HMS Hood & USS Arizona Magazine Explosions

[steffen19k]

I read William Jurens "Loss of HMS Hood" for the umpteenth time.

Bear with me as I compare this to the loss of Arizona, who was about the same age, and also suffered a critical magazine hit.

One thing about Hood strikes me as suspicious. The X turret was flung into the air at the time of her magazine explosion. The USS Arizona suffered a Magazine explosion, and yet both turrets remained in its place. In fact, A turret was untouched, and B turret (closest to the magazine blast) had its barrels removed for installation as coastal guns, while X and Y turrets were completely removed. A Turret is still in position today as she sits on the bottom.

All I can think of about the differences at the moment are the flash protection measures as they were in effect at the time of battle within the turret casemates and barbette.

the Arizona's was indisputable. She was not prepared for action in any way as the fatal hit landed.

Hood on the other hand had been at action stations for at least an hour prior to engaging Bismarck.

I can't help but believe that there is a strong possibility her safety systems were bypassed to permit the fastest possible time between broadsides. Perhaps not as bad as the BCF at Dogger Bank, but certainly enough to cause the effect noticed by witnesses aboard PoW who saw the turret get flung into the air.

Before you discuss the Hoods armor containing the blast to create the uplift, I point out that Arizona blew out to the sides, which is how I percieve the Hood SHOULD have blown out, if the armor had anything to do with it.

[pg55555]

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No way.

Scuttles would have to be physically removed to be "by passed" and hatches in hoists were basically inaccessible except for major work. The interlocks mechanism only worked one way,

There was no room for extra storage.


Somewhere on the web is a set of plates from a 15-inch handbook - it will give you an idea of the impossibility. IF you know anything of the fail safe mechanical inter-locking used in steam age railway signal boxes then you will realise the fallacy of your "idea".

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[steffen19k]

Really? you're claiming that its impossible to bypass the ammo interlocks? Have you ever heard of the basics of "Nothing can truly be fool proof because fools are so ingenious?"

Furthermore, if you have access to this 15 inch thick book, then why didn't you provide some links or excerpts or something? I'd like to see the data you speak of, and not just as a matter of dismissing your arguments.

And there is a significant difference between railway interlocks and ammo handling equipment.

[pg55555]

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Post your evidence if you have any.

The 15-inch handbook is in the PRO

The interlocks were produced by one of the railway interlock companies.

Sanity please !

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[tommy303]

Most likely the explosions would have been similar had they both involved the forward magazine groups. In Arizona there was much more structure above the magazines forward. In Hood the after magazines had less structure above them because, like Arizona, she was not flush decked. This meant it was easier for the expanding force of the explosion to vent upwards. Had the explosion been forward, then she might have blown up similarly to Arizona. It is also possible that the Arizona had different arrangements in the turret barbette structure which more firmly locked the turret to the barbette. In Hood, if memory serves, gravity held the turret and rotating structure in place.

[steffen19k]

Most likely the explosions would have been similar had they both involved the forward magazine groups. In Arizona there was much more structure above the magazines forward. In Hood the after magazines had less structure above them because, like Arizona, she was not flush decked. This meant it was easier for the expanding force of the explosion to vent upwards. Had the explosion been forward, then she might have blown up similarly to Arizona. It is also possible that the Arizona had different arrangements in the turret barbette structure which more firmly locked the turret to the barbette. In Hood, if memory serves, gravity held the turret and rotating structure in place.

Thank you for your information Tommy. I guess the issue in question then would be how thick is the barbette surrounding the ammunition handling, and whether or not the magazine explosion would have been enough to breach it.

Do you, good sir, have more concise data on that?

[tommy303]

The actual magazines in both Hood and Arizona were located below the armoured deck and not within the barbette. Arizona did store her shells within the rotating structure of the barbette, as was common in US battleships, but the powder magazines were below and outside of the barbettes themselves (which terminated on the armour deck). Hood's magainzes were likewise below the armour deck with an additional armoured crown placed over the after 15inch magazines, but not over the 4in magazines just forward. Hood's shells were stored in shell rooms below the magazines.

The powder rooms in both surround the handling rooms where the hoist trunking was located. The hoists were part of the rotating structure of the turret, but at handling room level were below the point where the barbette armour terminated.

