BRITISH AA OF WW2

Historical what if discussions, hypothetical operations, battleship vs. battleship engagements, design your own warship, etc.
als_pug
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BRITISH AA OF WW2

Post by als_pug »

Could the uk aa have been more efficent with twin mountings for the land based 3.7 aa gun . each vessel would have fired faser and had more mounts.
also if the 40 mm bofors had been mass produced earlier. what i am suggesting is all the single 4 inch aa on cruisers is exchanged for twin 3.7 . all destroyers change over to twin 3.7 mounts . all single 4 inch mounts used on land mountings near the coast. or as fortress guns. all battleship and battlecruiser get additiuonal mounts and proper high angle fire control . i belive the 3.7 mount for land was built to be remote guided . ie following a director right from the start. instead of 10 twin 5.25 mounts on a kgv you would have 12 or 14 twin 3.7 mounts firing faster
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Re: BRITISH AA OF WW2

Post by Tiornu »

The cruiser 4in single mounts were almost all replaced by 4in twin mounts. Why is a smaller gun preferable?
All large RN warships had AA directors.
Compared to the 5.25in, the 3.7in has a tiny shell and short range.
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Re: BRITISH AA OF WW2

Post by als_pug »

unfortunately i have had to use wikipedis here however the data and opinion is correct.

in relation to the 5.25

The dual mount turret proved too heavy to track quickly enough to engage the higher-speed aircraft of the Second World War.[1] The cramped gunhouse also reduced the rate of fire from the designed twelve rounds per minute to seven or eight (nine on HMS Vanguard).[1] These problems rapidly made themselves felt in the loss of Force Z[1], and the Battle of Crete[citation needed].

Bore Diameter: 5.25 inches (133 mm)
Barrel Length: 6.668 m (50 claiber)
Shell weight: 80 lbs (36.3 kg)
Range: 21,397m at 45 degrees
Anti Aircraft Ceiling: 46,500 ft (14,170m)
Rate of Fire: 7-8 Rpm (9 RPM in MkII mountings on HMS Vanguard)
Mounting weight: 78.7 metric tons
Mounting elevation : -5 to +70 degrees

in relation to the 3.7

Weight 20,541 lb (9,317 kg)
Length 4.96 m
Barrel length /L50 185 inches (4.7 m)
Crew 7

--------------------------------------------------------------------------------

Shell 28 lb (12.7 kg)
Calibre 3.7 inches (94 mm)
Carriage Mobile and static versions
Rate of fire 10/20 rpm
Muzzle velocity 792 m/s (2,598 ft/s)
Maximum range Maximum horizontal 18,800 m (61,679 ft)
Maximum slant 12,000 m (39,370 ft)
Ceiling 9,000 m (29,527 ft)

my words below lol
the 20 rpm was for the auto loader version . this would equate in a twin turret to approximately 40 rds per minute.
the mount as shown weighs 9 ton . a twin mount would come in at less then 30 ton as compared to 87 ton . so you could theoreticlly mount twice as many mounts . so the curent kgv setup of 4 twin mounts per side could change to 8 twin mounts per side . the rate of fire goes from ( assuming the 10 rpm for the 5.25 is per gun ) 160 rds per minute to a staggering 320 rds per minute . the shell wieghed 28 lb as compared to 85 lb so throw weight is down but lethality is increased . more shells = better chance of hit .

also i stated that proper high angle fire control would have helped. My understanding is that the RN had poor high angle fire control equipment compared to for example the USN . in fact 1 RN cruiser was fitted with 5 inch guns and USN high angle FC to see the difference.

http://navweaps.com/index_tech/tech-066.htm excerpts below .

The Mark 37 GFCS was introduced to the Royal Navy when the old cruiser HMS Delhi was rearmed at New York Navy Yard in late 1941 with five 5-inch/38 Mark 12 guns and two Mark 37 GFCS. The combination of the predictive-based Mark 37 GFCS and rapid-firing 5-inch guns greatly impressed Royal Navy observers, and the British Admiralty placed orders for 82 more Mark 37 systems. Unfortunately, the rapid expansion of the US Navy during 1942-1944 precluded any additional diversions to the Royal Navy and no further British ships were equipped with them during the war.

