HMS Hood & USS Arizona Magazine Explosions

[tommy303]

I'm curious that Mullenheim-Rechberg never made a comment about that, being a gunnery officer (though of course Bruno turret wouldn't be directly his concern) and as such wou;d be privy to any problems, after the action?

I was probably not terribly concise in wording that. The problem with Turret B was on Prinz Eugen and is taken from the statement of first Gunnery Officer Jasper, and the Baron would not have had any knowledge of problems on the cruiser until after the war most likely.

It might well be true that he knew of a few missed salvos by one or more of Bismarck's guns, as his position also had an SFS-Anzieger, or gun ready board. It is equally possible that he might not have noticed any problems as he had been specifically ordered to keep Wake-Walker's cruisers under observation and was not concerned with directing any of the ship's armament during the course of the battle with Holland's battle squadron. Main armament direction was from Schneider's position in the foretop throughout the battle and the control of the secondary armament was from the Albrecht's position in the gunnery control position in the conning tower.

[paulcadogan]

Yes, however one does the math, her output is three shells less than one would have expected, 96 being equal to 12 full broadsides or 24 turret group salvos. In at least one photograph, she appears to be firing with only Bruno, Caesar and Dora in what appears to be a six gun broadside, while Anton is trained on a forward bearing. This would be at least two of the three unfired shells.

At the risk of going well off topic on the issue of that famous photo and the bearing of turret Anton, that was disccussed at great length elsewhere a few years ago. The thing is, that it is most probable that Anton was trained in alignment with the other turrets and the "forward" effect is an optical illusion generated by its position and the flash behind it obscuring most of its details. As a result, our brains - trying to reconcile a 2D image into 3D - can see it either way and perception can flip back and forth (c.f. those psychological drawings in which two competing images are visible and our perception flips betwee one and the other).

During those discussions, I took some photos of a very old Airfix Bismarck model to try to demonstrate the point. The first two have the model back-lit with a powerful beam that simulates the gun flash. Can you tell which way it is pointing - off the bow or to port? I'll put the photo with the actual position in a separate post.

If there's a problem topic-wise and a separate thread needs to be started for more discussion, let me know!

[paulcadogan]

OK now....this is the photo in question:



And the picture of the model fully lit to show the turret position - trained to port in the same orientation as the other four.

So in all likelihood, all Bismarck's turrets were trained on her target (PoW in the photo), but Anton did not fire in that particular salvo, confirming that Bismarck did not necessarily fire full broadsides, and maybe giving some explanation to Schneider's comment on the possible "misfire" as he saw the result of his salvo that put a shell into Hood's aft magazines (to come back on topic! )

[tommy303]

I actually concur with Paul that in reality Anton was probably trained on PoW and had been misled by the very contrasting photo originally referred to. The one Paul has presented is much better and likely taken from the original negative or film and is a bit clearer than the darker, oft reproduced photo. It may be that Anton and Bruno had just fired a salvo, and the smoke cloud can be seen being lighted up by the flash of a salvo from Caesar and Dora. The smaller flash somewhat in line Bruno might be a salvo from the secondary battery which was firing as well.

[alecsandros]

Very nice photos Paul,

Thanks very much.

I would have another question: is it certain that the 6th salvo against Hood was a complete salvo ? (4 +4 guns) ?

I'm asking because Hood exploded 2-3 seconds after the 5th salvo, thus maybe only some turrets fired the 6th one ?

Cheers,
Alex

[paulcadogan]

Thanks guys, glad you found the photos useful. I build that old Bismarck model as a kid in the late 70's and as you can see it's still around!

My take on the famous photo is that the huge puff of smoke drifting away is from Caesar and Dora's semi-salvo and Bruno is just firing its portion of the second semi-salvo with Anton silent. I doubt the firing of the 15 cm secondaries would have created such a large flash over Bruno.

The photographer's timing was brilliant - I'd think he was trying to catch the ship firing and snapped the photo within a couple seconds of C & D letting loose - precisely the time of the second half, so he caught the flash of Bruno without the smoke.

On the matter of the 6th salvo, that's really conjecture. Schneider had ordered full-salvoes-good-rapid once he had straddled Hood. I presume he would be shooting as fast as possible without waiting for fall of shot for correction - am I right? If so then the 6th salvo going at Hood would have depended on the flight time versus the reload/guns ready time. If Hood blew up before he "pulled the trigger" then I doubt he'd have wasted the shells!

