KGv class with different guns

[dunmunro]

..

About the salvo spread:
I also think the 14" salvos were generaly tighter than the 16" salvos. But both armaments had large spreads anyway. I remember reading of Rodney averaging 300y from "salvo firing" at 16.000y. I don't know for sure what a "salvo" meant, but I don't think it was a full salvo. The averages were done on good sea, good shooting conditions.
Under battle conditions, the spreads may have been higher, especialy as the sea was very bad and consequently the ship and main guns would roll and pitch wildly over the waves.

For example, a peculiar (for me) report comes from Norfolk during the Battle of Denmark Strait:

"Action with "Hood" and "Prince of Wales"

Both ships [Bismarck and PE] seemed to straddle early, but after Hood sank, Prince of Wales sustained the fire of both enemy ships with remarkably little damage but for the unlucky hit on the bridge. As the range came down to 15,000, this points to very poor shooting.

At the end, Prince of Wales had a spread of 2,000 yards at least and was going short. Her shots were evenly spaced out along the spread."
http://www.hmshood.org.uk/reference/off ... 09norf.htm

This indicates some pretty wild shooting by PoW...

Of course, that doesn't mean KGV must necessarily have shot the same 2000y spreads against Bismarck. But it does raise some question...
(This isn't necessarily off the norm. One US battleship, in 1935, fired several spreads of 1000-4000y, allthough the normal average was about 300y. Bismarck himself, in the evening of the 24th of May, fired "large spreads" against Suffolk, whatever that means)

=======

At the "end", PoW was firing under nearly full helm, and this probably caused a large spread, but the 3 salvos, #6, #9 and #13 that straddled and hit Bismarck, consisted of, 3, 4 and 3 rounds each, respectively, so a large salvo spread would make hits very unlikely. PoW's shooting suggests very tight salvo groupings.

[alecsandros]

A 14in AP shell would have no problem penetrating the 7" inclined face of the 38cm turret from about 10k yds and further

I don't think so Duncan... the obliquity was to high for a penetration to occur. Not to mention that during the battle a 14" shell fired at 10k actualy glanced off a turret's edge...

or the weather deck near the forward turrets and then penetrated the 220mm portion of the barbette

This is a theory I thought about for some time.
However, someone explained to me that in the post-war tests done against a replica of Tirpitz, ALL 14" shells fired had been de-caped by the 50mm upper deck.
A decaped shell has practicaly no chances of perforating 220mm of KCn/A, especialy as the lower-edge of the barbette was strongly curved.
So this theory, of the deck perforation folllowed by barbette hit, is hard to work in practice...

And the reports mention an explosion between the turrets, a fact that doesn't match the deck penetration theory.

[Herr Nilsson]

I wonder if the turrets shared a common hydraulic system, so that the loss of hydraulic pressure in one, could disable the other?

No, I don't think so. Each turret had two hydraulic pumps for elevation. There were also electric powered auxiliary elevating drives in reserve. The training of the turret was electric powered (one main motor and one auxiliary motor in reserve for each turret + one single transportable motor for all four turrets).

[RF]

...I suspect that a hit penetrated one turret, or the weather deck near the forward turrets and then penetrated the 220mm portion of the barbette and severed a hydraulic line and/or electrical line, which in turn disabled the turrets.

This would presumably be supported by the evidence of British observers that the guns of Anton turret were left at minimum depression, as if from a power failure.

[dunmunro]

A 14in AP shell would have no problem penetrating the 7" inclined face of the 38cm turret from about 10k yds and further

I don't think so Duncan... the obliquity was to high for a penetration to occur. Not to mention that during the battle a 14" shell fired at 10k actualy glanced off a turret's edge...

or the weather deck near the forward turrets and then penetrated the 220mm portion of the barbette

This is a theory I thought about for some time.
However, someone explained to me that in the post-war tests done against a replica of Tirpitz, ALL 14" shells fired had been de-caped by the 50mm upper deck.
A decaped shell has practicaly no chances of perforating 220mm of KCn/A, especialy as the lower-edge of the barbette was strongly curved.
So this theory, of the deck perforation folllowed by barbette hit, is hard to work in practice...

And the reports mention an explosion between the turrets, a fact that doesn't match the deck penetration theory.

