Fuso V Queen Elizabeth

[tommy303]

I dunno, it doesn't sound like a low order detonation

Even a low order detonation can cause severe damage, however in photographs the damage, though considerable in the area where the shell was photographed, seems less than what one would normally see with a proper high order detonation.

[alecsandros]

I may have mistakenly measured a greater slope. Double checking (and assuming my drawing is correct) it ends up about 24 * instead of about 27*. Remember this is FH armour instead of high quality homogenous armour (where the penetration would be much less in this type of impact). The penetration of FHA is between 160mm and 140mm for a shell that breaks up, which this shell did. Its about 130 for a shell that remains intact. Did the ship develop a slight list before this and the deck hit were received?

I have also thought about a possible list of the ship, but I can't say if that was the case.
To the best of my knowledge, the Dunkerque was moving slowly, at 12kts, at the time of the impact over the turret. Several minutes had past since it completed its turn, in order to align itself with the exit from the harbor, so a slight list coming from the turn is unlikely.

And another thing: what about the penetration of the armored deck of Dunkerque (115mm thick)? Clearly the deck was horizontal class B armor.

[Dave Saxton]

And another thing: what about the penetration of the armored deck of Dunkerque (115mm thick)? Clearly the deck was horizontal class B armor.

As you have mentioned it's yet another damning indicator of the quality of the French homogenous armour. But we do need to find out whether or not if the ship was listing.

[Terje Langoy]

And another thing: what about the penetration of the armored deck of Dunkerque (115mm thick)? Clearly the deck was horizontal class B armor.

As you have mentioned it's yet another damning indicator of the quality of the French homogenous armour. But we do need to find out whether or not if the ship was listing.

From pg 80 in the book French Battleships by authors Jordan & Dumas it appears that the 15-inch shell to land at the roof of turret II (currently trained about 100 degrees to st.bd.) aboard the Dunkerque came in on a green 90 bearing and on a rather flat trajectory. From the account at pg 79 (based on the official report by Ingeneur des I.N. Tessier du Cros, dated 01.10.1940) shell impact was `at an angle of 20 degrees to the armour plate´ - which I interpret to consider both shell trajectory and obliquity of turret roof.

The account further state that:

...the shell pushed in the plate as it ricocheted and continued on its course without any appreciable deviation. It did not explode and landed ashore some 2000 metres from the ship and at a height of about 150 metres above the village of St. Clotilde. The plate of cemented armour was pushed in at its centre producing a crescent-shaped opening and punching out plugs of armour beneath the hardened face with a maximum thickness of 10-12 cm, which were found on the floor of the firing chamber.

From the book I read that one fragment (possibly of the turret armour but more probably a shell fragment according to the report) was found on the floor of the firing chamber in the turret while another large fragment is reported to have struck the fire control top of the battleship Provence.

It is written that H.M.S. Hood let loose her first salvo at 1755 hours. In response to this Admiral Gensoul gave the order to cast off and open fire - the Dunkerque appears to have replied fire immediately. It is further written that four minutes into the action Dunkerque was still secured to the jetty and from an official enquiry made afterwards - as to why she had not cast off sooner - it appears that her deck parties fore and aft had either rushed to their battle stations or fled for cover once the British shells began to land. By 1759 hours Dunkerque had finally cast off but then, as the ship was about to steer clear of the jetty, she received the first hits; being the relatively harmless turret roof hit but also the more unfortunant hit aft. (This hit sliced the eletrical cabling for the rudder and she had to switch to an emergency manual helm control) To follow these were two more hits; both landed amidship where they penetrated her armour belt and exploded inside the ships vitals, resulting in the loss of both speed and eletrical power. These hits were, according to the book, recorded `just after 1800 hours`

In plenum it seems that Dunkerque was disabled by the second of two consecutive salvos fired at 1759-1800 hours and this while she was still trying to steer clear of the jetty. Fact that the ship then was beached on the opposite side of the jetty ( and facing the village of St. Andre bow on) would suggest she hardly made any significant maneuvre whatsoever. (A sketch on pg. 76 display a soft turn) With the distance between start point (jetty) and stop point (St Andre) being less than 1000 metres she would hardly reached even moderate speed. I´d suggest a mere steering speed when hits were landed.

