Vanguard and Bismarck

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Thorsten Wahl
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Re: Vanguard and Bismarck

Postby Thorsten Wahl » Mon Sep 11, 2017 4:08 pm

I have problems in understanding british armour efficiency diagrams especially the vertical protection.
obviously they greatly understate the armour penetration performance of all guns versus vertical armour.
line in red minimum performance(Perforation, projectile whole and fit to burst) of the 38 cm Psgr according german fireeffect tables versus 14" FH armour

(even the performance of their own projectiles is not in line with armour testing.)

to make a difference; for horizontal penetration performance of the german gun there was good agreement between german fireeffect tables and british expectations in the upper diagram.

Image

the armour efficiency diagram for Tirpitz completely ignores the additional protection provided by the scarp for vertical protection and the upper deck for horizontal protection

Image
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Iranon
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Re: Vanguard and Bismarck

Postby Iranon » Mon Sep 11, 2017 6:34 pm

These graphs seemed very strange to me as well. Also striking:

According to them, the WW1-vintage 15" outperforming both Nelson's 16" and KGV's 14" guns.
Bismarck vs. Queen Elizabeth with almost identical immune zones against one another, apparently the Germans wasted 20 years and a tremendous amount of metal.

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Re: Vanguard and Bismarck

Postby paul.mercer » Wed Sep 13, 2017 10:28 pm

Gentlemen,
I often wonder why Vanguard was not fitted with 8 x16" to make her more comparable with US ships. I realize that the 15" gun was a tried and tested weapon, but was it because the RN knew that the battleship era was over and so just fitted whatever they had available at the time?

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Re: Vanguard and Bismarck

Postby dunmunro » Thu Sep 14, 2017 2:54 am

paul.mercer wrote:Gentlemen,
I often wonder why Vanguard was not fitted with 8 x16" to make her more comparable with US ships. I realize that the 15" gun was a tried and tested weapon, but was it because the RN knew that the battleship era was over and so just fitted whatever they had available at the time?


Pretty much. They recycled 4 x 15in twin turrets. No such turrets existed in 16in calibre. Ideally Vanguard would have mounted 9 x 16in in three turrets or 12 x 14in in quad turrets, but that would have involved restarting/extending battleship turret and gun production and there simply wasn't the money and spare industrial capacity for that.

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Re: Vanguard and Bismarck

Postby Iranon » Sat Sep 16, 2017 12:12 am

The British put some credible effort into designing new battleships towards the end of WW2, which would likely carried 16" guns (they considered 14" and 15" as well though). So that's not it.

They had spare 15" lying around, and considered it an excellent weapon despite its age. Their armour efficiency diagrams wrt Tirpitz had it as their best deck penetrator, and inferior to the 16" in belt penetration only at rather high obliquities. It was also their most accurate gun.

Since guns were the bottleneck for new battleship construction, Vanguard made a lot of sense even though some aspects weren't ideal (e.g., 4x2 wouldn't have been their preferred gun layout at the time).

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Re: Vanguard and Bismarck

Postby Maciej » Sat Oct 14, 2017 2:12 pm

spicmart wrote:I wonder if a more powerful main armament could be installed on Vanguard.
So with the TDSs being equal Bismarck should have had the better overall protection.

In short - Yes.
Vanguard was not what Royal Navy want, but what was possible with existing limitations.
British wanted Lions (A bit shorter hull, with the same displacement as Vanguard, but with belt 15" thick all citadel length, 15" barbettes and turret faces, and 9x16" guns.
But bottleneck in production of guns and turrets limited production to new battleships to 2 per year (+1 extra every 3 years).
But there was shortage of battleships, and it was possible to build 1 extra battleship if source of heavy guns could be found.
So in August 1939, just before start of WWII there was acceptance to use old turrets and start new battleship, based on Lion, but with 15" belt over magazines, and 14" over machinery and stronger machinery than Lion for 1 extra knot.
Outbrake of war ended that design, but only for a while.
Later it was resurected but this time with machinery from Lion (so less powerful than originally wanted) and the same armour.
Later as during design process and alternations due to war experience displacement grow up, so to save some mass bet was thinned by 1" all citadel.
But anyway - the only reason of such a "weak" armament was that this armament was available, and only needed to be upgraded, not produced from 0.
From any technical point of view it was possible to mount on such hull 9x16" guns and a stronger armour. Of course on design stage, not during construction.

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Re: Vanguard and Bismarck

Postby Maciej » Sat Oct 14, 2017 2:14 pm

spicmart wrote:But Bismarck had better compartmentation, doesn't she? If so does that mean that she was harder to sink than Vanguard with the compartmention offsetting the advantages that Vanguard has, to say deeper belt ?
Maybe Bismarck also had a better armor scheme below waterline to her advantage?

