Why didn't IJN ships have better AAA ?

[pad152]

Why didn't IJN ships have better AAA?

It always amazes me that a lot of Japanese ships had such poor AAA defence. They knew better than anyone else what air power could do to ships.

[mdiehl]

They made the same mistake as the Germans and UK. They went with dedicated medium caliber (6-8") weaponry for use against surface vessels and dedicated medium caliber (IIRR, 4-5.5") weaponry for AA. As a result alot of weight that was dedicated to the task of DD bashing was used up that could have been used for AAA.

The US solved that problem by adopting the 5"L38 as a dual purpose gun. The mount design was superior to most in that it could traverse and elevate across wider ranges than the Axis anti-ship and anti-aircraft guns.

[TIMJOT]

Its true IJN pre-war BBs had seperatel Med Cal surface guns and Med. AA guns. But to be fair all USN Pre-war BBs also had separate Med. Surface and AA armorment. The Yamato's had those silly 6" guns from the Mogamis, but half were removed during the war to make way for DP guns.

In general IJN pre-war AA amorment was better than most USN pre-war amourment on most classes of ships, but this was quickly remedied with the advent of 5"DPs, 40mm Bofors and 20mm Orks.

[Damien Thorn]

The Japanese 25mm AA gun was very good (on paper) but it suffered from some problems in real-life. Mainly, the way that ammo was loaded was very complex and cut the rate of fire (in terms of shots per minute) by more than 50%.

[CynicAl]

True. But to be fair, I should point out that the newest of the US pre-war BBs, the Colorado class, were designed in 1916. Adopting a DP secondary battery at that time would have required more than mere foresight. More like "prophecy." What's Yamato's excuse?

[TIMJOT]

ORIGINAL: CynicAl

True. But to be fair, I should point out that the newest of the US pre-war BBs, the Colorado class, were designed in 1916. Adopting a DP secondary battery at that time would have required more than mere foresight. More like "prophecy." What's Yamato's excuse?

True, but I was refering to the IJN pre-war BBs (Kongos,Fusos, Ises, Nagatos) which were just as old or older. No excuses for the Yamotos, just expediancy. A convient use of all those left over 6" guns after the Mogamis were upgraded to 8". Not a particularly good design desision but one that was corrected once they developed their 3.9" DPs.

[SouthernAP]

Just like in most of the navies of the West, all of the upper echleons of the Japanese Navy still believed that the Battleship ruled the wave that the carrier and its aircraft were to serve as a supporting role the few admirals that believed airpower was now the queen of the waves were few. Adm. Isoroku Yamamato was one of those few. It was very, very fortunate for the Japanese Navy that he assumed command of the combined fleet when he did.

That being said early on in the war no one had effective AAA. Cause no one really knew how much the speed had changed when some of the initial AA mounts were introduce and no one really thought that a carrier base aircraft with its limited bomb load could hurt a mighty battleship. Both the US and the UK had 1.1 rapid fire guns, the Japanese had thier 25mm guns as light weight AAA. Anything heavier then that usually consided of between 4in and 5in mounts some of these mounts though rated as dual purpose really weren't and couldn't keep up with the faster speeds of the aircraft and ,if memory serves me right from reading something, shell weights for AA were on the light side. After that everyone mounted from 1937- late 1942 as many dang machine gun mounts as they could through out the upper works. It wasn't until the US gained the rights to produce the Bofors 40mm mount that they and effective weapon against divebombers and the 5"/38cal mount for against land based medium and heavy bombers. The 5"/38 was so popular that the US factories and shipyards actually had trouble meeting demand so a number of allied ships that were slated to be backfitted never were and probably suffered cause of it.

[tsimmonds]

No excuses for the Yamotos, just expediancy. A convient use of all those left over 6" guns after the Mogamis were upgraded to 8". Not a particularly good design desision but one that was corrected once they developed their 3.9" DPs.

To an extent far greater than is commonly realized, the IJN was a combat fleet designed and built around a doctrine of decisive battle. The composition of the fleet and the characteristics of each unit were all determined by their vision of how they intended this battle to unfold. In their view, the decisive battle centered around a massive nighttime torpedo attack carried out by cruisers and destroyers, followed up by an artillery battle that would commence the following day when there was enough light to engage at long range. Their battle range of choice was between 20,000 and 30,000 yards, which was Yamato's calculated zone of immunity from having its armor penetrated by its own weapons. The 6.1" gun was an ideal secondary weapon for this scenario. It could range out to 30,000 yds, and its high muzzle velocity gave it a flat trajectory, which meant a short flight time for the projectile, making it an ideal weapon for use against destroyers closing from 30,000 yards down to torpedo launch range. Their heavy AA battery consisted of the 127mm/40 cal weapon, which was inferior to the US 5"/38 cal in range, ceiling and rate of fire. The battery was increased from 12 guns to 24 in the late-43 refit in which the wing 6.1" gunhouses were removed. The 127mm guns were mounted in shields to protect them from the tremendous blast pressure wave generated by the 18.1" main battery. These shields were similar in appearance to the 3.9" gunhouses carried by the Akitsukis. The 3.9" DP weapon was never fitted to the Yamatos however, although it was planned for follow-on battleship designs.

