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Hello RCAFson
Quote:"The 5.25 forced two bombers to abort..."
Thanks for that info, IMHO that was an achievement, not that of damaging lightly x planes. IMHO the badly damaged plane, if it was one of those damaged in this occasion, was an achievement.
Quote:"I don't understand, you are arguing that KM AA wasn't hopeless, yet Tirpitz's 4.1in guns had a slower traverse than the RN 5.25in."
Simply because to me the real results are what counts, so 2 out of 12 and effectively prevent accurate torpedodropping was a good achievement.
Quote:"So agree that RN was ahead in AA capability in Oct 1942?"
No, unless you can show that RN AA did better than what USN AA achieved at Santa Cruz
BTW Repulse had 6 4" AA guns and 3x 8 pom-poms IIRC and might well has been able to use it 9-12 x 4" LA guns against VTs
Juha
Hello RCAFson
on that 40deg, now the plan was during the Pedestal that appr 3 DDs were 2000ys out of the heavy ships, other DDs 4000-6000y out. But when ships manouvered wildy under air attacks the distanced changed and sometimes even the outer DDs were much nearer to heavy ships than 4000y. And the 85 deg elevation of US DDs allowed that USN's anti-aircraft formation was that DDs were around heavy ships 2000y out. AND if you look pictures of RN Pacific Fleet under air attack in 1945 you can see that for some reasons the DDs (Ts and Us) were much nearer than 6000y from carriers. Why, for some reason when 55 deg elevation allowed it, also RN DDs operated much closer to carriers than that 4000-6000y.
Juha
When I was in the RN I was told that the 3in 120 rpm and it did in trials but 90rpm as the max in real life so I have a certain caution about things like this. Caution based on real life and personal experience. So when I am told that the 5.25 couldn't do the designed 12rpm because of practical problems in real life I believe them.I did address it. But a 10 deg/sec traverse gun can swing 90 degs in the time it takes a 205 knots aircraft to fly about 1000 yds. This is hardly a serious handicap, and again 10degs/sec is better than most Axis AA guns.
The RN was an "an organisation that specialises in this topic" and they say 10-12 r/m and I believe them.
So the British wanted to improve the training speed of their AA guns because of guided missiles in 1942, a new idea that I will grant you. You can of course support this statementIt was becoming apparent by 1942 that the Luftwaffe would be introducing high speed guided missiles while very high speed fighter bombers were also appearing. These trends were not evident when the 5.25in gun was designed, nor was VT ammo, and a 20deg/sec 5.25 mount with VT ammo would be better able to engage very close range, very high speed targets.
When I was in the RN I was told that the 3in 120 rpm and it did in trials but 90rpm as the max in real life so I have a certain caution about things like this. Caution based on real life and personal experience. So when I am told that the 5.25 couldn't do the designed 12rpm because of practical problems in real life I believe them.
A clue was in the demonstration detailed when they managed 10rpm in an ideal situation. You never did explain why they didn't manage the 12rpm.
So the British wanted to improve the training speed of their AA guns because of guided missiles in 1942, a new idea that I will grant you. You can of course support this statement
Hello RCAFson
if you read carefully WW2 Cruisers, they gave the right info, 6 4" HA guns for Repulse, and she had 2 HACS.
Quote:" My point is that Navweaps says that 10/sec traverse is too slow yet Tirpitz was able to use her 4.1in AA effectively. Navweaps opinion on traverse rates is, therefore, wrong."
Based on what? I don't know which type of guns shot down those 2 Albacores, 20mm, 37mm or 105mm (4.1") or even 150mm, do you? And after all slow training didn't made it impossible to shoot down a/c it just made it more difficult.
Quote:" The RN did better during PQ-18 and Pedestal and did so against heavily armoured Luftwaffe aircraft"
Have you info on the real LW losses during PQ-18 attack? I have and on no day they were not as bad as was IJNAF's at Santa Cruz.The total number of a/c lost to all causes (incl. those shot down by FAA fighters) during the whole several days attack period (from 13 to 18 Sept 42) was not much more than that USN AA shot down in one day, LW losses during the attacks on PQ 18 were some 28-31 planes. And if we counted also those shot down by F4Fs at Santa Cruz, well.
And can you give me info what heavy armour there was in the nose of He 111. Now He 111 could take more damage than Kate, but not because it was armoured, the armour protected it from fire from behind, but being twin engine plane with good bullet proof fuel tanks. But it was also bigger plane with stricter torpedo dropping parameters. So maybe somewhat more difficult target to AA but not significantly, but for pilot there was only Plexiglas between him and the target.
Juha
I fully agree that one should be skeptical, but in this case we have an RN gunner confirming the stated ROF. I don't undestand why you are fixated on 12 r/m when the reference states 10-12 r/m.
As I explained, this was not an "ideal situation" as the loading tray is at it's most difficult loading angle when the gun was being loaded at low angles of elevation. You can see in this film clip at 3:39 how the 4" twin mount actually has to be elevated to be loaded at low angles:
NARVIK MATERIAL - British Pathe
So you are claiming that the aerial threat didn't evolve during WW2? That is also a "new idea" that I am sure you can support with abundant references?
Because in the real world the 5.25 was seen as a dissappointment in the AA role. Why when you are being questioned about the 5.25 do you present a clip of the 4in totally different in every way as a type of support?
Of course the threat developed, mainly in the numbers used, not individual speed, but the idea that the RN developed their weapons because of guided missiles in 1942 is a joke that does you no credit and only make you look foolish. You cannot possibly support that statement.
