BISMARCK armor scheme = BADEN?

[Karl Heidenreich]

Interesting statements:

The changes were based upon the viewpoint repeatedly expressed by the Navy-namely, to build the battleships in such a way that they would be as nearly unsinkable as possible.

and. again the numerical superiority issue:

But at the time when we resumed battleship construction, when we could see that we would have a very small number of battleships in any case, it occurred to us that the resistance to sinking of ships should be increased as much as possible to render the few we had as impregnable as possible.

[RF]

RF what is your definition of spectacular hitting power

Weight of salvo being above the norm for the size and tonnage of ship. That would imply a sacrifice in terms of either speed or armour protection.

My impression of Bismarck is that hitting power was sacrificed for armour protection and speed, instead of say triple 15 inch gun turrets, or dual 16 inch as the next battleships in the Z Plan were intended to have.

Hood in my view did have a greater measure of spectacular hitting power - equal to that of Bismarck but unlike Bismarck Hood was unable to absorb its own weight of salvo without blowing up, because of the armour sacrifice.

The pocket battleships, classed as heavy cruisers, also had what I would define as spectacular hitting power - for a cruiser.

[Djoser]

The pocket battleships, classed as heavy cruisers, also had what I would define as spectacular hitting power - for a cruiser.

Hard to argue with that!

Hood for her day (as in when she was commissioned) might have had spectacular hitting power, but by '41, not so much I would think. But I am factoring in advances in fire direction, which brought the science of gunnery up an order of magnitude. You can hardly fault a ship designed in the teens of the new century when going up against the next generation.

[Karl Heidenreich]

RF:

My impression of Bismarck is that hitting power was sacrificed for armour protection and speed, instead of say triple 15 inch gun turrets, or dual 16 inch as the next battleships in the Z Plan were intended to have

The German, and British, artillery experts never liked the triple turret arragement, specially if it meant less turrets. The double gun turret was the better arragement for them.

[Dave Saxton]

My impression of Bismarck is that hitting power was sacrificed for armour protection and speed, instead of say triple 15 inch gun turrets, or dual 16 inch as the next battleships in the Z Plan were intended to have.

Hood in my view did have a greater measure of spectacular hitting power - equal to that of Bismarck but unlike Bismarck Hood was unable to absorb its own weight of salvo without blowing up, because of the armour sacrifice.

The pocket battleships, classed as heavy cruisers, also had what I would define as spectacular hitting power - for a cruiser.

It has long been my opinion that weight of salvo is not a good indicator of hitting power against armoured opponants in the modern era. A better measure is penetrative power. Penetrative power against vertical cemented armour is largely effected by striking velocity rather than size and weight, with in reason of similar calibers of course. Other factors are the head shape and the size and weight of the cap but V remains more important. This is why the new breed of European high velocity 15" guns represented a new level of hitting power at the more likely battle ranges. This may be one reason the British procrastinated changing their head shapes to a more blunt shape. The sharper head shapes required less energy for penetration close to the normal, and this allowed the British guns not to be too far out classed in terms of belt penetration.

Weight of course takes on more importance for penetrative power vs homogenous armour. Nonetheless, the advantages of extra weight can be off set by the head shape. The head shape takes on great importance in cases of oblique impact against homogenous armour as in the case of deck hits. Thus the British shells had little advantage against decks compared to the higher velocity guns.

[Bgile]

Dave, you seem to be saying you feel the 11" gun used on the Scharnhorst is the ideal. Very high velocity.

[RF]

The German, and British, artillery experts never liked the triple turret arragement, specially if it meant less turrets. The double gun turret was the better arragement for them.

Well, the RN went for quads with the KGV's which certainly reduced the number of turrets. And the Germans post WW1 always had their 28 cm in triple turrets; and for light cruisers again we had triples for the 15 cm, though on the battleships the 15 cm were in double turrets and not triple.

[RF]

It has long been my opinion that weight of salvo is not a good indicator of hitting power against armoured opponants in the modern era. A better measure is penetrative power. Penetrative power against vertical cemented armour is largely effected by striking velocity rather than size and weight, with in reason of similar calibers of course. Other factors are the head shape and the size and weight of the cap but V remains more important. This is why the new breed of European high velocity 15" guns represented a new level of hitting power at the more likely battle ranges.

