Alaska Class vs Dunkquerke Class

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APDanno
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Alaska Class vs Dunkquerke Class

Postby APDanno » Fri Feb 10, 2017 4:43 pm

This has always been a "what if" that I've pondered over the years. The Alaska class with their 12" super heavy projectiles and armor intended to protect them against heavy cruiser fire vs. Dunkquerke with 13" guns and theoretically armored to withstand the German 11" of the Deutschland class heavy cruisers. Slight speed advantage to Alaska, slight protection advantage to Dunkquerke. Alaska surely had an advantage in fire control if for no other reason than that she completed so much later. Dunkquerke technically had the advantage in firepower but the 12" super heavies could penetrate nearly as well as the earlier 14/50 so I'm not sure that it would be a major difference at all. Thoughts?

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Re: Alaska Class vs Dunkquerke Class

Postby Dave Saxton » Sat Feb 11, 2017 2:50 am

The French 13-inch could defeat the Alaska's belt all the way out to 30,000 yards. It's difficult to see the Alaska's winning this one unless the Alaska's superior fire control enables it to knock out the Dunkerque before the French can score a significant hit. That is unlikely because the Dunkerque can withstand many more low velocity 12-inch hits, than the Alaska can withstand high velocity 13-inch hits.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: Alaska Class vs Dunkquerke Class

Postby APDanno » Sat Feb 11, 2017 4:32 pm

I don't disagree with any of the points you've made but I do feel that you may have overlooked a few others. While it is true that Dunkquerke's 13/50 was able to penetrate Alaska's belt to 30000 yds., Alaska's 12/50 was also able to penetrate Dunkquerke's belt past 30k as well. Dunkquerke had an appreciable advantage in maximum gun range, but conversely Alaska's speed advantage should have allowed her to more or less control the terms of engagement. And additionally, Dunkquerke suffered from excessive dispersion from her battery arrangement, a problem which was somewhat repeated in the later Richelieu class. I'm inclined to think that with her advantages in fire control and general accuracy combined with the ability to dictate engagement Alaska would be able to gain the upper hand in fairly short order.

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Re: Alaska Class vs Dunkquerke Class

Postby Dave Saxton » Sat Feb 11, 2017 8:48 pm

The Dunkerque had a sloped belt while the Alaska didn't. Even if the French face hardened armour was as poor quality as American Class A, it should provide protection down to about 20,000 yards against the the 12"/50. The French deck armour should provide protection against the Alaska's 12" out to about 32,000 yards.... assuming it's quality was up to par.

The French homogeneous armour might be a wild card though. German engineers who examined incomplete French construction stated that the French armour quality was very, very, poor, and we also have Massachusetts's 16-inch shell defeating the Jean Bart's deck protection at a range that it should not have at Casablanca.

I agree that the Alaska's shooting will probably be better, given the French didn't have radar ranging and in addition to the dispersion problems. Nonetheless, the Alaska was much more vulnerable to a few hits than the Dunkerque was.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: Alaska Class vs Dunkquerke Class

Postby OpanaPointer » Sun Feb 12, 2017 1:32 pm

Wrecking the superstructures to the point the ship can't be fought is something that should be considered? :think:

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Re: Alaska Class vs Dunkquerke Class

Postby Thorsten Wahl » Tue Feb 14, 2017 9:56 am

Dunkerque had a large unprotected bow. Even the relatively much smaller forward spaces of Bismarck cause considerable problems by flooding, when riddled, despite extensive compartmentalisation.
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Re: Alaska Class vs Dunkquerke Class

Postby 1T6VDTYX » Sun Mar 05, 2017 11:52 pm

Dave Saxton wrote:The Dunkerque had a sloped belt while the Alaska didn't. Even if the French face hardened armour was as poor quality as American Class A, it should provide protection down to about 20,000 yards against the the 12"/50. The French deck armour should provide protection against the Alaska's 12" out to about 32,000 yards.... assuming it's quality was up to par.

The French homogeneous armour might be a wild card though. German engineers who examined incomplete French construction stated that the French armour quality was very, very, poor, and we also have Massachusetts's 16-inch shell defeating the Jean Bart's deck protection at a range that it should not have at Casablanca.

I agree that the Alaska's shooting will probably be better, given the French didn't have radar ranging and in addition to the dispersion problems. Nonetheless, the Alaska was much more vulnerable to a few hits than the Dunkerque was.


What actually happened in that engagement/

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Re: Alaska Class vs Dunkquerke Class

Postby paul.mercer » Sun Mar 12, 2017 7:30 pm

The French homogeneous armour might be a wild card though. German engineers who examined incomplete French construction stated that the French armour quality was very, very, poor, and we also have Massachusetts's 16-inch shell defeating the Jean Bart's deck protection at a range that it should not have at Casablanca.


Gentlemen,
I'm not familiar with that engagement, what actually happened?

