Hood v Vittorio Veneto

[alecsandros]

Concerning 3 KGV versus 3 Littorios, in the same setup as above,

the British response would probably be different, with Cunningham actualy attacking head-on while Iachino would be doing the same.

With both squadrons limited at same max speed (29kts under normal loads) , extreme vertical protection (KGV 374mm belt, 50mm oakwood backing, multiple splinter shields in way of main magazines, situated anyhow very low in the ship, Littorio 80 + 280mm armored array, multiple splinter shields, etc) , and high-mv guns with large shell dispersions per range, also making deck penetrations unlikely, it would be a matter of pure and total luck, with the battle being in the realm of possibility for crushing defeats for either side.

As a personal note, the BRitish radars and electronics of the time were excellent, but on the other hand, the KGV class had thinner upper armor then QE class (turret fronts 317mm vs 330mm on QE class, con tower 100mm vs 250mm QE class), making complete destruction of upper structures possible even at extreme range (30km turrets and 40km con tower)*.


* This vulnerability turns into a benefit below 20km ranges, as any normaly functioning APC shell in the world would go through and through the con tower, without explodig inside (as it would, for example, inside the con of HMS Warspite).
The turrets though suffer from this lack of armor, and their 317mm frontal armor is vulnerable out to 30km to Italian attack, with no mitigation per range decreasing...

I would sum up KGV vs Littorio as: 2 , fully armored archers, attempting to kill each other firing arrows through the enemy's vision slit.

[Alberto Virtuani]

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....

you wrote: "Concerning 3 KGV versus 3 Littorios, in the same setup as above, the British response would probably be different, with Cunningham actually attacking head-on while Iachino would be doing the same.

I agree that , knowing A.B.C. attitude, he could have done this way. However, doing so, he would have reduced the approach phase to a very limited number of minutes, thus limiting the advantage of KGV horizontal protection vs Littorio. At very short ranges, again the KGV (at least machinery) had no immunity vs Italian 15" while the British 14" is not posing a real thread to the Italian vitals.

A cautionary British admiral, weighting the odds, would have kept far from Littorio's, counting on superior British precision. Littorio's had not enough speed advantage to force a short range battle in this case.



Bye, Alberto

[Dave Saxton]

As a personal note, the BRitish radars and electronics of the time were excellent,

At night and/or in bad weather the British would hold a significant advantage. However, in daylight with good visibility the Italian Gufo radars can do the job of measuring range to target good enough to negate such an advantage.

Nonetheless, by 1943 the RN was keen to force surface battle at night if at all possible. The chance of a surface action occurring in daylight was only about 10% after 1941 anywhere in the world. This was a a source of frustration to American Admiral Lee because he wanted to bring his battleships into battle during daylight if possible, I suspect partly because night battle will invariably be a relatively short range affair.

[alecsandros]

@Dave
Quite possibly so...

@Alberto
The BRitish 14"/L45 gun had a less stable/predictable fall of shot then the 15"/L42 , and precision was smaller beyond 20km, from what I can tell. KGV had 400meters patterns of 4-gun shells at 20km, and that is comparable (allthough probably somewhat better) then Veneto's 3-gun patterns of 500meters at 23km...

Thus I would expect the British to attempt the decisive action at 12-18km , according to their usual rules of engagement in battleship line versus battleship line.

At a reasonable 30* target angle, KGV's machinery would be safe to perforation outside 15km, while Littorio's machinery would be safe probably down to 8-9km (thanks to the decapping array).

I still am unsettled over the modifications done to the KGV class quad turrets post-1941, and I do not know to what extent jamming/misfirings may still occur in such a sept 1943 engagement...

[Alberto Virtuani]

Alecsandros wrote: "At a reasonable 30* target angle, KGV's machinery would be safe to perforation outside 15km, while Littorio's machinery would be safe probably down to 8-9km (thanks to the decapping array)................ I still am unsettled over the modifications done to the KGV class quad turrets post-1941"

Hi Alec,
I share your same doubts about the 100% reliability of the quad turret still in 1943.....

However, I'm not sure KGV 350 mm belt (at machinery) could be considered safe outside 15 km with a 30° inclination against the Italian 15" (credited of 380mm penetration with 30° inclination at 19 km according to the cautionary "fighting instructions", much more according to OTO). I would say KGV machinery was safe outside 19 km at least.

I also doubt that the British 14" could defeat the 70+280 mm 15° inclined array of Littorio's from 8-9 km. The 14" gun is credited of a penetration of "just" 350mm vertical armor at around 13 km with 0° inclination......
I couldn't find any 14" penetration data for the various target angles, however, combining the 30° inclination, the AoF and the 15° of the belt, I suspect that the 14" British gun could not pose a threat to the Littorio's vitals even at shorter distances.