The difficulty for someone like me with this line of argument is that this European 15 inch gun had virtually no opportunity to demonstrate this extra effectiveness. Of Bismarcks' main armament shellfire, only one shell to be certain of did spectacular damage (the one that sank Hood) while the four hits on POW didn't actually pose any substantial threat to the ships survival. The two opportunities that could have offered such demonstration was if the POW hadn't broken off at DS, or if the Bismarck had hit Rodney first on 27 May.
The Italians similary didn't have the opportunity to demonstrate the effectiveness of the main armament fire of VV either.

[alecsandros]

Hello all,
...The performance of European 15" guns ranged from poor to mediocre in practical terms, with the only exception being the SK34 guns mounted on Bismarck class.
Thus, although the Italian 15" looked impressive on paper (in terms of striking energy and perforation), the turret design and shell defficiencies made it a poor weapon. The same arguments for the French 15"... which only after turret modifications in the US, and 1944 re-designed shells started to function properly (although some problems of dispersion and rate of fire remained).

Bismarck's guns, although powerfull, did not posses the same destructive potential as, let's say, Rodney, a 25% smaller vessel. Why ? Because the guns had similar perforation at most practical ranges, BUT, once inside the ship, the British 16" shell had a bigger burster and mass (both caped and decaped) then the German 15" shell. Consequently, 5-6 penetrative hits from Rodney would had the potential to cause more internal damage than 5-6 hits from Bismarck.

And, if the British 9x16" gun battery was, potentialy, more deadly (in itself, not counting the fire control system and stability issues, which change the situation quite a bit) than the German 8x15" arrangement, it is only natural to accept the superior destructive potential of the American 9x16" L50 gun batteries...

The point: I concur with RF's opinion, that Bismarck class sacrificed hiting power for armor and speed (this being in fact the KGM design philosophy, visible in all heavy ships except panzerschiffs).

[Dave Saxton]

Dave, you seem to be saying you feel the 11" gun used on the Scharnhorst is the ideal. Very high velocity.

What I said was more complex than that. I said within reason of similar calibers, such as 14",15", and 16" for example, and I specified the striking velocity vs cemented armour. A larger, heavier, shell carries more momentem, so it therefore loses less velocity from it's initial velocity per distance travelled than a lighter shell. It's possible for a heavier shell -although with a lower MV- to have a greater striking velocity once it reaches 30,000 yards down range, than a lighter shell fired at a higher initial velocity. For example, if we compare the Bismarck's 800 kg shell to the Scharnhorst's 330kg shell the 800 kg shell will have V of 460 M/s at 33,000 yards, while the 333kg shell will have fallen to around 420 M/s by that range. Moreover, the German tests revealed that the 38cm once it penetrated the vitals of an opponant was likely to destroy the penetrated compartment, while the 333kg shell may not, which is one of the factors Alex alluded to.

If we compare the 800kg 15" shell to the H-class 1030kg 16" shell, the 16" starts at only about 10 M/s less velocity, and it will have a greater striking velocity at say 27,500 yards down range than the 800 kg sister. These dynamics mean that steeper angles of fall against decks also occur at slightly greater ranges. The effect of larger, heavier, shells is to shift the break over point of favorable striking dynamics vs vertical armour to favorable dynamics against horizontal armour to a greater range. For example, the French 38cm used a 879kg shell fired at a higher MV than the German 15". At 30,000 meters range the French shell will have greater velocity and so it's angle of fall will be only about 27* while the German shell's angle of fall will be about 31*. The lighter shell attains more favorable striking angles vs decks at a lesser range. A way to manipulate these dynamics is to significantly decrease the MV of the heavier shell, but the trade off is reduced belt penetration and less favorable danger space short of extreme ranges, and other ballistics factors.

[lwd]

A reader recently asked exactly how the center of gravity shift was measured. Traditionally, the center of gravity of a projectile is measured from the base, and that's what was done in this case. In other words, the center of gravity would move roughly 3" aft towards the base if the cap were removed. ...

