Churchill CDL?

[Kingsman]

Listening to one of David Fletcher's tank chats on CDLs on the Tank Museum You Tube channel, he said that there was a single regiment of Churchill CDL (152 RAC) and that these had a more heavily armored turret than the ones used on Matilda and Grant.  He also said that he's never seen a picture of one despite his years of research work.

 

I've never heard of the Churchill CDL before.  Has anyone else ever come across it or have any further info?

[fatalbert]

If you search on google images,you get some info come up showing some models that have been made and also some plans.

[Kingsman]

I guess it didn't cross my mind that Google would find something that a lifetime of research had failed to reveal.  And it didn't.  No original photos and little really definite information other than confirming they almost certainly did exist and that 152 RAC were the users.  Although one source suggested that the Churchills used by 152 were standard gun tanks and that no CDLs were actually built.  Which makes no sense as the CDL school at Lowther Castle was about the tactics of using the lights, not driving the tanks.  Tanks with no lights would have served no training purpose there.

 

I am not entirely convinced by the models and plans that simply graft the Grant version of the turret onto a Churchill hull unaltered.  DF was clear that the turret was more heavily armoured and that the Churchill hull was chosen for its ability to carry the extra weight as well as being roomier than Matilda.  This could just have been the same design made in thicker plate, which would have made production sense and would not have looked a great deal different but would inevitably have been slightly larger.  But it could have been quite different: look at the US' own Shop Tractor design.  However, it seems that there was a version of the standard turret with 85mm armour (frontal?) rather than the 65mm on the Matilda and Grant and that up to 100 of these thicker versions may have been made: about 25% of total turret production.  So potentially those were the Churchill turrets.

 

It is unclear if the Churchill pre-dated the Grant or whether they were contemporaneous, but there is mention of Matildas and Churchills together at Lowther Castle and the Churchill regiment was disbanded or converted pre-D Day.  Which certainly suggests that the Churchill pre-dated the Grant.  Potentially it may not have had the dummy gun: Matilda didn't, but Grant did.

 

One imagines that the Churchill CDLs were re-converted back to gun tanks, AVREs, ARKs or some other useful function in anticipation of a role post-D Day.  Hull type is entirely uncertain, but Mk III/IV seems most likely for 1943-44.

[John Tapsell]

The Churchill CDLs were equipped with the Type B turret which had a thicker (80mm) turret wall. I believe they were fundamentally similar except for the thicker turret walls.

 

They were contemporaries of both the Matilda and later the M3 but only one Regt (152 RAC) was ever equipped with them. There are a couple of drawings available of the Churchill CDL. The turret was mounted on top of a 9-12 inch 'collar' on the turret ring. The collar contained the exhaust port for the Meadows auxiliary engine mounted below the turret to power the lamp generator (the Matilda had a power take-off from the engine to power the generator and the M3 had a power take-off from the transmission shaft running through the main compartment). The Churchill CDL had a crew of three - driver, commander (in the hull) and operator. The Churchill proved unpopular due to the poor vision for the driver and commander caused by the protruding track units (critical at night when the vehicle had to be kept as level as possible and where driver vision was important). There is a published memoir (Sutherland's War or Sutherland at War, can't remember the title) written by a Troop Commander from 152 RAC that goes into some detail about their training (but not the technical side especially).

 

The Type A turret (with 60mm turret walls) was the classic Matilda CDL turret and these were later transferred to the M3 Lee/Grant hulls (same turret ring diameter). The Type B was heavier and therefore unsuitable for other hulls.

 

Later still, the Type A turrets were rebuilt to Type D standard. This is when the access hatch was welded up and additional spall protection was added inside the air vents. It was also when the false gun and a few other mods were added.

 

Meanwhile, the Type B turrets were also rebuilt to the Type D standard but never with the false gun and they were not redesignated - actually, the Type B turrets were initially given priority for rebuild (which is odd as the decision had already been taken to go with the M3 as the only hull type).

