World War II light ack-ack

Discussion in 'Military History and Militaria' started by baboon6, Mar 6, 2012.

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  1. I had never seen or heard of this triple Oerlikon mounting on a Crusader chassis:

    British Forces - Crusader AA - Oerlikon

    So this was used (in small numbers) by RA LAA regiments in 1944/45, who otherwise mainly had towed and portee 40mm Bofors guns? While armoured regts were meant to have a troop of Crusaders with a twin 20mm turret like this:

    Crusader AA History - More Features

    The 6th SA Armoured Div's support battalion, the Royal Durban Light Infantry, had a coy armed with 20mm AA guns, which was soon converted to an additional Vickers MMG coy. Any idea what type they might have been? A quick Google search shows a bewildering variety of types (Oerlikon, Polsten, Hispano-Suiza) and mounts (from single to quadruple).
  2. Its complicated. I don't know the full answer, but am currently researching this. The people I would have asked are dead.

    The brits brought iinto the 20mm AA guns quote late in the war. The Germans had a range of AA Guns from 20mm 37mm and then 88mm. The Brits used the 40mm bofors as their sole LAA gun.(1) (There was an acute shortage of ANMY LAA for the first two years of the War. From memory, the decision to deploy 20mm LAA was triggered by the difficulty of engaging low level fighter bombers whoich offered AA only a very short engagement time. Initlaly this was a single Polsten 20mm gun, but, as the Gemans discovered, the rate of fire wasntl enough, so they went for a multiple mount - as the Germans did with the 20mm Flak Vierling.

    Thje crusader Mk II AA had a twin 20mm cannon mount. This is the version that equipped the AA Troops in armoured Regiments in 1944.

    The triple mount was originally produced as a towed equipment. This had reliability problems. It had some kind of electircal system, which was temremental and not good itf wet. There were lots of complaints from the unit given this kit before D day. The triple mount on the Crusader was seen as more reliable anmd 93 LAA were issued with this before D day. Lots of familiar exchanges with soldiers saying the kit is inherently useless (see great rbitish procurement mysteries) Manufacturers and RSA saying its not that bad. 93 AA deploy with it.

    The 6th SA Div may have had te 2 x 20mm crusaders OR it may have been some local lash up.

  3. Thanks. RDLI was as I said the divisional support battalion so I suspect they used a towed type of 20mm mount.
  4. It is a fiendishly complicated subject as to who got what. I've seen a painting, by a Dutch officer, of some sort of SP triple 20mm (possibly on a truck, as the thing's under a camo net) somewhere in the Orne Bridgehead.

    Thus far, I've never found anything other than the twin-20mm type (Mk II/III) in the AA Troops of Armoured Regiments. They would normally have been issued six of these, but hardly any turned up in the Med. In NW Europe the Armoured RHQ AA Troops were disbanded were disbanded in Normandy to provide replacements, but quite a few regiments kept one or two Crusader AAs on-strength as part of the RHQ Troop. The disbanded Crusader AAs ended up as OP tanks, command vehicles for SP AT or as 17pdr Tractors (some being used as they were, simply with a tow hook added, while some were fully converted to the open-topped Crusader Tractor, which was like a mega-Bren Carrier).

    As for the 40mm and multiple-20mm AA tanks, all the ones I've seen belonged to Corps or higher LAA Regts. A load of them came ashore on D-Day marked up as Line-of-Communications Troops and there's a good photo of one driving through Creully marked up for I Corps.
  5. The problem with the towed triple 20mm was that its electrical power system was innacurate (The file notes in the pre D Day RA 2 Army dscribe it as NBG)

    Some of the LAA are retrained during the battle - 27 LAA are ordered to take over 8 x Centaur 95mm as specialist Counter mortar troops and the LAA command system is used to create a counter mortar operation.

    What is the evidence that Crusaders were used as OP vehicles? As far as I know OPs had thesame tank as per the armoured unist they were attached to.
  6. just thought i would throw this into the mix
  7. That looks like the triple Polsten/oerlikon mount on the Morris SP Bofors chassis. Where was the picture taken? Routledge's book on AA guns says that 93 LAA were entriely equipped with SP triple Polsten. This looks like a mount which fits that desctiption.
  8. That's a very good question and to be honest, I don't know. It's trotted out in a number of books, but I've never seen any evidence for Crusader AAs being used as OP tanks or 17pdr tractors in their unmodified form.

    OP tanks could sometimes be of a different type - remember that command tanks for SP AT were also designated as 'OP Tanks'. 'Unarmed Crusader IIIs' were definitely used as OP Tanks for some M10 SP AT units in NW Europe (21 & 84 AT Regts being two), but were these simply Crusader IIIs with dummy guns or were they Crusader III Tractors? Nobody seems to know.

    Stuarts (probably 'jalopied') were also used as OP Tanks for M10 units and were also used (by the Canadians for sure) as command/OP vehicles for some towed 17pdr Troops.

    Some Field Artillery Regiments also used a mixture of OP tanks - for example, 7th Armoured Division (4 RHA?) used unarmed Sherman V OPs as battery commanders' mounts, while the Troop Commander-FOOs had armed Cromwells. Guards Armoured Division and some Canadian regiments also used a mix of unarmed Ram Cruisers and Shermans.

