40 mm Bofors AA guns made in GB and US

[Tony Smith]

Never heard the name Kerrison before.

[Tony Smith]

..is marked "Predictor, AA, No.3, Mk1". Is Kerrison the Patent holder's name or the first manufacturer's name? Does it only apply to US built versions?

[Stellan Bojerud (RIP)]

Yes Sir, I can boogie, boogie-woogie all night long after seeing those marvelous pictures.

It is surely a GB made Kerrison Predictor. I think the US never made them but bought them from GB.

Instead the S.C.R 584 Automatic Gunlaying Radar was developed in USA. When Hitler started dropping not only V 1 but V 2 on London General Marschall sent 165 of these and 20 US AA Btys to GB.

Colonel Kerrison (RA) is credited as inventor of this mechanical computer.

I am sure that some of our British friends could deciphre the factory M & P. Ltd.

Thank You Tony! Your pictures have helped me a lot in my research.

Here You can see how it was deployed. The Kerrison Predictor to the right behind the gun. The sight operator standing on the gun platform. The gunlayers hadn´t to calculate speed and course but only keep the target in the middle of the "spider-web" sights. US gun North Africa 1943. (US Sight Computing M7 or M7A).

[Stellan Bojerud (RIP)]

Tony,

Is the searchlight on the picture 90 cm (35,5 inch). Reflector in glass or metal? Hand or remote control?

[Tony Smith]

The searchlight is an 18 inch model made by the General Arc Light Co, Long Island and is powered by an Onan 2 cyl 40 volt, 50 amp (2Kva) generator. The reflector is polished aluminium. Rotation and elevation is hand controlled, but carbon rod feed to maintain the Arc is automatic

[Tony Smith]

John, that is sad news regarding Stellan.

We communicated by email regarding Australian/Commonwealth Bofors guns and AA equipment, a conversation from which I'm sure we both benefitted from and enjoyed.

In post #59, Stellan was interested in this Carbon Arc searchlight:

Originally Posted by Tony Smith

The searchlight is an 18 inch model made by the General Arc Light Co, Long Island and is powered by an Onan 2 cyl 40 volt, 50 amp (2Kva) generator. The reflector is polished aluminium. Rotation and elevation is hand controlled, but carbon rod feed to maintain the Arc is automatic

This is a small light by AA standards, but quite effective. It was recently illuminated from a lookout over town for the 100th Anniversary of Armistice Day in November. The photos below were taken from the town below the lookout, over 4Km away!

While it was lit to commemorate Armistice Day, the next opportunity we will salute Stellan too!

[Stellan Bojerud (RIP)]

Thank You Tony. Never saw such a Searchlight before.

Here is an interesting piece. The gun carriage is MK I. The gun could also be an updated MK I (1937 type).

Anyhow the 1944 type "Stiffkey-Stick" sights and the shields have been added later.

To the left a S.C.R. 584 Automatic Gunlaying Radar - one of the 165 supplied to GB from USA in 1944 to counter the German V-missiles attack.

During June - September 1944 the AA was able to shoot down approx 1.550 V-missiles = 65%. The record was 68 shot down on one single day.

[Tony Smith]

Stellan, from your pictures I see that the predictor seems to be missing a pair of sighting scopes - Something more to track down!
Mike, you wouldn't happen to have a British/ Canadian handbook relating to predictors, would you? This thing is fairly complicated inside (think Swiss watch) and I suspect some bits might be absent. I'd like to know a bit more on the technical side.

Originally posted by Stellan Bojerud
Here a 40 mm Bofors on MK II carriage training before D-Day.

I think someone could identify the unit by blue-red sign with white 73.

I have just taken a print down the road to Dave and Rory Ballard, they are far better at this stuff than I.

The sign that we can see, if it is red top half and blue bottom, is the 15th (IOM) Light AA Rgt and it seems something like the 73 is repeated again on the gun axle. It was customary to have the the sign is combined with the "usual" desert rat as Dave's truck has. It may be the rat is depicted separately on that lower right sign or this may perhaps be the 20 mph speed plate. From another thread, this alludes to convoy speeds, with the crew on the gun I doubt if you'd want or be allowed to exceed 10 mph.

There is another insignia in the centre panel which we cannot clearly see but believe this to be battery number sign.

The truck is a CMP but difficult to tell if its a 12 or 13 cab, the side light is prominent and the mirror somewhat higher than expected; it is a GS not a LAAT owing to the metal tail-gate whereas the LAA tractors have a canvas arrangement and a proper seat placed centrally facing rearwards for the gun brakeman; this duty being performed here by the soldier in the middle probably crouching or kneeling, perhaps even on a makeshift seat like an ammo box.

The Crusader on the left is interesting, the white cross denotes it is acting as an enemy tank and parked as it is, probably KO'd for the exercise.