 

There were two British schools - Lowther Castle was the main one but there was another one at Rafah in Egypt for a couple of years. There were also two American schools - at Fort Knox (technical training) and also Camp Bouse in Arizona (for tactical and field training). Six British regiments were trained at various points during WWII, along with six US Battalions. Nearly 1000 turrets (British and US) were manufactured. In 1944, some training (mostly for US units arriving in the UK) took place in the Presili Hills near Fishguard in Wales.

 

British and US units were shipped to Normandy in August 1944 - the British units (11 and 49 RTR) concentrated on Carpiquet airfield near Caen and were eventually (October) re-quipped for other duties (11RTR with LVTs and 49 RTR with Ram Kangaroos) - the 200 CDLs in Normandy were returned to Lowther Castle. The same happened to the US units who generally became mineclearing specialists. In Feb/March 1945, three of the US battalions were partially re-equipped with CDLs, as was a reinforced Sqn from 49 RTR (ironically made up mostly of 11 RTR personnel) and the CDLs operated along the Rhine for 3-4 weeks. At the height of operations, some 80-90 CDLs were operational along the river.

 

43 RTR were the last British unit to be trained on the CDL, with the intent that they would go out to the Far East. They got as far as India before the war ended. US CDLs got as far as Okinawa but arrived after the island had been captured. They would have been used for the invasion of Japan.

 

The Bovington Matilda appears to have a Type D turret fitted, which makes no sense in terms of the development timeline so it may be a development vehicle or a mash-up from available parts.

 

The observant amongst you will have spotted the lack of a Type C turret in my notes - 200 Type C turrets were built for the Royal Navy to be fitted to landing craft. After some initial testing, they were all scrapped. They were built by Vickers from 20mm (IIRC?) plate.

 

The Type E was a turret with two CDL lamps to be mounted on a Sherman (the test vehicle was a Sherman V) - Both the British and Americans developed very different Type E solutions. The Type F would have been a new-build turret to Type D standards.

 

Regards,

John

Edited July 22, 2018 by John Tapsell
spelling

[Seahawk]

Magnificent answer, John, and welcome to the site.

 

One question, if I may: I assume that, when you speak of the turret access hatch being welded up during conversion from Type A to Type D, you mean the one on the turret side in the 8 o'clock position.  Did the hatch remain but welded up (in which case it makes little difference in modelling terms) or was all trace of it removed?

Edited July 22, 2018 by Seahawk
Correction: Type A, not Type B, to Type D

[John Tapsell]

Type A to Type D (Type B  was upgraded to the same standard but retained the Type B designation) - Yes, the hatch was welded shut rather than being removed but the hinges were sometimes removed as well.

 

The changes were the result of firing tests against a test turret. It was found that 'spall' (splinters) from the fire was finding its way into the turret through the cooling vents so additional baffles were installed. Similarly, the hatch was welded up because the hinges were considered to be vulnerable. Also, if you look at the Bovington turret you'll see three 'hooks' sticking up above the front plate of the turret - actually these were designed to protect some of the roof bolts (couple more on the rear plate too). 

 

Regards,

John

[Kingsman]

Thank you for the most excellent and comprehensive info on the Churchill CDL.  Ask and thou shall truly receive!

[EwenS]

John, many thanks for the additional information. Funnily enough I looked into the history of the CDL units myself at the beginning of the year due to the detail about the unot that ended up in India in 1945. I came away with more than a few queries especially about the Churchill CDL, so much so that I actually begin to wonder if it existed as a few trials vehicles only rather than a whole regiment being equipped. Below I've set out the results of my research on the CDL project which may be of interest to the group.

 

It seems that the original British plan was to equip 2 Tank/Armoured Brigades, one in the UK, originally to have been the 35th, and one in the Middle East, to have been the 1st Tank Brigade, although neither ever fully equipped. The latter was returned to the UK around April 1944. I found it very confusing trying to trace exactly which regiments were CDL equipped and at what times with what vehicles as they moved around between Brigades and switched back to the gun tank role or other roles, but came to the conclusion that 6 regiments had them at some point as John says. Those were 152 RAC, 155 RAC, 49 RTR, 43 RTR in the UK and 11 RTR and 42 RTR in the Middle East which returned to the UK in 4/44.

