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First dual-purpose armament

Discussion in 'Ships & Shipborne Weaponry' started by Carronade, Aug 22, 2011.

  1. Carronade

    Carronade Ace Patron  

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    While many guns can engage multiple types of targets, dual-purpose guns may be defined as those specifically intended to engage both surface and air. They generally appear in lieu of separate low-angle and high-angle batteries. By these criteria I suggest that the first dual-purpose armament appeared in the British aircraft carriers Glorious and Courageous, converted from "light battle cruisers" under the Washington Treaty. These carried sixteen single 4.7"/43 caliber guns, pairs on forecastle and quarterdeck and the rest in sponsons at main deck level. These were the same guns that appeared as AA armament in Nelson and Rodney, but sixteen guns were far in excess of AA requirements as understood at the time. The placement of most of the guns was also similar to that of capital ship secondary armament.

    Anti-surface armament was considered a necessary feature of carriers at the time. Comtemporaries like Furious and Eagle had 5.5" or 6" low-angle guns plus 4" AA weapons. Foreign carriers Hosho and Bearn had both types, while USS Langley had only low-angle guns. Larger Washington conversions like Akagi and Lexington featured 8" guns with 4.7/5" AA. So it seems likely that the 4.7s on G&C were intended to fulfill the low-angle role, at least to fend off destroyers or light cruisers, in addition to AA; as far I know, the first time a battery was specified to serve both purposes.

    One oddity, the identical guns on Nelson and Rodney would not be described as DP, since those ships had a dedicated 6" low-angle secondary.
     
  2. urqh

    urqh Tea drinking surrender monkey

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    What did the Furious have then? Genuine question.
     
  3. Carronade

    Carronade Ace Patron  

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    Furious, when first converted to a carrier, had ten 5.5" low-angle guns, the same ones that formed her secondary armament in her orginal light battle cruiser configuration, and six 4" AA guns. If you consider aircraft to be her "main battery" you could call it the same combination of secondary and AA armaments found on a capital ship.

    Furious was modernized in the 1930s and her armament updated to twelve 4" in six of the new Mark XIX mounts; these also carried a new, more powerful 4" gun, Mark XVI vice Mark V. No more 5.5s. This reflected the newer understanding that a carrier's armament was primarily for air defense.
     
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  4. harolds

    harolds Member

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    Dual-purpose armament was something the naval planners in many nations didn't forsee a real need for. It was only after Taranto and Pearl Harbor did the need for such become apparent. The increased need for adequate AA defences meant that much more than a few 2cm and 3.7/4.0cm guns would be needed. The usual responce was to put on more dedicate AA guns increasing the weight of the ship beyond the designer's specifications. I don't remember any incident in WWII where a carrier used its guns on a surface adversary. The only carrier I know of that was sunk by enemy gunfire was Glorious and that was by long-range gunfire where its secondary armament would have been useless. However, air attacks on carriers were a routine event. Other surface warships had a much greater chance of having to fend off destroyers and MTBs, but for that, guns in the 5"/120mm range would have been more than adequate. Of course the big problem wasn't necessarily the guns but mounts that wouldn't let the guns elevate high enough.

    Given the above, I think that the USA had a wonderful dual-purpose weapon in the 5"/38. It threw a fairly heavy shell and had a high rate of fire. This high rate of fire was a function of crew training and most ships had a simulator that allowed the gunners to drill regularly even in port.

    In contrast, the Kriegsmarine outfitted its heavy units with 150mm secondaries which were good against attacking destroyers, but way too cumbersome for AA defence even if the mounts had let them elevate to engage aircraft. The Germans then added a few 105mm twin AA mounts that I understand had a rather slow rate of fire. The upshot was that when it was time for Operation Cerebrus (the "Channel Dash") the Germans had to put Luftwaffe AA units on board and tack-welded the guns (probably 88mm and quad-20s) to the deck in order to get adequate AA firepower.
     
  5. Takao

    Takao Ace

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    harolds,

    How could you forget Leyte Gulf, the CVEs most certainly used their dual-purpose 5-inch/38s in the low-angle role.

    If, as you say, "Dual-purpose armament was something the naval planners in many nations didn't forsee a real need for. It was only after Taranto and Pearl Harbor did the need for such become apparent.", then, why did dual-purpose armament begin appearing in the early 1930's? This is well before Taranto and Pearl Harbor. According to Navweaps.com the first true dual-purpose gun was the French 130mm/45 Model 1932 France 130 mm/45 (5.1") Model 1932 and Model 1935
    and the US 5-inch/38 was designed in 1932, and entered service in 1934
    USA 5"/38 (12.7 cm) Mark 12
    So, the benefits of such a weapon were recognized well before you claim. Still, it was more a choice between having a lesser number of two types of guns, but each better suited for their given purpose, or having more guns that might not be as capable in a given role.

    The air attacks against naval units and greatly improved aircraft, while not heralding the advent of dual-purpose weaponry, did prove that early naval AA defenses were inadequate, and that warships would need to carry many more and better AA guns then pre-war naval planners had deemed necessary for a warship's protection.
     