[steffen19k]

That's so much help. I think I can finally visualize what happened now when the magazine blew to cause the turret to lift off.

The handling rooms probably had reasonable stash of ready ammo, and when the magazine blew, the handling room went, and turned the barbette into a giant venturi tube which lifted the turret...

Thank you for helping me understand why I was wrong. This thread can be deleted now.

[tommy303]

One of the interesting points of the Hood's design was the inclusion of, if I recall, splinter bulkheads abreast the after magazine group. These were inside of the main belt armour and anti-torpedo bulkhead and were intended to intercept splinters from a shell which pierced the main armour and burst outboard of the magazines. To my knowlege Arizona did not have this feature and in Hood's case, may have helped contain, momentarily, the expanding gases as the magazine went. This might have directed the gases into the handling room and from there up the barbette, which would represent the primary route of least resistance. This would have occurred without any charges being in the handling rooms themselves--somewhat like a venturi effect. Eventually though, the massive overpressure would have conspired to completely wreck the after part of the ship as the contents of the magazines completely exploded and side and deck structures in the area disintegrated.

[pg55555]

..............The handling rooms probably had reasonable stash of ready ammo, and when the magazine blew............

NO.

The handling room received the charges through flash-tight scuttles, MECHANICALLY transported them to the flash-tight scuttles of the hoists and that's all. IF a charge was incorrect it would have to be returned to the magazine.

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[Djoser]

I am thinking the Arizona's turrets were almost certainly heavier than the Hood's, as well. For one thing, they were triple turrets. For another, I believe they had thicker armor in general.

[RF]

Before you discuss the Hoods armor containing the blast to create the uplift, I point out that Arizona blew out to the sides, which is how I percieve the Hood SHOULD have blown out, if the armor had anything to do with it.

I am a layman here and not an engineer or munitions expert, but my understanding is that on Hood the after 4 inch magazine ignited and flashed over into the main after 15 inch magazine, some 300 tons of ordnance. The explosion (apparently without sound) blew Hood in two, suggesting to me that the force of detonation vented a full 360 degrees and not in one direction only, be it upward or through the sides.

[tommy303]

From descriptions from eye witnesses submitted to the court of inquiry, the first sign that anything was seriously wrong were jets of flame that appeared around the main mast, most probably the engine room vents. These had the appearance of flame from a blow torch and probably represented the ignition of the contents of the 4-in HA magazine; this indicates to me that the hull and armour scheme was initially containing the expanding gases and causing them to move forward and probably aft into the turbine rooms and X Magazines respectively. Other escaping jets of flame appeared around X Barbette, again appearing to coincide with vents and probably represented the beginning of the ignition of X Magazines. At this point the whole after part of the ship between Y turret and the main mast seemed to disintegrate in a massive explosion.

As one would expect, there is some contradictory testimony concerning where flame was first spotted, but the general sequence seems to be either just ahead or just aft of the mainmast, then around the base of X-barbette, and finally the explosion that tore the ship apart. It is probable that X turret was blown free just as the whole of X and probably a good portion of Y magazines exploded.

[RF]

As one would expect, there is some contradictory testimony concerning where flame was first spotted, but the general sequence seems to be either just ahead or just aft of the mainmast,

Is there not a compounding factor here in that Hood was already on fire midships from one hit from Bismarck and two from Prinz Eugen? Aircraft observing from above did report two separate fires on Hood prior to the fatal hit.

[paulcadogan]

Is there not a compounding factor here in that Hood was already on fire midships from one hit from Bismarck and two from Prinz Eugen? Aircraft observing from above did report two separate fires on Hood prior to the fatal hit.

The fire from Prinz Eugen's hit was still burning when the initial jet of flame from the final explosion appeared and, thus, was a separate entity. I am probably much more of a layman than you RF, but I doubt that boat deck fire had any significant effect on the ship's break-up.

The second fire, reported by the Sunderland, was apparently at the base of the bridge structure from the hit witnessed by Bob Tilburn that supposedly killed or wounded many men sheltering there. (This is further corroborated, I think, by Ted Briggs' account in which he describes the cries of the wounded coming up through the voice pipes, including his "oppo" Ron Bell on the flag deck.) This second fire, again, would not have affected the breakup of the ship.