R.

[Stellan Bojerud (RIP)]

Yes,

You are right. My copy is slightly better and the round sign on the truck is the 20 mph speed plate.

The Tank with white cross belongs to "Eastland" (= German)Forces opposing "Northland" (=Allies).

The place should be Whittlesbury, Northlants.

Stellan

[Stellan Bojerud (RIP)]

1. The Kerrison Predictor owned by Tony Smith was made by
M & P. Ltd. - sounds as a British factory. But wich? To make this sofisticated mechanical computer a highly specialized factory is needed.

2. By coincidense I met an old friend in my favourite pub yesterday. He is an ex-RAF Officer. He told me that his father had been involved in making Bofors guns during WW 2. The factory was:

A.Reyrolle & Co. Ltd. Hebburn - on - Tyne, County Durham.

3. I have found out a few things regarding Otis-guns in Canada. The factory was ready 1st March 1941. The first gun test fired 10th Nov 1941. By Mrs 1943 the production rate in Hamilton (Ont) was 350 guns/month. Totally approx 5.000 guns made.

But - - - the number series shows that more than 20.000 guns were made 1942 - 43. So there must have been more factories involved.

Did Otis Fensome operate a gun factory in Vancouver? Did Dominion Bridge in Vancouver make Bofors guns?

I would be very thankful for help solving these questions.

Stellan

Picture: The very first Bofors gun prototype 1932.

[Stellan Bojerud (RIP)]

O.K. I got it confirmed.

Bofors guns were made by Ordnance Factory Maribyrnong. In Australian War Memorial (AWM) there is a photo dated 12 Oct 1942 showing a Bofors gun beeing assembled. The carriage is marked "13" which seems to be the factorys internal working number.

Another photo show an Australian-made Bofors on display in Melbourne 14 Apr 1943 for rizing funds for 3rd Liberty Loan.

AWM photos nr 127871 - 127875 show a 3-ton 40 mm Bofors SP (Australian) gun. But which type of truck?

Stellan

[Hanno Spoelstra]

Originally posted by Stellan Bojerud
AWM photos nr 127871 - 127875 show a 3-ton 40 mm Bofors SP (Australian) gun. But which type of truck?

Canadian Military Pattern Chevrolet C60L 3-ton 4x4.

[Tony Smith]

also on a CMP Ford F60L 4x4.

[Stellan Bojerud (RIP)]

Thank You Hanno and thank You Tony for these pictures. How do You get them from AWM? I havn´t been able to find that out yet.

Bofors 40 mm SP trucks/carriages so far found:

1. Chevrolet C 60L
2. Ford F60L
3. Ford F60S
4. Morris C 9/B

Kerrison Predictor

What I wrote earlier was not right. USA took up production. In (Aug?) 1940 Sperry got the job but did not have capacity enough. Instead Singer Corporation got the contract in Dec 1940 for 1.500 pieces pro month.

Production started in Jan 1943. The US called it Director Antiaircraft M 5 and it came into service mid 1944.

Picture: French Bofors (US M 1 on carriage M 2) with Kerrison Predictor (right). Note mixed US and French "Casque Adrien" helmets on guncrew. Italy 1943.

[Gunner]

Hanno: Your photo is very interesting.

Analysing some of the details: the truck is earlier production with the fender mounted coolant expansion tank (as you know, later production it was tucked up under the fender where it was better protected from brush; the cab is a 13 not a 43 so there must be seating for the detachment (in the Commonwealth guns have 'detachments' not 'crews', but even many Gunners don't know the distinction) out of sight of the camera; the gun doesn't appear to have any sights fitted but it could be that they are in a protective case in one of the lockers.

Tony's truck is really interesting too, as it appears to owe much to the German designs with fold down sides and lockers accessible from the top.

The profusion of CMP variants nevers fails to amaze me!

Cheers, Mike

[Stellan Bojerud (RIP)]

I have come across information that 40 mm Bofors guns were also made by Waygood Otis Ltd in GB.

Where was this Factory located?

I also learnt that Otis Fensom Elevator did not have a factory in Vancouver. But the question about Dominion Bridge does so far have no answer.

Re Tony´s picture. It was SOP to remove the sights from the gun before travelling.

[David_Hayward (RIP)]

Above: The new photograph I have added shows a different scene in the same street

The above shots of Ford Model C39Q F60B Bofors trucks dates from 1943...Canadian made guns? Note the original arrangement when built/assembled in England with Willys MBT [?] trailers and 'H' prefixed trucks as tractor. However in 1944 this had changed and David's photo above shows I believe the rebuilt version to 'SPM 40 mm' which carried 'S' prefixes, having lost their trailers. All British orders were to S/M 2645 by the way.

