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Mike Williams
14 Feb 08,, 15:14
Dear all, (My first Post)

I have long been intrigued by the mystery of the Japanese battleship Mutsu’s explosive demise on the 8th June 1943, while lying safe and secure within the main fleet anchorage off Kure.

There are various theories and hypotheses, ranging from an accident connected to the Japanese atomic bomb project, Allied sabotage, suicide of a crewman, and faulty munitions (the simple explanation). There is nothing really definitive and conclusive in any published (English language) work or web site.

Does anyone have any idea were I can finally discover the truth behind this cataclysmic event.

I am an amateur naval enthusiast who has long been fascinated by the life and times of the world’s great capital ships, and despite so much information released over the years and authoritative research conducted by experts, I am still amazed that something like a clear explanation into the reasons behind the loss of the Mutsu should still be so hard to faithfully determine.

Any information, opinions, or views on this subject will be greatly welcome to settle this quest to discover the truth about this event. Is there anything in Japanese (which might have been translated), I have looked but can find nothing.

Regards
Mike Williams (Edinburgh, UK)

Dreadnought
14 Feb 08,, 19:02
There are many interesting theories surrounding the sinking of IJN Mutsu in home waters. There are several different accounts of what "could" have happened. All seem to have atleast some coincidence involved in them given the time frame from when she was dry docked and serviced days before to the arrival of the airwing instructors and cadets that were aboard when she exploded and the fact that she was carring the incindiary shells aboard at the time of explosion that were previously involved in a fire at the Sagami arsenal years prior. Also was the theory of a lone Allied sub or British X craft midget subs entering the harbor undetected during operation "Source" (the same mission as to where the British attacked the Tirpitz in Norway 1943).

I have read about most of the theories and even know that eye witnesses to the explosion claimed the fire burned reddish/brownish (magazine explosion) over the whittish smoke from the incindiary shells some still seem to favor a sub attack in the home anchorage.

In my own reasoning if the Brits or U.S. attacked Mutsu in the anchorage why did they not wait but hours until Nagato would have entered the anchorage and you also would have had heavy cruiser Morgami in the very same anchorage. That in itself would have been "Carte Blanche" on any firing solution deemed good and claim three capital ships at once instead of only one and have to avoid the others while leaving the anchorage undetected.

One reason why I rule out the USN is due to the facts behind Nagato's surrender to the USN. After the surrender of the ship according to the reports the IJN was thoroughly questioned as to the whereabouts of Mutsu. Playing a smart dumb or honestly unknowing. Could be either.

By the way Interesting first post and welcome to WAB.

Mike Williams
15 Feb 08,, 10:38
Dreadnought,

Thank you very much for the very detailed reply, confirming the various theories available.

I can see Occam's (Ockham's) razor taking effect here, the exquisitely simple principle which states that the explanation of any event should make as few assumptions as possible, removing those that make no difference in the clarification of a theory. Often paraphrased as “All other things being equal, the simplest solution is the best.” That is just spontaneous detonation of defective cordite.

But why did this occur just onboard the Mutsu, and not other WWII Japanese capital ships if this was the case, that is the great question, why just her.

Could a disgruntled (suicidal) crewman have instigated such an explosion. How easy or difficult would this be onboard a busy battleship.

It looks like I am back to considering all the options again. Thanks for your very welcome and interesting contribution.

Regards
Mike

flogger
15 Feb 08,, 13:34
In my own reasoning if the Brits or U.S. attacked Mutsu in the anchorage why did they not wait but hours until Nagato would have entered the anchorage and you also would have had heavy cruiser Morgami in the very same anchorage. That in itself would have been "Carte Blanche" on any firing solution deemed good and claim three capital ships at once instead of only one and have to avoid the others while leaving the anchorage undetected.

.

If such attacks had ever happened why would the British or Americans have kept it secret for so long, especially if they had been such a success ? This theory is as a consequence a non starter in my view.

