Fuso V Queen Elizabeth

[dunmunro]

You didn't read what I quoted closely... It struck "2.50 metres beneath the upper edge of the armour belt". The armor belt was 5.75m deep, therefore it struck the belt 3.25m *above* it's lower edge. So yes, another belt penetration is exactly what they are suggesting.

If you didn't notice it you had to scroll down to see their second diagram I had posted. Presumably the "entire base of the projectile (350-400kg)" marked off in the diagram is the one you were refering to in the picture?

OK, yes, I assumed it passed under the belt somehow, but it would have been clearer to state that it penetrated the main belt 2.5m below its upper edge and you're correct that I neglected to scroll down to see the 2nd image showing the belt penetration and entry of the shell into the boiler room. G&D don't make it clear which of the two belt penetrations the burst 15" shell belongs to.

[alecsandros]

Hello guys,

I've re-read the pages in Garzke&Dulin "British, Soviet, French, Dutch Battleships of WW2" (pg 43-48). Also, I tried to take a look at their sources, that at presented on pages 377-380.

From the looks of it, it seems they had some troubles with the French archives, but they nevertheless managed to reconstruct the most plausible sequence of events, with help from various French officials.

Oh well, let's get on with the comparison between Dumas and GD. I must first say that I don't have Dumas book, so I am going to take Boredatwork's and Terje's quotes as they are.
------------------------
First of all, the account of the battle as it appears in G&D:

Battle of Mers-el-Kebir, July 3rd 1940.

Time the battle started: 17:54

Range at the start of the battle: 14km
"At 1754 the British ships, which were some 14,000 meters from the French ships, opened fire" (pg 43)

Time the Dunkerque opened fire: 18:00
"At this time, the captain of the Dunkerque ordered the immediate emptying of the aviation gasoline tanks and at 1800 gave orders to the main battery to commence fire"

Time the Hood targeted Dunkerque: ~ 18:03

"At this instant the old battleship Bretagne was hit, and at 1803 the Provence was struck by a 381-mm shell. By 1807, Bretagne was aflame from bridge to stem, and two minutes later the old battleship began to capsize, when suddenly she exploded. Meanwhile, the Strasbourg was heading for the main channel at 15 knots, and the Hood concentrated her fire on the Dunkerque, which was the nearest to her"

Image from GD with the 4 hits:



First shell hit on Dunkerque: aft, in the seaplane hangar ~ 18:05
"The Dunkerque was also now under way at a speed of 12 knots, but rangefinding was difficult due to the terrain and the fact that Fort Santon was situated between her and the British ships. Just as she began her tum, the first 381·mm shell from the Hood struck aft, passing through the seaplane hangar and a petty officer's space and exiting through the shell plating, 2.5 meters below the waterline"

3 shells salvo-hit on Dunkerque ~ 18:08
- 1 shell >> turret roof
"The first of these struck the roof of Turret II over the gunpoint of the outer barrel and gouged the armor severely.
Most of the shell ricocheted and fell to the ground some 2000 meters from the Dunkerque. A piece of armor or a portion of the projectile struck the loading platform in the gun chamber, setting fire to the first two quarters of powder bags in the process of being unloaded. The smoke and fire asphyxiated or burned to death the entire gun crew in the starboard half turret"

- 1 shell >> slightly above the armored belt, passing through the upper armored deck
"The second 381-mm shell struck inboard of the 225-mm armor belt's top and pierced the 115-mm armor deck near the centerline of the starboard twin mount. The shell severely damaged the ammunition-handling room for this mount and jammed its hoist. It continued its trajectory inboard, passing through two splinter bulkheads and exploding in an air-conditioning and fan room"

- 1 shell >>beneath the waterline
"The third projectile had a slight underwater trajectory, dived under the 225-mm armor belt, and pierced all structure between the starboard side shell and the torpedo bulkhead before exploding on contact with the torpedo bulkhead"

Time the DUnkerque ceased fire: ~ 18:10

----------------

Main differences between Dumas/GD:
a) the order of the shell hits
GD mentions the hangar hit as first; Dumas mentions it as part of the 3-shell salvo
b) the trajectory of one of the shells in the salvo: GD say it passed over the armoured belt, through the armored deck, while Dumas describing a belt penetration.

