IJN Yahagi 1944

[Laurence Batchelor]

Dear all

Something I meant to ask about 2 weeks ago but forgot.
I finished reading Hara's Japanese Destroyer Captain book again and it raised something I knew nothing on.
Namely by 1944 on his last active mission in Yahagi with Yamato his cruiser was fitted with homing torpedoes.
I checked my copy of Campbell, but found nothing on them.
Did Japan develop its own homing torpedoes by 1944 or did they recieve technical help from Germany who developed their own Zaukonigs by late war?

Here are Hara's own words which talks of her refit just before she sailed:

But not all news was bad. New weapons and equipment for Yahagi arrived almost daily. There were proximity fuses, homing torpedos, and, most important of all, efficient radar sets. Gun crews began to learn how to use radar-controlled gunfire. Many of these devices were still in the experimental stage, but their appearance was a sign that Japanese technology was moving forward. Too late to catch up with the enemy, to be sure, but it was a tremendous morale booster in those days of adversity

also during the battle:

"okay, dump the fish!" I shouted. Almost at once sixteen powerful homing torpedos slithered unarmed into the water.

Can anyone tell me more please! Were they oxygen based?
Cheers

[Guest]

I had no idea the Japanese actually fielded proximity fused shells during WWII. If they had, they were ahead of Germans.

I also had no idea that the Japanese fielded homing torpedos. However, if the torpedos were German, they would be 533mm. Japanese surface ships used 610mm torpedo tubes. How were the launching facilitated.

There were a number of areas where the Japanese were in advance of the Germans. This includes many technical aspects of Radar. I suppose it is not implausible that the Japanese fielded some advanced prototype which where then largely forgotten in the confusion at the end of the war.

[Laurence Batchelor]

I know I think I hit a gold mine!

Does anymore information exist on any of this late war weaponry?
Anyone know any decent technical articles? I wish to know more!
I've located zero!

[chuck]

1. The Japanese had always indicated that type 22 horn antenna were used for surface gunnery fire control. There seems to be no reason to doubt it. The device's assessed accuracy in range and bearing is better than what a blind firing battleship might have receivied by reading the turret training scales and range clocks of other ship in the line during an earlier era, and in blind firing situation it is certainly much better than nothing.

2. I have seen no evidence that the Japanese had any radar that could perform full anti-aircraft fire control, rather than just an anti-aircraft plotting aid. In order for a radar to perform AA FC, it needs to be able to determine range, bearing and elevation. The antenna design and rovolving axis of all Japanese shipboard radar I've seen suggests they are capable of focusing the beam only in bearing, and can only sweep horizontally. None of them could focus a beam in elevation and sweep in azimuth. They can not use radar for blind fire AA barrage because they can not determine target elevation with their radar. At best they can use radar for range and bearing, and they still need optical device to assess target elevation.

3. The performance of AA fire during Yamato's last sortie leaves no evidence for a highly effective proximity shell. Proximity shell fuse requires perfecting the technique to produce printed circuit boards. While printed circuits are ubiquitous today, making them was no mean feat in 1945. The Soviets did not manage to make them until the 1950s. If one could point to evidence that the Japanese knew how to make printed circuit boards (The Germans didn't, AFAIK), then I would say it is plausible they could have perfected proximity fuse. Otherwise I don't believe they could have deployed workable proximity fused shells.

4. The story of homing torpedos on the Yahagi sounds fishy to me. In principle I see no reason why the Japanese could not have either developed a usable homing torpedo guidance system on their own, or acquired one with German assistance. BUT. Why would such torpedos be on a cruiser? Homing torpedos of WWII, whether German or American, were low speed affairs designed to attack low speed targets, either a submerged submarine or a slow moving merchant ship. At high speed homing capability would be masked by torpedo's self-noise. In 1944 it would be far fetched to imagine Japanese cruisers making surface attacks against slow moving American convoys. I can't believe that cruisers would be used to hunt submerged submarines. So why would cruisers have homing torpedos?

[Werner]

I agree with Chuck, especially in light of the USNI's oral history from the Japanese Navy's "Father of Radar".

Maybe the homing torpedoes came from one of the German U-Boats handed over in 1945.

Remember, Fuchida set the standard for Japanese memoirs as an obfuscation of Japanese procedure, honor and efficiency. Sounds to me like Hara is trying to out-"Fuchida" Fuchida!

[ChrisC]

Could also be a mistranslation. Awhile ago I was speaking with a fairly well known author and he stated he was interested in re-editing this book to correct quite a few errors caused by a mistake in translation.

[Laurence Batchelor]

The book Hara's quote comes from is the new tweaked USNI version I own where 2 other authors (Fred Saito and Roger Pineau) correct and fill in the gaps of his accounts.
I read the original paperback in the late 1990s, but don't have that to hand to compare.