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Re: Alaska Class vs Dunkquerke Class

Postby Dave Saxton » Tue Mar 14, 2017 4:42 am

paul.mercer wrote:......at Casablanca.


Gentlemen,
I'm not familiar with that engagement, what actually happened?


http://www.eugeneleeslover.com/USNAVY/U ... v_1942.pdf

The Jean Bart was tied to the pier in Casablanca Harbor. It was incomplete and immobile. It had one 15" turret installed with ammunition. At 0705 the Jean Bart opened fire on the American bombardment task group straddling some warships, and the Massachusetts replied from a range of 24,400 yards.

In the war diary you will notice that the Jean Bart was shrouded by a smoke screen throughout the engagements. Massachusetts' spotter plane could not get close and could not see the target well. The radars of Massachusetts were knocked out by concussion of its own first salvos and were not operative thereafter. As a result the fire solutions against Jean Bart were very much a guess. Indeed the shooting was so wildly inaccurate (relative to Jean Bart) that the French didn't even know Massachusetts was firing at the Jean Bart for the first 30 minutes. The American captain writes in the war diary that he was getting rather 'annoyed" with his gunnery officer because he could not find the target. The range decreased to about 23200 yards after six minutes and then Massachusetts began to open up the range after changing course. One can also note that each time there was a significant change of course it ceased fire and reopened fire after settling in on the new course.

At 0717 Massachusetts divided the fire of its main battery between the El Hank shore battery and the Jean Bart, with turrets 1 and 2 firing at the French battleship and turret 3 firing at the shore battery.

The first damages caused to the French battleship came from USN dive bombers at 0718-according to the French narratives. They remained unaware that BB59 was even firing 16-inch shells at Jean Bart. Water tight integrity was breached from the bomb hits/near misses, and the French battleship took up a list and a trim.

At 0735 shells from the American battleship landed close enough for the French to take notice, with a salvo landing forward of the stem and a shell striking the wharf. Shell fragments from the Wharf "hit" peppered the Jean Bart. The range was about 28,000 yards.

At 0741 with the navigational range estimated at about 29,000 yards the Massachusetts ceased fire and changed course again to reduce range to both El Hank and Jean Bart. It opened fire on Jean Bart again at 0747

At 0803 the navigational range was back down to about 24,000 yards and the course was changed to start opening the range again.

At 0806 the first direct 16" hits were scored on Jean Bart. The forecastle and the main battery turret and also a barbet were hit, jamming the main battery turret. These shells were duds. The shell striking the barbet broke up. A piece from the broken shell passed through several compartments, killing the first officer.

According to the French, the last 16" hit scored occurred at 0810, which would have been from around 24,500 yards. This hit penetrated the main armoured deck and the splinter deck, finding its way to an empty magazine. This shell burst and caused additional flooding according to French narratives.

Recorded at 0811 the American spotter plane reported that they had observed some of Jean Bart's secondary turrets "firing." This probably confirms the shell burst in the secondary magazine.

Massachusetts continued to fire at both El Hank and the Jean Bart until 0833. The reason the captain wrote that they ceased fire was because they only had 40% total ammunition remaining.

They later used up an additional 5% of the ammunition against light forces and cruisers during additional combats. They expended a total 786 rounds of 16-inch during the day's battles. There were 84 rounds remaining for turret 1, 110 rounds for turret 2, and 99 rounds remaining for turret 3. There were 94 reserve rounds in turret 2 magazines as well. The record does not discriminate the types of 16" rounds.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: Alaska Class vs Dunkquerke Class

Postby Alberto Virtuani » Wed Mar 15, 2017 10:10 am

Hi Dave, Paul and all,
according to John Jordan / Robert Dumas (French Battleships 1922-1956) who reproduced the Jean Bart damage report schemes, the overall timings of the action are almost the same as per Dave account, but the number, sequence and consequences of the hits quite different. In extreme synthesis:

Jean-Bart took seven 16" hits, the first one at 07:25 and the last at 08:10. No distances are reported.

The first one (No.1) was the only one that penetrated the citadel passing through the 2 armored decks and exploding against the aft transverse bulkhead in a (luckily empty) 152 mm lower magazine. The angle of descent of this 16" shell was estimated at 33°. See image below:

Hit_No1.jpg
Hit_No1.jpg (116.3 KiB) Viewed 653 times

The hit that temporarily jammed the main turret I was no.5 (at 08:06): it deformed the glacis plate under the sub-caliber firing gun, but did not penetrate the armor despite an angle of descent of around 35°. This damage was repaired in some hours.
At the same time another shell (No.6) hit the barbette of main turret II, ricocheted over the main upper armor deck, broke in two and stopped without penetration.

The only shell (No.4, received at around 7:40) that hit the main armor belt was also unable to penetrate it (due to the high obliquity too, around 60°).