Here is an interesting site with some of the latest (lets be frank) guesses as to her loss. Good salvage photos here too.

http://www.bobhenneman.info/mutsuwrk.htm

My view is that it was probably some kind of magazine refrigeration failure given that it was a warm day when she was lost. Some tests had been done on the incendiary shells she had on board after earlier problems and they were found to be satisfactory .
Magazine explosions were not unknown aboard Japanese battleships, the Kawachi having been previously lost to such causes in 1918. It is unusual for such an incident to have occurred in late WW2 however.

Dreadnought
15 Feb 08,, 15:22
If such attacks had ever happened why would the British or Americans have kept it secret for so long, especially if they had been such a success ? This theory is as a consequence a non starter in my view.

Here is an interesting site with some of the latest (lets be frank) guesses as to her loss. Good salvage photos here too.

http://www.bobhenneman.info/mutsuwrk.htm

My view is that it was probably some kind of magazine refrigeration failure given that it was a warm day when she was lost. Some tests had been done on the incendiary shells she had on board after earlier problems and they were found to be satisfactory .
Magazine explosions were not unknown aboard Japanese battleships, the Kawachi having been previously lost to such causes in 1918. It is unusual for such an incident to have occurred in late WW2 however.

The above I posted is exactly why I rule out a British or Allied sub taking her out. If it had been a sub attack they would have studied the anchorage over and over again (same with the Tirpitz attack) to find exactly when more then just Mutsu was in anchorage and make it worth the risk of loosing one of their boats for just one prize.

Lets us also recall days before when she was in drydock and having the hull serviced. Anyone could have been aboard her in the IJN that was disgruntled or sabateor but why place a bomb on her this early into the war. Things had not yet gone bad for the IJN (with exception) as did in the years to follow had. And I in my opinion dont believe she was destroyed by a shipman who was accused of theft and blew up the ship. Seems extremely petty and grasping for straws. Since eye witness accounts state the flash was reddish brown that indicates a mag explosion as the primary detonation point (same as Hood and several others). This could have been caused by faulty shell fuses or a number of things could have gone wrong. One thing eye witness accounts did state is that there was no fire or flame noticed prior to the explosion. And the tests conducted on the suspected shells failed to produce the same results. We know from reports that the Japanse fuze detonators were sound to a point. But they also didnt consider certain mechanical aspects that could in all theory iniciate through the detonator itself. I will come back to this later after rereading the reports.

I am very familiar with Mr. Hennemans writings and his web sites.

flogger
15 Feb 08,, 15:36
Anyone could have been aboard her in the IJN that was disgruntled or sabateor but why place a bomb on her this early into the war. And I in my opinion dont believe she was destroyed by a shipman who was accused of theft and blew up the ship. Seems extremely petty and grasping for straws.

I agree the psyche of the Japanese bushido code was big on self destruction but not on the destruction of ones comrades outwith a battle arena.


Lets us also recall days before when she was in drydock and having the hull serviced.

Without knowing the exact details on what that servicing entailed it is difficult to draw conclusions there. Perhaps if it had happened during the servicing rather than after and they had been welding or rivetting in the magazine area then I would put more emphasis on this as a potential cause.


Since eye witness accounts state the flash was reddish brown that indicates a mag explosion as the primary detonation point (same as Hood and several others).

I agree, but the cause of that explosion may well never be determined. Only a magazine explosion could have caused the scale of damage witnessed on the hull the after part of which was missing !

flogger
15 Feb 08,, 15:46
Deleted post.

Dreadnought
15 Feb 08,, 15:46
My view is that it was probably some kind of magazine refrigeration failure given that it was a warm day when she was lost. Some tests had been done on the incendiary shells she had on board after earlier problems and they were found to be satisfactory .