R Waygood & Sons Limited were in Falmouth Road, Newington, London SE1, manufacturers of elevators and cliff railways etc. In 1916 they were taken over by Otis of the US to become Waygood-Otis Limited. They had branch offices in Manchester, Newcastle, and Australia..... My dad's company used to make components for Waygood-Otis and I rang him to confirm if he knew anything about them but sadly did not know anything about them during the war. Waygood-Otis later became Otis Elevator.

If anyone can identify where the 40 mm Ford versions were manufactured please, this would be of great interest.

Oh! The MCC truck looks as though it was a rebuild by Morris Commercial Cars Limited in late 1943, about the time that MCC rebuilt C/8P Predictors, AT Portees and Gun Tractors to 17-pounder tractors.

[Hanno Spoelstra]

Originally posted by David_Hayward


Note the original arrangement when built/assembled in England with Willys MBT [?] trailers and 'H' prefixed trucks as tractor.

It is not a Willys MBT, as that is a ¼-ton 2 wheel GS trailer more commonly know as "jeep trailer". These were also built by Bantam (known as T3) and a wealth of other manufacturers, both during and after WW2.

The F60B in the top picture is towing a 1-ton 2 wheel GS trailer, popularly know as the "Ben Hur" trailer after the Ben Hur Mfg Co. They were also built by American Trailer, Bantam, Checker Cab Mfg Co and various other manufacturers - apparently Willys as well (ref. Richard's note).

If anyone can identify where the 40 mm Ford versions were manufactured please, this would be of great interest.

The Ford F60B was built in Canada. The other versions shown in this thread were Australian-built, and although built along a similar concept, they differed in large and small details. One main difference was the use of the so-called No.43 cab, which incidentally is not the same as an open No.13 cab. As you can see it is much wider to seat the gun crew and it only shares the cowl portion with the No.13 cab. I reiterate this as I have seen you mentioning No.43 cabs in other threads on portees and the like.

HTH,
Hanno

[Hanno Spoelstra]

Originally Posted by Hanno Spoelstra

The F60B in the top picture is towing a 1-ton 2 wheel GS trailer, popularly know as the "Ben Hur" trailer after the Ben Hur Mfg Co. They were also built by American Trailer, Bantam, Checker Cab Mfg Co and various other manufacturers - apparently Willys as well (ref. Richard's note).

This question came up on another forum, so also sharing info from David Hayward's book on Pearson's of Liverpool here.

IMG_4692_cropped.jpg F60B.JPG

This text is not entirely correct: 1-ton trailers were not used with Jeeps, nor was the "F60B converted to SP units and the trailers re-allocated for further use" - the F60B was a SP unit from the onset.

IMG_4693.jpg

[Stellan Bojerud (RIP)]

Thank You Hanno!

Another piece in the puzzle. The "Ben Hur" truck was used for transporting the No 3 Kerrison Predictor (see earlier posts) equipment.

(No 1 Predictor was Vickers-Armstrong used for 3"7 AA guns. No 2 - I beleive - was US Sperry imported to GB from 1938).

Stellan

[David_Hayward (RIP)]

Hanno, thanks for the input. The trailers were apparently to contract S/M 6288 'Trailer 1 ton 2wh G/S' with one batch 'G/S and/or Gen.'.

There was supposedly a Number or Type 41 Cab, which was the open version of the 11, though I have never seen one. The 42 was the equivalent of the 12, as fitted to say the Chevrolet 2-pounder Portees to S/M 2029, although these were modified as you know when some were rebuilt to 17-pounder tractors. The 43 was the open version of the 13 as fitted to say the 6-pounder C60L tractors, again rebuilt about a year later to G/S trucks with a modified 43 Cab. Then there was the 'open' version of the 13, although this is not a correct description as it was the 13 Cab with a soft canvas top of course. The final open cab as you say was the Type or Number 43S which was a hard, open, wider, cab with little relationship to the 43 it seems unless the windscreen had common parts!! Also, no doors, and no provision for any. So, there were indeed two distinct types, 43 and 43S as you rightly suggested, plus the 13 Cab with the canvas roof as fitted to say the F60H Wreckers for the Indian Army in N Africa.

[Stellan Bojerud (RIP)]

Thank You for those interesting photos David!

If I understand it right, the portees F60 B were made in Canada. If the guns were also made in Canada it seems likely that they could be delivered complete to the forces.

So finding the trucks at Waywood-Otis in London indicates that the guns were fitted there. Probably also produced there.

After WW 2 a number of Ford F60B Bofors SP were used by the Danish Army (Danish Army Vehicles Hompage).