Bye, Alberto
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Re: Alaska Class vs Dunkquerke Class

Postby Dave Saxton » Wed Mar 15, 2017 3:43 pm

Hi Alberto,

Yes, I'm aware of these differences. I put more weight on the French narratives and chronology of the battle than I do the secondary account, although I do not dismiss it. It is possible that the French remained unaware of some hits at the time, such as the alleged belt hit.

It is always good to remember this rule when evaluating data and evidence: A correlation does not prove causation, but a lack of correlation does disprove causation.

There is little correlation between the French observations of 16-inch salvos landing on or around Jean Bart to any possible hits received prior to 0735. A discrepancy of 10 minutes unless there was a faulty time recorded by one or the other accounts.

The French chronologies claim that the deck penetration hit was the 0810 hit though. This correlates with the US spotter plane observation at 0810 but it does not prove it per the rule above.

Either way, 0810 or 0725, it puts the range of that hit at about 24,000 yards. Massachusetts didn't know the exact gun range to the Jean Bart and was relying on ambiguous spotter plane adjustments, but it was recording navigational ranges. Were these navigational ranges to El Hank or the harbor? The ranges to El Hank were greater than the ranges to the harbor in any case. This means that speculation about extreme long range hits are just wishful thinking.

As for the 33 degree entry angle, assuming it is accurate, we must remember that Jean Bart had a list and a trim from 0718 hours.

33 degrees angle of fall and a velocity of 1470 feet per second should yield only about 140 mm of total deck penetration if the armour quality was up to snuff. But if the ship was listing and the likely range was about 24,000 yards, then the velocity would be about 100 feet per second greater.

Massachusetts probably fired over 390 rounds at Jean Bart over about a 90 minute time span.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: Alaska Class vs Dunkquerke Class

Postby Alberto Virtuani » Wed Mar 15, 2017 5:18 pm

Dave Saxton wrote:"As for the 33 degree entry angle, assuming it is accurate, we must remember that Jean Bart had a list and a trim from 0718 hours."

Hi Dave,
I absolutely agree. Also the 33° descent angle looks to me a bit too much for a 24000 yards distance (and even for a 28000 yards....). Therefore I guess the impact was made more favorable for the shell due to the trim caused by bombs.
This does not exclude a "weakness" of the French armor grade steel. :think:


Bye, Alberto
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Re: Alaska Class vs Dunkquerke Class

Postby paul.mercer » Wed Mar 15, 2017 6:51 pm

Thanks for the info chaps,
I have to say that the shooting by Massachusetts makes the initial opening shots by Rodney on Bismarck look positively accurate!
I believe that this was not the first time a US BB lost her radar through concussion (was it Washington?), it seems to be very fragile.

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Re: Alaska Class vs Dunkquerke Class

Postby Dave Saxton » Thu Mar 16, 2017 1:12 am

paul.mercer wrote:I believe that this was not the first time a US BB lost her radar through concussion (was it Washington?), it seems to be very fragile.

It was a general problem with all radars of the WWII era, not just on American warships. This is because that was during the vacuum tube era. It is the nature of vacuum tubes and vacuum tube circuits. The problem was lessened with time as engineers learned to design more robust radar equipment and as naval personal learned how to better manage such problems. However, such problems could never really be solved completely. Late war there remained several incidents of radars -of all nations- getting "knocked out."

The problem of reliability and durability actually became more vexing with the advent of higher powered sets late war. For example, the SJ radar used by USN submarines was updated late war with a PPI and much more transmitter power. This SJ-II radar was constantly breaking down due problems of the high power modulator. SJ was not unique in having these problems. Such problems affected most high power sets of all navies.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: Alaska Class vs Dunkquerke Class

Postby paul.mercer » Tue Mar 28, 2017 9:59 am

APDanno wrote:I don't disagree with any of the points you've made but I do feel that you may have overlooked a few others. While it is true that Dunkquerke's 13/50 was able to penetrate Alaska's belt to 30000 yds., Alaska's 12/50 was also able to penetrate Dunkquerke's belt past 30k as well. Dunkquerke had an appreciable advantage in maximum gun range, but conversely Alaska's speed advantage should have allowed her to more or less control the terms of engagement. And additionally, Dunkquerke suffered from excessive dispersion from her battery arrangement, a problem which was somewhat repeated in the later Richelieu class. I'm inclined o think that with her advantages in fire control and general accuracy combined with the ability to dictate engagement Alaska would be able to gain the upper hand in fairly short order.


Gentlemen,
I realise we have had this point before when discussing other ships that have a speed advantage over their rival (Bismarck v Rodney)
but i have to confess that I still do not understand it, surely if two ships decide to fight it out within the normal range of their guns - say 20,000 yards or so, speed would make very little difference as they would only have to manoeuvre a relatively small amount to keep all their guns baring on the target. perhaps speed might have a small baring when manoeuvring between shell splashes, but not that much as to make a decisive difference. Of course speed would make a difference if the faster ship was getting the worst of the battle and made a run for it!


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