WW II Historical Thread, Discussion, Pics, Videos

[chuck731]

Yes. I just checked a credible source describing the duel of the HMS Warspite with two Italian battleships during the Battle of Calabria on 9 July 1940: between 1553 and 1600 thirteen salvos fired at Guilio Cesare; then the direction changed by 20 degrees and the fire ceased to obtain new firing solution but at that time one of the shells of the last salvo hits heheh; after that, four partial salvos (stern turrets only) fired "at both" Guilio Cesare and Conte di Cavour (Conte di Cavour took over Guilio Cesare). So: 13*8 + 4*4 = 120 shots ... all fired from distances exceeding 20 km.

I believe only 1-2 hits were obtained, for a hit rate of ~1%.

 

[Jura The idiot]

I believe only 1-2 hits were obtained, for a hit rate of ~1%.

Interestingly, though, the Italian commander (Vice Admiral I. Campioni) thought (OK, according to the source I just checked) the optimal range for his two battleships would be between 20 and 21 kilometers as he assumed the armor deck of the (modernized) Queen Elizabeth-class battleships was three-inch thick (the Italian 320 mm AP shells fired from "Ansaldo 320 mm/44 1934" guns of Campioni's battleships according to tests should penetrate: 61 mm deck armor from 18 km; 75 mm ... 20 km; 81 mm ... 22 km); well, the modernized HMS Warspite had up to five inches of horizontal protection Now I wonder about this: if Caio Duilio had not been hit quickly from that record-long distance, would the Italians had been able to actually stay within that range and shoot effectively?? frequent maneuvers would have been likely required but their speed advantage was not huge (I just checked: 26 knots maximum for Caio Duilio against 23.5 knots of the modernized Warspite)

 

[chuck731]

Interestingly, though, the Italian commander (Vice Admiral I. Campioni) thought (OK, according to the source I just checked) the optimal range for his two battleships would be between 20 and 21 kilometers as he assumed the armor deck of the (modernized) Queen Elizabeth-class battleships was three-inch thick (the Italian 320 mm AP shells fired from "Ansaldo 320 mm/44 1934" guns of Campioni's battleships according to tests should penetrate: 61 mm deck armor from 18 km; 75 mm ... 20 km; 81 mm ... 22 km); well, the modernized HMS Warspite had up to five inches of horizontal protection Now I wonder about this: if Caio Duilio had not been hit quickly from that record-long distance, would the Italians had been able to actually stay within that range and shoot effectively?? frequent maneuvers would have been likely required but their speed advantage was not huge (I just checked: 26 knots maximum for Caio Duilio against 23.5 knots of the modernized Warspite)

Optical range finders have an accuracy well below 1 Kms at 20 Kms, So if the Italians determined it was imperative to remain between 20-21kms, it could be done.

But keep in mind if the deck can be penetrated at 20km, the it can be penetrated at any range beyond 21km, out to the gun's maximum range. Hit rate will fall off with range, but would not fall off abruptly at 21km, but maneuvering excessively will degrade both the firing solution, as well as accuracy of gun pointing, and increase salvo dispersion. So even if 20-21 km is theoretically optimal, maintaining that range should not be an absolute imperative.

 

[Jura The idiot]

Optical range finders have an accuracy well below 1 Kms at 20 Kms, So if the Italians determined it was imperative to remain between 20-21kms, it could be done.

But keep in mind if the deck can be penetrated at 20km, the it can be penetrated at any range beyond 21km, out to the gun's maximum range. Hit rate will fall off with range, but would not fall off abruptly at 21km, but maneuvering excessively will degrade both the firing solution, as well as accuracy of gun pointing, and increase salvo dispersion. So even if 20-21 km is theoretically optimal, maintaining that range should not be an absolute imperative.

Well, there were some assumptions made which I didn't include in my latest post; maybe the most important was that the Italian deck (up to 100 mm plus up to 40 mm) would survive a 15" punch at that range! According to the source I used, the Italian commander was not aware of the increased range of main guns on the modernized Warspite (due to increased elevation of the upgraded turrets) ...

 

[chuck731]

Well, there were some assumptions made which I didn't include in my latest post; maybe the most important was that the Italian deck (up to 100 mm plus up to 40 mm) would survive a 15" punch at that range! According to the source I used, the Italian commander was not aware of the increased range of main guns on the modernized Warspite (due to increased elevation of the upgraded turrets) ...

Increasing range of guns by increasing elevation expands the ballistic envelop of the gun, but it does not change the ballistic or the penetrative characteristics of the gun within the area previously covered by the old envelop.

So the changes to British gun elevation will not change the closest distance at which Italian deck armor can be penetrated. But changes to propellant charges or shell design can.

