Could not have explained it better. As an addon – you might have come across the term ‘soft kill’ in respect to battleship encounters. That is a situation where you did not manage to get a shell into the (relatively small – just engines and magazines) vitals of the battleship but the structural damage in unarmoured or lightly armoured spaces is so great that the ship is rendered virtually defenceless.
So a cruiser could ‘soft kill’ a battleship but it could not land a blow into the vitals.
An armour piercing shell is against the (quite small) vitals and fairly useless if it hits anywhere else; a high explosive shell is useless against the vitals but should heftily damage the much greater rest of the target.
Ciao,
ufo
HMS Prince of Wales received hits on DS
Moderator: Bill Jurens
"Okay then, was the Hood too well protected for her own good?"
Let's restate the question. What is the right amount of armor for a ship to have? Because armor and shells each went through processes of development, we can't answer this question with a blanket statement. Different things worked at different times. For example, the Russo-Japanese War showed that the 6in armor of cruisers was nearly impenetrable to the shells then in use. Just ten years later, Jutland showed what could happen to cruisers with 6in armor protection--and it wasn't pretty.
The fact is that most battleships of WWI used vertical armor of about 6in thickness. The newest AP shells turned this thin armor into a liability; it did little to keep out heavy shells and actually increased the amount of damage they caused. They made AP shells more likely to explode on board, and they became a source of splinters capable of causing dramatic damage. This led to the use of All-or-Nothing armor in most post-WWI designs.
Any plate of about 1in thickness will be enough to initiate a fuze. (There are formulae available if you want more exact info.) The shell that hit PoW's compass platform probably had its fuze started, but with nothing substantial in its path, it may have continued all the way into the sea before exploding. If the shell had hit PoW's forecastle deck instead of the compass platform (the metal was about the same thickness in each spot), it might have continued overboard the same way, unless it hit something hefty along the way or its path remained inside the hull for a long distance. This is the benefit of the Nothing part of All-or-Nothing. The All part doesn't require much explanation. Thick armor can stop a shell.
In Hood's case, because she was never modernized (the way Queen Elizabeth and other battleships were), she didn't have the thick deck armor that she needed to defeat Bismarck's shell. The shell would have exploded anyway, but modern armor could have kept it in the upper hull.
"All 7 hits on the PoW missed her heavy armour. If a ship's armour is that hard to hit, why use AP instead of HE shells."
I think it's already been explained that ship armor is there to prevent critical damage from shell hits. Heavy HE shells are defeated by heavy armor, but AP shells have a chance to get through. This is exactly what happened to Hood. If the shell that hit her had been HE, then Denmark Strait would have been a completely different battle.
Let's restate the question. What is the right amount of armor for a ship to have? Because armor and shells each went through processes of development, we can't answer this question with a blanket statement. Different things worked at different times. For example, the Russo-Japanese War showed that the 6in armor of cruisers was nearly impenetrable to the shells then in use. Just ten years later, Jutland showed what could happen to cruisers with 6in armor protection--and it wasn't pretty.
The fact is that most battleships of WWI used vertical armor of about 6in thickness. The newest AP shells turned this thin armor into a liability; it did little to keep out heavy shells and actually increased the amount of damage they caused. They made AP shells more likely to explode on board, and they became a source of splinters capable of causing dramatic damage. This led to the use of All-or-Nothing armor in most post-WWI designs.
Any plate of about 1in thickness will be enough to initiate a fuze. (There are formulae available if you want more exact info.) The shell that hit PoW's compass platform probably had its fuze started, but with nothing substantial in its path, it may have continued all the way into the sea before exploding. If the shell had hit PoW's forecastle deck instead of the compass platform (the metal was about the same thickness in each spot), it might have continued overboard the same way, unless it hit something hefty along the way or its path remained inside the hull for a long distance. This is the benefit of the Nothing part of All-or-Nothing. The All part doesn't require much explanation. Thick armor can stop a shell.
In Hood's case, because she was never modernized (the way Queen Elizabeth and other battleships were), she didn't have the thick deck armor that she needed to defeat Bismarck's shell. The shell would have exploded anyway, but modern armor could have kept it in the upper hull.
"All 7 hits on the PoW missed her heavy armour. If a ship's armour is that hard to hit, why use AP instead of HE shells."
I think it's already been explained that ship armor is there to prevent critical damage from shell hits. Heavy HE shells are defeated by heavy armor, but AP shells have a chance to get through. This is exactly what happened to Hood. If the shell that hit her had been HE, then Denmark Strait would have been a completely different battle.
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Six Gun Kid
- Junior Member
- Posts: 4
- Joined: Tue Feb 21, 2006 1:35 pm
- Location: Wyoming, USA
Gary, Tiornu, ufo,
Thanks for your responses. Things are much clearer now, I think.
Correct me if I am wrong here but just looking at the Hoods armor particulars, I assume a 15 inch shell from the Bismarck would have to pass through either the Hood's 12 inch main belt or her 7 inch upper belt + 2 inches of deck armor + 12 inches of barbette armor to reach her main magazine. Is this possible or did the Bismarck's shell hit a secondary magazine outside the main barbette?
Thanks for your responses. Things are much clearer now, I think.
