Japanese get ship-based radar 1940

MatthewB

Banned
Germany had radar by 1938 and installed air intercept and gunfire surface radars on their ships by 1940. Lets have Japan get German sets for all its aircraft carriers by the end of 1940.
 

MatthewB

Banned
I want any reasonable means of fleet wide use of air intercept radar and fighter direction in time for Coral Sea.
 

trurle

Banned
I want any reasonable means of fleet wide use of air intercept radar and fighter direction in time for Coral Sea.
The research environment in Japanese labs was ”stifling" since 1928, resulting in significant brain drain and diminished research efficiency. Also, Japanese research efforts were at "bleeding edge" of their industrial capability (or lack thereof), resulting in additional delays due necessary procurement of foreign tools. Also, Japan had problems with raw materials. In particular, nickel shortage (used for vacuum tube cathodes) shortage was severe in 1939-1944, and even nickel-containing coins were confiscated and remelted. Same problem was with barium for tube getters.

Overall, most plausible would be for Japanese to import radar sets from Germany.

Regarding military effect of early warning radars in battle of the Coral Sea, it would be likely close to zero given Japanese doctrine of epoch. Japanese put emphasis to stealth for their carrier operation (i.e. eggs armed with sledgehammer doctrine), which mean radars will be prohibited to operate until enemy bombers are already in the visual range, and switched off as soon as attack departs, in the effort to avoid next attack instead of interception.
 
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The research environment in Japanese labs was ”stifling" since 1928, resulting in significant brain drain and diminished research efficiency. Also, Japanese research efforts were at "bleeding edge" of their industrial capability (or lack thereof), resulting in additional delays due necessary procurement of foreign tools. Also, Japan had problems with raw materials. In particular, nickel shortage (used for vacuum tube cathodes) shortage was severe in 1939-1944, and even nickel-containing coins were confiscated and remelted. Same problem was with barium for tube getters.

Overall, most plausible would be for Japanese to import radar sets from Germany.

Regarding military effect of early warning radars in battle of the Coral Sea, it would be likely close to zero given Japanese doctrine of epoch. Japanese put emphasis to stealth for their carrier operation, which mean radars will be prohibited to operate until enemy bombers are already in the visual range.

Could you elaborate further on why the research for Japanese labs was 'stifling' and what could be done to reduce brain drain and improve research efficiency? Are there any potential research bottlenecks that could have been addressed by 1940 to improve their research into Radar?
 

MatthewB

Banned
Japanese put emphasis to stealth for their carrier operation (i.e. eggs armed with sledgehammer doctrine), which mean radars will be prohibited to operate until enemy bombers are already in the visual range.
Obviously the doctrine would need to change.
 

trurle

Banned
Obviously the doctrine would need to change.
Yes. Trigger for doctrine change would be much more important than any hardware. IOTL, Japanese placed first radar sets on battleships (Hyuga in particular), not on carriers, because it was believed battleship, operating closer to enemy, would have less chances for remaining undetected anyway, therefore constant radio emissions from radar will be less disadvantageous.

I.m.h.o., you need another pitched carrier battle with damaged yet fighting back Japanese carriers before Coral Sea, for Japanese commanders to seriously consider the operation of air warning radars from carriers in battle of Coral Sea.
 
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Yes. Trigger for doctrine change would be much more important than any hardware. IOTL, Japanese placed first radar sets on battleships (Hyuga in particular), not on carriers, because it was believed battleship, operating closer to enemy, would have less chances for remaining undetected anyway, therefore constant radio emissions from radar will be less disadvantageous. ...

This leads to the same outcomes for the carrier battles of Coral Sea, Midway, Santa Cruz, The surface actions vary; The night cruiser action 'Savo Island' does not change much. The Allied cruiser force was caught by surprise, even without Japanese radar.

At Cape Esperance October OTL a night battle the USN cruisers located the Japanese force with its radar, tracked it & reached a decent tactical position, and seems to have better opening accuracy. If the IJN only has radar on its BB at this point then no change from OTL as there were no BB present. If one or more of the IJN heavy cruisers has radar then they are not tactically surprised & in theory their opening salvos are more accurate.