IMO, the following image describes the trajectory as I understand it from GD:



-----------------------
The boring part:

Sources for G&D, French Battleships:

They do not have references for each battle, but provide instead a bibliography at the end of the volume.

"The technical details in this work are based upon official documents of those T nations concerned, primarily upon those found in the design archives, supplemented by official reports and material from books or articles by noted authorities on the subject of warship design, construction, or operation. The authors and their representatives were permitted access to
classified material" (pg 377)

"Few published sources were available on the design or operation of French capital ships. This fact was further complicated by the incompleteness of the French archives on the design, construction, and operation of the Dunkerque- and Richelieu-class ships because of the German military occupation of both Paris and the major shipyards from June 1940 through July 1944 Paris, or May 1945 in the case of the Brest Navy Yard. In many instances, the plans and files had been scattered and were never completely reorganized. However, the Service Technique des Constructions et Annes Navales (STCANI), the French Military Mission to Washington (Commander A. P. Laget), the French naval attache (Rear Admiral E. Challnel), and individuals such as Henri Le Masson and Jean Meirat gave the authors much assistance in the absence of complete official documents. The translation of official French documents was accomplished by Mr. Richard van Hooff, a naval architect and marine engineer, who also aided in their analysis" (pg 377)

"Individual assistance provided by Henri Le Masson and Jean Meirat was extremely helpful in describing the operations and battle damage of the Dunkerque. Strasbourg. Richelieu. and Jean Bart. In this regard Mr. David Baker III also provided helpful
information from his files. M. Le Masson provided information from his personal library and files on the design and operations of all French ships. This was supplemented by interviews with former naval constructor personnel and visits to the naval archives. M. Jean Meirat furnished detailed information on the wartime operation of the completed French ships and also provided much material from his personal files. Both gentlemen over the years of manuscript development provided detailed criticisms and additional infonnation when it was requested. Preliminary manuscripts were reviewed for completeness and accuracy by several noted authorities on French warship design, such as Vice-Amiral Paul Morel, who was
the chief naval constructor at the time of the Richelieu's construction, and ContreAmiral Lucien Poirer who took part in the building, sea trials, and first months of operation of the Richelieu. Ingenieur General Pascal reviewed the text and provided
several key plans and data"

Then a 2 page list of books, periodicals, interviews, proceedings, etc, about the French ships.

[Bgile]

From your description it would seem to me the shell exploded in the room labeled "Turbo Ventilators", not where you have shown it.

It is still incredible to me that the shell would penetrate a 115mm deck, since that is well beyond any theoretical capability in any ballistic computation I've seen.

Edit: I'm also puzzled by the fact that these shells all seem to be going further than a .025 fuse delay would imply after passing through that thickness of belt armor. Maybe I'm incorrect in that.

[alecsandros]

It is still incredible to me that the shell would penetrate a 115mm deck, since that is well beyond any theoretical capability in any ballistic computation I've seen.

Edit: I'm also puzzled by the fact that these shells all seem to be going further than a .025 fuse delay would imply after passing through that thickness of belt armor. Maybe I'm incorrect in that.

I am also very surprised by the performances of the 381mm shells.

What is also very intriguing is that a 3shell salvo was delivered at 14km. From what I've read so far, at this range, the most probable hit is that of 1 shell (out of 8). 2 shells from 1 salvo at 14km is considered to be highly unlikely, and 3 shells, well, almost impossible... (I remember reading an article by Bill Jurens on the matter at hand, but I can't find it)

[Terje Langoy]

A third source of interest - it does not correspond with G&D´s timing of hits as "cease fire" apparently was ordered at 1804 hours aboard H.M.S. Hood. This again would suggest Dunkerque stopped firing long before 1810 hours

http://www.hmshood.org.uk/reference/off ... 34-317.htm

[Byron Angel]

What is also very intriguing is that a 3shell salvo was delivered at 14km. From what I've read so far, at this range, the most probable hit is that of 1 shell (out of 8). 2 shells from 1 salvo at 14km is considered to be highly unlikely, and 3 shells, well, almost impossible... (I remember reading an article by Bill Jurens on the matter at hand, but I can't find it)

..... Here is some data from a WW1 source document re mean spread of British 15-inch 4 shot salvo patterns taken from gunnery exercises in 1917 and 1918:

Ship-------------------[ Date / Mean Range (yds) / Mean Spread (yds) ]