Magazine refrigeration? Please explain.:confused:

flogger
15 Feb 08,, 16:08
Magazine refrigeration? Please explain

The British introduced magazine cooling ventilation plants (we called it refrigeration but it was probably no more than a cooling of 5 -10 degrees or so) into our dreadnaughts after the catastrophic loss of HMS Vanguard to spontaneous magazine explosion in 1917 while at anchor in Scapa Flow (see R. A. Burts. British Battleships of WW1 for details... exc publication BTW). One of the causes ascribed to this loss was ashes from boilers being placed near or against bulkheads for P or Q magazines. There was some suspicion too that the loss of the earlier HMS Bulwark may have been partially attributable to such factors, and certainly the later loss of the monitor HMS Glatton most certainly was. One of the Admiralty board decisions taken at the time as a consequence of this particularly devastating loss was to fit cooling systems to future designs and retro fit where possible existing designs as required . As the British and Japanese were allies I dont doubt that such technical data would have been passed on to them by the British and would have been incorporated into thier designs at the time. The USN 'Big Five' had just such a system too if memory serves. I honestly dont know if such cooling plants did exist aboard Mutsu its just an assumption on my part that there were for the reasons I've already espoused.

I admit its 'stretching' it a bit as a cause for the loss of Mutsu but .... who will ever really know ?

Dreadnought
15 Feb 08,, 18:40
The British introduced magazine cooling ventilation plants (we called it refrigeration but it was probably no more than a cooling of 5 -10 degrees or so) into our dreadnaughts after the catastrophic loss of HMS Vanguard to spontaneous magazine explosion in 1917 while at anchor in Scapa Flow (see R. A. Burts. British Battleships of WW1 for details... exc publication BTW). One of the causes ascribed to this loss was ashes from boilers being placed near or against bulkheads for P or Q magazines. There was some suspicion too that the loss of the earlier HMS Bulwark may have been partially attributable to such factors, and certainly the later loss of the monitor HMS Glatton most certainly was. One of the Admiralty board decisions taken at the time as a consequence of this particularly devastating loss was to fit cooling systems to future designs and retro fit where possible existing designs as required . As the British and Japanese were allies I dont doubt that such technical data would have been passed on to them by the British and would have been incorporated into thier designs at the time. The USN 'Big Five' had just such a system too if memory serves. I honestly dont know if such cooling plants did exist aboard Mutsu its just an assumption on my part that there were for the reasons I've already espoused.

I admit its 'stretching' it a bit as a cause for the loss of Mutsu but .... who will ever really know ?

Ok,that sounds better when I saw refrigerated I thought I was misreading.
FDA or forced draft air through ventilators was commonly used to provide the magazine with positive flow of air so as to keep it imo positively pressurized and cooler (or always exausting a postive air flow instead of inductive). How many degrees cooler? That one I cant answer. I guess if we knew the measurments and the means used we could formulate some kind of calc to figure it out. I have been in the mags of a few WWII BB's and from what I seen they are pretty large rooms and if you were to include the shell deck/decks of the turret then the space becomes either two or three fold. I know the Iowa class shell decks are very large indeed. But considering the hydraulics and huge electric motors used for these spaces and equipment I'm not sure that it could be but maybe 10-15 degrees cooler pending on the outside air temps.

Tiornu
17 Jun 08,, 07:56
The official enquiry never came up with a convincing explanation of what happened. The theory that sits best with me involves crewmen brewing up some illicit beverage in a suitably isolated place.
Unlike Glatton, Mutsu had no old newspapers stuffed into her as insulaton--I'm pretty sure....
Eyewitnesses reported billows of white smoke, which cast suspicion of the Type 3 shells. As Dreadnought has noted, tests later effectively disproved that theory.
The Japanese continued to be closely familiar with British designs up to about 1923 when Japanese designers were barred from Greenwich due to IJN secrecy about the latest cruisers (Furutakas). They knew all the capital ships pretty well up to Hood, and you will see some unmistakable N3/G3 features in Japanese battleship sketches of the late 1920's.