Bismarck/Tirpitz = most powerfull European battleships

[lwd]

at the relevant distance we are talking about even a 430 mm armor is not able to prevent a penetration.
Aditional we dont know for sure the relative quality of french and german armor

Where did we define a distance?

[Dave Saxton]

Thickness means little with out the context of the IZ it can potentially provide. If the thickness of an AoN armour protection is insufficient at a given range it is of no more value than no armour. The zone of protection at a given battle range provided by such thickness is meaninful.

Assuming the French cemented armour was of equal quality to German KCnA, the frontal face of the Rich. turret of 430mm, laid-back 17*, is penetratable by the German 38cm to approx. 23,000 meters. The Rich. like Dunkerque, used cemented armour for the roofs, but was up to 195mm thick and not as sloped. Assuming the sloped portion of the roof of approx. 7* was 195mm then it is good to approx. 30,000 meters.

The Bismarck's 360mm Kc, sloped and curved, turret face plate, provided protection to impact velocities of approx. 505 M/s, and angles falls not less than 16*, or good down to Approx. 20,000 meters range, vs BB caliber projectiles. The turret roof of 130mm homogenous armour was good to about 30,000 meters vs a wide variety of BB caliber projectiles. The angled facet of 180mm Wh was angled ~65* and good at ranges of less than ~23,000 meters. Here we find the angled facet provided enhanced protection at battle ranges where it was more likely to be hit, at the trade off of protection at battle ranges where it was less likely to be hit.

It would appear that the Germans got better overall turret protection at the cost of less armour weight. Whether the total armour weight expended on turrets and barbets was more efficient is more complex to determine considering the different lay outs.

[lwd]

Why not use the French gun rahter than some "wide variety of BB caliber projectiles"

[Dave Saxton]

Because the French 15" has less deck penetration at 30,000 meters battle range than a wide variety of BB caliber guns. It certainly has less deck penetration than the German 15" at that battle range.

[lwd]

But doesn't it have better verticle pentration? If you are going to compare the two battleships particualrly use Bismarck's gun vs the French ship then the other comparison should either be the French gun vs Bismarck or Bismarck's gun vs her own turret. Using a generic gun in one case and a specific one in another doesn't yield a good basis for comparison.

[Dave Saxton]

Because I have exact data handy for the German gun and I already know the French and German guns are fairly equal in vertical penetration performance.

The French 38cm will carry slightly more V and this is an important componant when it comes to penetration of cemented armour, more so than the mass. However, another crucially important componant is the caliber radius of the head of the AP shell's main body.

The German shell had a relatively blunt CRH and this will improve its performance relative the French 38cm at all striking angles but the normal, or very close to the normal. Where the French shell is always striking any componant of the Bismarck turret with obliqity and in some cases a compound obliqity, it's performance relative to the German shell will be somewhat inferior with a much greater probability of scooping.

The caliber radius of the shell's main body also is very important to the penetration of horizontal armour since it is always an oblique impact. This is why the British found their 14", 15", and 16" shells did not penetrate 6" deck at any range less than 32,000 yards in post war tests. This is why I used the term "a wide variety of BB caliber shells" because in most cases 130mm homogenous armour for the turret roof is sufficient to 30km battle range.

[lwd]

.... This is why the British found their 14", 15", and 16" shells did not penetrate 6" deck at any range less than 32,000 yards in post war tests. This is why I used the term "a wide variety of BB caliber shells" because in most cases 130mm homogenous armour for the turret roof is sufficient to 30km battle range.

Yet Hood's hit on Dunkirque disabled her half her turret at considerably shorter range did it not? And wasn't the turret roof ~6"? and if we look at the tables at: http://www.navweaps.com/index_nathan/Pe ... ermany.htm
and
http://www.navweaps.com/index_nathan/Pe ... France.htm
They show the French gun being equal or supperior in deck penetration to the German gun at all ranges and if we are looking at effective penetration the German gun is inferior under 16k and over 30k and has a only a marginal advantage in between. Using the US shells even this advantage vanishes.

[Dave Saxton]

Those are actual British trials results. This is why we must be careful about placing too much emphasis on results and tables from penetration formulas and models. They are useful but have their limitations.

The French 15" has a less favorable striking angle at 30km battle range against horizontal armour than the German 15", and it has a less favorable head shape when striking at such obliqity.

The wild card in the Hood's 15" partial penetration of the Dunkerque turret roof before scoopping off is the use of cemented armour and not homogenous armour. Had it been homogenous armour of high quality this almost certainly would not have happened this way. An additional factor is the slope angle of the turret roof in this case.

[JtD]

2) Problems with the Richelieu
[...]
Mostly known by the members of the forum[...]

Well, tell me.

[RF]

I echo that last comment.

[alecsandros]

I echo that last comment.

viewtopic.php?f=1&t=3265#p37736

[JtD]

...feel free to delete...

[JtD]

- high impurities in the French homogenous armor, leading to somewhat poorer resistance to perforation

Made up through greater thickness.

- highly complex and excessively concentrated main battery, leading to low rate of fire, and extreme vulnerability against battleship fire (1 shell can knock-out 50% of the main battery)

Bismarck lost 50% of her artillery to a single shell hit as well.

- short citadel (51% of the waterline, IIRC) leaving ~ 120 meters of ship un-protected against torpedoes and shells.

54% was the citadel. 93% of the ship featured some protection. 60% of the ships length was well protected against torpedoes.

- problems with the machinery, making the designed ~ 180.000shp not-attainable after corrections and revisions in the US (140.000 shp was the new maximum)

Source for unattainable? And what you call "corrections and revisions" I'd call "improvisation".

- finaly, problems with shells and charges, leading to huge dispersion and chances of in-gun explosions. AFter the refit in the US, the shells and charges were replaced with other designs. The new muzzle velocity, in 1944, was 800mps, down from 830mps. Perforation thus decreased (though I don't know how much)

The French used British shells, or were able to use British shells, after the US refit. That gave longer flying times, decreased belt penetration and increased deck penetration. Source for the bad French shells?

Anyway, imo the Vanguard and Jean Bart were more powerful than the Bismarck and Tirpitz ever were.

That said, I think you left out one of the major drawbacks of the Richelieu class, the lower range when compared to the Bismarck at high cruising speed.
I also think that, depending on the purpose, Richelieu can very well be judged as more powerful than the Tirpitz.

[lwd]

.... The French used British shells, or were able to use British shells, after the US refit. That gave longer flying times, decreased belt penetration and increased deck penetration. Source for the bad French shells?
....

The first time Richeleu fired her guns she ended up loosing 4 of them due to problems with the shells. However the source of the problem was quickly discovered and a work around in place. A permament fix was impacted by the French surrender. I believe Richelue used shells made for her in the US have her refit there. I'm not sure teething problems like this should be held against her either as many battleships had things that needed to be fixed once they got a little sea time.

[JtD]

First time she fired were the trials and there was no problem.

Read up on this in the meantime, thanks.