[Howard Mitchell]

Gun performance is only part of the equation in the effectiveness of a ship's AAA defences. Fire control is an important factor as well, especially radar. This was an area the Japanese were well behind the Allies (and other Axis forces ) in. The Japanese also lacked the proximity fuses introduced by the Allies later in the war which greatly increased the effectiveness of larger calibre guns.

[tsimmonds]

Further to AAA, the single most important wartime development was the VT (variable time?) fuse for the US 5"/38. This was essentially a miniature radar built into the shell that would detonate it in proximity of a target. Together with the Mk4 radar operated dual-purpose fire control system, this replaced the earlier, vastly inferior technology that relied on visually estimating the range to the target and manually or semi-automatically setting the fuse to explode after the duration of time the shell would need to travel that distance. The new technology resulted not only in many more hits per round fired, it also increased the rate of fire that could be sustained. During this weapon system's operational debut on October 26, 1942 during the Battle off Santa Cruz, USS South Dakota is credited with destroying 26 Japanese aircraft. The Japanese never developed anything remotely as effective, using what was basically prewar technology right through to the end, their AAA improvements being limited mainly to mounting additional 25mm AA weapons at the expense of 5"SP and torpedo mounts.

Hats off to Howard Mitchell, who posted the above while I was writing this....

[TIMJOT]

Irreverant,

I stand corrected regarding the 3.9" guns on the Yamatos. Thanks for the heads up.

Regards

[tsimmonds]

No TIMJOT, thank you for just another opportunity to parade my stock of useless information.....[>:]

[Mike Scholl]

ORIGINAL: pad152

Why didn't IJN ships have better AAA?

It always amazes me that a lot of Japanese ships had such poor AAA defence. They knew better than anyone else what air power could do to ships.

It's really simply another example of the fact that the Japanese lacked a broad technical
and industrial base compared to the Western Powers. By the standards of the late '30's
their ships DID mount an adequate anti-air capability. They had their 25mm, and had
been mounting their 5" guns with 70 degrees of elevation to give some barrage AAA as
well. They were even developing and beginning to deploy a true DP weapon with their
3.9" mountings. On December 7th, their AAA was substantially on par with the US.

But they never really got much better, while the Americans deployed entire new techno-
logies in detection, fire control, ammunition, and AAA artillery. They had a huge consu-
mer based electronics industry that could be mobilized for building the photoelectric
circuits for VT fuzes and multiple types or radars and all kinds of gadgets. They bought
and refined and improved the best light and medium AAA guns available, as well as pro-
ducing the 1,000's of tons of ammunition to make use of them. Chrysler built a plant
even bigger than Ford's Willow Run just to produce 20mm guns. Now the Japanese
COULD have produced all these things too. One at a time, over a number of years. But
under the stress of war they just didn't have the industrial or technological "muscle". So
like most of their military technology, what they produced was more of the same things
they went to war with. I know.., they did produce better aircraft as the war progressed.
But they were never able to complete the change-over in basic infantry weapons they
began before the war. Their ASW tech remained pretty much static while the West came
out with a dozen new techs and weapons for the purpose. They did make some progress
in "germ" warfare---but the West didn't have a captive Chinese population to experiment
on. Basically, they took on a challange that was much too big for their economic base to
support..., and they sufferred the inevitable result.

[Rainerle]

Hi,
well some things seem to be wrong in the whole discussion and I will try to point my finger on it (with a little bit of irony that is).
O.K. so most people think that USN AA was much better than IJN AA but how do they come to that conclusion ? Were they ever tested under the same conditions ? Used in earnest against the same opponents?
As for the superiority of the USN AA please read the following:
It seems to be widespread opinion on this board by many members that:

a) That the Japanese were incapable of designing a good airplane !
b) Those planes that were designed suffered from the usage of bad/unrefined materials/fuel resulting in low-quality a/c.
c) Those low-quality a/c were flown by complete morons since the IJ training program was long broken.
d) Those that did get of the ground alive and managed not to misdirect themselves to the north pole were opposed by the finest Airforce ever to walk eh fly the earth the USNAF/USAAF (or allied AF).
e) This AF was not only the finest but biggest in numbers as well outstripping the poor japanese by (fill in from other thread).
(for any point mentioned here there was or is a thread somewhere here or the UV board [;)])

... so in the end all the 'superior' USN AA was shooting at were lucky leftover/unnoticed morons in obsolete rundown inferior designs (or so it would be if I would take the often mentioned remarks/opinions/statements on these boards for the truth).

