Hood v Vittorio Veneto

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slaterat
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Re: Hood v Vittorio Veneto

Post by slaterat » Sun May 15, 2016 5:56 pm

Aberto wrote
Hi,
the belt of Littorio's was 4.4 meters high, extending for 2 meters under water at normal battle load (source: E.Bagnasco, pag 56-58 "Littorio class battleships", Italian edition). It was considered enough for Mediterranean seas and for a ship that did not change much her draught due to her limited range (not much fuel could be embarked anyway).
It's a very small belt, but Bismarck's was 4.8 meters only as well, and the 14" hit from PoW was not able to detonate directly within the vitals (albeit flooding them)
I stand corrected as I found some numbers off the internet and I take yours from a published source as correct.

I also am mistaken on the KGV belt as it appears that the figures,also derived from wikipedia, are reversed.
So the corrected values would be .

V. V. mb 4.4 meters in height 2.4 above/2 below the waterline
KGV mb 7.2 meters in height 4.6 above/2.6 below the waterline and for comparison
Bismark 4.8 meters in height 2.6 above/ 2.2 below the waterline


Still a big advantage to the KGV, a much larger protected volume. At longer ranges in its imunity zone the KGV will have a much larger protected volume than the V V . With this plus 10 vs 9 guns, that have more than twice the bursting charge, a long range action favours the KGV. The KGV needs to play the angles right in a closer action.

I wouldn't dismiss low hits so quickly, at Denmark Strait the PoW took 2 hits below its 2.6 meter deep belt , and the Bismark took one hit below its belt 2.2 meter deep belt.

Slaterat

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Alberto Virtuani
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Re: Hood v Vittorio Veneto

Post by Alberto Virtuani » Sun May 15, 2016 6:32 pm

Slaterat wrote: "a long range action favours the KGV. "
Hi,
I do agree with you, as I said in my first post regarding a potential confrontation between KGV's and Littorio's. At long range the better British precision and KGV's horizontal protection would have given RN the advantage. At short range, the odds are in favor of RM.


UW hits were unusually common at DS, but, even there, the PoW hit against BS was unable to penetrate and detonate inside the vitals and the BS one against PoW was a dud and did not explode at all. That's why I say that an UW shell, still active and with a sufficient force to penetrate Littorio's vitals would have been a very lucky one.

Bye, Alberto
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Re: Hood v Vittorio Veneto

Post by dunmunro » Mon May 16, 2016 4:30 am

Alberto Virtuani wrote:
Slaterat wrote: "a long range action favours the KGV. "
Hi,
I do agree with you, as I said in my first post regarding a potential confrontation between KGV's and Littorio's. At long range the better British precision and KGV's horizontal protection would have given RN the advantage. At short range, the odds are in favor of RM.


UW hits were unusually common at DS, but, even there, the PoW hit against BS was unable to penetrate and detonate inside the vitals and the BS one against PoW was a dud and did not explode at all. That's why I say that an UW shell, still active and with a sufficient force to penetrate Littorio's vitals would have been a very lucky one.

Bye, Alberto
PoW's UW hit on Bismarck detonated in Bismarck's TDS and it caused the immediate flooding on in two inboard compartments and slow flooding in a boiler room.

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Re: Hood v Vittorio Veneto

Post by Alberto Virtuani » Mon May 16, 2016 7:52 am

Hi Duncan,
AFAIK Bismarck UW protection system presented 73 mm steel (20+8+45) to an UW shell before the vitals over a max of 5.5 meters distance. Littorio's system was 94mm (14-10+7+7+40+16 at normal impact) over a max of more than 7 meters) . The PoW shell detonated against the BS 45 mm internal torpedo bulkhead, causing the flooding.