 

My research revealed approx 300 CDL turrets were produced in the UK (sources vary as to exact numbers - c.300 to 335, with 6 sent to the USA). One source has 100 of those being for Churchills. The 152 RAC was the only unit I could connect to the Churchill CDL but from my research there seemed to be a lot of doubt as to exactly how many of the 100 turrets were actually put into tanks and reached the 152nd RAC. Clearly it wasn't a success so wasn't pursued and the reasons given by John make sense to me.

 

There is a reference in Hunnicutt's Sherman book, that a General Fuller stated that 1850 M3s were converted in Britain to CDLs. Given that Britain and the Empire received only 2887 M3 in total with only some 216 being delivered to the UK that figure seems fanciful. Most M3s were sent direct to the Middle East, India and Australia. By D-Day there were only 3 CDL regiments in existence (11, 42 and 49 RTR in 1st Tank Brigade) each of which was supposed to have an equipment of 54 CDL and 31 gun tanks. So a total CDL requirement of 162 vehicles (which was fulfilled) from 216 M3s delivered to the UK seems doable allowing for losses. The gun tanks were Sherman I & II and only numbered 77 in total plus some OP and ARV.

 

As John notes the final British use was by a reformed B Sqn of 49RTR operating independently for the Rhine crossing in 3/45.

 

Despite little operational use being made of the CDLs British interest in them never seems to have faded. As late as January 1945 a training unit (43 RTR) with various "Funnies" was wholly re-equipped with Grant CDLs and shipped out to India in July 1945 arriving at Bombay less than 2 weeks before the end of the war. These must have been scrapped in India or passed to the Indian Army at the time of Indian Independence. A single vehicle has survived in the Cavalry Tank Museum, Ahmednagar, India with photos on wiki.

 

The US converted 497 vehicles between 6/43 and 2/44 under the designation "Shop Tractor T10" and codenamed "Leaflet". These used both the M3 and the M3A1 cast hull model as the basis. Only 300 M3A1s were produced, all between 1/42 and 7/42, and these had a mix of petrol (262) & diesel (28) engines and all of which were retained by the US forces for training purposes in the USA so a mix of 60/40 M3 / M3A1 petrol seems likely allowing for losses etc. Hunnicutt notes that the UK and US turrets were almost identical.

 

As John notes, 6 US tank battalions were equipped, each with 54 Grant CDLs and 18 gun tanks. These were 701,736, 740 and 748 Tank Battalions which all converted to gun tanks in October 1944 due to the level of armour losses in the summer of 1944. The 738 and 739 Tank Battalions converted to Tank Battalions (Mine Exploder) around the same time. Despite this CDLs remained in the inventory. In 1945 21 were assigned to First Army, 28 to Third Army and 15 to Ninth Army. The 738th Battalion (part of Third Army) used 13 at Remagen in 3/45. Around the same time the 748th Battalion is also supposed to have used some. Some 60 with trained crews were sent back to the USA in spring 1945 for use elsewhere.

 

Despite the lack of use in Europe the US Tenth Army on Okinawa requested 18-20 and some were shipped from the USA arriving on Okinawa in late June 1945, too late to see combat, just like the M26 Pershing.

 

Hunnicutt refers to the later US developments based on the Sherman including a single vehicle that mounted a 76mm gun alongside the searchlight on an M4A1 chassis. Development ended with the end of the war.

 

What I was surprised to learn is that the concept didn't end there. As late as 1950 and the outbreak of the Korean War the CDL concept was revisited. This time around development led nowhere as the cost of equipping a single tank battalion with such vehicles was the equivalent of 4 18" searchlight equipped battalions.