I'm not so sure about this.
Vanguard had 4 boiler rooms, 4 turbine rooms + 9 auxilary machinery rooms. With alternate BTBT
Birmarck had 6 boiler rooms, 3 turbine rooms and how many auxilary rooms? 4? 6?, with linera BBBTT
In my mind more or less the same level.

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Re: Vanguard and Bismarck

Postby Maciej » Sat Oct 14, 2017 3:20 pm

Dave Saxton wrote:
In terms of firepower the Bismarck was more powerful. Its 15" guns were more modern than those used by Vanguard. The barrels were significantly longer which creates greater muzzle velocity. This translates into greater belt armour penetration and greater range sans supercharges. Supercharges were available to Vanguard for use in a pinch though. The German 15" L/4.4 armour piercing shell was also of superior design and could penetrate more heavy armour without breaking up at acute obliqities.

In case of higher MV no doubt with all consequencesm, but I'm very interested in data about such "superior" design of German shell.
Hard data from tests.
British 15" shell (Cardonald) were tested at 40 degree oblique angle against British 12" face hardened plate and passed it with condition to burst with striking velocity corresponding to ~15 000 yards (standard charges). Older Hadfield or Mrss shell could not pass that test, but in 1946 Caronalds were available in numbers.
Any data about superiority of German shell? Hard data from test with higher obliquity hit on similar armour?

Many sources list the British 15" as giving impressive deck penetration, but post war tests proved that all British battleship guns could not penetrate more than 5" of deck armour at ranges of less than 32,000 yards or about 30km. The Bismarck's gun penetrated 5.2" of deck armour at 30km, so there's virtually no difference there.

Could You give data from live tests?
And another thing into considerations.
At high obliques British shell could brake up but will generate considerable flash and splinters (see Dunkreque turret roof hit). Bismarck magazines were just under the deck, so those splinters could start fire.
In case of Vanguard shell had to make similar hit as Mass made on Jean Bart.

Added
Why I'm asking about data? At 30 km range, striking angle of 15" shell is ~40 degree (standard charges), so oblique ~50 degree.
At 40 degree oblique, those shells passed penetration of 12" face hardened plate. 10 more degree such removes capability? Possible, as armour is different, but see another thing
BUt tests of armour taken from Tirpitz. 15" shell, penetration of German 200 lbs plate (~5") with 65 degree oblique, with 1100 fs.
65 degree oblique = 25 degree descend = ~25 000 yards = ~23 000 m, and at that range striking velocity s 1400+ f/s, so easy penetration with considerable remaining velocity
End add

In terms of belt protection the Bismarck was superior to the Vanguard and really all other battleships. It was a heavy belt (320mm) of top quality face hardened armour plus a heavy scarp arranged at an ideal angle. It could not be defeated according to some experts.

The German ballistian B Hoyer stated in 1943 that if the scarp was heavy enough, in order for a shell to defeat this type of arrangement its velocity would need to be so great that it would shatter against the face hardened main belt first.

Vanguard's belt was also from top quality armour but it was 360mm and no heavy scarp. Bismarck's hull IZ was essentially from point blank range to 30km vs most battleship caliber guns. Vanguard's IZ was essentially 21km to 30km vs the same guns.


Depends on definition.
Clearly direct hit into machinery through scrap was not possible (say very low probability), but penetration through 15 cm upper belt or 32 cm belt was quite possible. Detonation over main deck was less disastrous than inside boiler room, but many detonations there could be devastating and ship will loose efficiency after those hits.
Difference is that shell which penetrate belt over say machinery on Vaguard will probably generate more damage, but it does not mean that Bismarck was "invulnerable"

It can now be shown that the Bismarck's two deck system provided at least the sum total of its two armoured decks which would be 130mm over the machinery and 150mm (TP) over the magazines. Vanguard's deck protection was 5" over the machinery and 6" over the magazines, so virtually the same there as well.

If You add 2 thickness of deck on Bismarck add 2 thickness (or more if existed) on other ships.
Vanguard had weather deck ~30 mm thick, so sum was ~180 (magazines) and ~155 (machinery)
It is difference.
And more – magazines of Bismarck were just under the main deck. On Vanguard much deeper and with extra 38 mm splinter protection, to total was much over 200 mm over magazines.
Bismarck's turrets and barbets were better protected with 130mm turret roofs and 360mm turret faces, and 350mm exposed barbets. Vanguard's barbets and turret faces were 330mm. The turret roofs are listed as 180mm but that is laminated plates.

Turret roofs of Vanguard were 152 mm not laminated, with “turret roof quality armour”. That mean stronger requirements than ordinary deck armour.
But it is pure academic. Both could knock out each other turrets in considerable range.
OF course conning tower of Bismarck was considerably thicker. Good question if thick enough to allow command of ship after direct hit. Even non penetrating.