If what Hara states is so wrong, which I doubt, why would they not put some footnotes or correction onto these statements?
They do it on a number of author points in the book.
As I said the word homing torpedo is used in 2 sperate contexts in his final chapter, it isn't mentioned in any of the earlier torpedo engagements.

I agree with you on IJN radar abilities, but I still find it interesting.
Also Hara was speaking more about surface engagement gunnery radar than air warning radar or for HA prediction etc.

Filipe told me one German U-boat, on its way to Japan in 1945, was reported to have their homing torpedoes onboard.
But they would need to be earlier if they were modified and onboard a IJN cruiser by 1944?
One speculates if these might have been early Japanese prototypes.

[Tiornu]

The Japanese did use a proximity fuze during the war. A. As in one single proximity fuze. It was photo-electric and non-rugged, and it worked perfectly well on the bomb in which it was installed, causing it to explode above an airfield causing extensive damage to B-29's parked there.

[Filipe Ramires]

Filipe told me one German U-boat, on its way to Japan in 1945, was reported to have their homing torpedoes onboard.

Let me bring some more light on this subject. Actually I was speaking of one of the japanese submarines that made part of the Yanagi operations during WWII (round trips from Japanese territories to German occupied France and vice versa). Taking a closer look here at Carl Boyds book "The Japanese Submarine Force and WWII" apparently only two japanese submarines succeeded in reaching France and coming back being one sunk in the way back home to Japan. I-8 was the first one of the two to get to France, her journey lasted from July 1943 to December of the same year... she carried back to the Japanese with military machinery, German officers, radar and hydrophon technicians and civilian advisers. She was the only submarine that managed to complete the round-trip successfully. The other one was I-29 that made her way to France as well and was coming back to Japan when she was sunk by USN submarines but not before she left some of her cargo back in Singapore. Her journey lasted from December 1943 to July 1944. She was carrying German scientific equipment and blueprints of new weapons. The cargo she left at Singapore was related with new planes blueprints and technicians which were flown away to Japan in safety. However, Allied Intelligence intercepted a message from the submarine describing her cargo and speaks of "special weapons", radar settings, Enigmas, ordnance, rock-launch systems, bombsights plans plus a few more extras. All of those were lost with her. There's no mention to homing torpedoes but the cargo manifests of both submarines are not entirely clear. To see for yourselfs take a look on Boyds book pages 127-130.
Regarding U-boats making their way to the Dutch East Indies/Malaysia/Singapore I have no data here at hand but it might be possible that they could have carried "stuff" for the Japanese too.

Regarding the homing torpedoes themselves I tend to agree with Chuck on this as well. If the IJN didn't developed yet an homing torpedo by their own it was probably because either they lacked the material to build them or lacked interest... I would take the first one more into consideration. The Zaukonigs like it was said were the birth of the homing torpedoes in wartime practically and they were SLOW being favourite only in use against slow escorts or merchants...or eventually in an "up-the-throat" kind of attack.

[Werner]

The Japanese did use a proximity fuze during the war. A. As in one single proximity fuze. It was photo-electric and non-rugged, and it worked perfectly well on the bomb in which it was installed, causing it to explode above an airfield causing extensive damage to B-29's parked there.

I doubt the technology you refer to could survive the hundreds of "G" accelleration needed to be shot out of an AA gun. Also, the area where the VT fuse fits in the 5-inch /38 is very small.

The move from 40mm to 3-inch/50 in late 1945 was because a second-generation VT fuse could be mounted in the 3", but not a 40mm.

Fusing wasn't the only defect in Japanese AAA. Although their 12cm director is rated for a target speed of 500 knots, it was relatively ineffective over half that speed.

[Werner]

Regarding the homing torpedoes themselves I tend to agree with Chuck on this as well. If the IJN didn't developed yet an homing torpedo by their own it was probably because either they lacked the material to build them or lacked interest... I would take the first one more into consideration. The Zaukonigs like it was said were the birth of the homing torpedoes in wartime practically and they were SLOW being favourite only in use against slow escorts or merchants...or eventually in an "up-the-throat" kind of attack.

This is completely inconsistent with Japanese submarine doctrine. Subs were meant to "tell-tale" fleets, and attack major combat units. So many of their combat reports of 1942-4 especially refer to sighting destroyers and concluding they were not worth an attack, or were "too far away for useful prosecution".

In that sense, a homing torpedo of the German style would have much lower priority than Kaiten weapons which provide nearly a guarantee of an honorable destruction of a major unit.

[Laurence Batchelor]

Gentlemen please can we keep on my original question and not diverge onto IJN AA which you frequently talk about.

But Filipe did any German U-boats make the trip?

Now having read Hara's book twice (both the original paperback and this newer tweaked USNI version), the impression I get of him is he a methodical and well respected Captain.