Correct me if I am wrong here but just looking at the Hoods armor particulars, I assume a 15 inch shell from the Bismarck would have to pass through either the Hood's 12 inch main belt or her 7 inch upper belt + 2 inches of deck armor + 12 inches of barbette armor to reach her main magazine. Is this possible or did the Bismarck's shell hit a secondary magazine outside the main barbette?
The best explanation I have seen is that the shell exploded in one of Hood's engine rooms and that splinters then set off an adjacent magazine. The magazine could have been a secondary gun magazine, and it's explosion resulted in the after main battery magazine exploding.
This has been described in detail elsewhere.
This has been described in detail elsewhere.
A thorough examination of what is possible and what is not you can find in this:Six Gun Kid wrote: ...
Correct me if I am wrong here but just looking at the Hoods armor particulars, I assume a 15 inch shell from the Bismarck would have to pass through either the Hood's 12 inch main belt or her 7 inch upper belt + 2 inches of deck armor + 12 inches of barbette armor to reach her main magazine. Is this possible or did the Bismarck's shell hit a secondary magazine outside the main barbette?
http://www.warship.org/no21987.htm
very fine article.
If I remember correctly your guess with the 4” magazine that then in turn sets of the mains comes out top of the list.
Ciao,
Ufo
Hood's barbette armor covers the ammunition train, but not the magazines themselves. It extends above the protective deck only, so a shell would not be penetrating both the deck and the barbette.
Hood was one of the many ships built before All-or-Nothing became the standard, and her armor scheme is thus rather complex. The barbette armor has its full thickness only above the weather deck. The decks vary widely in their thickness, and the word "deck" does not mean it is always horizontal. The protective deck is flat only in the portion covering the centerline of the ship. At the sides, it turns downward to connect to the bottom of the main belt. The metal is not the best; HT steel was considered adequate against splinters, but against an intact shell, it's actually worse than the nickel steel that was used in ships before HT became popular. Also, Hood's decks would not be a single thickness of HT but mulitple layers fastened together, which is not as good.
As Bill J's article indicates, the most likely trajectory has Bismarck's shell going through the upper belt then through the protective deck where it is sloped rather than flat.
Hood was one of the many ships built before All-or-Nothing became the standard, and her armor scheme is thus rather complex. The barbette armor has its full thickness only above the weather deck. The decks vary widely in their thickness, and the word "deck" does not mean it is always horizontal. The protective deck is flat only in the portion covering the centerline of the ship. At the sides, it turns downward to connect to the bottom of the main belt. The metal is not the best; HT steel was considered adequate against splinters, but against an intact shell, it's actually worse than the nickel steel that was used in ships before HT became popular. Also, Hood's decks would not be a single thickness of HT but mulitple layers fastened together, which is not as good.
As Bill J's article indicates, the most likely trajectory has Bismarck's shell going through the upper belt then through the protective deck where it is sloped rather than flat.
Tiornu is essentially correct, but to add a little more to the explanation he gave, the flat area of the protective deck had an extension over the slopes in the way of the magazines; this flat extension was carried all the way to the ship's side when a test in 1920 showed that a 15in shell could penetrated the lower portion of the 7-in middle belt and still hit and penetrate the slopes and subsequently the 2-in HT crowns over the 15in magazines. The shell bust in the 2x1-inch plates that made up the crowns and flash and splinters ignited cordite charges placed below the crowns to represent the magazines. A subsequent test showed that carrying the protective deck flat to the side of the ship was effective. However, this was only done in way of the magazine groups and not in way of the engineering spaces, presumably due to weight considerations.
The theory put forward by Bill Jurens and some others was that a 38cm shell from Bismarck might have come in from forward of the beam, striking and penetrating the lower edge of the 7in belt abreast the after turbine room, penetrated the sloped protective deck, and burst either in the turbine room or in passing through through the bulkhead separating the the turbine room from the after HA 4-inch magazine. Either way incandescent splinters could have then set off the contents of the 4-inch magazine which then set off the cordite of X-magazine. The British board of inquiry was in general agreement with this scenario stating that it was likely the 4-inch HA magazine was ingnited first.
The theory put forward by Bill Jurens and some others was that a 38cm shell from Bismarck might have come in from forward of the beam, striking and penetrating the lower edge of the 7in belt abreast the after turbine room, penetrated the sloped protective deck, and burst either in the turbine room or in passing through through the bulkhead separating the the turbine room from the after HA 4-inch magazine. Either way incandescent splinters could have then set off the contents of the 4-inch magazine which then set off the cordite of X-magazine. The British board of inquiry was in general agreement with this scenario stating that it was likely the 4-inch HA magazine was ingnited first.
Their shoulders held the sky suspended;
They stood and Earth's foundations stay;
What God abandoned these defended;
And saved the sum of things for pay.
Curiously enough, I just read where it is now presumed that the loss of the Queen Mary at Jutland was also due to a heavy shell igniting the forward 4" magazines, venting through the weaker areas around the first funnel for the observed initial explosion, and also exploding the 13.5" magazines.
How ironic would it be that the two biggest battlecruisers lost were both lost due to relatively small calibre shell magazines exploding?
How ironic would it be that the two biggest battlecruisers lost were both lost due to relatively small calibre shell magazines exploding?