If the minimum range at which 15" gun can penetrate Italian armor is 21km, and the minimum range for 12.6" guns yo penetrate British deck is assumes to be 21kms, then the Italian commander does have strong incentive to keep within the band.

 

[Jura The idiot]

Increasing range of guns by increasing elevation expands the ballistic envelop of the gun, but it does not change the ballistic or the penetrative characteristics of the gun within the area previously covered by the old envelop.

So the changes to British gun elevation will not change the closest distance at which Italian deck armor can be penetrated. But changes to propellant charges or shell design can.

Of course you're right, and I didn't mean to imply that only increasing the elevation would extend the range. Just raising the barrel wouldn't do it Additional changes included shooting the six-Caliber Radius Head shell (879 kg) which could now fly almost 30 kilometers (I wanted to be more specific but two sources I just checked had differed), but only Warspite used them during the Battle of Calabria as the Malaya and Royal Sovereign couldn't (the maximal range for those two was, at the maximal elevation of 20 degrees and using the 4-crh 871 kg shell: 22265 m).

If the minimum range at which 15" gun can penetrate Italian armor is 21km, and the minimum range for 12.6" guns yo penetrate British deck is assumes to be 21kms, then the Italian commander does have strong incentive to keep within the band.

I think the Italian commander hoped to stay in a kind of immunity zone (that 20 -- 21 km) but this was unlikely to work against Warspite due to BOTH reasons I mentioned (1. thicker deck armor than the Italians expected, which probably wouldn't have been pierced if hit from 20 km, and 2. plunging fire, which Italians didn't expect), and it didn't; but that's what we know now and I'm not armchair-admiraling Ammiraglio di Squadra Inigo Campioni LOL

 

[Lezt]

Increasing range of guns by increasing elevation expands the ballistic envelop of the gun, but it does not change the ballistic or the penetrative characteristics of the gun within the area previously covered by the old envelop.

So the changes to British gun elevation will not change the closest distance at which Italian deck armor can be penetrated. But changes to propellant charges or shell design can.

If the minimum range at which 15" gun can penetrate Italian armor is 21km, and the minimum range for 12.6" guns yo penetrate British deck is assumes to be 21kms, then the Italian commander does have strong incentive to keep within the band.

Just 2 cents here, changing the elevation can change the fall of the shell within the old envelope. bascially, higher angle with a lower propellant charge can have the same range but much more accurate angle. velocity will be lower but deck armor penetration would be much higher due to the angle changed.

Did they take advantage of this; or if the firing controls are smart enough to compensate is another story.

 

[chuck731]

AFAIK, the only mention of any British attempt to incorporate special shell/ propellant mix to attack horizontal protection occurred in a off hand remark in Winston churchill's memoir about a meeting concerning desired properties in post WWII British battleships. Researchers who followed this up failed to find any corroborating evidence in admiralty archives.

 

[Jura The idiot]

I believe only 1-2 hits were obtained, for a hit rate of ~1%.

I was just in the mood to look up how many main-caliber shells the remaining battleships fired at each other during the Battle of Calabria (HMS Warspite: 120 http://www.sinodefenceforum.com/mil...tartegy-discussions-11-6728.html#post266723);) the Italians during 15 minutes of carefully directed, slow fire, Guilio Cesare: 74, Conte di Cavour: 41; the HMS Malaya fired the first salvo from 27 km and missed short by almost 5 km (but by that time Guilio Cesare had been hit, Italians put up a smokescreen) and fired three partial salvos (from only three turrets each )afterwards, so: 8+3*6=26; the HMS Royal Sovereign didn't make it (40000 hp, modernized Warspite: 80000); I believe all those shots were fired from ranges exceeding 20 km. 120+74+41+26=261. 1/261 = 0.38 %

 

[chuck731]

I was just in the mood to look up how many main-caliber shells the remaining battleships fired at each other during the Battle of Calabria (HMS Warspite: 120 http://www.sinodefenceforum.com/mil...tartegy-discussions-11-6728.html#post266723);) the Italians during 15 minutes of carefully directed, slow fire, Guilio Cesare: 74, Conte di Cavour: 41; the HMS Malaya fired the first salvo from 27 km and missed short by almost 5 km (but by that time Guilio Cesare had been hit, Italians put up a smokescreen) and fired three partial salvos (from only three turrets each )afterwards, so: 8+3*6=26; the HMS Royal Sovereign didn't make it (40000 hp, modernized Warspite: 80000); I believe all those shots were fired from ranges exceeding 20 km. 120+74+41+26=261. 1/261 = 0.38 %

I think it is reasonable to suppose pre-war Japanese expectation of hit rates at 30km was unrealistic, and the new theory about Yamato making hits from 29km+ In Leyte is an extraordinary claim, requiring extraordinary evidence of a kind I have not seen to be taken seriously.