What was the most powerful battleship in a straight duel, May 1941?

[Juha]

Hello Psteel
Quote:"Hi Juha, since the main armored deck joined at the top of the main belt, any shell can only penetrate one or the other, not both."

And who had claimed that a shell penetrated both the belt and the main armoured deck???

Juha

 

[psteel]

Hello Psteel
Quote:"Hi Juha, since the main armored deck joined at the top of the main belt, any shell can only penetrate one or the other, not both."

And who had claimed that a shell penetrated both the belt and the main armoured deck???

Juha

OK thanks Juha, that clears things up, because the other sources claim it went through the main deck armor. If it went through the 228mm plate and the sloped plate [40mm @ 58°] and then the 30mm torpedo bulk head , this makes sense. However, the trajectory can't also go through the two thin longitudinal bulkheads, since they are between the main and lower decks, which are above these slopes.

OK so 228mm @ 11.5° + 40mm @ 58°[V] + 30mm . At 17,500 yards the 15" shell should have a descent angle of 16-17° which combined with the inclined belt is ~ 28° . The 'slopes' become 75° [V]. So the net resistance should be roughly 330mm x 1.37= 451mm or about 17.8". At that range the British 15" gun perforates about 17-19" against British/American/German belt armor plating. So the Hood can just manage that penetration.

 

[Juha]

Hello Psteel
I don't have the Jordan Dumas at hand but if you look the p. 72 in "Allied Battleships in World War II", you see at least one bulkhead inclined as a belt between belt and the slope of lower armoured deck, the slope being in fact 50mm thich , horizontal part of the lower armoured deck being 40mm (like Bismarck's 110mm slope and 80mm horizontal in the main armoured deck, if we forget that the belt was inclined and the slope deeper in Dunkerque, systems are not so far away but in Dunkerque the heavier armour deck was the upper one, in Bismarck other way around). The shell also went through the upper part of fuel oil tank, so machinery spaces got also some fuel bath, and through a main steam line, which was fatal to the personel nearby.

Yes, those 15" shells didn't do miragles, simply functioned as they should. That not be always a case.

Juha

 

[psteel]

I read that the 20mm vertical bulk heads are specially treated STS steel , which is why they might not be considered armored. But any trajectory passing through the main belt and the slopes can't go through these bulkheads , since they are above the slope deck level. The 30mm torpedo bulk should be included though in such a trajectory.

This is not really in the same league as the Bismarck since the Bismarck slopes are 22° below the horizontal and they are 110mm thick. That makes the LOS value roughly 178mm plus 45mm torpedo bulkhead plus the 320mm main belt. Combined that's roughly 540mm LOS, which would also be increased by the spaced armor effects. Since this is in effect a three plate spaced array the T/d of both the outer plates must be included [Belt and slopes] . Against a 16" shell that should be roughly 1.45 x 1.2 or 37" needed to get through to the engine area. If the outer main belt was only 145mm, that would still be 368mm x 1.26 x 1.2 = 22".

Penetration above the slopes , would have to pass through the 30mm bulkheads and the deck @ 80mm @ 17° below the horizontal or 303mm + main belt. If this is, say 145mm main belt, the T/d is still 1.26 x 1.03 and the combined resistance should be in the region of 22-23", but most shells that get through the outer belt should still ricochet off the main deck away from the vitals anyway.

Now a penetration of the upper belt, at flat trajectory through to the uptakes , should require > 9" penetration against a 6-8" shell.

 

[Juha]

Hello Psteel
what the shell penetrated was a different bulkhead, if you look carefully the plan on page 72, you will notice it, its marked to have only 6-7mm thickness.

And of course it is different thing with Bismarck, as I wrote the protection of Dunkerque was designed only against German 11" shells from 16,5 km, that of Bismarck against much heavier shells. Also the design philosophies were different. French was a kind half-way house between German and British thinking, but it is interesting how much it looked, only looked, like the German one.

Juha

 

[davidow]

If you were to be recruited as a rating or commissioned as an officer aboard H.M.S. Rodney
(10 November 1927- Scrapped 26 March 1948) you would probably have survived to tell the tale.
Or you could have suffered the misfortune to be posted to the Bismarck (24 August 1940 - Sunk 27 May 1941)
I know which ship I'd have rather have been on.