Following the end of the war, the battleship Vanguard, the carriers Eagle and Ark Royal and the last eight “Battle” class destroyers were completed with Mark 37 GFCS. These units had modified analog computers in order to accommodate the differences between US and British weapons. These post-war units were fitted with British Type 275 radar systems and were significantly heavier than the HACS, with the Mark 37 on HMS Vanguard weighing some 16.5 tons compared to about 12.5 tons for the HACS Mark VI used on HMS Anson.

END OF EXCERPTS
My words and opinions below

if the estimate of shells fired to a/c downed stands at 1000 shell per aircraft then firing 360 rds per minute with better HA fire control would have to help matters. once again this is purely hypothetical . of course it does not help that i would have liked to have seen the KGV's equipped with triple 16 inch guns similar to the nelson with minor improvements. so i would have armed the KGV with 9 * 16 inch in triple turrets . 32 * 3.7 high angle mounts in twin turrets and replace the POM POM's with multiple 40 mm bofors . say 20 to 30 twin mounts . now fast forward a little and look at the bismark operation . ok the secondary mountings can not scratch a battleship. but the main mounts are not going to fail in the denmark strait . POW may have gained a kill . the look at malaysia. yes the japanese would most likely have sunk both ships . however the aa would have actually worked. the bofors could have hit torp bombers before they dropped as opposed to the short range POM POM . and the 3.7 would have been quite comfortable at the height the jap high level bombers flew at.
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Re: BRITISH AA OF WW2

Post by Bgile »

The British used 14" guns on the KGVs because that was the treaty limit.

The 40mm Bofors in mass production version (quad and twin mounts) wasn't ready in the US until mid '42. The original mounting had to be completely reengineered to make it suitable for mass production.

I don't see how you are going to fit 16 secondary mounts on a KGV.
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Re: BRITISH AA OF WW2

Post by Tiornu »

We seem to be laboring under a false assumption here that a battleship's secondary battery is there to shoot down aircraft. That is only one if its functions. The secondary battery is there to strike surface targets. Since the Admiralty was uneasy with the 4.5in gun (which was quite adequate as an AA weapon), dropping to a smaller caliber would be unthinkable.
For smaller ships, the RN had its 4in gun. In a fleet plagued with an overabundance of calibers, why would anyone want another? Hm, and the 4in gun actually served as a secondary battery aboard Hood and Repulse.
These problems rapidly made themselves felt in the loss of Force Z[1], and the Battle of Crete[citation needed].
Here we have a statement without foundation. It certainly wouldn't have hurt PoW to have carried a better AA gun, but whether or not it made a difference in that particular engagement is entirely a matter of speculation. Did Repulse's rapid-firing 4in guns accomplish any more than PoW's 5.25-inchers? And exactly which battleship was sunk at Crete? Placing a footnote in the text does not help if there is no footnote to read.
this would equate in a twin turret to approximately 40 rds per minute.
This compares to 36 rounds that the 5.25in RP 10 Mk I* twin mount could manage. The smaller gun could be present in 2.5x as many numbers and still not equal the output of the larger gun. The best solution to the 5.25in problem was to fix the mount, not to replace it with another weapon that was ill-suited to the role. You are absolutely right that the 5.25in Mk I was a failure as an AA weapon, but your suggested solution would never have been accepted, and for good reason. What was the barrel life of the 3.7in gun in a naval environment, and how much would it weigh when adapted for naval use?
also i stated that proper high angle fire control would have helped.
Hee! You are dubbed today's King of Understatement, befitting also your judicious use of capitalization.
if the estimate of shells fired to a/c downed stands at 1000 shell per aircraft then firing 360 rds per minute with better HA fire control would have to help matters.
This is a false premise. A thousand 3.7in shells weigh 28,000 lbs; a thousand 4.5in shells weigh nearly twice that. Which will generate a larger kill radius?
i would have liked to have seen the KGV's equipped with triple 16 inch guns similar to the nelson with minor improvements.
You're describing something that looks like the Lion class. It had nine 16in guns, and the guns were actually better than Nelson's by a considerable margin. Lion would have been a superb ship if she'd been completed. Unfortunately, she broke the treaty limit of 14in guns as Bgile has mentioned, as well as the 35,000-ton limit. So you're going to have to yank 4000+ tons off of her if you want to build KGV this way.
but the main mounts are not going to fail in the denmark strait .
Unfortunately, you don't know that. PoW's guns had problems in part because they were new. Our hypothetical 16in mounts would be not only new but heavier.
and the 3.7 would have been quite comfortable at the height the jap high level bombers flew at.
No one cares about high-level bombers. A 5.25in gun can engage targets earlier than the 3.7in gun (meaning it can put more shells on target), can get the shell to the intercept point sooner at any range and at a straighter trajectory, and has the more destructive shell. The best solution, then, is a properly engineered 5.25in mount; barring that, the 4in and 4.5in guns are perfectly adequate and already available.
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Re: BRITISH AA OF WW2