    Re 27 LAA; That's interesting. Are they the unit that became 'X' Bty RA (under command of I Corps) and then changed again to 1st Canadian Composite (Centaur) Battery?
  9. A look at the War diary for 15 LAA (7 Armd Div) provides some supporting evidence. On 6-7 July they receive 7 x Crusader AA tanks to be served by W 20mm troop of 41 Bty. (That looks like an AA Troop from an Armoured Regiment less one u/s )

    The WD for 65 Atk Regt (also 7 Armd Div) says 7 July received 4 x Crusader as OP vehicles for BC and 3 x TpComd, but by the 13th they receive Cromwell in place of the crusaders which were "withdrawn". I can see why the ATk BCs and Tp Comd didn't have a fighting vehicle in ATk regts. One Tp Comd wins an MC for leading his guns on foot to engage the Germans threatening Bayeux on 9th June. He had to hang on the outside of the M10.

    On 31 July 15 LAA war diary recounts 45 men setn to 65 Atk to replace casualties and on the 9th Aug they hand over their Cruisader AA tanks to 65 Atk - presumably as gun tractors.

    The big problem with the Crusaders is that they are in to use a 1944 TLA they were NBG. Like the Cromwell they were powered by classic engines originally designed for aircraft. Except that while the 500hp Meteor in the Cromwell was derived from the contemporary Merlin, the Crusader's 350hp Liberty 12 was designed in 1917 and powered the aircraft of the Great War. It also had exposed rockers etc which collected dust and weak spots in cooling and oil systems which regularly failed in locations that could only be solved with a pack lift. I suspect the Crusader is one reason the gunners preferred wheeled tractors post war.
  10. The WE for an M10 battery dated July 1943 calls for Universal carriers for this role but I suppose lots of WEs were modified. I have definitely read about turretless Stuarts being used for this role, besides their typical use in recce troops of armoured regts.

    Another use I have read about but have not been able to confirm is as platoon commander and company commander vehicles in Imperial Light Horse/Kimberley Regt, who were 6th SA Armoured Div's motor battalion. Have not heard of any other motor battalions using Stuarts like this.

    WE simply says "Tank Observation Post" which leaves it wide open.
  11. You chaps seem to be extremely well informed on all things AA.

    Could any of you inform me of where I could get information relating to AA batterys that would have been stationed around the East End of London during the war.

    My Grandmother operated a search light and latterly some form of AA gun which I believe was located on Wanstead Flats, not far from the the London Docklands (Royal Albert Dock etc).

    I believe in the lead up to D-Day, Wanstead Flats was used as a harbour area with tens of thousands of troops under canvas, and the AA units were on a high state of alert to protect them.

    I also found a photo online of one of the guns on the flats, and it appears to be something quit substantial. Fig 10 of the enclosed link:
    The Second World War in the Park

    It would be nice to find out a bit more about what she may have done.

    Thanks in advance.
  12. That's fatastic information. I've not come across 20mm Crusader AAs being handed to LAA Regts before and that's the first direct evidence I've ever seen regarding re-assignment of Crusader AAs. It's also the first time I've heard of Cromwells being used in AT Regts!
  13. There was a Canadian unit in Italy that used Stuart 'Jalopies' to carry infantry in a coup de main attack to secure river crossings, but I can't for the life of me remember exactly who, where or when.

  14. Reading the history of the South Albertas, they seemed to be quite taken with their Crusader AA tanks, and their CO regularly dispatched them on 'other' missions, including as extra recce patrols to support the Stuarts.

    They were effective on a number of occasions in the direct-fire role, notably during the major battle at St. Lambert-sur-Dives, during which their automatic firepower was very welcome when C Sqn looked like they might be over-run by German infantry. On another occasion, the CO had them dispatched as armoured supply wagons (carrying sores on their back decks) to support the squadrons pinned own in heavy fighting.
  15. Thanks for the flattery, but AA is one of the dustier corners of the RA cupboard. Even Nigel (?) Evans who has an excellent site on the field artillery has yet to trad this ground. I am struggling to understand exactly which batteries formed which regiments and what they were armed with for Normandy, one of the most significant campaigns.

    40% of the Army were gunners, mostly AA Command. After the war AA command shrunk with the threat and the RA. Its not the sexy bit of the RA. There are no RHA gunners and there are fewer medals to be won spending the war on Wanstead flats. However, AA Command did their bit in the battle of Britain , the various blitzes and in the war against the V weapons.

    They became rather good at shooting down German aircraft. It took 10,000 rounds for each bomber shot down in the blitz - but only 300 for each V1.

    There is an official History of Anti Aircraft in the Blue Book series. A History of the Royal Regiment of Artillery: Anti-aircraft Artillery, 1914-55: N.W. Routledge: Books It doesn't go into the detail but it does say that before D Day there were 212 heavy aa guns protecting London docks and Tilbury and that the total strength of AA Command was 177k men and 77k women, a quarter of a million AA gunners. That figure had reduced from over 300k earlier in the war.

    Wanstead was battery ZE 9 in the Inner Artillry Zone in London. There is a comprehensive book about the AA sites in England published by English Heritage called "AA Command which lists the grid reference of every AA site and the strength in guns at different parts of the war. It doesn't do the human side as well.

    The picture of the guns on Wanstead Flats may make it easier as these look like the single barreled mount for these beasts.
    [​IMG] The author of the article in your link is mistaken to claim that these were the target of bombers, but it is correct that the firing of these types of giuns caused all sorts of problem. This pair were sited on the top of Primrose hill. They fired once in action and broke every pane of glass within a mile.
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