Hood Sinking

[DesertFox]

I have read a great many source about exactly what sunk teh hood...one for example was a shell going two the torpedo tube into an anti-aircraft magazine which was not properly protected.

 

What si teh most common concensus today on what happened?

[Guest Sargent]

There was obviously a magazine explosion. How it occurred is open to conjecture. I would favor a spreading fire rather than a direct penetration of the magazine.

 

Does anyone know how old Hood's propellant was?

[Redbeard]

A 15" shell penetrating the upper belt (7" IIRC) and then the sloped part of the main armoured deck into the after magazine. Already at the time of construction this possibility had been foreseen but it was too late to change, and anyway I guess considered unlikely - in which I agree.

 

Hood actually was among the absolutely best protected ships when entering service and wasn't so bad in 1941. The "thin decks" getting all the blame is probbaly too simplified. First Bismarck's flat trajectory guns probably couldn't penetate the decks of Hood at the battle range, but the main belt probably could be penetrated, as was the case of all other ships afloat in May 1941.

 

So what happened to Hood any ships could have been experienced by any ship, but Hood just happened to be there and with no luck...

 

Regards

 

Steffen Redbeard

[DesertFox]

Would the same round have taken the Colorado class the same way assumign you are correct?

[Tiornu]

The most likely cause of Hood's demise was a 15in shell that penetrated the upper belt, passed the main deck level amidships through the outboard area where there was no horizontal protective plating, penetrated the turtledeck slope, and exploded in the aft portion of the machinery spaces. This area is separated from the magazines by an unarmored bulkhead, so blast and splinters and especially that big shell nose piece would most likely carry into the secondary magazines (in this case 4in rather than 5.5in). An explosion there would touch off an explosion in the adjacent main mags.

In my opinion, the second most likely cause would be a straight-up penetration of the decks. The hit took place right at the minimum range where we could expect a German 15in shell to "bite" into a deck.

The third most likely would be a penetration below the belt, or perhaps a barbette hit.

And then there's a slew of lesser theories, ranging from the inexplibable to the Serlingesque. Many people have tried to blame it all on Prinz Eugen, but without any plausible explanation of how it could have happened. One book not too long ago claimed that an 8in shell could have passed down the funnel, the author apparently being unaware that shells don't plunge vertically out of the sky. I've also heard at least two variations on the "Hood killed herself" theory, and even a claim that Norfolk did it. No idea is too ridiculous. That explains my own pet theory that the culprit was a Klingon star cruiser.

[Tiornu]

Would the same round have taken the Colorado class the same way assumign you are correct?

It would probably not be the case, except for the fact that Hood was probably turning at the moment of the hit, which could cause an increase in deck penetration--so I wouldn't rule it out. For an unmodernized ship, Colorado had pretty good deck protection.

[Tiornu]

I will disagree somewhat with Redbeard. It certainly is true that Hood's deck protection was no worse than you'd find in most battleships of that period, but much had changed in 20 years, and there were cruisers in service with better deck protection than Hood.

Hood had no immune zone to Bismarck's guns but there were ships afloat at that time that did have one. Just looking at North Carolina as an example, a Bismarck shell from that range and from that bearing could not have effectively penetrated either the deck or the belt armor. The same would hold true for Nelson and PoW. Littorio...that would be interesting. Richelieu would also be okay. For older ships, Nagato would not have suffered the catastrophe, though her engine rooms might be messed up. I suspect the rebuilt US Standards would have managed also.

But when these big chunks of steel are flying around, who knows...?

[DesertFox]

Originally posted by Tiornu:

It would probably not be the case, except for the fact that Hood was probably turning at the moment of the hit, which could cause an increase in deck penetration--so I wouldn't rule it out. For an unmodernized ship, Colorado had pretty good deck protection.

 

Enough to stop a Klingon Star Cruiser

[sabotshooter 88]

This link may help

http://www.hmshood.com/ship/history/bmhood/BMHood.html

 

 

KC

[lucklucky]

What was the sea state at the time and the possible worst case scenario for Hood "inclination" ? Anyone checked that?

[Michael Eastes]

I have a copy of the Admiralty investigation paper, and they agreed with Comrade Tiornu.

 

Edit to include quote:

 

"We conclude

1)That the sinking of the Hood was due to a hit from Bismarck's 15-inch shell in or adjacent to Hood's 4-inch or 15 inch magazines,causing them all to explode and wreck the after part of the ship. The probability is that the 4-inch magazines exploded first."

 

By the way Richard,I got the book in the mail, and am enjoying it. Anyone with an interest in WW2 warships should pick one up.

 

[Edited by Michael Eastes (28 Nov 2004).]

[Tiornu]

"I have a copy of the Admiralty investigation paper, and they agreed with Comrade Tiornu."

See how smart those Admiralty fellows are?