Penetration results against turret 220mm face according to NAaB 1.0:
14in against 220mm at 60deg inclination @ 19.5k yds = 15.55deg descent @ 1670 fps and 44.45deg final inclination = 229mm and complete penetration.
14in against 220mm at 60deg inclination @ 15.7k yds = 11.16deg descent @ 1788 fps and 48.84deg final inclination = 226mm and partial penetration.
14in against 220mm at 60deg inclination @ 9.7k yds = 5.73deg descent @ 1670 fps and 54.27deg final inclination = 231mm and partial penetration.
Of course the final target angle is highly variable, but penetration is certainly possible.

Against the 50mm deck, 30mm bulkhead and 220mm barbette:
19.5k yds against 50mm deck = shell decapped, penetration with 1477fps remaing velocity and 17.15deg exit angle, = penetration with 1464fps @17 degs, = 239mm and complete penetration.
15.7k yds against 50mm deck = shell decapped, penetration with 1585fps remaining velocity and 12.2deg exit angle, = penetration with 1585fps @17 degs, = 269mm and complete penetration.
Again, final target angle is highly variable...

The 340mm portion of Bruno barbette was penetrated during the action.

[dunmunro]

...I suspect that a hit penetrated one turret, or the weather deck near the forward turrets and then penetrated the 220mm portion of the barbette and severed a hydraulic line and/or electrical line, which in turn disabled the turrets.

This would presumably be supported by the evidence of British observers that the guns of Anton turret were left at minimum depression, as if from a power failure.

Exactly, thanks.

[alecsandros]

Again, final target angle is highly variable...

The 340mm portion of Bruno barbette was penetrated during the action.

I know the output from NaaB. I had adressed this earlier: British war and post-war tests showed that oblique performance for 14" shells was less than expected. About 100mm (4inch) of horizontal homogenous armor at 30k y, normal angle of fall.
This was mainly due to the shape of the shell, as the pointed nose of the 14inchers was better suited for perforating vertical plates (at various inclinations) than horizontal plates. The shell tended to scoop during oblique attack because of the elongated shape, and while scooping the base would generaly slap against teh armor plate and cause the fuze to malfunction. The shell thus became an inert missile.

Perforating 50mm of Whotan would mean that the shell's cap would be removed, thus affecting it in 2 ways:
a) The penetrating capability of a decaped shell is far less than that of a caped shell
b) the shatter velocity for a caped shell is lower than that of a caped shell.

Thus, a 14" shell going through 2" of homogenous armor would not have the capability of perforating 220mm of armor, especialy as the armor was also very curved. Most likely the shell would break or explode directly on impact with the 220mm of armor.

As for the events during Bismarck's last battle, I remember reading the 14" shell that hit Bruno to have glanced off, but the turret lost hydraulic pressure because of the impact shock, and the guns depressed and became un-serviceable.

[Dave Saxton]

Penetration results against turret 220mm face according to NAaB 1.0:
14in against 220mm at 60deg inclination @ 19.5k yds = 15.55deg descent @ 1670 fps and 44.45deg final inclination = 229mm and complete penetration.
14in against 220mm at 60deg inclination @ 15.7k yds = 11.16deg descent @ 1788 fps and 48.84deg final inclination = 226mm and partial penetration.
14in against 220mm at 60deg inclination @ 9.7k yds = 5.73deg descent @ 1670 fps and 54.27deg final inclination = 231mm and partial penetration.
Of course the final target angle is highly variable, but penetration is certainly possible.

Against the 50mm deck, 30mm bulkhead and 220mm barbette:
19.5k yds against 50mm deck = shell decapped, penetration with 1477fps remaing velocity and 17.15deg exit angle, = penetration with 1464fps @17 degs, = 239mm and complete penetration.
15.7k yds against 50mm deck = shell decapped, penetration with 1585fps remaining velocity and 12.2deg exit angle, = penetration with 1585fps @17 degs, = 269mm and complete penetration.
Again, final target angle is highly variable...

The 340mm portion of Bruno barbette was penetrated during the action.

Your not factoring in that a de-capped shell will shatter at those striking velocities and angles against face hardened armour at least 30% thick the diameter of the shell.