  6. USMCPrice

    USMCPrice Idiot at Large

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    I'd take issue with this point. The U.S. adopted the 5"/38 DP in 1934, well before Pearl Harbor (Dec 1941) or Taranto (Nov 1940). The U.S. Gridley class DD's, 1st ship launched Dec 1936 had the single enclosed base ring mount with integral shell hoist allowing for loading at all angles. So at least U.S. Naval planners were planning for dual purpose use prior to the actions you mentioned. The U.S.S. North Carolina, laid down Oct 1937, was designed from the start to have a dual purpose secondary battery of 20 5"/38's mounted in 10 twin turrets.
     
  7. 4th wilts

    4th wilts Member

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    QF 18 pounder 12cwt naval gun.cheers.
     
  8. harolds

    harolds Member

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    Boy did I fire off something without getting my facts straight! That's what I get for posting before having coffee. I didn't know the ranges at Leyte gulf were close enough for the 5 inchers.
     
  9. Takao

    Takao Ace

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    That's what you get for breaking Rule #1!

    Never ever, under any circumstances, post before having your morning cup/s of coffee.:D:D:D
     
  10. Markus Becker

    Markus Becker Member

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    One thing not mentioned so far were the 4" guns on RN sloops. From 1930 onwards the QF 4 inch Mark V was installed, an AA-gun designed in WW1 but obviously useful aginst surface tragets too. So was the American 5"/25. Technically it was a "pure" AA-gun but in exercises the gunners regularly demonstrated its effectiveness against surface targets.
     
  11. Markus Becker

    Markus Becker Member

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    By the way, you mean the QF 12 pounder 12cwt naval gun, on´t you? The only QF 18 pounder wiki and google know is the field gun that preceeded the famous 25pdr.
     
  12. Carronade

    Carronade Ace Patron  

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    No offense, harolds, but by the time of Taranto, let alone Pearl Harbor, the designs of warships big enough to have secondary armaments were already set. Even those laid down during the war were generally continuations or slight modifications of classes under construction when it began, rather than new designs which would take too long to get into service. While automatic AA weapons could be (and were) added to ships either existing or under construction, changes to installed secondary or heavy AA armament were more profound and relatively rare.

    The Germans and other navies included separate secondary and AA armaments in their capital ships from the start; for example the panzerschiffen had eight 150mm and six 88mm, later upgraded to 105mm. Again, there were few additions to heavy flak in wartime.
     
  13. 4th wilts

    4th wilts Member

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    @markus,well I'm sure I seen it yesterday.
     
  14. Takao

    Takao Ace

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    I think you reversed the numbers, and it was the 12 pounder 18cwt QF Mark I naval gun. A few were converted to AA purposes during World War I.
     
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  15. harolds

    harolds Member

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    All navies upgraded their AA armament after Taranto and PH. Looking at drawings of American ships one is struck by the increase in 20 and 40mm guns. You are correct that adding the heavier AA guns is going to require a major refit. Please notice in my original post I said "most navies" certainly not all of them. The USN was particularly forward thinking in this regard as was, perhaps to a lesser extent, the RN. I apologize for over-generalizing in that post because I was particularly thinking of the KM and other Axis navies.

    The example you provide re. the Panzershiffen, or for that matter any of the KM major units, was what I was thinking about. First of all, they were too light in all AA guns anyway. Having separate secondaries and heavy AA, is in my opinion, inefficient and adds a lot of weight. Many pre-war major units, and here I'm thinking of Germany, Italy and Japan, put on heavy secondaries and then a relatively few heavy AA guns. Six 105mm guns for AA defence was inadequate and thus they had to borrow Luftwaffe guns later in the war. (Another example of the German talent for improvisation.) There was quite a bit of spare deck space on most German ships so the adding of additional 105s was not out of the question. However, had they gone to something like 128mm guns in dual-purpose mounts they would have had all their bases covered. The Italians were an even more extreme example. Their newest BBs carried four triple 150mm gun turrets as their secondary armament, then had twelve 90mm AA guns in addition, plus light AA guns. Japan's Yamato started out apparently with NO heavy AAs, but added twenty-four 127mm AA guns in 1944, having had half of its 155mm secondaries removed. So, at least one navy did some major changing during the war.

    Which leads to another question now that I'm thinking about this: How effective were these heavy AA guns prior to VT fuses? The heavy guns were mostly to be used against level bombing at higher altitudes. I'm sure most of us know this type of bombing was extremely ineffective against ships at sea, so it wasn't used much later in the war. They were also used against dive and torpedo bombers beyond the range of light AA. But again, how effective were they in these roles?
     
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  16. Carronade

    Carronade Ace Patron  

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    Many pre-war major units, and here I'm thinking of Germany, Italy and Japan, put on heavy secondaries and then a relatively few heavy AA guns.

