Richelieu vs. South Dakota

Historical what if discussions, hypothetical operations, battleship vs. battleship engagements, design your own warship, etc.
delcyros
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Re: Richelieu vs. South Dak

Post by delcyros »

Salvo dispersion is basically meaningless in a battle between ships. It only really makes a difference when engaging a stationary target like a shore battery; there, any dispersion means most of your shells won't hit the target. Against ships, dispersion doesn't matter. At long ranges, your shells will take over a minute to reach the target (at extreme ranges, it can grow to a minute and a half). During that minute, a 30 knot ship will move 1000 yards in some direction. Therefore, you have to guess where the target will be a minute from firing and aim for that point. The odds are that you will guess the aim point wrong so dispersion may actually help you get hits (shells dispersed from the wrong aim point might accidentally wander off to where the target actually is). Tight groupings of shells look pretty in practice shoots; in combat, they have little importance.

That´s also the first time I heard someone proposing that salvo dispersion is tactically meaningless in a battle between two ships. This appears to be in contradiction with almost all primary sources dealing with the firecontroll problem I have had opportunity to read and it certainly contradicts to how the french rated RICHELIEU´s main battery efficiency owing to excessive dispersion or the significantly lower hit rates experienced by the USN off Scapa Flow in 1917/18 when training long range fire with elements of the GF.
Excessive (and inconsistent) disperison pattern was identified the prime reason in both cases, so I take it serious. While I agree that long range MPI deviations are considerable and a somehow larger dispersion may compensate for this, it also means that the probability to miss the target in a straddle increases. And there is a difference between widened up patterns and excessive ones. In RICHELIEU´s case dispersion was excessive by period standarts, the fall of shot could land, concentrated or scattered around, anywhere in within a circle of >500 yards around the MPI, with some wild shots not accounted for. You have not only to be very lucky to achieve a hit from a straddle of eight rounds but You also have difficulties to correctly assess the MPI in such a large deviation zone, which enhances firecontroll problems in the next salvo.
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Re: Richelieu vs. South Dak

Post by boredatwork »

paulcadogan wrote:Anyway, we do have a "sort of" actual battle between Massachusetts (and aircraft) and Jean Bart and the damage inflicted on Jean Bart looks impressive - at least on the surface. Not sure if the damage pictured was caused by 500 lb bombs or 16-inch shells, but imagine this occuring at sea in the heat of a high speed engagement:

Image

Image
The damage seen in the Photos is from 1000lb aircraft bombs and while it looks spectacular it doesn't seem to me to likely to be any worse than what any other AoN Battleship would have suffered had she been similarly hit outside of the citadel.
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RNfanDan
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Re: Richelieu vs. South Dak

Post by RNfanDan »

lwd wrote: Was that suppose[d] to be sarcasm or were you demonstrating that there is more than one poster here who makes use of strawmen?
Such a disingenuous question deserves no further response than this: Go figure... :stop:

With my sincerest regards otherwise,

--Dan
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Re: Richelieu vs. South Dak

Post by boredatwork »

Richelieu is a special case and any hypothetical scenario involving her must ask the question is she being considered as she was during the war or as she might have been had France not fallen.

Case and point the "excessive dispersion" - while it's true that late war her pattern was on the large side it's also true that post war (1948) the French fitted her with delay coils which reduced dispersion to an acceptable level.

Given that Vichy France was already fitting ships with delay coils as early as 1941 to reduce dispersion it doesn't seem to me to be much of a leap to suggest that had France not fallen and Richelieu had been able to conduct proper main battery tests with full access to the industrial infrastructure that designed and built her the problem might have been identified and fixed much sooner than was historically the case, possibly in time for a hypothetical engagement with SD in 1942/43.
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Re: Richelieu vs. South Dak

Post by alecsandros »

@Michael:
That's a possibility.But that;s only one of the many problems that affected the said BB class.
What about the rate of fire.. ? What about the quality of the radar and range table calculators.. ? Also, problems of the shells themselves.. homogenous armor quality... etc