[boredatwork]

And another thing: what about the penetration of the armored deck of Dunkerque (115mm thick)? Clearly the deck was horizontal class B armor.

As you have mentioned it's yet another damning indicator of the quality of the French homogenous armour. But we do need to find out whether or not if the ship was listing.

"3rd 15" pierced 115mm deck, secondary ammunition handling room causing fires and detonation of two shells , passed through several splinter bulkheads, then detonated, in a fan room "totally" destroying that compartment, blast and fumes damage to forward engine room through airvents putting all machinery there out of action and killing 20 of 30 crew in the engine room.

4th 15" dived under the main belt and exploded on contact with the SPS armoured bulkhead, causing fires and severe damage to adjacent machinery spaces, leaving only one engine room in operation. 2nd Edit Note: Dunkerque had 6 boilers in 3 compartments and 4 shafts with two engine rooms. Her main machinery spaces did not have centre line bulkheads. G&D state that only the after engine room and one boiler room remained operational."

It must have been the 3rd hit, where the shell body was photographed.

Is the above taken from G&D allied BBs? If so I'm curious what their source is. Jordan & Dumas' list the "official report of ingeneur des I.N. Tessier du Cros (member of the armour committee) dated 01.10.40" as their source and, unless I've misread their work, I can't find any mention of the shells penetrating the 115mm deck:


Shell 1 hit the turret

Shell 2 (p.80)"...struck aft, in the unarmored part of the ship. It passed through the lower hanger, pierced the main deck and exited the port side of the hull without exploding." According to the Armour Diagrams on p44, 47 & 48 the main deck was not armored ajacent to the lower hanger, except forward of it. Unfortunately it is the only hit which didn't merit a diagram in the book. The only way it could pass through the lower hanger, then the 115mm portion of the main deck would be a shot from the aft quarter of the ship - which could have been a possibility - but then presumably, it would have passed through something else noteworthy as it exited the hull like the main belt or TDS. Given the detail gone into about hits 1,3, & 4 I would assume that wasn't the case.

Shell 3 (p.80)(my italics)(see diagram below)

... [it struck] 0.40m beneath the upper edge of the armored belt. It passed through the armored belt and penetrated the handling room J133 of Turret III (twin 130mm to starboard) [...] it pass through the 20mm bulkhead which was an upward continuation of the torpedo bulkhead, and finally burst in the medical store J141. Shell splinters and the blast [...long description about the internal effects of the explosion including destroying ventilation, smoke, effects on the engine room below, etc]

Shell 4 (p81)(my italics)(see diagram below)

...at the waterline to starboard in the ajacent section L, 0.3m abaft transverse bulkhead KL and 2.50 metres beneath the upper edge of the armour belt [belt depth being 5.75m][...]It passed through the inclined part of the lower armored deck [40mm] in section I and penetrated into fuel bunker K225 which was almost full [...]. It's passage opened up large breaches in bulkhead KL [...]. The shell passed through the Torpedo bulkhead and the watertight bulkhead behind it, severing a number of cables in tunnel K211, and then penetrated into boiler room 2. In this compartment it severed steam collector 1, which connected boiler 21 [the starboard boiler] with the forward group (BR1 + the wing turbines) then smashed into collector 2 (saturated steam) and the exhaust collector of the auxiliaries. It went on to penetrate the starboard casing and the upper steam drum of boiler 21 and the broken remains - three fragments of the shell body and the entire base of the projectile (350-400kg) rolled back along the room of the boiler containment box.

If that's the case then there was no 115mm deck penetration... or am I missing something?

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[boredatwork]

Hello guys,

Mers-el-Kebir:
Hood opened fire at 14km from Dunkerque, and hit it with 4 shells. The 2nd and 3rd pierced 115mm of deck armor and caused severe damage inside. (G&D, British, French, Dutch Battleships)

^Again if you have the book handy I'm curious if they credit a source for their info. (see previous post)

[Bgile]

Thank you for the nice picture.