 

"By the way I got the book in the mail, and am enjoying it."

Very good. I suppose that means you'll be wanting to get a reserve copy, in case of emergency."

 

Notice that the page cited by sabotshooter 88 has on it a link to the Bill Jurens article on Hood's loss, which certainly is the best examination of the topic. I believe he also addresses the topic of Hood's roll during her final turn. Note that since the writing of that article Bill has had the chance to examine the Hood wreck, and her rudders are in position to steer a turn.

[Scott Cunningham]

Hood blew up due to a propellant fire in the rear (C Turret) powder magazine. How the powder got ignited is the big question.

 

This is pretty much the same thing that took the USS Arizona apart a few months later.

[Redbeard]

Originally posted by Tiornu:

Hood had no immune zone to Bismarck's guns but there were ships afloat at that time that did have one. Just looking at North Carolina as an example, a Bismarck shell from that range and from that bearing could not have effectively penetrated either the deck or the belt armor. The same would hold true for Nelson and PoW. Littorio...that would be interesting. Richelieu would also be okay. For older ships, Nagato would not have suffered the catastrophe, though her engine rooms might be messed up. I suspect the rebuilt US Standards would have managed also.

But when these big chunks of steel are flying around, who knows...?

 

 

What range are you using? Judging from your excellent penetration tables, the range would have to go beyond 20k before any imunity for any belt can be counted on. IIRC the range at which Hood was hit is usually estimated at somewhere between 13 and 19k? At the lower end I doubt any belt would be safe and at the higher you would have to count on target angle and good luck, but nothing is guaranteed.

 

Regards

 

Steffen Redbeard

[Tiornu]

For lack of a definitive figure, I usually peg the fatal hit at a 16,000yd range. This would be well to the inside of NC's immune zone, but note that I was also considering the target angle. NC would have an immune zone, but I would estimate it at somewhere around 25,000-32,000 yards.

[Redbeard]

Originally posted by Tiornu:

For lack of a definitive figure, I usually peg the fatal hit at a 16,000yd range. This would be well to the inside of NC's immune zone, but note that I was also considering the target angle. NC would have an immune zone, but I would estimate it at somewhere around 25,000-32,000 yards.

 

16k sounds reasonable, and Hood, or her substitute, really could have been hit at any angle, depending on when in the manoeuvring. In short my claim is, that at 16k we can't find any ship in service by May 41, that was safe from a belt penetration from Bismarck, and in the US/British types there apears to be very little behind the belt to outrule a fatal contact with magazines. In that context Scharnhorst might be the best to take a belt hit from Bismarck

 

Regards

 

Steffen Redbeard

[Tiornu]

Ah, Scharnhorst...!

On the other hand, Scharnhorst took 14in hits at similar ranges and had two magazine hits.

Littorio might manage pretty well with her composite belt.

Any of the steeply inclined belts might have been able to break a German shell: Iowa, SoDak, Nelson, Yamato. And then there's Nagato, whose magazine protection in some ways rivaled Bismarck's.

[Redbeard]

Originally posted by Tiornu:

Ah, Scharnhorst...!

On the other hand, Scharnhorst took 14in hits at similar ranges and had two magazine hits.

Littorio might manage pretty well with her composite belt.

Any of the steeply inclined belts might have been able to break a German shell: Iowa, SoDak, Nelson, Yamato. And then there's Nagato, whose magazine protection in some ways rivaled Bismarck's.

 

 

Yeah, that infamous "humb" in the deck, but her belt protection appear at least as good as Bismarck/Tirpitz. How do you rate the Richelieus? They had something resembling a turtledeck, but at 50mm appearing a bit flimsy - just splinter protection? Do we have any indications of German shells being prone to breaking up on inconvenient impact angles?

 

Regards

 

Steffen Redbeard

[Michael Eastes]

Originally posted by Tiornu:

For lack of a definitive figure, I usually peg the fatal hit at a 16,000yd range.

 

The Admiralty report put the range at approx. 17,000 yards, or 8.5 nautical miles.

[Tiornu]

"but her belt protection appear at least as good as Bismarck/Tirpitz."

Ah, that's a different hit. Scharnhorst took about thirteen 14in hits. Of these, three got into the vitals: one exploded in a boiler room (that's the hump shot), two caused magazine fires. It always struck me that the percentage of critical hits was rather high.

Richelieu's armor scheme looks a lot like that of the US Standard ships, though with greater thickness and an inclined belt. That full-length splinter deck with slope also appeared in the Nevadas, Pennsylvanias and New Mexicos. Richelieu had very good protection, which is why the effects of Mamie's gunnery on Jean Bart is so impressive.