And very important, the quality of the fire control system overall. Did Vichy France had the technology to equip good quality RPC onto Richelieu during the war ... ? Because, if it didn't, the battle is almost won from the start by South Dakota... It's no fair game to fire at an enemy that can manouvre while salvo-firing, while your ship has to keep on a steady course...
delcyros
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Re: Richelieu vs. South Dak

Post by delcyros »

The problems to cause excessive dispersion of french 38cm quad mounts cannot be reduced to missing delay coils. Even with them added, the data´s proposed in Dumas book suggest that the dispersion is on the poor side in comparsion.

Problems arised from many seperate problems, of which delay coils were only one:

(A) double two-gun turrets instead of quad turrets. This problem is technical and cannot be fixed easily. The two left and the two right barrels are each to close to each other and share a common weige. Introduction of delay coils helped to reduce issues, it couldn´t delete them. Even after addition of DC, dispersion patterns were inconsistent. Some of the salvo´s fell nice and tight while other came down and were scattered around.

(B) propelleant inconsistencies and issues with overpressure with SD-21 standart charges (see C). Modified SD-19 charges gave to low a muzzle velocity

(C) projectile design issues. The original APC projectiles had 4 cavities in the base which were designed to accept cartridges containing toxic war gases. These cavities were protected by a base cap, but this broke under the pressure generated when the guns fired. Premature explosions wrecked three barrels off Dakar.

(D) gun layout issues. More a question of layout but given the fact that the 380mm gun had a comparably short barrel length (45 cal- only the UK 15in had a shorter barrel) but fired one of the heaviest 380mm APC projectiles at one of the highest 380mm muzzle velocities is asking to much of it. Barrel stress and incomplete combustion of the propellent meant that larger projectile-gas-barrel interactions have to be reckoned with. The US reduced muzzle velocity in order to bring down the muzzle energy to tolerable (for the barrel length) limits. The design muzzle velocity was lowered from 2723fps to 2575 fps, the weight of the APC was reduced from 890kg to 885 kg (obviously You can´t change barrel length)....
boredatwork
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Re: Richelieu vs. South Dak

Post by boredatwork »

delcyros wrote:The problems to cause excessive dispersion of french 38cm quad mounts cannot be reduced to missing delay coils. Even with them added, the data´s proposed in Dumas book suggest that the dispersion is on the poor side in comparsion.
Nowhere did I claim that the design could be made perfect - what I do claim is the ~66% reduction in despersion recorded + a further reduction with lower wear barrels would have much lessened the disparity between the ships. Would SD still have been superior? Yes but not by near so large a margin as she had been historically.
(B) propelleant inconsistencies and issues with overpressure with SD-21 standart charges (see C). Modified SD-19 charges gave to low a muzzle velocity

(C) projectile design issues. The original APC projectiles had 4 cavities in the base which were designed to accept cartridges containing toxic war gases. These cavities were protected by a base cap, but this broke under the pressure generated when the guns fired. Premature explosions wrecked three barrels off Dakar.
Both issues that had been investigated and theoretically solved by the Vichy french navy, without access to half their country, by 1942. Had their full resources and expertise been available and had the ship been in a French Port as opposed to an African back water again I don't see it as unlikely they would have been quickly identified and fixed and propellant and shell manufacture ajusted accordingly.
What about the rate of fire.. ? What about the quality of the radar and range table calculators.. ? Also, problems of the shells themselves.. homogenous armor quality... etc
The loading systems had never been finished prior to leaving France and the main battery had only been briefly tested. In America due to the lack of parts to finish them the Americans had to improvise a new loading arrangement however test shoots which might have suggested improvements were limited due to the finite life of the irreplaceable barrels and the limited stocks of amunition. Postwar the French modified the American modified loading systems and cut loading times from ~45 sec to 32 seconds which is an entirely reasonable RoF. The question is, which can't be definitively answered, is could the French have modified the loading arrangements to achieve a similar RoF without American assistance, and how long would it have taken them to do so? A question which IIRC Dumas' book didn't answer was how were the turrets of JB completed postwar? Did they copy the American modifications to Richilieu or did they adopt a French solution to achieve the same effect?