Bye, Alberto

[alecsandros]

@Alberto
I forgot about the 350mm belt... I thought it was 375mm still... but it is not, you're right. KGV class also has some nice inclinations of plates near magazines (between 7 and 10 degrees, they are not vertical), but I do not know if they continue along machinery. So you are right, macinery is only safe beyond 18km or so...

British 14" shell was around 9-10% less perforating power then German 15" shell, so very roughly, about 20% less perforating power then Italian 15" at same range.

Still, it was a very powerfull weapon, and at 8km it would perforate ~ 530mm of armor plate (impact velocity 604m/s).

http://www.navweaps.com/index_nathan/Pe ... ritain.htm

[Steve Crandell]

@Alberto
I forgot about the 350mm belt... I thought it was 375mm still... but it is not, you're right. KGV class also has some nice inclinations of plates near magazines (between 7 and 10 degrees, they are not vertical), but I do not know if they continue along machinery. So you are right, macinery is only safe beyond 18km or so...

British 14" shell was around 9-10% less perforating power then German 15" shell, so very roughly, about 20% less perforating power then Italian 15" at same range.

Still, it was a very powerfull weapon, and at 8km it would perforate ~ 530mm of armor plate (impact velocity 604m/s).

http://www.navweaps.com/index_nathan/Pe ... ritain.htm

The British 14" AP had thin walls, and I doubt it would be able to penetrate armor much thicker than it's diameter at any range. I suspect it would deform and/or break up.

[Alberto Virtuani]

@Alecsandros,
I forgot too the inclination of the belt of KGV at the most fore and aft turrets/magazines.
However it was not the case at machinery, where it was perfectly vertical. It was almost vertical already at B turret level (source Tarrant).

Thanks for the interesting link...

Bye, Aberto

[alecsandros]

The British 14" AP had thin walls, and I doubt it would be able to penetrate armor much thicker than it's diameter at any range. I suspect it would deform and/or break up.

Possibly...
Still, Littorio had a 70+10mm decapping plate, then a 280mm main belt, and several armored bulkheads behind it.

I am not sure over the behavior of a British 14" shell attacking that arrangement - perhaps David could shed some light over the possibility of the shell perforating the array or not at around 10km or less...

[Dave Saxton]

The principle being employed here is based on the fact that any un-capped shell will shatter if it is going above a certain critical velocity when striking the main plate. So as long as de-capping happens; the higher the striking velocity, or the shorter the range, the more the destruction of the shell is insured.

[alecsandros]

... The key then is: would the 14" shell be actualy decapped when striking the 280mm main belt ?
I'm asking because at 600m/s and with a 0,6meters interspace between Littorio's frontal and main belt, the time required for the projectile to pass through the first plate and hit the second plate is around 1/1000 of a second. Is it enough for successfull and complete decapping ?

The Italians considered Littorio safe down to 16km when attacked by their own 381mm/L50 guns. So below 16km, they considered the armor array as not protective over such attacks...

[Alberto Virtuani]

Hi Alec,
at 16 km the Italian shell has still a striking velocity of around 605 m/sec and a mass of 885 kg. The British 14" at 9 km has a velocity of 590 m/sec and a weight of just 721 kg (it just has an AoF of a couple degrees more favorable).
If the Littorio's belt was safe at 16km against the Italian gun at 0° inclination, as per Italian tests, it should also be against the British 14" at less than 9 km and 0° inclination.

It means that at 30°inclination Littorio was probably immune at any distance against KGV, while KGV was not under 18-19 km (machinery) and 15-16km (magazines). An important reason for the KGV's not to engage closely the Littorio's, IMHO.

Bye, Alberto

[dunmunro]

PoW did quite a bit of damage to Bismarck with two hits. The VV class is even more vulnerable to diving hits than Bismarck. Even if VV's belt was impenetrable the class is still highly vulnerable to UW hits and it seems that a 14in AP round could easily reach VV's magazines by diving under the belt.

[Alberto Virtuani]

Hi Duncan,
I agree, but such UW hits are quite rare and I would not count on them to approach an otherwise immune opponent, if I can more "easily" prevail staying at long range.
KGV's could keep far from Littorio's, while QE's, being extremely slow, simply could not.

Bye, Alberto

[alecsandros]

@Alberto

AFAIK, Littorio was considered safe through the vertical armor beyond 16km, against his own guns. That is with angle of fall included...

At 8km, British 14" gun shell retains 605meters/second impact velocity...

I know the belt and decapping plate were declined at 12*, making the job of the shell harder. But still, at such high velocities, I think there is some chance (and somebody with better knowledge could quantify it) that the armor piercing cap would start to be dettached from the body of the shell, on perforating the decapping plate (70+10mm), but the immediate deceleration of the cap would not be so powerfull as to ensure total decapping. In the immediate tenths of thousand of second, the body of the shell would continue to push through the hole done by the cap, and slam immediately afterwards in the main armor plate (280mm thick), with the cap not entirely pushed aside.

I agree that at 30* target angle, the 14" round would probably NOT perforate the main armor system on Littorio.