So if the AP cap is 3" long the distance from the point of the projectile to the cg is identical because the point is also moved 3" closer to the base. If the AP cap is longer than that the cg is actually moved closer to the point of impact if the AP cap is lost.

[Dave Saxton]

The difficulty for someone like me with this line of argument is that this European 15 inch gun had virtually no opportunity to demonstrate this extra effectiveness. Of Bismarcks' main armament shellfire, only one shell to be certain of did spectacular damage (the one that sank Hood) while the four hits on POW didn't actually pose any substantial threat to the ships survival. The two opportunities that could have offered such demonstration was if the POW hadn't broken off at DS, or if the Bismarck had hit Rodney first on 27 May.
The Italians similary didn't have the opportunity to demonstrate the effectiveness of the main armament fire of VV either.

Yes, its a matter of opportunity and luck for scoring a hit at the right location on the target. The European (including the British shellite loaded shells and the German TNT loaded shells) shells through their great explosive effect could certainly be very effective but they must first defeat the armour protection of their opponant.

[Karl Heidenreich]

RF:

Well, the RN went for quads with the KGV's which certainly reduced the number of turrets. And the Germans post WW1 always had their 28 cm in triple turrets; and for light cruisers again we had triples for the 15 cm, though on the battleships the 15 cm were in double turrets and not triple.

This is an interesting argument which has been answered before. If we research on the British design doctrine post 1921 in Raven and Roberts on "British Battleships" or in Garzke and Dullin the answers are there (and I think that have been posted in the "Bismarck and her Contemporaries" thread a year ago).

The RN was handcuffed by the Naval Treaties, which was their call anyway for that assured that all other naval powers will be also very limited. The battleships they can produce were of a standard displacement of 35,000 tons which limited the armouring of the citadel (meaning it has to be as short as possible) and so the overall lenght of the ship was constrained. Structurally the ships also need to be as "light" as possible which mean that the stress produced on the hull by the weight of the turrets have to be minimized. The British first attempt was to come with the Nelson design with three triple 16" which was very disfavoured by them even before the ships was commisioned. Then the KGV was what can be an ideal balanced design that came with the undergunned 10 x 14" arragement. The Lion design also called for triples, however this was due, in part, for a self constraint of 40,000 tons the British put on themselves, when the USN already was escalating to 45+ K tons. If you see, the Vanguard have 8 x 15", in a great measure due to the already existing 15" guns... however they could have made it, Richelue style, and putting all the eggs in just two baskets.
I recommend the reading of R&R and G&D on this issue. In G&D's chapter on Bismarck a great deal is explained in the four double turrets arragement.
Of course, if we can come with a design of the Montana Class, with four turrets with three guns each, we are talking of another league.
Regards,

[Dave Saxton]

And, if the British 9x16" gun battery was, potentialy, more deadly (in itself, not counting the fire control system and stability issues, which change the situation quite a bit) than the German 8x15" arrangement, it is only natural to accept the superior destructive potential of the American 9x16" L50 gun batteries...

But do the smaller cavity, Explosive D, loaded American shells actually have more destructive power than the British or the German shells?

[Bgile]

And, if the British 9x16" gun battery was, potentialy, more deadly (in itself, not counting the fire control system and stability issues, which change the situation quite a bit) than the German 8x15" arrangement, it is only natural to accept the superior destructive potential of the American 9x16" L50 gun batteries...

But do the smaller cavity, Explosive D, loaded American shells actually have more destructive power than the British or the German shells?

Clearly not, but they have a better chance to remain intact when penetrating thick armor and are less likely to explode due to high velocity impact on thick armor as a number of British shells seem to have done on Bismarck's. In any case, if a shell explodes in an area protected by thick armor it will likely do serious damage no matter the filler ... actually even if it doesn't explode at all it will probably kill everyone there and wreck something important. I don't know of any case where a shell exploded in the citadel that it didn't do serious damage. The US shell which exploded in Jean Bart's 15cm magazine certainly wrecked that compartment. The one which didn't explode and exited out of the ship through the engineering compartment certainly rendered that compartment usless. The ones which hit Kirishima left her very seriously damaged and seem to have had the intended effect. I don't think there is any doubt that these shells were extremely destructive.