 

What I do find surprising in David Fletcher's video is the comment that the whole CDL project seems to have been almost too secret for enough commanders to be able to build them into their plans. This seems at odds with so much time being devoted to their development and the training of so many units in their use over a 3 year period. Also they weren't being hidden. Photos exist of them sitting alongside other armoured units in broad daylight in Normandy uncamouflaged. In addition word had clearly filtered half way around the world to Okinawa about their existence and potential benefits. So the mystery must continue.

[John Tapsell]

A few thoughts on your notes Ewen,

 

11 RTR was the first unit to be trained (at Lowther) and was then shipped out to Egypt. 42 RTR then joined them and was also trained. Three of the other four Regts were definitely trained at Lowther but there is some suggestion that 43 RTR was trained in Suffolk (but I don't see that as logical given that the entire school infrastructure was still at Lowther).

 

British production totalled 537(?) turrets - that included the 100 Churchill turrets. There were plans to order more of the heavier turrets but by this time I think they were already looking at the M3 family as a better alternative.

 

Sufficient Grants were converted in Egypt to equip both Regts stationed out there (42 RTR got priority whilst 11 RTR had to soldier on with Matildas until they had received enough Grants). Matters came to a head when the 11 RTR Battalion Technical Officer eventually declared the whole Matilda CDL fleet in Egypt as 'unfit' due to most of them having damaged transmissions and no suitable spare parts. In the UK, Grants were sourced from ex-Canadian stocks but also through additional orders from the USA.

 

Yes - American CDLs were a mix of cast and riveted hull types (photos exist of the riveted hull type). The turrets were identical except for the fitting of a .30 cal mg in place of the Besa used in the British turret - I say 'identical' but I suspect there were subtle differences in the manufacturing standards and tolerances. Whatever the official American designation for them was, contemporary American documents refer to the tanks almost exclusively as CDLs (both in official correspondence and After Action Reports - the US equivalent of the British regimental War Diary).

 

Many senior officers were fully aware of the CDL - some of them like Gen Hobart had been party to the pre-war development programme in the mid/late 1930s (the concept was originally proposed during WWI). Winston Churchill had been kept equally up to speed with the pre-war work, even when he was officially out of the government. Demonstrations were regularly held at Lowther Castle for visitors during WWII - everyone from Churchill, to Eisenhower and King George VI as well as more junior operational commanders.

 

For me, the real reason they remained unused for their intended purpose was logistics and the need to save them for a major operation where their impact would be greatest. It was never the 'right' operation and the pace of the war was so fast that there was never enough time to train the troops who would operate with them before an operation - how do you find time to take whole brigades out of the line, spend 3-4 weeks training them in the nuances of operating with a new weapon (in secret) and then get everything in place for a major offensive? This was not helped by an agreement between British and American leaders not to introduce the CDL into combat separately - it had to be a joint offensive to ensure maximum effectiveness on a large scale. Similarly, the decision to abandon the concept in 1944 and re-equip the trained units for other duties was also a joint decision.

 

The use of CDLs along the Rhine in March 1945 was to fulfil an entirely different tactical role and was a short term requirement (eventually performed by searchlight and artillery units).

 

The tactical use of the CDL on the battlefield was complex and it was appreciated that conditions needed to be ideal for them to make a real difference - smoke, fog and dust for example negated much of their effectiveness. It was also appreciated that as soon as they were introduced onto the battlefield, the Germans would very quickly find a counter to them - indeed, some of the experimentation at Lowther was to determine just what those countermeasures might be. Thus, even in training, the limitations of the concept were appreciated. They weren't exactly a 'one shot' deal but their tactical effectiveness would reduce steadily in subsequent battles.

 

Regards,

John

 

 

[EwenS]

John

Thankyou for the additional comments. 

I’m on the iPad just now so find it difficult to post links to additional information. I have more info about 43 RTR movements for you which i’ll Post tomorrow when I get a moment.