[tommy303]

My take on the famous photo is that the huge puff of smoke drifting away is from Caesar and Dora's semi-salvo and Bruno is just firing its portion of the second semi-salvo with Anton silent. I doubt the firing of the 15 cm secondaries would have created such a large flash over Bruno.

The photographer's timing was brilliant - I'd think he was trying to catch the ship firing and snapped the photo within a couple seconds of C & D letting loose - precisely the time of the second half, so he caught the flash of Bruno without the smoke.

That seems reasonable.

Schneider had ordered full-salvoes-good-rapid once he had straddled Hood. I presume he would be shooting as fast as possible without waiting for fall of shot for correction - am I right?

Yes that is correct. Bismarck would fire rapidly without waiting for each salvo to land; instead, fire would continue as fast as the guns could be loaded going by the predictor element of the fire control computer and with Schneider making slight corrections for enemy changes in course to keep the MPI on target.

[alecsandros]

Yes that is correct. Bismarck would fire rapidly without waiting for each salvo to land; instead, fire would continue as fast as the guns could be loaded going by the predictor element of the fire control computer and with Schneider making slight corrections for enemy changes in course to keep the MPI on target.

Yes, indeed

I thought about it several times, and I am still not sure how it worked:

Salvo 5, fired from A+B and C+D, was fired at a probable distance of 15-16km (not sure if there's a consensus about the range ?).

There would be a delay in the firing, of about 3-4 seconds: first A+B would fire, and then, after a few seconds, C+D. [I would expect this to happen because of the previous semi-salvos: if the reloading time was not different, than the early salvos would impose a certain tempo. ]

And now it gets interesting:
--- Time of flight for GErman 38cm shell at 15-16km was 23-24seconds.
--- Salvo 5 landed at least 1 shell that destroyed Hood. It is likely that the shell was coming from the first group of 4 shells fired. There is also a possibility that the second group of 4 shells fired in that salvo also "ate into it".
--- Time between the impact and Hood's massive explosion was probably 1-2 seconds. The explosion was visible instantly...

Thus, if I understand it correctly, the interval between firing of the first semi-salvo of salvo 5 and Hood's explosion, as seen by the crew of Bismarck, was around 24-25seconds.

----

Now, if salvo 6 was fired using all 8 guns (4+4), it would imply that firing cycle at that time was 25 seconds at the most for semi-salvo 1 and 21 seconds and the most for semi salvo 2. Because that's what it looks like - the Germans must have already fired salvo 6 when Hood was blowing up, otherwise they wouldn;'t have fired it at all.

Of course, given certain metrics that we know, it is possible that Bismarck's guns could deliver 24 shells/minute (3/gun), corresponding to a firing cycle of 20sec.
However, it would be an extreme happening in this case [as the firing cycle of semi-salvo2 from salvo 6 appears to have been 21 sec at the most]

So this is why I think the possibility exists that at least some turrets did not participate in the firing of salvo 6...

I know it's a lot of guesswork, but lacking better info....

[paulcadogan]

Alex,

I'm not sure I follow your reasoning. How can the firing cycle for semi-salvo 2 be less than that of 1? Also, from the battle film, to me, the interval between semi-salvoes is at the most 2 seconds.

I think the interval between the fall of salvo 5 and Hood's explosion was a little longer than 2 seconds - Leach had the chance to watch Hood for the result of what he thought had "arrived aboard", plus others did not associate shell splashes with the explosion, suggesting that the water columns had subsided by the time the flame shot up.

All in all that suggests that salvo 6 would indeed have been fired - but with Hood's rapid deceleration as she broke apart, it would probably have landed some distance ahead of her and not have been noticed by the awestruck onlookers....

[alecsandros]

Dear Paul,

I took a look again at Prinz Eugen movie, and you're right! The firing sequence is perhaps 2 seconds long between semisalvos... I took the 3-4 seoncds interval from my memory, as I seem to recall that was the recommended interval in German turretgroup firing (IIRc).