Post by als_pug »

i would like to see were the rate of fire being 36 rds per minute came from as that is nearly twice the rate previously quoted and nearing the rate of the premier naval antiaircraft weapon . the american 5 inch. .

also this is a hyperthetical part of the forums . i have [osted a question and you are answering with facts that are not relevant . i know the RN had an abundance of gun calibre's it was one of their biggest problems . this is why i was suggesting moving to a faster and lighter mount with commonality with the land forces. the 3.7 was well respectede and had very good range as far as field guns go. the simple fact is that their was not a huge number of surface engagements were a 3.7 could not have done well . also if someone had of pointed at the UK 4 inch naval gun also not a bad mount and said this is the rate of of fire wieght etc all would have been good.

as far as fire control goes the uk had brilliant surface fire control . no complaints their short of radar it was as good as it could get . their aa fire control however was and is aknolleged as being less then good. i would like to point at the malta convoys. and the bombing of the invincible . look it up then look up the HACS and come back to me . i know by 1945 it was considerably improved however i am talking 1939 / 1940

also as far as the KGV . the 14 inch gun was qa very good weapon with from the data tables i have seen good penetration to range capabilities . however effect on target was not as good after penetration due to a smaller bursting charge. i said i would have liked to have seen !!!!! The treaty limits are not mentioned and are irrelevant to what i would have liked to have seen .
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Re: BRITISH AA OF WW2

Post by Bgile »

als_pug wrote:also as far as the KGV . the 14 inch gun was qa very good weapon with from the data tables i have seen good penetration to range capabilities . however effect on target was not as good after penetration due to a smaller bursting charge. i said i would have liked to have seen !!!!! The treaty limits are not mentioned and are irrelevant to what i would have liked to have seen .
Where did you get your info on the bursting charge? I can't find it anywhere. The navweaps site only gives one and doesn't identify the type, but it's almost identical to the US 14" HC round. I can't seem to find one for the AP.
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Re: BRITISH AA OF WW2

Post by Tiornu »

i would like to see were the rate of fire being 36 rds per minute came from as that is nearly twice the rate previously quoted and nearing the rate of the premier naval antiaircraft weapon . the american 5 inch.
It's from Garzke & Dulin. That a 5.25in RoF should nearly match that of a 5in entering service ten years earlier is not surprising.
i know the RN had an abundance of gun calibre's it was one of their biggest problems
Then you understand that adopting a British army gun merely makes the problem worse. The fact that another organization also uses the gun does not make RN logistics any easier.
also if someone had of pointed at the UK 4 inch naval gun also not a bad mount and said this is the rate of of fire wieght etc all would have been good.
You can find all the 4in stats at Navweaps.
their aa fire control however was and is aknolleged as being less then good. i would like to point at the malta convoys. and the bombing of the invincible . look it up then look up the HACS and come back to me . i know by 1945 it was considerably improved however i am talking 1939 / 1940
I don't suggest anyone waste his time trying to look up the bombing of Invincible, and everyone knows about the deficiencies in the HACS system.
The treaty limits are not mentioned and are irrelevant to what i would have liked to have seen
I didn't realize you were suggesting the 14in gun as an AA weapon, which would make it relevant in this discussion of "BRITISH AA OF WW2." The bursting charge of large RN AP shells was roughly 2.5%. This gives the British 14in shell a burster almost as large as that of the US 16in shell. Obviously the Lion's 16in bursters would be significantly larger.
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Re: BRITISH AA OF WW2

Post by dunmunro »

Some prior discussions on this topic:

viewtopic.php?f=9&t=672&st=0&sk=t&sd=a

http://www.bobhenneman.info/forum/viewt ... ab6d97f2e6

The idea that the maximum rate of fire of the 5.25" gun is 7-8 RPM is absurd. It comes from a narrow interpretation, and selective reading, of available sources from readers that are biased in the extreme. The statement for 9 RPM for Vanguard has absolutely no historical basis whatsoever.

