by Starinov himself.
  2. More technical details of the Russian F-10 radio controlled device.
  3. Some more details and photographs of Ilya Starinov, and an interesting story about the F-10 radio-controlled devices he deployed to assassinate German General General Braun in Kharkov in November 1941, and the role of a young commissar called Krushchev (yes, that one) in the operation, protecting Starinov from being arrested by Beria’s agents and “purged” before the device was detonated.
  4. An odd and fascinating series of parallels between this 1950s American report and another American report written in 1865 showing almost identical devices. History repeating itself again. Some of the Russian devices of WW2 are identical to Russian devices of the 1850s, and some other Russian devices of WW2 are very similar to American revolutionary devices of 1778.

All in all, this document is a bit of a treasure trove when put within the larger context of the history of IEDs over several centuries.

 

Ship-Borne IEDs

The Operation Chariot IED

Sometimes doing historical research on IEDs, you get stuck finding out technical detail and the post dies. Just occasionally the subject matter is really interesting and deserves telling anyway – but with some caveats. This is one such incident but there’s a fair bit of speculation from me on some technical matters.  I’m very happy (as always) to be corrected, and happy if more technical details surrounding this incident come out – and then I’ll update.  I’m very grateful for Norman B and Ian J for their valuable inputs on technical matters – there’s no-one who knows more about explosive  devices of this time than these two gentlemen.

I’ve written before about a fascinating historical trend of ship-borne IEDs used in ports on the Northern coast of Europe since the 1580’s – follow the link in the connections on the right hands side of the page to ship-borne IEDs.  One I have mentioned, if only in passing, was the most recent – The St Nazaire Raid – Operation Chariot – that took place in 1942.  This is an interesting story and if some of the details are a little grey, then that’s the way it is.

If you don’t know the story of “the greatest raid” you should google it and get your head around this audacious operation – designed to prevent the Tirpitz from using the Atlantic, by taking out the huge “Normandie” dry dock in the German-held port of St Nazaire.  The characters involved all have individual tales that are quite remarkable, but this is a blog about explosive devices, so I’m going to concentrate on that.    The crucial part of that raid was a large IED hidden deep within the hull of “HMS Campbeltown” which literally was rammed into the gates of the huge dry dock at the St Nazaire Naval Base.

Once the ship was lodged in the gates, the stern of the ship was flooded to prevent the Germans perhaps pulling the ship out from the gates, and so the stern was stuck and the ship, for the time being, was going nowhere.  The occupants of the ship either died in the approach action or fought their way ashore, many of them with missions to blow-up the dry dock infrastructure. Unknown to the German forces though, the fuzes in the ship had been set, and in a few hours the explosive device would indeed detonate to destroy the dry dock gates.  So let’s explore what that device consisted of, and here are the caveats:

  • We can’t be sure exactly how the device was fuzed, because the man who perhaps designed it and who set the fuzes died. Or alternatively the secrecy procedures of the time simply kept it all under wraps and it wasn’t discussed and recorded as we’d hope.
  • Most of my sources, at this stage are not primary sources, so I’m left scrabbling for odd unreferenced mentions relating to the device that I can’t fully confirm. These are open to interpretive filters by those “swinging the lamp”.
  • Some of the limited technical details about the device and its components vary between sources.
  • Even if I had all the facts of the device design some of the reasoning behind the design is going to be open to interpretation anyway.

So, despite all that, here’s what I think may have been the idea. I suspect the design of the device was a collaborative affair. Lt Nigel Tibbits DSC RN was the naval officer detailed by the captain to oversee it, and he probably had the key role in deciding where the main charge was placed, and the concept of its use. I’m unsure as to his level of expertise – some sources describe him as an explosives expert and others that he was the ship’s navigator. I think he was maybe unlikely to be both.  I suspect he had some form of assistance from two Royal Engineer demolition officers who are vaguely referenced, and also I suspect, from the SOE, who provided, perhaps/maybe/probably, some of the fuzes and possibly some ideas regarding concealment of the components.  The device itself seems to have some of the characteristic fingerprints of an SOE sabotage device in terms of its components and its concealment.   I suspect Tibbits came up with the idea of placing the device in the fuel tank, and the demolitions officers placed the charges and initiation system, and the SOE may have provided advice on concealing the initiation system and provided some key components.