[Dave Saxton]

Belt penetrations are more plausible given the range (is the range also in question?). We need to find out which among these conflicting sources presents the more accurate version of events.

[alecsandros]

I agree, Dave.
I'll have another read at G&D, and I'll post a more lengthy reply (hopefully with their sources) tomorrow

All the best

[boredatwork]

Dumas makes no mention of the range when the British ships actually opened fire, but assuming his map is accurate it looks like approximately 15,000m.

[Thorsten Wahl]

What we are finding out is that the head shape has a significant effect on penetration dynamics beyond such obvious factors such as mass and striking angle.

There also some other factors (according Hoyer Berechnung schwerer Panzer) you should keep in mind and their effects on penetration are significantly higher than varying the shape.
1 Weight portion of the cap. The higher the better
2 Hardening (depth) of the cap (german caps achieve 200 kg/mm²)

unfortunately there are not more informations as the pure statement available

[dunmunro]

The summary that I posted was from another board, but it is an accurate summary of Allied BBs by G&D from pages 43-47. It is strange that G&D would have photos of the damage but be so wrong about the deck penetration.

[dunmunro]

Shell 4 (p81)(my italics)(see diagram below)

...at the waterline to starboard in the ajacent section L, 0.3m abaft transverse bulkhead KL and 2.50 metres beneath the upper edge of the armour belt [belt depth being 5.75m][...]It passed through the inclined part of the lower armored deck [40mm] in section I and penetrated into fuel bunker K225 which was almost full [...]. It's passage opened up large breaches in bulkhead KL [...]. The shell passed through the Torpedo bulkhead and the watertight bulkhead behind it, severing a number of cables in tunnel K211, and then penetrated into boiler room 2. In this compartment it severed steam collector 1, which connected boiler 21 [the starboard boiler] with the forward group (BR1 + the wing turbines) then smashed into collector 2 (saturated steam) and the exhaust collector of the auxiliaries. It went on to penetrate the starboard casing and the upper steam drum of boiler 21 and the broken remains - three fragments of the shell body and the entire base of the projectile (350-400kg) rolled back along the room of the boiler containment box.

This sequence of events seems unlikely. I don't see how the shell could dive under the belt armour yet still strike the "inclined portion" of the armoured deck. Another belt penetration seems more likely.

[Dave Saxton]

There also some other factors (according Hoyer Berechnung schwerer Panzer) you should keep in mind and their effects on penetration are significantly higher than varying the shape.
1 Weight portion of the cap. The higher the better
2 Hardening (depth) of the cap (german caps achieve 200 kg/mm²)

unfortunately there are not more informations as the pure statement available

ADM213/951 contains some detailed additional Krupp data and findings on those points. This is partly (among many factors) why the ability of an armour defense system to remove the cap before the projectile can attack the main armour is of such significance. The shape we are concerned with here is the shape of the head of the main body, that, of course, the cap is fitted over top of. Once the cap is destroyed the head shape comes into play.

[boredatwork]

Shell 4 (p81)(my italics)(see diagram below)

...at the waterline to starboard in the ajacent section L, 0.3m abaft transverse bulkhead KL and 2.50 metres beneath the upper edge of the armour belt [belt depth being 5.75m][...]It passed through the inclined part of the lower armored deck [40mm] in section I and penetrated into fuel bunker K225 which was almost full [...]. It's passage opened up large breaches in bulkhead KL [...]. The shell passed through the Torpedo bulkhead and the watertight bulkhead behind it, severing a number of cables in tunnel K211, and then penetrated into boiler room 2. In this compartment it severed steam collector 1, which connected boiler 21 [the starboard boiler] with the forward group (BR1 + the wing turbines) then smashed into collector 2 (saturated steam) and the exhaust collector of the auxiliaries. It went on to penetrate the starboard casing and the upper steam drum of boiler 21 and the broken remains - three fragments of the shell body and the entire base of the projectile (350-400kg) rolled back along the room of the boiler containment box.

This sequence of events seems unlikely. I don't see how the shell could dive under the belt armour yet still strike the "inclined portion" of the armoured deck. Another belt penetration seems more likely.

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?

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