Alternately the Night Action of 12-13 November may be more of a defeat for the USN,since the Krishna at least would have radar. OTL the USN had a advantage with its radar, but doctrinal decisions and tactical errors lost much of the advantage. Spotting the US cruisers early with the radar probably gives advantage to R Adm Kondo. Maybe that leads to the same confusion and error on the US side, maybe not.

Similarly the first battleship vs battleship action of the Pacific war, 14-15 Nov started with a radar blessed tactical advantage & surprise to the USN. Presumably the Hiei with radar spots the US squadron & the start is more even. However Japanese radar does not waive away the electrical failure of the South Dakota, & probably not the momentary masking of the Washington by the S Dakota. Assuming the same courses the SD masks the Washington from radar as well as visual identification. So Kondo & his captains may be just as confused at targeting as OTL & miss the Washington to their loss.

Tassafaronga night 30 November OTL had the Japanese cruiser squadron running close inshore & there fore masked by the radar returns from Guadalcanals forested hills. They spotted the US cruiser squadron visually in good time and achieved good tactical surprise, getting a salvo of 70+ torpedoes in the water & damaging hits on four US cruisers. Even if the IJN cruisers here had radar nothing may change since the dispositions of R Adm Tanaka make sense with radar as well as with visual spotting.

So, thats at least one action where the outcome is likely to change with IJN radar. The 14-15 November battle might change with IJN radar, but the variables alter a lot if Kondo deploys differently due to having radar on the Hiei. In the first & last battles the IJN beat a radar equipped enemy with out that gizmo. If possessing radar alters their doctrine, tactics, or decisions enough then in theory they might do worse in those two.
 

trurle

Banned
Could you elaborate further on why the research for Japanese labs was 'stifling' and what could be done to reduce brain drain and improve research efficiency? Are there any potential research bottlenecks that could have been addressed by 1940 to improve their research into Radar?
Most startling example is history of Yagi antenna. Invented in Japan in 1926, it was shelved until Yagi antenna equipped radars were captured from British in 1942.

Overall, i have no coherent picture, but remember written stories and personal communications about funding cuts, security harassment, spy allegations, purge of foreign engineers, cancelled scholarships, cut short oversea research programs, and general assault on non-patriotic speakers.

It all started from purely economic troubles in 1927, but by late 1928 scapegoat mentality and scramble for diminishing resources was in place in all major Japanese universities and engineering companies, with political arguments used to evict the rivals.

Overall, the
https://www.jil.go.jp/english/JLR/documents/2014/JLR43_moriguchi.pdf
page 64 plot suggests the militant labor unions have played the role in developing adverse mentality in response to economic crises. Less prominent labor unions may result in better research community environment, at the cost of temporary reduction of GDP from the general rule.

Rule of general research productivity: in any large organization, R&D output is proportional to square of allocated funds divided to number of researchers. (this is another approximation of 80/20 rule)

Japanese communities in crisis of 1927+ have failed to orderly lay off researchers/engineers, therefore researchers in-fighting adversely affected research output.
 
Air warning radar will have the most impact.
The most obvious example would be allowing to divert some of the fighters to intercept the dive bombers before they start their attack in Midway, potentially saving the carriers.
 
Air warning radar will have the most impact.
The most obvious example would be allowing to divert some of the fighters to intercept the dive bombers before they start their attack in Midway, potentially saving the carriers.

That would also require them to have decent radios and disciplined pilots, and probably an entirely new doctrine for CAP in the first place. They could have a goddamn time traveling AEGIS set, and it wouldn't make a damn bit of difference if their only way of informing the CAP is to have the escorts fire their guns in the direction of the dive bombers. Not when practically every single CAP pilot has been sucked into the swirling furball with Thatch or is preying on the constant stream of Torpedo Bombers.
 