Lt Tibbits DSC RN

The main charge was to consist of 24 Mk VII depth charges, each containing 132Kg of Amatol, giving a total of over 3000 kg.   Amatol was a commonly used explosive in the first part of WW2, and in crude terms was a mix of TNT and Ammonium Nitrate. It’s a reasonably stable, quite effective, explosive, better than straight TNT because the “oxygen deficiency” of TNT is made up with Oxygen ions in the Ammonium Nitrate.

To give you an idea of scale, here’s a single Mk VII depth charge being lifted:

 

The remainder of the explosive components used were from a stock probably delivered to the ship before the operation, I think from the SOE and detailed in one report as follows:

  • 10 x 2.5-hour waterproof delays
  • 20 x 2.5-hour pencil delays
  • 10 x underwater initiators for Cordtex leads
  • 20 x 8.5-hour AC delays
  • 20 x Bickford fuses.

I believe that quite significant attempts were made to disguise and conceal the presence of this large device.  On HMS Campbeltown a main fuel tank is located deep in the hull, behind the forward gun, just forward of the bridge super-structure and about 12 feet down under the main deck, under the Petty Officers’ Wardroom. The top part of this fuel tank was sectioned off to create a compartment. Into this the depth charges were placed in 4 columns, front to back, of six each.  The spaces between were then filled with concrete, and a steel lid with (disguised?) access holes placed on top.  I assume that the holes was accessed from the deck of the petty officers wardroom.  I think any reasonable explosives specialist would fit a cordtex ring main around at least the central depth charges if that were possible.

The device was carefully constructed before the operation and I have found the attached photograph of the ship at this time of preparation, in Devonport.

A few things strike me about this photo.  This was taken during the preparation for the operation – additional bolt-on armoured shielding is being put in place.  But there are several other interesting things in this picture which shows the key deck space above the charge (between the superstructure and the forward gun). Firstly, I think those cylinders at the feet of the seaman are Mk VII depth charges – just at the moment of being loaded aboard – I think I can see six. So that’s interesting. Secondly, so are two of the characters on the picture. Just behind the seaman and the officer are two men dressed in civilian clothes – trilbies and overcoats.  They can’t be dockyard workers, as such clothing would be inappropriate. I wonder if they are SOE explosives specialists visiting the preparation to advise on device construction, which one assumes is going on below.   Forgive me a little speculation on that!  The SOE had a department, at the time called “ISRB” (Inter Services Research Bureau) who conducted research and development of some of the stranger weapons of war. ISRB supported SOE directly but also, and significantly, they supported “Combined Operations” the organisation, under Mountbatten, who coordinated and planned Operation Chariot.  ISRB played a key role in developing the AC Time delays, time pencils, sand underwater initiators, so the “shopping list” of components listed earlier looks like they were from ISRB. So I think it’s reasonable for us to assess that the firing system had very significant input from ISRB, who also where masters at disguising and concealing devices.    A number of the central depth charges were under the access holes, allowing the charge to be primed.  There was a variant of the MkVII depth charge, that had a built in detonator adaptor to allow initiation from a detonator or cordtex , but it’s not clear if this was available to this mission, or indeed if it was developed as a result of this mission’s requirements.

The fuzing of the system is where we have to make a few speculative assumptions, and where there are only a few facts. What follows is a bit of a ramble through the technical aspects.