His writing style also shows good reserach methods whereby he double checks US and with his fellow IJN officers post-war before he passes comments on the important engagements of the Pacific war that he was part of and writes covers.
He also isn't afraid to criticise his fellow Captain's and Admirals, many of them personal friends, which is most useful to the historian.

My point being I think it unlikely he would make key mistakes in the quotes I used above.

[Filipe Ramires]

This is completely inconsistent with Japanese submarine doctrine. Subs were meant to "tell-tale" fleets, and attack major combat units. So many of their combat reports of 1942-4 especially refer to sighting destroyers and concluding they were not worth an attack, or were "too far away for useful prosecution".

In that sense, a homing torpedo of the German style would have much lower priority than Kaiten weapons which provide nearly a guarantee of an honorable destruction of a major unit.

Well, Laurence was asking for home torpedoes which apparently, like Hara states, were aboard Yahagi and not in a submarine. Also by mid-late war IJN sumarines, regardless of doctrine, were pretty much doing nothing useful other then some ocasional successes. They were most of the times compromised even before reaching their patrol area due to Allied codebreaking, sometimes they were even like taking a place in line just to be sunk (Ulithi). Providing them with a guided torpedo would have done very little difference just like the Kaiten.

[Werner]

Gentlemen please can we keep on my original question and not diverge onto IJN AA which you frequently talk about.

But Filipe did any German U-boats make the trip?

Now having read Hara's book twice (both the original paperback and this newer tweaked USNI version), the impression I get of him is he a methodical and well respected Captain.

His writing style also shows good reserach methods whereby he double checks US and with his fellow IJN officers post-war before he passes comments on the important engagements of the Pacific war that he was part of and writes covers.
He also isn't afraid to criticise his fellow Captain's and Admirals, many of them personal friends, which is most useful to the historian.

My point being I think it unlikely he would make key mistakes in the quotes I used above.

Well, I obviously cannot comment on the book, not having read it. Fuchida was well regarded on both sides until well after his death. Have you read Shattered Sword? The authors are at pains to explain Fuchida's duplicity in his memoirs. He was more interested in rehabilitating the IJN as an institution in a hostile post-war era than in scoring points against his former internal or external opponents. Perhaps Hara has a similarly veiled purpose which only makes sense in his context as he wrote it.

[Filipe Ramires]

But Filipe did any German U-boats make the trip?

Yes they did at least part of it, from memory here. They were operating from Singapore and Sourabaya to the Indian Ocean. One of the famous last photos of Myoko in Singapore shows her with 2 or 3 Type IX's berthed next to her. There were even some italian submarines there in fact. So it might be quite possible that such submarines could have passed on to the japanese some stuff. I will have to check that... I have a book somewhere from Paul Kemp I think on the subject.

[Laurence Batchelor]

Hara also praises many officers in the IJN, he gives his own opinions both post-war and what he was thinking at the time.
This adds to the value of his work, you get the inside as the war goes along and also the reflective post-war opinion of perhaps Japans greatest torpedo expert.
He wrote their torpedo manual in 1934 for example and is widely considered one of her greatest officers of WW2.

He writes, for example, how at the time of a certain command change he would question it and it made him most angry as a certain Admiral would be drafted one of the Navy training schools to then command a flotilla or squadron having no battle experience what-so-ever in WW2, no appreciation of night fighting tactics or ideas how to over come American skip-bombing or their advantage in radar guided gunnery etc etc.

His criticisms of how the war was being prosecuted, how the missions and tactics in naval command and planning circles were being drafted is revealing.

and no I've not read the new Shattered Sword, carrier battles bore me.

[Werner]

The Japanese actually took and operated several German U-Boats and Italian subs after the surrender of their respective powers.

[Werner]

and no I've not read the new Shattered Sword, carrier battles bore me.

You ought to. At least a third of the book deals with policy, issues of planning, the relationship of the Army and Navy, Fuchida and his book, and so on.

I would say no current study of the Imperial Navy of WW.II could be complete without reading Shattered Sword.

It's very interesting for revealing how misconceptions leak into the record, no matter how hard historians try to keep them out.

It's only 500 pages or so... you ought to be able to polish it off in a weekend.

[Filipe Ramires]

The Japanese actually took and operated several German U-Boats and Italian subs after the surrender of their respective powers.

Yes, some even with the respective italian-german crews I believe. Either they would serve under the Japanese or faced less luck in POW camps.

[Werner]

The Japanese actually took and operated several German U-Boats and Italian subs after the surrender of their respective powers.

Yes, some even with the respective italian-german crews I believe. Either they would serve under the Japanese or faced less luck in POW camps.

I'd have sailed with my Japanese officers and then slit their throats at the first opportunity. Plenty of uninhabited islands in the Pacific to wait for the surrender to occur.

If you trip down to the Solomons, there are even Lutheran churches and wooly-headed natives that speak German. Maybe a little North of Cape von Moltke on Bougainville.