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Dave Saxton
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Re: Vanguard and Bismarck

Postby Dave Saxton » Sat Oct 14, 2017 3:50 pm

Thorsten Wahl wrote:I have problems in understanding british armour efficiency diagrams especially the vertical protection.
obviously they greatly understate the armour penetration performance of all guns versus vertical armour....


The AoN armour schemes adopted by most are only viable if the penetration power of guns vs vertical armour remained at Approx. WW1 through 1920s performance levels. However, by the 1930s the penetration power of battleship caliber guns had increased greatly. 12-inch, 13,-inch, 14-inch, 15-inch belts.... were simply not up to the task anymore. Such designs are only viable given the WW2 gun performance, if the ships command is careful to maintain rather oblique target angles during the heat of battle, and/or remain at very long ranges.

When this fact is understood the German scarp triangle protection scheme is appreciated. In documents the Germans reveal that the advent of aircraft bombing requiring greater effective deck protection. This in turn meant that the weight of the deck protection would need to be applied to both horizontal and vertical protection if the vertical protection was to be up to the task. The low position of the panzer deck along with heavy scarps brought this to realization.

An upper citadel was stacked atop the main citadel. This along with greater protected length provided a good protected internal volume.

The designs of the Allies were based much on 1920s thinking. However, by the time of war many of the concepts developed during the 20s had been overran by new technology developments, such as naval air power and radar, which caused surface battle increasingly to happen during night time or bad weather-which in turn meant relatively short battle ranges, not longer ranges.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: Vanguard and Bismarck

Postby Maciej » Sat Oct 14, 2017 5:25 pm

History turns circes.
In 70thies of XIX century in Barnaby era, British build battleships with AoN scheme.
The only real thred was heavy AP shot/shell so logic was quite simple.
In early 90-thies of XIX century British recognized increased performance of heavy guns, and the same time thred from medium QF guns. So armour area had to be larger, and armour thicker. Impossible, so scrap was designed for HMS Renown soon follow by Majestics and later ships.
Logic was simple - any armour at battle range would be penetrable, so scrap had to stop heavy shell, and medium armour will stop medium shells, so area covered by armour could be large.
Later it was recognized increased thred of pluging fire. Yes pluging fire in XIX century. British expected that French will mount howitsers or even mortars on board ships, so deck had to be thickened. Co thick deck (1.5 to 2" - depends on ship) was put as high as possible, but it was quite obvious that it will be penetrated by howitzer, so another thick deck (1.5" to 2" depends on ship, but total thickess of those two decks rarely exceed 3") was added to stop splinters, and of course any shells/splinters which penetrates belt.
Exactly the same logic as Bismarck, only 50 years before.
That was continued untill WWI. "Ideal battleship 1919" desriberd by post war question comitee describes exact Bismarck only with 25 knots speed.
Birmarck seem to be exact that design only with more modern materials and 30 knots. Everything else is virtually the same
And a bit later British switch to AoN (returned to AoN actually), as with increasing ranges again heavy AP shells were most dangerous thing. And bombs, but heay deck armour could stop both bombs and shells.
So Bismarck desined in 1935 was actually the same as British concepts in 1919. If somebody designs ship with 25+ old concept... Conclusions make yourselfe

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Re: Vanguard and Bismarck

Postby Maciej » Sat Oct 14, 2017 6:46 pm

If we thrust Nathan Okun research, IZ graphs should be more or less like this
https://www.dropbox.com/s/q3mnjp6o1efz4 ... d.jpg?dl=0

and on the same picture Bismarck, Vanguard and modernized Hood (after full modernization that never happen)
https://www.dropbox.com/s/5f6xx96w08nwj ... d.jpg?dl=0

Actually I used existing range tables for those calculations, which provet to be wrong. New tables had to be calculated with the same atmosphere conditions, initial velocities (new gun for example both cases), and than recalculations.
But I don't have time now. Lines will move somehow, but general impression should be like that.

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Alberto Virtuani
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Re: Vanguard and Bismarck

Postby Alberto Virtuani » Tue Oct 17, 2017 1:24 pm

Hi Maciej,
is the Bismarck IZ diagram you posted above referred to the KGV 14" or to the British 15" gun ? The title says 15" but then you speak about KGV guns....

Also, the Bismarck diagram is misleading compared to the one for the British battlewagons (in case of vertical penetration).
The orange area is NOT the vulnerability area but (as it was for the optimistic Admiralty WWII diagrams) just the area where the British guns can puncture her external belt. They don't take into account the slope/deck combination (despite in the legend you recognize that the combined belt+slope cannot be defeated over 2 km....).
The effective (short range) area where Bismarck vitals are exposed should be very, very small compared to the one of the British ships.

Am I correct ?