  1. The charge had at least two separate initiation systems, and it is very likely indeed that some of these were duplicated to ensure detonation.
  2. Both the primary and back-up initiation systems employed time delay switches. The challenge here is that many sources contradict each other on the lengths of time delays available, and then after that they are all dependent to a greater or lesser degree on the temperature. I’m conscious that in discussing some of the timings, there are queries over the “2.5” hour time pencil delays and “8.5” hour AC time delays that I have not resolved completely because of conflicting information.
  3. The primary initiation system was designed to function some time after the ship had been evacuated, probably 2.5 hours after the crew “disembarked”. It probably used at least one (and probably/almost certainly more than one) 2.5 hour pencil delays.
  4. The planned time between disembarkation and detonation was the reason that the device needed to be concealed.
  5. I have found one reference (not all that well sourced) that suggests that the primary ignition system (the 2.5 hour time pencils) were hidden, somehow, in the leg of a wardroom table.  I’m going to assume that this is the wardroom above the main charge, and that from the time pencil (or much more likely, multiple time pencils) was a detonator(s) and then an explosive link of cordtex that went down the table leg, through the deck below, and into the main charge.  But it is possible that the time pencil was connected to Bickford fuse and that the detonator was at the end of this, perhaps inside the false fuel tank attached to cordtex ring main.
  6. The 2.5 hour time pencils had a white-coloured safety strip.  Now 2.5 hours seems like a long time to me, but I think this was because of the other explosive demolition operations planned for the pumping house and other dock facilities – these would explode first, the commandos clear the area, and then the main charge in the Campbeltown would destroy the gates. Exploding the Campbeltown first may have compromised the ability to destroy all the supporting mechanisms.  So the concept of operation assumed that the device would be undiscovered for 2.5 hours – (in the middle of the night, during a battle, with raiding parties all around so not unreasonable). The main part of the raid was expected to take no more than 2 hours.
  7. Now, time pencils are a bit fiddly. They need some inspection during the process of initiating them, involving checking in sight holes, crushing a copper vial, crimping on safety fuze or detonator, inspecting again, and then removing the safety pin.  So the hidden compartment would need to allow fairly easy access. We know nothing more of this concealment. I sense the hand of ISRB in this concealment design. It is also possible that they fitted some sort of mechanism to aid the ease of initiation of the time pencils to reduce the fiddly process at the height of battle. here’s a pic of the the pencil:
  8. I suspect that the plan was for Tibbitts or one of the Royal Engineers to set these immediately after ramming the dock gates.  It would have been sensible to assign back up personnel to this task given the expected battle.
  9. The “back up” initiation system seems to have involved the use of “AC” delay devices.  These involved acetone dissolving a celluloid barrier, and different concentrations of acetone varied the timing.  Here’s a picture:

And a photo of one:

 

9. The delay is varied in these igniters by inserting different coloured ampoules of acetone. They are set by removing the safety pins then screwing the top in to break the ampoules   The ones supplied to the Campbeltown were supposedly “8.5 hour” delays, but other convincing sources don’t offer that as an available time delay. So that’s an anomaly I haven’t resolved. These, attached to a detonator, were embedded in the main charge or a ring main (I suspect there may have been a booster of some sort or some cordtex in the mix there to ensure the explosive train).  This 8.5 hour timer (if that is what it was) then has the consequence that the charges needed to be set several hours before the final stages of the operation commenced. But there’s some interesting maths here and some challenges.

10. The operation planned for the Campbeltown to ram the dock gates at 0130 hrs. (it did so 4 minutes late, at 0134 hrs.) .  The plan must(?) have been for the main delay mechanism. in the wardroom table leg, to be set at that point – with a 2.5 hour delay then the explosion was to have been at 0400.  The back up initiation system, to coincide with that, should therefore have been set, theoretically, at 1930hrs the previous evening.   Given that that was long before the approach to St Nazaire, and these fuses were known to have reliability issues, I think they would have been set later – hence the delay in initiation until next morning.  Added into all of this the AC fuses were known to have quite a range of variation in timing – by as much as 20% due to variables such as the temperature, and also variables in the concentration of the acetone due to poor quality control during manufacture. So some leeway would be given, as well as a fudge factor.  As it was , I understand from one source that the AC delays were “set” at 2330 hrs – but I can’t be sure what time zone that’s in – “British” or “local”.  Either way, at some point in the night, during passage towards St Nazaire,  Lt Tibbits (if it was him) set the AC time delays, I think by reaching somehow through the wardroom floor/deck, setting the devices, (remove the pin, screw the head in) then concealing the access hole with a wooden bung.

11. Then of course battle ensued and things went wrong, as they always do in battle. At some point during the attack, the wardroom was struck by a German shell. Fire ensued, and brave attempts were made to extinguish it.  In this picture, taken after the ramming but just before the ship exploded, I think you can see the resultant fire damage to the hull on the outside of the wardroom, just under the forward gun.  If you look carefully perhaps you can see a hole where the shell hit.

12. It was probably due to this shell that the primary initiation system was damaged and un-usable. It must also be luck that the device wasn’t initiated at this time, early.    So then the attack was relying on the back up AC delays deep in the hidden compartment. The hit on the wardroom also probably made a compete mess of the interior of the wardroom and perhaps added to the reasons why the charge was not found in the ensuing hours. But imagine crewing this ship, sat above (literally) a 3 ton explosive charge, knowing that there’s been a hit and a consequent fire around the initiating systems. Wow.  Encouragement to get off as soon as possible I think.  Here’s another picture showing how the sea cocks had been opened at the stern to prevent a rapid tow away by German forces.