Had the same hit been against a Littorio, it would probably have detonated (after having traveled for several meters within water....) inside the "Pugliese" cylinder or (worst case) against the 40 mm inboard part of it, after which there was another splinter bulkhead (16 mm) that could have possibly contained the flooding outside the vitals.... In theory, of course, we will never know for sure..... :think:

Bye, Alberto
Last edited by Alberto Virtuani on Mon May 16, 2016 9:04 am, edited 9 times in total.
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Re: Hood v Vittorio Veneto

Post by alecsandros » Mon May 16, 2016 8:01 am

I would add that the fuze delay on British APC projectiles was on average 0.025 seconds, so a 500m/s projectile would travel 12,5 meters, on average, after the fuze had been initiated (presumably on striking the waterplane). Because water would further decelerate the shell, it's velocity after the fuze was initiated wouldn't be 500m's, but less - around 300-350m/s maybe, thus further reducing the trajectory until detonation.

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Re: Hood v Vittorio Veneto

Post by dunmunro » Mon May 16, 2016 5:40 pm

Bismarck also had a liquid layer in her TDS.

The inclined belt on VV and the reduced depth of the belt means that a 14in shell could strike about 1-1.5 meters closer to VV, compared to the under the belt hit on Bismarck, and still dive under VV's belt. it seems to me that such a hit would have a good probability of penetrating the entire VV TDS.

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Re: Hood v Vittorio Veneto

Post by Alberto Virtuani » Mon May 16, 2016 5:51 pm

Hi Duncan,
the belt of Littorio extended 2 meters UW, the one of Bismarck 2.2, therefore if the 20 cm difference can make the shell path easier (possibly 1 meter shorter), the 1.5 meters longer path within the "Pugliese" system and the 21 mm thicker steel would compensate this difference.

As in Bismarck (and in many modern battleships), the Littorio system was as well composed of voids and liquids (with 2 smaller liquid layers (instead of 1) around the inner cylinder, please refer to the scheme at page 12 of this thread).

As Alec has said above, a shell should travel 10 meters underwater (or 9 in the case of Littorio...) and 7+ meters inside the TDS (voids, liquids and bulkheads). It's very unlikely it can penetrate within the vitals before exploding, if correctly activated at water impact. It would be a very, very lucky hit, but of course we can't exclude it, as it happened to Bismarck at DS.

Bye, Alberto
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"There's always a danger running in the enemy at close range" (Adm.W.F.Wake-Walker)

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Re: Hood v Vittorio Veneto

Post by dunmunro » Mon May 16, 2016 6:58 pm

Alberto Virtuani wrote:Hi Duncan,
the belt of Littorio extended 2 meters UW, the one of Bismarck 2.2, therefore if the 20 cm difference can make the shell path easier (possibly 1 meter shorter), the 1.5 meters longer path within the "Pugliese" system and the 21 mm thicker steel would compensate this difference.

As in Bismarck (and in many modern battleships), the Littorio system was as well composed of voids and liquids (with 2 smaller liquid layers (instead of 1) around the inner cylinder, please refer to the scheme at page 12 of this thread).

As Alec has said above, a shell should travel 10 meters underwater (or 9 in the case of Littorio...) and 7+ meters inside the TDS (voids, liquids and bulkheads). It's very unlikely it can penetrate within the vitals before exploding, if correctly activated at water impact. It would be a very, very lucky hit, but of course we can't exclude it, as it happened to Bismarck at DS.

Bye, Alberto
VV's belt was inclined where Bismarck's belt was vertical. An inclined belt makes it easier for a diving shell to pass under the belt because the inclined belt slopes away from the waterline. It is the combination of the inclined belt and the lower height of the belt that makes it easier for UW hits to penetrate deeper into VV's TDS.

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Re: Hood v Vittorio Veneto

Post by Alberto Virtuani » Mon May 16, 2016 9:03 pm

Dunmunro wrote: " An inclined belt makes it easier for a diving shell to pass under the belt because the inclined belt slopes away from the waterline."
Hi Duncan,
it's the other way round. Being inclined inboard, the Littorio belt forces the shell to travel more distance in the water before hitting it. An outboard belt would facilitate the task to the shell....

It is anyway irrelevant, the distance difference is minimal and the Pugliese system under the belt was extending outboard compared to the belt, thus compensating this very slight increase in the distance traveled UW.