In WWI, the Germans proofed their shells versus half-caliber plates at 30deg impact, which was excellent at the time. In WWII, they proofed at the exact same official conditions. It may be that Krupp independently decided to exceed the government's requirements (!), but the standards remained at WWI levels. The fuze design was similarly stagnant. This helps explain why we have the impressions that German shells did well in WWI and poorly in WWII. The shells didn't change to much, but the standards did. For example, US shells (as I recall) proofed with caliber-thick plates at 15deg in WWI but with caliber-thick plates at more than 30deg in WWII.

[Tiornu]

"The Admiralty report put the range at approx. 17,000 yards, or 8.5 nautical miles."

Yeah, we have dueling sources on the precise figure.

At new-gun velocity, a Bismarck shell will start descending sharply enough to dig into a deck at right around 16,000 yards. At that range, the best she can penetrate is 2in of modern British NC armor. But Hood did not have modern British deck armor. She had HT steel decks laminated in strips of about 1in max thickness. So her best deck (74.7mm) is actually no better than 2in armor (approximately). You can see how protection standards changed rapidly between the war's. There were light cruisers in WWII with more shell-resistant decks than Hood's.

[Redbeard]

Originally posted by Tiornu:

"but her belt protection appear at least as good as Bismarck/Tirpitz."

Ah, that's a different hit. Scharnhorst took about thirteen 14in hits. Of these, three got into the vitals: one exploded in a boiler room (that's the hump shot), two caused magazine fires. It always struck me that the percentage of critical hits was rather high.

Richelieu's armor scheme looks a lot like that of the US Standard ships, though with greater thickness and an inclined belt. That full-length splinter deck with slope also appeared in the Nevadas, Pennsylvanias and New Mexicos. Richelieu had very good protection, which is why the effects of Mamie's gunnery on Jean Bart is so impressive.

In WWI, the Germans proofed their shells versus half-caliber plates at 30deg impact, which was excellent at the time. In WWII, they proofed at the exact same official conditions. It may be that Krupp independently decided to exceed the government's requirements (!), but the standards remained at WWI levels. The fuze design was similarly stagnant. This helps explain why we have the impressions that German shells did well in WWI and poorly in WWII. The shells didn't change to much, but the standards did. For example, US shells (as I recall) proofed with caliber-thick plates at 15deg in WWI but with caliber-thick plates at more than 30deg in WWII.

 

We know of 14 hits (a combination of British observation and survivors accounts?), but considdering the large number of stradles I suspect the real number of hits was bigger.

 

From what I can figure the German test standards really doesn't say when the shell will break up, but only that the "guarantee" was set lower than that of the competitors in WWII. Anyway at the short to medium ranges were Bismarck was optimised for impact angle would be low. From the penetration tables it appears like the impact angle at 16k is 10 degrees which must mean that a 20 degree inclination of the belt is needed in order to get above the 30 degree "guarantee". The belt on NC class was inclined at 15 degrees. Am I counting the degrees from the same side?

 

(sorry this is early in the morning and I'm in a hurry)

 

Regards

 

Steffen Redbeard

[Tiornu]

Yes, at 16,000 yards the impact angle on NC's belt would be 25deg if the shell is coming from exactly abeam. However, the 12in belt is well above half-caliber thickness. Kongo is the dreadnought with the belt closest to that (8in ~ 38cm x 0.5).

[Przezdzieblo]

Originally posted by Stuart Galbraith:

Im just curious, what was Royal Navy ammunition stowage practices like at the time of the Hoods loss? There was an interesting documentary on Channel 4, which produced some new evidence (including study of the wrecks)that many of the losses at Jutland were probably due to poor stowage of bagged charges. In fact, there was apparently a tendency during WW1 to keep charges outside magazines just to improve the rate of fire.The RN was still working on that theory that speed of fire was more important than accuracy....

 

Of course its unlikely the same problems would exist over 20 years later. But I just wondered how their ammunition stowage practices compared with the other Naval powers.

 

 

 

Indeed, especially on British battlecruisers there was tendency to keep charges outside magazines to improve rate of fire. It was after Dogger Bank where British saw effects of German rapid fire. But main problems with Invincible and co. were some design flaws: poor flash protection, weak and not thick enough turret roofs, gunshields and barbettes. And unstable propelant which had tendency to explode rapidly. If fire appeared inside turrets or barbettes, the doom was very near.

After loss of three BCs in Skagerrak there were made some changes: improved flash protection, thicker roofs, more strict procedures of ammo stowage etc. Hood had new model of turrets, with no "bullet trap" sighting hoods on roofs. Her sisters, if build, would have thicker roof armour.

End of Hood was very like the doom of Invincible, Indefatigable and Queen Mary, but the way it happened was different. Turret hit on Hood probably would not lead to her destruction.

Another thing - on British BCs (but, IIRC, not on Hood) charges stores were instantly below lower (protective) deck, and were more vulnerable to splinters than similar stores on battleships.

 

 

[Edited by Przezdzieblo (02 Dec 2004).]

[Colin Williams]

BTT