The RN 4.5" gun in the "cramped" BD turret fired a hand loaded (by a single loader) 90lb + round and used a loading tray and fuze setter that was practically identical to the 5.25" gun. Yet Campbell states: "The gunnery report of illustrious on the attacks of Jan 1941 in which the 8 available 4.5" fired about 3000 rds at an average of 12 per gun per minute...", and since the "average" was 12 RPM the peak RoF must have been higher. The 5.25" gun fired an 80lb shell and separate ~40lb cartridge each handled by its own loader.

RN documents on cruiser design list the RoF of the 5.25"/ 6" guns as 8/5 RPM, for comparison purposes, yet 5 RPM is much less than the maximum RoF of the 6" gun, which could achieve up to 12 RPM for short periods of time according to Engage the Enemy More Closely, by Brookes. So the RN was using a much lower figure for the 6" guns than was achievable in service, yet the idea that the max RoF of the 5.25" gun is 8 RPM has been accepted and unchallenged. The prototype 5.25" turret on HMS Iron Duke averaged 8 to 10 RPM under trial conditions and by way of contrast the USN 6"/47 triple turret..."During gunnery exercises in 1939-40, the Brooklyn class averaged about 5.05 rounds per gun per minute at a range of about 14500 yards, expending about 140 rounds per ship..." according to Bill Jurens.

Great claims are made for the performance of the USN 5"/38 and the Mk33/37 AA FC systems, but accounts published by the gunnery officers of Yorktown and Enterprise express great disappointment in the system (even Enterprise in 1945 with the Mk 37), especially when engaging dive bombers, and Yorktown's (CV-5) gunnery officer recommended removal of all 5"/38 guns and their replacement by 40mm guns on USN CVs. Does this mean that the RN HACS was superior? No, but the differences between the HACS system and USN equipment was much less in practice than "on paper".

wiki articles:

http://en.wikipedia.org/wiki/QF_5.25_in ... _naval_gun

http://en.wikipedia.org/wiki/HACS
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Re: BRITISH AA OF WW2

Post by Bgile »

... and then USS Des Moines was commissioned with no weapon smaller than the 3"/50, due to wartime experience with Kamikazes.
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Re: BRITISH AA OF WW2

Post by als_pug »

Tiornu wrote:
The treaty limits are not mentioned and are irrelevant to what i would have liked to have seen
I didn't realize you were suggesting the 14in gun as an AA weapon, which would make it relevant in this discussion of "BRITISH AA OF WW2." The bursting charge of large RN AP shells was roughly 2.5%. This gives the British 14in shell a burster almost as large as that of the US 16in shell. Obviously the Lion's 16in bursters would be significantly larger.

at no point in time was i suggesting the use of the 14inch quad turret as an AA gun . :clap: of course most of what i have said has been seriously misrepresented by you . i could understand severe dyslexia as a starting point :pray: . i have mild dyslexia myself :lol: .

ok now to go back to the start . lets look at the hypothetical scenario.

1936 or whenever . the Royal Navy looks into it's future AA needs it see's the guns on offer and realizes they do not get the job done . maybe they see the performance oif italy's air force . it being one of the most advanced in the world in the 30's . they then look at the multitude of calibre's on offer.
3 inch / 4 inch / 4.5 inch 4.7 inch 5.25 inch . then the cost of maintaing the war stocks of all these guns . the army looks at it's AA defences and says 3 inch is inadequate . the senior service gets to choose which aa gun is used be all services. the army says this is the requirements the navy says this is ours and then a gun is chosen . mass produced etc . i see no p[roblems with the navy going for a 4 or 4.5 . but the army is going to look at the wieght and say no way . the 3.7 had excellent performance . of course mating the breech and propellant of the 4.5 to the 3.7 calibre produces an excellent weapon and the factories only have to produce 1 shell and 2 cartridge cases . much more economic. The bofors company was producing 40 mm guns in 1933 . it would have been available for mass production in the UK prior to WW2 if looked at early enough . oh and on the topic of twin mounts .