Stellan

[David_Hayward (RIP)]

Stellan, the trucks were assembled by Pearsons of Liverpool. I have been considering whether because of the importance of such weaponry manufacture that Waygood-Otis used their branch offices in Newcastle and Manchester rather than London, although for instance Delco-Remy & Hyatt Limited, GM subsidiary that produced wiring looms for tanks etc. only moved part of their production to 'safe' Dunstable in Bedfordshire and retained production at their London factory near Victoria station on the north bank of the River Thames throughout the war.

Do I take it that the Predictors mentioned were in the G/S trailers, and that in due course these were no longer required and so the F60B trucks reverted to SP units?

[Stellan Bojerud (RIP)]

Originally posted by David_Hayward
Do I take it that the Predictors mentioned were in the G/S trailers, and that in due course these were no longer required and so the F60B trucks reverted to SP units?

The Bofors guns could in an emergency be fired from the truck platform without stabilization and aiming with open "spider-web" sights even when driving at a moderate speed.

Normally however the truck halted, the outriggers and jacks were folded out and the truck-gun platform was secured to the ground. So the truck type SP Bofors was not a fighting vehicle but only a means of transportation.

Then the Predictor was offloaded from the G/S trailer and put up on a tripod mount. Thereafter the electrical cables were attached between the Predictor and the gun platform.

[David_Hayward (RIP)]

Stellan, what then happened in early 1944 then please, as the Tractors became Self-propelled units with no trailers? I can imagine that new US equipment came on line. However are these Canadian guns can anyone say please from the photos? If they were British-built then Pearsons added the guns to the bare chassis on assembly and then coupled up the US-built trailers. The IWM has an official shot of a H-prefixed tractor. I have photos as I mentioned before of tractors and rebuilds.

Thanks!

[Stellan Bojerud (RIP)]

What happened was that the firing units had two trucks.

One with a 40 mm gun. Driver + 3 detachment (crew) + 120 rounds.

Another truck with the Kerrison Predictor. Driver + 2 men + 192 rounds.

The gun truck could fire with "open sights". (Gunlayer right = traverse, gunlayer left = elevation plus trigger with foot pedal).

To use the Predictor both trucks had to stop and an electric cable attached between them.

The British MK III Bofors and the Canadian MK 1 C are Chinese copies and I cannot on a photo distinguish one from the other. Must read the brass plate or marks stamped into the breech.

[David_Hayward (RIP)]

Stelland..please excuse my gross ignorance here. I am trying to work around some photographs that I have of the same basic trucks from 1943 and then 1944 to caption them for my book. The IWM official photo by the way is of H 5582702, whereas the one in the top photo is H 5582746.

The 1943 photographs show as you can see F60B tractors + Willys-built 2-wheel GS trailers. Then I have an early 1944 photograph from the same company, in Liverpool as well, and this time [same truck batch] they are 'self-propelled mountings' with the same guns as before.

I am intrigued as to whether there were initially 2 sets of F60B units, one with a G/S trailer with ammo, and the other with the Predictor that connected by cable? It seems that by early 1944 as I said before the Predictors were no longer required and the Ford Bofors trucks were self-contained units. The 1944 Census states that all three batches of the British orders were 'SPM 40 mm' with 'S' prefixes. This reflects the conversion of all F60B trucks left to self-propelled units.

http://clubs.hemmings.com/clubsites/...lk/BOFORS3.jpg

ABOVE: this photograph from early 1944 shows two F60B Bofors trucks [S 5582815 leading] converted to SPM 40 mm specification, less the Willys trailers. A close inspection of the rear truck S 5582667 suggests that the driver's window pane is missing.and there is no left side wiper either.

[Stellan Bojerud (RIP)]

Originally posted by David_Hayward
The MCC truck looks as though it was a rebuild by Morris Commercial Cars Limited in late 1943, about the time that MCC rebuilt C/8P Predictors, AT Portees and Gun Tractors to 17-pounder tractors.

C/8P Predictors could be a Morris C/8 rebuilt as Predictor platform (P = Predictor?). Operated in pair with a C/8B (B = Bofors?).

On your 1943 and 1944 photos you can see the outriggers and jacks swung in under the floor (is it called so?) between the wheels.

Except in emergencies the SP trucks were allways secured to the ground with these outriggers and jacks (see attached photo of a Morris SP Bofors).

So I think that when there were enough trucks available the Predictors were put on a truck platform ready for use instead of beeing transported in crates on a trailer.

[Stellan Bojerud (RIP)]

This very bad picture is from the swamped Netherlands near the German border in spring 1945. I guess my copy is slightly better than the image reproduced here.

Outriggers and jacks are out (although difficult to see). The gun portee has a Bofors with 1944 Stiffkey-stick sight, which made the unit self-contained.

But still it was better with a Predictor. And I suggest (but have no evidence) that the second truck is a Predictor platform.