Bye, Alberto
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Dave Saxton
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Re: Vanguard and Bismarck

Postby Dave Saxton » Tue Oct 17, 2017 4:00 pm

Could You give data from live tests?


I have boxes and boxes of documents. Unfortunately, because of my present circumstances they are in storage and they are not handy. Nonetheless, if I recall correctly the British study that found that no British battleship gun could defeat more than about 5-inches effective deck protection at less than 32k was documented in the ADM281 set of documents. This was a post war (WW2) live ammunition study.

Several years ago, I graphed various battleship gun’s deck penetration attainments on the Y axis vs range on the x axis. Seeing this in graphic form instead of on a chart was very interesting, particularly when put into the context of IZ. About 5 ½ -inches effective was the point of diminishing returns in terms of how much IZ it bought. 130-140mm was good to around for 30,000- 32,000 yards with just about every gun 14” and larger-including super heavies. Adding a couple of more inches only bought a marginal increase in IZ.

If You add 2 thickness of deck on Bismarck add 2 thickness (or more if existed) on other ships.
Vanguard had weather deck ~30 mm thick, so sum was ~180 (magazines) and ~155 (machinery)
It is difference.


The problem is that the 30mm in not armour grade steel. It is not likely to induce much yaw because it is incapable of consuming much energy (and the distance between the weather deck and MAD is too small for much yaw to become manifest anyway), and it is unlikely to de-cap incoming large caliber ordnance. In that case the Krupp rule for calculating effective thickness comes into play using the square root of plate 1^ + plate 2^+ plate 3^… method. This means its addition to the effective thickness is not significant. The British understood this, because they made sure that KGV’s deck protection was 5-inches over the machinery and 6-inches over the magazines, counting the homogenous armour plates only. This was deemed adequate against 16-inch fire out to ~30k in their IZ calculations.

Splinter decks, as well as structural decks, in my opinion, are very inefficient allocations of armour weight. Why not just include that weight into the primary plate (or decapping plate if applicable) where it can do some good? Or exclude that weight from the design if it only provides a marginal or insignificant improvement of protection?

Bismarck seem to be exact that design only with more modern materials and 30 knots. Everything else is virtually the same


I disagree that it the same thing even if it looks similar on a cross sectional drawing. It is fundamentally different in concept. The earlier designs were based on arresting splinters after ordnance was fused by the outer layer. Hoyer’s lecture and other documents make it clear that the two armoured decks, and the scarps of the more modern design were part of the effective thickness calculations in the context of modern IZ requirements.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Dave Saxton
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Re: Vanguard and Bismarck

Postby Dave Saxton » Tue Oct 17, 2017 4:10 pm

I have always liked the Vanguard. The old 15" twins were good weapons and the Vanguard included many improvements based on war experience with the KGVs. Vanguard was also the first British warship built using extensive electric arc welding.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: Vanguard and Bismarck

Postby Maciej » Wed Oct 18, 2017 8:51 am

Alberto Virtuani wrote:Hi Maciej,
is the Bismarck IZ diagram you posted above referred to the KGV 14" or to the British 15" gun ? The title says 15" but then you speak about KGV guns....

Hi.
Bismarck protection is against 15" British guns using Cardonald shells with "new gun" muzzle velocity.
I made a lot of various graphs in short time, and presented on navweaps board (topic "various IZ graphs", so possibly sometimes title could be from odler graph

Also, the Bismarck diagram is misleading compared to the one for the British battlewagons (in case of vertical penetration).
The orange area is NOT the vulnerability area but (as it was for the optimistic Admiralty WWII diagrams) just the area where the British guns can puncture her external belt. They don't take into account the slope/deck combination (despite in the legend you recognize that the combined belt+slope cannot be defeated over 2 km....).

Read description on graph. There is comment about it just on graph, what each line mean. With comment that belt + slope is unpenetrable at all byt this shell.

The effective (short range) area where Bismarck vitals are exposed should be very, very small compared to the one of the British ships.

Am I correct ?

Yes/no
As mentioned more early combined protection of belt + slope was very unlikely.
But detonations inside hull even above main armour deck could not be ignored. Bismarck was destroyed by exactly this form of detonations (+ hits on turrets, superstructures and so on). Who cares if remains afloat if could not fight nor go anywere? So graph "total invulnerability" is exactly misleading, as this is not "invulnerability"
And those detonations above armour deck could happen at virtualy all ranges, as shell cold go through 145 mm belt or 50 mm deck. Just enough thick to activate shell.
Again see description on graph.

Of course such detonations are potentially much less devastating than inside "citadel" on ships based on AoN principle.
So in short - on "safe are" AoN ship should get less damage when hit compared to Bismarck (Bismarck had no "safe area" at all), but outside "safe area" AoN ship could get more devastating hit than Bismarck.

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