REVENGE--------------1917 / 22100 / 154
-------------------------1918 / 21000 / 150-200

RESOLUTION----------1917 / 10400 / 300
-------------------------1917 / 22500 / 200-300
-------------------------1918 / 21000 / 125-200

RAMILLIES-------------1918 / 17200 / 340
-------------------------1918 / 21000 / 175

ROYAL SOVEREIGN---1917 / 21250 / 400

ROYAL OAK------------1916 / 16000 / 180
-------------------------1917 / 20000 / 400


DUNKERQUE's beam was 102 feet. Assuming a 150-200 yard pattern at 14,000 yds, an angle of fall of about 15 degrees, a line of fire from abeam, a good straddle, and a 30 foot freeboard amidships, about 1.5 hits could statistically be reasonably expected.

Re Bill Jurens, you are probably thinking of his two part Warship International article on post-WW1 USN BB gunnery which is available online at Navweaps IIRC.


Byron

[Dave Saxton]

From your description it would seem to me the shell exploded in the room labeled "Turbo Ventilators", not where you have shown it.

It is still incredible to me that the shell would penetrate a 115mm deck, since that is well beyond any theoretical capability in any ballistic computation I've seen.

Edit: I'm also puzzled by the fact that these shells all seem to be going further than a .025 fuse delay would imply after passing through that thickness of belt armor. Maybe I'm incorrect in that.

Consider that the belt was only 240mm and the shell would be going about 500 M/s at impact. Doing some energy consumption math, it could travel up to ~9 meters before bursting. I don't see this as out of the ballpark.

In the case of deck penetration (using the curves for 875kg 15" APC) it would indicate that the deck armour was about 80% of standard quality. Not really out of the ball park.

[Byron Angel]

..... Here is some data from a WW1 source document re mean spread of British 15-inch 4 shot salvo patterns taken from gunnery exercises in 1917 and 1918:

Ship-------------------[ Date / Mean Range (yds) / Mean Spread (yds) ]

REVENGE--------------1917 / 22100 / 154
-------------------------1918 / 21000 / 150-200

RESOLUTION----------1917 / 10400 / 300
-------------------------1917 / 22500 / 200-300
-------------------------1918 / 21000 / 125-200

RAMILLIES-------------1918 / 17200 / 340
-------------------------1918 / 21000 / 175

ROYAL SOVEREIGN---1917 / 21250 / 400

ROYAL OAK------------1916 / 16000 / 180
-------------------------1917 / 20000 / 400


DUNKERQUE's beam was 102 feet. Assuming a 150-200 yard pattern at 14,000 yds, an angle of fall of about 15 degrees, a line of fire from abeam, a good straddle, and a 30 foot freeboard amidships, about 1.5 hits could statistically be reasonably expected.

Re Bill Jurens, you are probably thinking of his two part Warship International article on post-WW1 USN BB gunnery which is available online at Navweaps IIRC.


Byron

Edit - should read "1.2 to 1.5 hits".

[alecsandros]

Consider that the belt was only 240mm and the shell would be going about 500 M/s at impact. Doing some energy consumption math, it could travel up to ~9 meters before bursting. I don't see this as out of the ballpark.

In the case of deck penetration (using the curves for 875kg 15" APC) it would indicate that the deck armour was about 80% of standard quality. Not really out of the ball park.

Hello Dave,
I am not familiar with the "quality" factor of the armor. If the deck was indeed "80% of standard quality", is it safe to assume this 115mm deck would behave as well just as a 92mm one of standard quality?

All the best,

[alecsandros]

[...]
Edit - should read "1.2 to 1.5 hits".

Thanks Byron!
Very interesting..

[boredatwork]

From the looks of it, it seems they had some troubles with the French archives, but they nevertheless managed to reconstruct the most plausible sequence of events, with help from various French officials.