Hello RCAFson
maybe a third try, 2 LA 4" and 2 3" HA replaced by 4 4" HA, then 2 twin BD turrets put in but removed later (in fact because PoW went to an official visit to Canada and needed suitable suits and a pool and not put back when Repulse returned in UK) and replaced by 2 single 4" HA. You can see the HA guns in photos, first pair was on main deck just front of the boats, second pair abreast the second funnel high up and those which replaced the BD turrets abreast the main mast on one deck above the main deck.
I gave the figures, I don't bother be more precise because most of planes are said "went missing near Spitsbergen, went missing after forced landing into sea etc", on some mentioned "shot down by the AA of PQ-18", on few "shot down by a fighter", I also incl those which crashed on landing while returning from combat mission, if damage was 60% or more.
As I wrote bullet proof fuel tanks increased survivability but armour, which increased significantly survivability against attacks by .303 mgs armed Sea Hurricanes, there was a heated after action debate on this because amongst the cargo of the merchantmen of PQ-18 there were cannon armed Hurricanes, hasn't so much effect because most of the AA became from frontal sector and from airburst most of the splinters go forward
Juha
I think its worth mentioning that the HACS worked to some degree over Force Z despite the problems. If I remember correctly a high proportion of the high level bombers were damaged and had to abandon the original plan for them to attack twice.
Could be wrong on this but its something that I recall
This discussion is about AA capability.
My opinion is that we should try and reach some consensus and then move back on topic.
I think that RN AA was effective, but I would never say it was the best. The RN had its share of problems, but it was still quite useful and effective. It had quite good success against divebombers.
Hopefully we can start to move back closer to the discussion topic
I think I've built a pretty good case for the RN being ahead of the USN in AA in Oct 1942, but of course by Jan the USN was introducing the VT round and mass producing the 40mm gun, so by early 1943 the USN must have overtaken the RN.
However, we are certainly getting off topic here. I think I've built a pretty good case for the RN being ahead of the USN in AA in Oct 1942, but of course by Jan the USN was introducing the VT round and mass producing the 40mm gun, so by early 1943 the USN must have overtaken the RN.
No, you haven't.
You have built a good case that the RN had more 40mm pom-pom barrels mounted than the US had 1.1in barrels mounted and you have shown that the RN may have had more even lighter AA mounted.
You have not shown that RN was actually ahead of of the US in larger DP guns, either in barrels mounted or capability of those barrels.
You have not shown that the RN was ahead in fire control, that is that their directors PERFORMED better than the US directors.
Radar is a sensor, it can feed more accurate information to a director than an optical sight/device can but if the director and or system of getting aiming information to the guns is defective or performs poorly the radar alone may not be able to make up the difference.
Many countries were working on advanced AA mountings for ships and advanced ideas for directors. The problem was turning the ideas into actual working hardware that would work and CONTINUE to work at sea. Another problem was that many of these "ideas" were tried one at a time instead of in combination or were tried too many at a time and so failed to keep working when needed.
The Germans who you seem to claim were so far behind not only had tri-axial stabilized mountings for their twin 8.8 and 10.5 cm guns but had a tri axial stabilized mounting for their twin 37mm AA guns. They paid a penalty in that the big gun mounts weighed as much as a British low angle twin 12cm mount. THE 37mm was let down by the fact that the guns were not automatic but were miniature big guns. Each round had to be hand loaded. There were also maintenance and reliability issues with both mounts, but the "idea" was advanced. The 37mm mount was also heavy and hand powered.
The Italians had a quad stabilized 90mm mounting but again it was stretching what was possible too far. And, again, sophistication has a price. Was 19 tons too much to pay for a single 3.5" AA gun no matter how sophisticated the mount? They were also working on RPC. Some Italian destroyers had both a pair of 40mm pom-pom guns and a pair of 13mm MG mounts, not either/or like too many British destroyers.
The British were certainly aware that the Japanese destroyers had main guns with high elevation, they may not have known the rate of fire or loading angle problems.
The cost associated with good AA defense was not the cost of the guns themselves, or even in some cases the mounts, but the cost of the increased size of the ship needed to carry the AA armament. For every ton of armament weight you need several tons of ship to support it and for every foot in hight above the water you need either ballast weight or a larger hull to maintain stability. Adding several tons of "improved" AA director on top of the bridge can call for extreme weight savings in other areas or a new hull in future classes. With destroyer tonnage limited by treaty Navy's had to accept limits on capabilities or limits on numbers.
The RN's .5in MG mount was an overweight piece that provided little firepower for the space and weight it took up. Awkward to use, it might have been a viable weapon in 1930 or so but by 1939 it was of little use. The tonnage may have been better used by free swinging mounts like the US was using on it's .50cals or the Germans were using on their 20mm guns even if they weren't the equal of the later Oerlikon
Almost every british destroyer had a quad 2pd and 6 - 8 20mm, some had more some less but this is a fair summary.
The problem that the USN had was that they were more or less limited to the 1.1 in one of the most dissapointing weapons used by the USN, the 0.5 mg which lacked firepower and the 20mm which was effective but on the small side....... Even the first Fletcher class DD's which entered service in 1942 had a quad 1.1in and 6 x 20mm arguably less effective than the LAA carried on the RN destroyers.
SR, very nice post, logical and informative. All the AA and radar that was added to ships in WW2 also required crew to man them and spaces to house the added crew and supplies to feed them. The ships got crowded and top heavy. CA25 of the USN stopped in Hawaii and exchanged two scout planes for two twin mount 40 mms but that does not sound like the trade was weight for weight.