    Scharnhorst and Bismarck classes were built with twelve 150mm and fourteen and sixteen 105mm respectively and retained those armaments throughout their careers; additions were automatic weapons only, mainly 20mm including quad mounts. If you can document them or the panzerschiffen receiving additional heavy guns, I would be interested to see it.

    There was a proposed 128mm DP gun, single or twin mounts, and consideration of rearming Lutzow, Scheer, and/or Gneisenau with it, but it never came close to happening.

    The Italians were an even more extreme example. Their newest BBs carried four triple 150mm gun turrets as their secondary armament, then had twelve 90mm AA guns

    Also as built, and unchanged, though again light AA were added, mainly 20mm.

    Japan's Yamato started out apparently with NO heavy AAs ???

    As built they had twelve 5"/40s, three twin mounts on either side of the superstructure. Both ships later had half their 6.1" secondary armament removed, the triple turret on each side amidships. Yamato received three more twin 5"/40s in place of each turret, making the referenced total of 24 5" guns. For some reason this was not done in Musashi, which received only additional 25mm light guns in these locations.

    The biggest changes were on some of the older American battleships. The reconstructed Tennessee, California, and West Virginia received sixteen 5"/38s, twin mounts in superfiring pairs, and four Mark 37 directors in a diamond arrangement. Nevada, although not reconstructed as extensively, got the same.

    Pennsylvania and Maryland also got eight twin 5"/38s, late in the war while undergoing damage repairs. The guns were all on one level atop the midships deckhouse. I suspect this was because the twin 5" was a base ring mounting, so the lower mounts in superfiring pairs would have required penetrating the forecastle deck, a significant structural modification. They had only two directors, one each side, which gave less flexibility in engaging targets. Pennsylvania at least got Mark 37s, not clear if Maryland did or retained her old Mark 19s.

    Mississippi got an interesting modification at the suggestion of her commanding officer while undergoing repairs. At this point she had her prewar AA battery of eight 5"/25s; she was given eight more for a total of sixteen, with her low-angle 5"51s removed as compensation. The 5"/25 was an open pedestal mount, so this was a quick and easy upgrade. She retained her pair of Mark 28 directors and got several additional Mark 51s to control the large number of 5". The Mark 51 was basically a lead-computing gunsight, usually for 40mm guns, so I doubt it could generate fuze settings; the VT fuze made its use with 5-inchers far more practical.
     
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  17. 4th wilts

    4th wilts Member

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    I read the navy bored the 18 pdr out.
     
  18. Carronade

    Carronade Ace Patron  

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    The benefits of dual-purpose armament seem clear in hindsight, but in the 1930s it was "high technology". The first capital ships with DP armament were the French Dunkerque and Strasbourg, with sixteen 130mm/50s in two twin and three unique quadruple turrets. There does not seem to be a lot of information about them - anyone? - but they were not considered very successful, largely due to a low rate of fire. I would be curious to know if this pertained to the quad mountings specifically; successful DP or rapid-fire mountings were commonly twins, a simple, reliable design which allowed ammunition to be brought up on the centerline of the mounting to serve both guns.

    Side note, I consider guns of this class, like the French or Russian 130mm/50s or the American 5"/54, close to ideal for DP secondaries. Similarly in the WWI era I think the 5"/51 or the Russian 130/55 were the best capital ship secondary weapons, and would also be useful for small cruisers.

    However there was a feeling (which I disagree with) that secondary guns needed to be closer to 6" in order to knock out destroyers, ideally with a single hit. So the French stepped up to a triple 152mm in their next battleship, the Richelieu class. These were originally intended to be dual-purpose (five turrets) but it was decided that the rate of fire was inadequate, so one turret each side was swapped for three twin 100mm mounts, total twelve guns.

    The British also went the DP route with their 5.25", which seems almost ideal in concept but proved disappointing in practice; rate of fire of the gun and rate of train and elevation of the mounting were all slow, and the 70 degree elevation limit was a further hindrance.

    So the only really successful DP secondary was the American 5"/38, which was lighter than all the above and according to the conventional wisdom a bit light for the low-angle role, though it turned out to be the only one actually to sink a destroyer (Washington > Ayanami at Guadalcanal). And it proved an excellent AA weapon, which proved to be by far the more important of the dual purposes.
     
  19. harolds

    harolds Member

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    "Japan's Yamato started out with apparantly NO heavy AAs???"

    According to Siegfried Breyer's "Battleships and Battlecruisers: 1905-1970", no. He doesn't mention any of the 5"/40s. He states that the AA guns added in 1944 were 127mms. According to him, Musashi did not get that upgrade.


    Will dig through my books on Operation Cerebrus.
     
  20. harolds

    harolds Member

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    RE. heavy AA armament on Sharnhorst, Gneisenau and perhaps Pr. Eugen. I quote fromTheodore Taylor's "Battle in the English Channel". "Kapitan Reinicke obtains permission from Gruppe West to temporarily transfer and number of shore based guns, and their naval artillery crews, (emphasis mine) to the ships." The reference to "artillery crews" would suggest probably 88mm AA guns, though Taylor doesn't specify what guns they are.
     

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