- 1 shell >> slightly above the armored belt, passing through the upper armored deck
"The second 381-mm shell struck inboard of the 225-mm armor belt's top and pierced the 115-mm armor deck near the centerline of the starboard twin mount. The shell severely damaged the ammunition-handling room for this mount and jammed its hoist. It continued its trajectory inboard, passing through two splinter bulkheads and exploding in an air-conditioning and fan room"

IMO, the following image describes the trajectory as I understand it from GD:

Dumas & Jordan in their preface make mention of the "Fonds Potsdam, an archive of material assembled by the german kriegsmarine during the occupation and transfered to Berlin, where it was seized by the Russians; the materials were returned to France after the fall of the Berlin Wall and have now been reclassified and distributed among the various French national archives." Perhaps a wealth of more accurate information might have been discovered in the 30 years since Allied BBs was published?

edit - According to G&D sources they had the french documents translated by a third party while Dumas & Jordan are both ex-teachers and fluent in French. Perhaps G&D mis-translated dessus (above) and dessous (below) in reference to where the shell passed,for instance:

"it struck 0.40m par-dessous the upper edge of the armored belt...." could have been mistaken for "0.4m par-dessus" and thence mistranslated as "0.4m above the upper edge of the armored belt," implying a deck penetration?

I also think your trajectory should be superimposed upon my first image as G&D and Dumas make mention of it passing through the handling room.

[Dave Saxton]

I am not familiar with the "quality" factor of the armor. If the deck was indeed "80% of standard quality", is it safe to assume this 115mm deck would behave as well just as a 92mm one of standard quality?

All the best,

All that means is that a given material of a given thickness is capable of consuming 80% of the energy that it should, or the average of what most homogenous armours do. It can be down as much as 20%. This was the case of the problem of brittle, heavy, Class-B plates in the USN, that the US Naval Research Lab studied during the war. Energy consumption, or the velocity required to penetrate...ect.., can be equated to effective thickness. Generally thin homogenous plates can be manafactured to a higher level of quality than thick homogenous plates. This type of problem would normally be enccountered the thicker the plate is, and would not really be expected of 115mm plates, unless the material has impurities, or a poor heat treatment, and so forth.

The fact of the distance travelled after penetrating would favor the theory of a belt penetration. If the armour quality of the deck was such that it would allow penetration of 115mm in this case, the energy should be such that the shell would have virtually 0 residual energy.

Another possibility to look into is how the armoured deck was constructed. Was it a single plate or the sum of two plates in contact with each other? British tests post war found that two armoured plates in contact with each other performed far worse than the same two plates spaced.

[boredatwork]

Another possibility to look into is how the armoured deck was constructed. Was it a single plate or the sum of two plates in contact with each other? British tests post war found that two armoured plates in contact with each other performed far worse than the same two plates spaced.

Dumas p 43

comprised non-cemented armour plates fixed to a 15mm steel deck. The plates [...] and were 115mm thick over the machinery and after magazines [...], increasing to 125mm over the forward frame [...]

So it sounds like a single thickness.

[alecsandros]

Dumas & Jordan in their preface make mention of the "Fonds Potsdam, an archive of material assembled by the german kriegsmarine during the occupation and transfered to Berlin, where it was seized by the Russians; the materials were returned to France after the fall of the Berlin Wall and have now been reclassified and distributed among the various French national archives." Perhaps a wealth of more accurate information might have been discovered in the 30 years since Allied BBs was published?

edit - According to G&D sources they had the french documents translated by a third party while Dumas & Jordan are both ex-teachers and fluent in French. Perhaps G&D mis-translated dessus (above) and dessous (below) in reference to where the shell passed,for instance:

"it struck 0.40m par-dessous the upper edge of the armored belt...." could have been mistaken for "0.4m par-dessus" and thence mistranslated as "0.4m above the upper edge of the armored belt," implying a deck penetration?

I also think your trajectory should be superimposed upon my first image as G&D and Dumas make mention of it passing through the handling room.

Excellent post!

[boredatwork]

edit - According to G&D sources they had the french documents translated by a third party while Dumas & Jordan are both ex-teachers and fluent in French. Perhaps G&D mis-translated dessus (above) and dessous (below) in reference to where the shell passed,for instance:

"it struck 0.40m par-dessous the upper edge of the armored belt...." could have been mistaken for "0.4m par-dessus" and thence mistranslated as "0.4m above the upper edge of the armored belt," implying a deck penetration?

Just to clarify in case anyone misreads my post - I have no clue what the original French sources both authors used actually said.

I'm just pointing out that, supposing Dumas' text is similar to an original french document both sets of authors might have had access to, if it talks in such relative terms - above or below the top edge of the belt - it could have been very easy to mistranslate:

Above and Below in English are spelt and pronounced very different.

Dessus and Dessous in French on the other hand are spelt and pronounced very similar.