Bye; Alberto
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Re: Hood v Vittorio Veneto

Post by RF » Tue May 17, 2016 7:57 am

Alberto Virtuani wrote:
Alecsandros wrote: "Well, Cunningham would know his ships had zero direct advantage over the Italians (he wouldn't know about dipsersion problems or lack of modern radars), so I don't see him charging onto the enemy."
Hi Alec,
it could well be as you say, or he could have decided to engage closing range, as per British consolidated tactics, counting on superior RN training, rate of fire and Italian former defeatist attitude to achieve a success and make Italians retreating once more......
who knows....

Bye, Alberto
I could well imagine Nelson, if he were in command doing just that.... charging in straight for the enemy. I am further reminded of Tovey's thoughts at the commencement of the final battle of the Bismarck, whem Rodney and KGV were pointed straight at Bismarck ''to unnerve the rangefinders and gunners on Bismarck.'

I suspect the tactic would have worked - however in charging in you have to get the angle exactly right. Holland couldn't at DS with disastrous results (albeit there were other factors coming in to that, not least Hood firing on the wrong ship).

Aggression, superior seamanship, faster rate of fire and tighter discipline usually would tell against a superior force especially if the latter was not boldly led - it did leave the foundation for Pax Britannica as exemplified at the Battle of Trafalgar.

In this particular case I cannot see any Italian leadership of the calibre to deliver victory - and that underpins the persistant underperformance of all the forces of fascist Italy in WW2.'
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Re: Hood v Vittorio Veneto

Post by alecsandros » Tue May 17, 2016 8:11 am

I suppose anything could happen,
But a charge of the 3 British BBs would be nearly suicidal.

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Re: Hood v Vittorio Veneto

Post by Alberto Virtuani » Tue May 17, 2016 8:30 am

RF wrote: "In this particular case I cannot see any Italian leadership of the calibre to deliver victory -"
Hi RF,
I have to agree with your historical analysis.... :(

This (very hypothetical) scenario however foresees the Italian admiral with clear orders to engage enemy to death in a final confrontation with the RN, without the usual constraints to agree tactics with Supermarina and without any recommendation to preserve the ships (e.g. engaging only when in clear superiority).... In this case, the performance is more linked to the characteristics of the ships involved, than to the skill of admirals (differently than at Nelson's old times, due to the technical progress).

I think much (not all....) of the Italian admirals "mediocrity" in WWII was due to their limited decision-making independence when at sea, but your considerations are correct.


Bye, Alberto
Last edited by Alberto Virtuani on Tue May 17, 2016 9:34 am, edited 5 times in total.
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Re: Hood v Vittorio Veneto

Post by alecsandros » Tue May 17, 2016 8:38 am

... Independent or not, the 381mm/L50 gun projectile "falls" at 8 degrees at 15 km range. This brings a huge danger space/hitting space, and it would be only a matter of time before it would fall into an ammunition magazine. Armor is irrelevant at this range against this type of gun.

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Re: Hood v Vittorio Veneto

Post by dunmunro » Tue May 17, 2016 5:50 pm

Alberto Virtuani wrote:
Dunmunro wrote: " An inclined belt makes it easier for a diving shell to pass under the belt because the inclined belt slopes away from the waterline."
Hi Duncan,
it's the other way round. Being inclined inboard, the Littorio belt forces the shell to travel more distance in the water before hitting it. An outboard belt would facilitate the task to the shell....

It is anyway irrelevant, the distance difference is minimal and the Pugliese system under the belt was extending outboard compared to the belt, thus compensating this very slight increase in the distance traveled UW.

Bye; Alberto
The RN abandoned inclined belts because they were likely to allow shells to dive under them. It's just simple geometry.

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Re: Hood v Vittorio Veneto

Post by dunmunro » Tue May 17, 2016 5:52 pm

alecsandros wrote:... Independent or not, the 381mm/L50 gun projectile "falls" at 8 degrees at 15 km range. This brings a huge danger space/hitting space, and it would be only a matter of time before it would fall into an ammunition magazine. Armor is irrelevant at this range against this type of gun.
KGV's magazines were placed at the lowest level of the ship. A shell which can penetrate the main belt will pass above the magazines.

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