 

i’ve never Seen the figure of 537 before. Can I ask for your source so that I can update my records.

 

Regards

Ewen

[EwenS]

John

If you follow the link then you will find a movement history for 43 RTR. http://ww2talk.com/index.php?threads/43rd-royal-tank-regiment.46087/

 

The bit relevant to the CDLs is as follows-

 

35th Tank Brigade – 13 July 1944 to 30 May 1945
The battalion joined the 35th Tank Brigade when this formation moved to Eastern Command on July 13th, 1944. ...........................
On February 1st, 1945, the battalion prepared to reorganise as a CDL (Canal Defence Light) unit for South East Asia Command. Individual troop training would take place in March 1945, ‘C’ Squadron would convert in April, ‘A’ Squadron in May and ‘B’ Squadron in June. ‘C’ Squadron left for CDL School at Penrith on February 20th and collected 20 tanks. ‘A’ collected its 20 tanks and moved to CDL School on February 24th. In early March 1945, the squadrons returned and did stints at the Tichwell Ranges. ‘A’ and ‘B’ Squadrons moved to High Ash Camp to train on March 12th and 13th. Training at Tichwell, Penrith, and High Ash continued during April 1945. On April 19th, the entire battalion moved into High Ash Camp and continued to train.

North-West District – 30 May 1945 to 10 July 1945
The 43rd RTR moved to Lowther Camp, Penrith on June 1st. It was ordered to mobilise on June 2nd, 1945. The battalion continued to train and mobilise during the rest of June. By June 30th, thirty-four tanks had arrived at the port of departure and were loaded on ship by July 4th. On July 9th, the troops left by train for Avonmouth and sailed from the port on July 10th.

War Office Control – 10 July 1945 to 2 August 1945
The battalion was at sea and arrived at Bombay, India on August 2nd, 1945.

172nd Line of Communications Sub-Area – 2 August 1945 to 31 August 1945
On arrival in Bombay on August 2nd, the battalion moved to Kalyan Transit Camp. It left there on August 5th for Secunderabad. It arrived there on August 7th and moved into Mahidpore Lines, Bolarum. On the 10th, additional personnel that arrived were accommodated at Haigh Lines. Training began on August 14th. Equipment began to arrive at the end of the month with 14 Grant CDLs and 8 Shermans on the 28th, 8 Grant CDLs and 6 Shermans on the 31st, 9 Grant CDLs and 5 Sherman ARVs on the 9th, and 5 Grant CDLs on the 6th. The regiment was now organised with HQ, ‘A’, ‘B’, ‘C’, and ‘D’ Squadrons.

 

So as you will see 43RTR trained on CDLs in both Lowther and Suffolk between 1/2/45 and 10/7/45.

 

I hope this helps fill a some gaps for you

Regards

Ewen

[John Tapsell]

Hi Ewen,

 

Thanks for the additional information. I studied a hard copy of the 43 RTR diary some years ago and made notes so I'll have to dig them out.

 

I think you need to be a bit careful with the phrasing of the notes you shared. It states that the Squadrons returned to the ranges at Tichwell at various points - it doesn't state that they took their tanks with them. Based on the war diaries of other CDL regiments, it was common for the personnel to be sent elsewhere for gunnery practice - sometimes taking their ordinary gun tanks with them (all the crews would take turns in the limited number of tanks for their gunnery practice). Units were regularly sent to Linney Head for gunnery practice for example (the Castlemartin ranges as they are known today). With the M3, it is feasible that some M3 gun tanks were available (they appear to have been used for driver/operator training -'operator' in this context being radio operator). There is evidence that a small number of tanks made a long road march from Lowther to Suffolk in 1945 and later returned the same way (a three day journey with overnight stops) but whether these were CDLs or standard tanks is unclear.

 

You asked about the figure of 537. Having checked my notes tonight it should read 567. In September 1942, this was the stated requirement to equip two 'Home' (UK) Brigades and one Middle East Brigade, along with a 50% War Reserve (126 per brigade = 378 + 189 reserves). My guess would be that the second 'home' brigade (never formed) would have been fully equipped with Churchills (126 + 63 reserves gets pretty close to 200).