On the other hand the 'inferior' IJ AA had to .... (I make it short)

... fight against the best planes, handled by the best and most mechanics per plane, flown by the best pilots to walk eh.. fly the earth, who in turn were never molested by incompetend moron pilots in their ramshackle planes (again widespread thinking of several board members) and so on.....

So where is the truth ? O.K. I don't know but don't let yourself be fooled by statistics. The fact that US AA shot down a high percentage of few planes to bypass the fighter screen does not indicate good AA. Vice verse a low percentage of shot down planes out of 'a hell of a lot planes' does not indicate poor AA.
An example, IJN, USN ten ships each with same AA (for convenience).
IJ approach with 20 planes, US with 300, IJN and USN shoot down each 10 for 50% US AA victory and 10 % IJ AA victory but who did the better job (i.e. has the better AA)?
Answer: IJN !!! Because their AA had to disperse among 100 A/c while the US AA could concentrate on 20 a/c and still get the same number of kills.
Note: Not everything here is dead serious, I am not attacking anybody on a personel basis.

[paullus99]

The 26 aircraft blown out of the sky by the crews on the USS South Dakota were piloted by some of the best pilots in the Japanese Navy (off the Shokaku & Zuikaku) during the Solomons Campaign.

Whereas the Japanese were able to start the war with an extremely experienced crop of pilots, well-designed aircraft, and the initiative - they were unable to keep up in the technology race with the United States. No one doubts the enhanced AAA on US ships during the 1944 - 45 campaigns (Proximity fuses, radar-direction) saved thousands of lives when the Japanese resorted to Kamakaze tactics. It is a lot harder to prevent someone from crashing directly into your ship than just worrying about bombs and torpedoes.

In "A Glorious Way to Die", the story of the last sortie of the battleship Yamato - accounts of the surviving Japanese crew members & US reports from the battle show the relative ineffectiveness of the Japanese flak vs. the US fighters, bombers, etc. All told, less than 20 US pilots and crew were killed during the battle - and Yamato had the most AAA on board as any ship on the sea at the time.

[Damien Thorn]

ORIGINAL: paullus99
In "A Glorious Way to Die", the story of the last sortie of the battleship Yamato - accounts of the surviving Japanese crew members & US reports from the battle show the relative ineffectiveness of the Japanese flak vs. the US fighters, bombers, etc. All told, less than 20 US pilots and crew were killed during the battle - and Yamato had the most AAA on board as any ship on the sea at the time.

Well, there is such a thing as overwhelming saturation. Increasing the number of attacking planes results in a much lower chance of any one of those individual planes getting shot down. It's like rush hour traffic. Once you get past a critical number of cars the delay time goes WAY up, much out of proportion to the number of extra cars added.

That having been said, I DO think the US had better AA from at least 1943 onward but, as mentioned a few posts above, one has to take into account other factors when looking at the final results.

I also think the performance of allied fighter planes is over rated in most games because it is hard to seperate the late war performance of those planes from the poor quality of pilots they faced. I think if the 1944 American pilots were flying the 1944 Japanese aircraft they would still have done very well even against the 1944 Japanese pilots flying 1944 American aircraft.

[Rainerle]

Ahhhh...
Damien understood !
Well, I too think that US AA was better make no mistake, but as I pointed out it is not so easy sometimes. (The Yamato did not sink because of poor AA, any BB in the World would have sunk that day against those odds)

[Nikademus]

ORIGINAL: paullus99

The 26 aircraft blown out of the sky by the crews on the USS South Dakota were piloted by some of the best pilots in the Japanese Navy (off the Shokaku & Zuikaku) during the Solomons Campaign.

she was credited with 9, possible 10. [:)]

-Lundsrom First Team.

[tsimmonds]

From: DICTIONARY OF AMERICAN NAVAL FIGHTING SHIPS, Vol. VI, pp. 561-64.

The first enemy attack was concentrated against Hornet. At 1045, South Dakota was operating near Enterprise to provide protective fire from her numerous antiaircraft guns when their group was attacked by dive bombers. Approximately an hour later, about 40 torpedo planes struck at the two ships. A third aerial assault, made by dive bombers and torpedo planes; came in at 1230. South Dakota sustained a 500-pound bomb hit on top of her number one turret. When the action was broken off that evening, the American forces retired toward Noumea, New Caledonia, with the battleship credited with downing 26 enemy planes.

Guess it depends on your sources....

[Nikademus]

yes it does.

however i was always suspicious of the score.....its extraordinary, considering that its pre-VT fuse and according to a 2nd source (Frank) heavy AA at Santa Cruz only accounted for 5% of the casualties.

Add to that, the total estimated direct AA casulties for the entire battle was something on the order of 29 Japanese planes.....i really dont see how SoDak could have accounted for 97% of them all by her lonsome [;)]