WIth this in mind, I made the following assumptons:

For easier calculus, let's say semisalvo 1 from salvo 5 was fired at 6h:00min:00sec, range 16km.
This would imply a 24sec time of flight, thus the semisalvo would strike at 6h:00min:24sec.

semisalvo 2 from salvo 5 would be fired at, let's say, 6h:00min:02sec, at same range.
This would mean semisalvo 2 would strike at 6h:00min:26sec

Now,
the Hood would be hit by at least one shell coming from one of the semisalvos.

the explosion would be clearly visible from Bismarck 1-2 sec later, or this is what I understand from Bill Jurens's paper on Hood's demise...

this would take us to 6h:00min:26sec or 6h:00min:28sec, depending on which semisalvo actualy destroyed Hood (if not both).

----
and this takes us to...

semisalvo 1 from salvo 6 must have been fired before 6h:00min:28sec, and semisalvo 2 from salvo 6 before 6h:00min:26sec

[paulcadogan]

semisalvo 1 from salvo 6 must have been fired before 6h:00min:28sec, and semisalvo 2 from salvo 6 before 6h:00min:26sec

Hi Alex,

What I'm getting at is that semi-salvo 2 - cannot be fired before semi-salvo 1 - or it will be semi-salvo 1...

So if 1 is fired at 6:00:28, then 2 must follow at 6:00:30 (not 6:00:26).

In any case, I think the way to work it is: if the firing cycle for Bismarck in good-rapid mode was 20 seconds, and the flight time 23 - 24 seconds, then chances are both semi-salvoes of salvo 6 were indeed fired (6:00:20 and 6:00:22) and would have been a few seconds outbound when Hood exploded, and then fallen out for line, ahead. Schneider would then have had to adjust his bearing left to take on PoW.

[tommy303]

I do not think one can be terribly precise down to the second when a salvo was fired. Normally, when firing from the directors, the director layer is responsible for firing when he judges his horizon wire is on target; it is possible that the time between one salvo being fired and the next might differ somewhat depending on the judgement of the director layer. There is also the matter of a slight delay as the rating at the gun ready board shifts from one turret group to the next.

[tommy303]

Another possibility might be if the firing was being done through the automatic stabilized firing circuits rather than having the layer fire the guns based upon his judgement of the timing of the roll. In this instance, the layer presses his firing key but the guns do not fire until the gunnery gyro closes the firing circuit when the mounts are level. Depending on how much the ship is pitching and rolling, there might be a very slight delay between the firing of the forward and after turret groups making it appear to be two separate salvos instead of a broadside. British witness did note the apparent ripple fire effect on both German ships, and this might well have been because the Germans were using the stabilized firing devices.

[alecsandros]

semisalvo 1 from salvo 6 must have been fired before 6h:00min:28sec, and semisalvo 2 from salvo 6 before 6h:00min:26sec

Hi Alex,

What I'm getting at is that semi-salvo 2 - cannot be fired before semi-salvo 1 - or it will be semi-salvo 1...

So if 1 is fired at 6:00:28, then 2 must follow at 6:00:30 (not 6:00:26).

Aaah, that's right,
My mistake,

I wanted to link the semisalvos with the turret groups (A+B and C+D).

That's why I wrote "semisalvo 1" (as coming from the same turret group as semisalvo 1 of the previous salvo - for simplicity let's say it was A+B)...

That's why, given the slight delay in the firing of the 2 turret groups, I would expect the second semisalvo from salvo 6 [let's say C+D], fired from the same turret group as semisalvo 2 of salvo 5, to be fired at 6:00:00:26sec at the latest...

----

Of course, Thomas is right and I'm actualy nit-picking on the subject... :) It's highly unlikely that perfect intervals were obtained during the actual battle...

I guess the problem of actual number of "missed" shells by Bismarck that day would never be solved after all....

[Djoser]

I am also wondering if the turrets of the US super dreadnoughts were somehow locked or held into the barbettes, as opposed to falling out when capsized.

Observe the salvage of the Oklahoma at Pearl Harbor. The ship was nearly upside down, to the extent that the forward superstructure was crushed. Yet when the ship was painstakingly and slowly righted, the turrets were still in place and apparently hadn't even budged.

http://www.history.navy.mil/photos/imag ... h63916.jpg

http://www.history.navy.mil/photos/imag ... 410533.jpg