13. The AC delays finally caused initiation, the main charge having been undetected, at about 10.30 am, perhaps 10 or 11 hours after the 8.5 hour delay (if that’s what they were) had been set.   40 senior German officers and civilians who were on a tour of what they supposed was the captured Campbeltown were killed.  Hundreds of others in the dock nearby were also killed or injured.  The charge, as you can see from the photo above, was probably 12 – 15ft behind the dock gates, which were blown apart by the explosion. The dock remained unusable until 1947.    What remained of the Campbeltown came to rest in the dry dock itself.

I think this photo (taken after the war, I think when the dock was being repaired) shows the immense scale of the Normandie Dry dock, with the little Campbeltown‘s remains occupying the space that would otherwise have held the mighty Tirpitz.

I have taken some liberties here with my sourcing and interpretation of the device design, and I’m very happy to be corrected. some of my assessments contradict some sources. (for instance one source suggests that the device was to be initiated  at 4.30 am, others after 0500 am). I put some of this down to the confusion of battle and also confusion over time zones.  I think I’d make the following points in summary:

  1. This attack has so much in common with a number of earlier ship-borne IEDs that occurred on the Channel or Atlantic coasts in the previous 400 years.
  2. It was fortunate it succeeded, particularly in terms of the enemy fire hitting the place where the primary initiation system was hidden.
  3. Disguise of the device was clearly a major factor in its construction. The disguise and concealment worked. If one regards this “ship IED” as essentially a large vehicle-borne IED, the key features of a VBIED are all here – mobility, disguise, speed, size of container.  As others in history worked out for themselves, (and as you can read on other pages of this blog), as vehicle-borne IEDs go, there are none bigger than ships.
  4. Exploring the “tactical design” of any IED attack is always fascinating, and the same is true here in spades.  Too little time is spent understanding this process (both by perpetrators and by investigators). That complex interrelationship of the mission, and the way that technical resources can be moulded to fit the mission, or the mission tweaked to take account of the technicalities of device design and construction is fascinating.  If you were in Tibbits’s shoes, how many back-ups would you have? How would you protect them, from enemy fire and from discovery?  What alternatives can you envisage? What other resources did he have available?  Complex attacks sometimes require complex devices. Simplicity usually works.  For simple, routine sabotage type operations the availability of explosive components leads to the design of the mission.  But for complex operations such as this, the components have to be adapted to suit the required characteristics, and that can pose challenges.  For those developing components for use by saboteurs, such as ISRB, they have to cover all angles they have to allow as much flexibility as possible and you can see that in the range of timers and initiation types available. There are some interesting parallels, as ever, with modern terrorism.
  5. The reliance on somewhat unreliable time delay devices is perhaps surprising in modern terms. The whole concept of operation screams for a mechanical rather than chemical timer, or in modern terms an electronic timer.
  6. We’ll probably never know the actual design, or if there were additional fallback initiation systems.
  7. IEDs are not always the sole provenance of the enemy. Often viewed with disdain, sometimes depending on your perspective, their use can be heroic. What a strange phenomena they are. Of course you may not regard this as an IED at all, but I do.
  8. Checking out a large vehicle or ship for hidden explosives is damned difficult if the device is well hidden.
  9. Bloody hell, it was a close run thing.

I think most of all about the challenge faced by Lt Tibbits. As the Campbeltown approached St Nazaire docks, its guns blazing , under heavy fire from everything the Germans could muster, he replaced two helmsmen, both killed by incoming enemy fire, and he was at the wheel, the skipper by his side, as it rammed the dock gates at full speed trailing the royal ensign that had replaced the ruse de guerre of a German flag minutes before.  He knew his primary initiation was gone – so he may have felt significant pressure to somehow ensure detonation.  Dare he rely on the back up charges?   Given the decks were strewn with injured, that would have restricted his options.  Would the device be discovered?  What choices were open to him? In any event he was cut down by machine gun fire a few seconds after disembarking and he died there on the dockside and that, I’m afraid, was that for Lt Tibbits.

In future, I may do a similar piece on the WW1 Zeebrugge raid which has a lot of similarities, including another big IED. If I can get enough facts together. One wonders too, that if earlier in the war Operation Lucid had succeeded, would the Germans have paid more attention to the likelihood of explosive charges. Or if they had access to the history of explosive ships along this European coast would they have dug a little deeper into the hull of HMS Campbeltown.

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