MatthewB

Banned
That would also require them to have decent radios and disciplined pilots, and probably an entirely new doctrine for CAP in the first place.
Yes, all that. We seem to be stuck in this thread where the IJN has air intercept radar on their carriers and other ships but have no idea how to use it, or have for some reason refused to adjust their doctrine and equip their aircraft on how to use it. Come on folks..... I've given the IJN effective shipborne air intercept radar in 1940, the IJN has a year or more to figure out how to use it. Japan has just watched Britain defeat the Luftwaffe through use of radar-vectored, radio-equipped interceptors - if they can learn from Taranto for PH, they can learn from the BoB.

So, by Dec 1941 we can assume the Combined Fleet has radar, radio-equipped aircraft, doctrine on how to use both to track incoming raids and to direct interception. What the IJN likely won't change is their re-arming of aircraft in the hangars, the doctrine not to launch strikes while receiving a strike, etc.
 
As others have pointed out , the Japanese issue was not their radar but their opinion of radar. As long as its seen as being at the low end of the totem pole, you are not going to get the operators and tactics for better sets to make a blind bit of difference.
 

SsgtC

Banned
Air warning radar will have the most impact.
The most obvious example would be allowing to divert some of the fighters to intercept the dive bombers before they start their attack in Midway, potentially saving the carriers.
Imperial Navy doctrine was that Torpedo Bombers were far more dangerous than dive bombers. So the majority of the CAP, even with good radar, fighter direction teams and radios, will still be vectored onto the torpedo bombers
 
Imperial Navy doctrine was that Torpedo Bombers were far more dangerous than dive bombers. So the majority of the CAP, even with good radar, fighter direction teams and radios, will still be vectored onto the torpedo bombers

"Oops."
 

SsgtC

Banned
Yes and no. In a way, they were right. A dive bomber can only blow holes open that let air in. A torpedo will blow open a hole that let's the ocean in. Their doctrine would have been proven correct except for two factors: the US caught the Japanese carriers in the middle of refueling and rearming their aircraft, the decks strewn with live ordinance and fuel lines. And second, the absolutely abysmal Japanese damage control.

So in a purely theoretical sense, the Japanese were right in their assessment of the Torpedo Bomber being the biggest threat to the fleet.
 
Yes and no. In a way, they were right. A dive bomber can only blow holes open that let air in. A torpedo will blow open a hole that let's the ocean in. Their doctrine would have been proven correct except for two factors: the US caught the Japanese carriers in the middle of refueling and rearming their aircraft, the decks strewn with live ordinance and fuel lines. And second, the absolutely abysmal Japanese damage control.

So in a purely theoretical sense, the Japanese were right in their assessment of the Torpedo Bomber being the biggest threat to the fleet.

They also had to operate under the assumption that American torpedoes actually worked.
 
Yes, all that. We seem to be stuck in this thread where the IJN has air intercept radar on their carriers and other ships but have no idea how to use it, or have for some reason refused to adjust their doctrine and equip their aircraft on how to use it. Come on folks..... I've given the IJN effective shipborne air intercept radar in 1940, the IJN has a year or more to figure out how to use it. Japan has just watched Britain defeat the Luftwaffe through use of radar-vectored, radio-equipped interceptors - if they can learn from Taranto for PH, they can learn from the BoB.

So, by Dec 1941 we can assume the Combined Fleet has radar, radio-equipped aircraft, doctrine on how to use both to track incoming raids and to direct interception. What the IJN likely won't change is their re-arming of aircraft in the hangars, the doctrine not to launch strikes while receiving a strike, etc.


My point was more the fix isn't going to be as easy as just instituting one or two things shipside. You'll also need to refit the ships themselves, and given the tiny size of Japanese carrier Islands, I'm not entirely sure where you're going to find space to put the radar operators. So it needs to be enlarged. So that's a period of some time where the Carrier is in a refit, which brings up the temptation of doing more things then just enlarging the island and adding RADAR, which means it takes longer. And the Refit is problematic anyways, given the shipbuilding conditions in the Home Islands. You'll also need to institute changes to operating procedures so pilots are not having the mechanics REMOVE THE RADIO FROM THE PLANE so their mount is lighter. If that's still going on then you run straight into the aforementioned problems of "You have no way to get this information to where it can do good." And get better Radios in the first place since the prevailing view seems to have been that the IJN fighter radios at Midway were terrible, and thus not worth the extra weight.
 
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