Alex is right to point out that a deck penetration could not come from a shell that exploded between the turrets.

[Dave Saxton]

Perforating 50mm of Whotan would mean that the shell's cap would be removed, thus affecting it in 2 ways:
a) The penetrating capability of a decaped shell is far less than that of a caped shell

b) the shatter velocity for a caped shell is lower than that of a caped shell.

Thus, a 14" shell going through 2" of homogenous armor would not have the capability of perforating 220mm of armor, especialy as the armor was also very curved. Most likely the shell would break or explode directly on impact with the 220mm of armor.

.

Indeed, removal of the cap not only sets up the shell to shatter, but the necessary velocity for penetration is altered by at least two factors. One is the mass of the shell is reduced. Another factor is that a uncapped shell of equal mass requires greater striking velocity for penetration than a capped shell of equal mass, if the armour is face hardened, or if in the case of homogenous armour the tensile strength exceeds 80kg/mm2. Another way of looking at this is that by removing the cap the quality of any further armour is increased relative to the standard. Yet another way of looking at it, is that by removing the cap, its as if any further armour is thicker than it actually is.

Curved armour also requires more velocity for penetration than if the armour is not curved.

[Dave Saxton]

Alex Wrote:

As for the events during Bismarck's last battle, I remember reading the 14" shell that hit Bruno to have glanced off, but the turret lost hydraulic pressure because of the impact shock, and the guns depressed and became un-serviceable.

We must remember that such is still just guess work. It may be a good guess, but it's still just a guess. It is not and can not be known for certain, just as any other theories about this issue also can not be known for certain.

[dunmunro]

Your not factoring in that a de-capped shell will shatter at those striking velocities and angles against face hardened armour at least 30% thick the diameter of the shell.

Alex is right to point out that a deck penetration could not come from a shell that exploded between the turrets.

There is a whole range of possibilities, and the deck angle from roll could easily cause a 10deg decrease in striking inclination, and even a hit, with shatter could cause spalling and damage to the hydraulic or electrical system.

[dunmunro]

Perforating 50mm of Whotan would mean that the shell's cap would be removed, thus affecting it in 2 ways:
a) The penetrating capability of a decaped shell is far less than that of a caped shell

b) the shatter velocity for a caped shell is lower than that of a caped shell.

Thus, a 14" shell going through 2" of homogenous armor would not have the capability of perforating 220mm of armor, especialy as the armor was also very curved. Most likely the shell would break or explode directly on impact with the 220mm of armor.

.

Indeed, removal of the cap not only sets up the shell to shatter, but the necessary velocity for penetration is altered by at least two factors. One is the mass of the shell is reduced. Another factor is that a uncapped shell of equal mass requires greater striking velocity for penetration than a capped shell of equal mass, if the armour is face hardened, or if in the case of homogenous armour the tensile strength exceeds 80kg/mm2. Another way of looking at this is that by removing the cap the quality of any further armour is increased relative to the standard. Yet another way of looking at it, is that by removing the cap, its as if any further armour is thicker than it actually is.

Curved armour also requires more velocity for penetration than if the armour is not curved.

I calculated all penetration figures, after penetration of the 50mm deck, as being with a 1399lb, decapped shell.

[Dave Saxton]

The fact that the barbet is round will cause the 220mm to be as if its closer to 260mm thick straight plate. But this is acedemic as the de-capped shell will still shatter upon impact with the face hardened barbet. There appears to be a spall catcher inside of the barbet.

[Thorsten Wahl]

As for the events during Bismarck's last battle, I remember reading the 14" shell that hit Bruno to have glanced off, but the turret lost hydraulic pressure because of the impact shock, and the guns depressed and became un-serviceable.

lookin at a scheme drawing of a 38 cm tutrret it seems to me there is a wormgear between hydraulicdrive and gearwheel of the gun. This should block any further change of elevation by weight. Furthermore the weight of the barrel is outbalanced.

So it seems more likely to me that the hydraulic drive didnt stop and drove the gun at full power into the end stop

[lwd]

.... Alex is right to point out that a deck penetration could not come from a shell that exploded between the turrets.

Why not? If a shell penetrated the deck between the two turrets and detonated after penetration I would expect a substantial blast signature from the hole of the initial penetration.