IJN Yahagi 1944

Laurence Batchelor · Post by **Laurence Batchelor** » Sat Jul 28, 2007 5:26 pm

Werner wrote: How would you define Japanese "production" by April, 1945?

This was mid-1944 Werner!

Gentlemen, I can only ask of you to read Hara's recently released book and make up your own mind.
I for one see him strikingly as a very thoughtful and methodical officer and commander.

I very much doubt the IJN would be sending their best cruiser (that was left) i.e. Yahagi on a one-way suicide mission with Kaiten suicide torpedoes.
Remember the fleet was something like 9 destroyers, Yahagi and Yamato and that was all the IJN had left of the 2nd fleet.
Consider their intended mission, to make it to the USN's landings off Okinawa and sink all they could.
This is why I believe it more likely this cruiser would be loaded with anything the IJN could 'pull out of the woodwork' e.g. the laboratory.
It's no coicidence Hara was pulled from the torpedo school to Captain Japan's best cruiser that was left to them.
They hoped their lucky Captain 'who always brought his destroyer home without a scratch' and their best torpedo Captain would work miracles for them once again.
This was desperation in the extreame and why also they gave him all the best tools the IJN had to offer at this time.

Werner · Post by **Werner** » Sat Jul 28, 2007 5:32 pm

Sorry, when you put Yahagi with Yamato, I thought "final sortie".

chuck · Post by **chuck** » Sat Jul 28, 2007 5:36 pm

Laurence Batchelor wrote:
Werner wrote: How would you define Japanese "production" by April, 1945?
This was mid-1944 Werner!

Which was when Kaiten human torpedo became approved.

Laurence Batchelor · Post by **Laurence Batchelor** » Sat Jul 28, 2007 5:44 pm

My mistake sorry correction December 1944 was the month Hara joined Yahagi and it would seem the new weaponry and equipment was fitted Jan/Feb 1945.

Werner · Post by **Werner** » Sat Jul 28, 2007 5:47 pm

Laurence Batchelor wrote:My mistake sorry correction December 1944 was the month Hara joined Yahagi and it would seem the new weaponry and equipment was fitted Jan/Feb 1945.

And the Final Sortie was after 1 April 45 while the invasion of Okinawa was underway.

I'm sure that the fact that Okinawa was technically part of the Tokyo Prefecture was a great morale reason for this one-way trip.

Laurence Batchelor · Post by **Laurence Batchelor** » Sat Jul 28, 2007 6:12 pm

I went through this USN report on Japanese weapons systems (I've been through this before, but as its so long I've never been through it all), thanks for reminding me of it!
Click section 0-01-1 and yes authors/researchers seem not to have been looking at these documents properly!:

"Homing Torpedoes": In an effort to develop a "homing" torpedo, the Japanese undertook experiments with hydrophone-equipped torpedoes designed to home on a sound source. Two principles were employed, one depending on the difference in sound intensity at two points, the other on phase difference. Only electric torpedoes (Type 92) were used for experiments.

The research met with only limited success, and the experiments were finally abandoned. p3

The date is not given when their development were abandoned, but at least this is supportive evidence they existed and the Japanese were developing them themselves.
Remember this report was compiled by an Allied technical mission to Japan mostly from whatever documentation survived and by talking to co-operative Japanese personnel.
They (the Allies) may not have been told the full story and what Hara is telling us is some actually were 'gambled' and fitted to the last remaining front line cruiser left the 2nd Fleet.

I've also just found something on page 31 which states Germany delivered 10 of their electric torpedoes to the Japanese in 1942.
Right thats it this thing is getting printed!

Werner · Post by **Werner** » Sat Jul 28, 2007 6:16 pm

I posted the German delivery above; It was reported in navweps.com....

I do not believe they were homing torpedoes, simply electric torpedoes.

Laurence Batchelor · Post by **Laurence Batchelor** » Sat Jul 28, 2007 6:22 pm

I must have missed your earlier post.
I never said they were, I was making two seperate points about two different types of torpedo development they seemed to be doing.

This same report suggest further down the IJN had a fully working electric 21" torpedo by 1934 they had developed themselves. (p76)

Furthermore after going through page after page the Homing torpedoes are detailed on page290-298:

The experiments appear to have been confined to electrically driven torpedoes, and no information is forthcoming whether any operational success was acheived.

One type of these IJN homing torpedoes were modified Type 92 electric models.

Werner · Post by **Werner** » Sat Jul 28, 2007 6:59 pm

I think if you look closely at the info, the "differential passive" system was probably indigenous. I believe the German homing system relied on doppler effect steering, which would mean "differential passive" was a Japanese development, and one a naturalist (like myself) would think of. The "right" and "left" ears of the torpedo would listen for the sound and when the amplitude was precisely equal, you were properly aimed. Of course, the torpedo would take a curved course to the target, the arc size dependent on target speed. The Japanese were well-suited with the fastest torpedoes and the longest range, so they could discount the cosine costs of this kind of guidance.