 

In terms of numbers

 

300 Type A turrets

100 Type B turrets (63 upgraded in 1943/44 to a Type D equivalent standard)

200 Type C (naval) turrets

289 Type D turrets (actually rebuilt Type A rather than new - although 53 turrets were 're-cast' as part of this programme)

5 Type G turrets (never seen anything else about these but they must be late-war experiemental or test items)

 

Regards,

John

[Kingsman]

Thanks again for the continuing revelations, gents.  I had fully expected this question to come up empty.

[EwenS]

John

Thanks for your additional comments. You make a good point about the units moving about with or without the CDLs.

 

Looking at your numbers though, you note the 567 as an estimated Sept 1942 "requirement" not an order or production. When I've looked at other items of equipment, requirements were stated and orders placed only for them to be changed and/or cancelled, sometimes before production had even become. So I've found that there are sometimes big differences between what is originally proposed and what finally gets produced. Another factor to bear in mind is that the shape of an armoured brigade changed between 1942 and 1944 with an effect on the actual number of tanks that would be needed, depending on how this might have affected the CDL brigades. I suspect that we might never know just how many CDL turrets of each type were actually produced let alone found their way onto tanks, at least so far as the UK is concerned.

 

What does seen certain is the June 1944 figure of 162 CDLs in 1 Army Tank Brigade.

 

http://www.niehorster.org/017_britain/44-06-06_Neptune/Land/z_tanks_44-06-22_21AG.html

[EwenS]

While looking for data on DD Shermans in India in 1945 with the 25th Dragoons. I came across some very poor quality photos which also include Grant CDLs from 43 RTR. These were taken around July 1946.

 

http://ww2talk.com/index.php?attachments/journal-page-05-jpg.205428/

 

 

[John Tapsell]

Hi Ewen,

 

I'm basing my data on primary sources that I have studied over the past six years, rather than secondary sources. I don't disagree that there is often a difference between 'orders' and 'output' but I'm fairly confident that my figures are as accurate as they can be because I've cross-checked them across several official sources.

In terms of the 300 Type A turrets, it is possible to trace their production from ordering to delivery, including manufacturers, delivery dates and the production problems encountered. With regard to the Type D, there is extensive correspondence available that makes it possible to follow the production schedule (planned and actual) in the re-work programme in 1943-44 for example. Similarly, I can trace the production figures for the Type B (Churchill) turret and the number of those turrets reworked in 1943/44 - as well as references for the 200 naval CDL turrets.

 

You are correct that the CDL regiment structure changed during the war but it never followed the standard armoured regiment structure (CDL Troops had more vehicles) - the War Establishment (WE) of a Grant-equipped CDL regt required more CDLs and more gun tanks than a Matilda-equipped CDL regt (the size of each Troop was further increased when the Grant was introduced). 

 

In terms of 1 Tank Brigade having 162 CDLs in June 1944, that may be correct for June but contemporary records suggest that 200 British M3 CDLs were stored at Carpiquet airfield near Caen (arriving early August 1944) and susbsequently returned to Lowther in October 1944. That would include the full WE for at least two regts, plus a war reserve.

 

My apologies for being slightly cagey with the detail I'm providing. I'm about 50% of the way through putting together a possible book on the history of the CDL programme and I don't want to give too much away at this stage. There is extensive technical and historical information on the subject which I'm in the process of translating into a coherent narrative. The story spans some 30 years from it's origins during WWI through to the late 1940s.

 

Regards,

John

[EwenS]

John 

no need to apologise, I now understand your reasons and look forward to your book being published. It is  these little known areas of ww2 history that intrigue me.

[SleeperService]

I've known John for many years and his research work is meticulous. I truly hope that he gets his book finished and published as it will clear up many of the myths and half truths about these enigmatic vehicles.