The first order for the "real" L/60 was made by the Dutch Navy, who ordered five twin-gun mounts for the cruiser de Ruyter in August 1934. These guns were stabilized using a unique system known as the Hazemeyer mount, in which one set of layers aimed the gun, while a second manually stabilized the platform the gun sat on. All five mounts were operated by one fire control system.

so their is no reason why i can not propose considerable changes to RN AA at the start of WW2 . :clap: :clap: :clap:

on another note their is no reason why a vessel can not have 2 tiers of smaller aa mounts. .
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Re: BRITISH AA OF WW2

Post by DB23 »

I'd say stick with the 4.5" as secondary guns on new CVs and BBs. Can mount 20 on the KGVs instead of 16 of the larger 5.25". Going smaller will not be accepted as RN wanted a relatively heavy shell for anti-destroyer work (they were DP guns, not heavy AA guns).

The 4" twin was fine as a secondary/AA gun for cruisers and old capital ships.

Produce the 5.25" exclusively for the Didos--perhaps make them a little beamier so they can take 4 x an earlier version of the RP10 Mk.I* mounts a la Vanguard (the earlier mounts were by most accounts compromised--slow train, lower RoF, etc.--due to results of treaty-induced weight saving measures).

Develop a single 4.5" UD or BD mount alongside the twins back in '34/'35--can mount 4 of these on the War Emergency Destroyers instead of the hodge-podge they rec'd historically.

Get the Bofors earlier to supplement/replace pom-poms if possible.

The Oerlikon was definitely "getable" earlier--having those in place of the .5 mgs on most ships on outbreak of war would've been a significant improvement.
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Re: BRITISH AA OF WW2

Post by hammy »

The 3.7 was an army heavy AA weapon and the optimisation there has to include humping the thing about with manpower , towing it with standard trucks , supplying it with ammo from other trucks , not taking an age to emplace or remove it , and so on .

None of those things need to be taken into account for the Naval Guns . I'd guess that something under 4 inch was needed and 3.7 was picked on because there was manufacturing capability straight away for that calibre , because of the old Pack howitzer/mountain gun in that size , with the barrel that screws together in two pieces .

In fact the two services did have a lighter AA weapon in common , the 3 inch 12 pounder
( projectile actually 14 pounds I think ) , which had gone into service in WW1 , initially as a semi-fixed position gun on the naval pedestal mount , in land use bolted down to a concrete pad to frighten Zeppelins and keep Londons Glaziers in work . :D
But by the late 1930s the shell had too small a lethal radius and something heavier was needed .
" Relax ! No-one else is going to be fool enough to be sailing about in this fog ."
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Re: BRITISH AA OF WW2

Post by johnalbion »

Bgile wrote:The British used 14" guns on the KGVs because that was the treaty limit.

The 40mm Bofors in mass production version (quad and twin mounts) wasn't ready in the US until mid '42. The original mounting had to be completely reengineered to make it suitable for mass production.

I don't see how you are going to fit 16 secondary mounts on a KGV.
The treaty limit for battleship guns was 16" not 14" The royal navy opted for the 14" in order to use more armor on the ships. personally I think they should have produced an up to date 15" mount with 45 deg elevation and using the same shell as the older 15"
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Re: BRITISH AA OF WW2

Post by johnalbion »

These problems rapidly made themselves felt in the loss of Force Z[1], and the Battle of Crete[citation needed].
Here we have a statement without foundation. It certainly wouldn't have hurt PoW to have carried a better AA gun, but whether or not it made a difference in that particular engagement is entirely a matter of speculation.

I strongly disagree with this statement. Had the ships at Crete and Force Z had every available bit of deck space paked with quad 40mm and 20 mm like most American ships were near the end of the war I believe it would have made a huge difference especially against the low flying Beatty bombers. Just look at the photo's of Japanese aircraft trying to fly through the wall of flak in 44. It is a terrible shame the RN did not put its pride aside an adopted the 5"/38 which was available to them for production in the UK. I was a 5/38 gun mount captain and tech and can tell you it was an outstanding weapon in every way. What I find amazing is after 2 years of war and suffering horrendous losses from air attack that RN warships were still so lightly armed with AA weapons.
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