The French were working on Radar and managed to manufacture and install sets prior to the scuttling at Toulon. As to the quality and availability of a French set for Richelieu in a hypothetical scenario where France not fallen is something as to which I would not hazzard a guess. I expect whether or not the British were still allies in this hypothetical scenario would play a factor here.

As for armor quality it's been a while since I looked at the other thread but aside from the hit on JB which penetrated the magazine, the circumstance of which I thought were not known with reasonable certainty, there was nothing else to suggest a gross deficiency in armor quality.
And very important, the quality of the fire control system overall. Did Vichy France had the technology to equip good quality RPC onto Richelieu during the war ... ? Because, if it didn't, the battle is almost won from the start by South Dakota... It's no fair game to fire at an enemy that can manouvre while salvo-firing, while your ship has to keep on a steady course...
Dunkerque had RPC (albeit unsuccessful) when completed. The Royal Navy partially equipped the KGV Class with RPC during the war. The French cruisers and Contre-Torpilleurs shot fairly well with French Fire control. As to whether or not a Free France could have developed a more successful system and refit it to Richelieu prior to the hypothetical engagement and how successful the result may or may not have been I have no clue.





I'm not saying that she would have necessarily been superior, or even equal to SD - I just disagree with the certainty with which your giving your odds based on your assumption that how she was was how she likely would have been. There's a disperity between a ship completed and improved by the people who built her versus the same ship a product of improvisation with whatever was on hand. Do you think Bismarck would have been all that she was had she had to flee Germany for completion in an American yard?
alecsandros
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Re: Richelieu vs. South Dak

Post by alecsandros »

Well, I also think a year or 2 of improvements may have helped quite a bit (who doesn't ?). Maybe in 1942 or 1943, Richelieu could have been fully completed, crew well trained, shell and gun issues resolved, at least in part... But I think the technological limitations of Vichy France and design limits of Richelieu class would have left her lagging behind a modern heavy BB like South Dakota...

P.S.: My appologies if I offended Keith; it was not my intention at all. And, for a given set of naval battles, he is correct: if both BBs lack RPC and make continous course alterations, a hit is very difficult to obtain.
But in our scenario, SoDak would most likely be equipped with RPC...

I find it surprising that he put together a battleship simulator. Maybe we can hear more about it and bring some input to upgrade it ?
Keith Enge
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Re: Richelieu vs. South Dak

Post by Keith Enge »

I think that some of the discussion here is confusing dispersion and accuracy. Dispersion is the scatter pattern around your aiming point. Accuracy is the deviation of the center of your dispersion pattern from the aiming point. Accuracy is very important; if you can't center your dispersion pattern on your aiming point, you might as well be shooting blindfolded. Dispersion, as I assert, is much less important because the target isn't likely to be at your aiming point.

alecsandros - You mentioned "offset salvo firing". This is, in essence, intentional dispersion; you are scattering your shells to cover a larger area because you are unsure where your target will be in that area. This, therefore, would seem to support my arguement that dispersion isn't particularly important if you purposely add your own artificial dispersion. Using your example, Richelieu moves 617 meters but can change course by plus or minus 30 degrees. Since the cosine of 30 degrees is 0.5, you get plus or minus 308.5 meters in range (your 310 meters). Therefore, to cover all of the places that the target could be, you need offset salvo firing of plus and minus 308.5 meters or a dispersion radius of 308.5 (which is quite a large dispersion, reinforcing my point that dispersion isn't important).

I should also mention that dispersion comes in two forms, range dispersion and bearing dispersion. I'm talking about range dispersion when I say that dispersion isn't important. Bearing dispersion, however, is important. If your shells vary too far from the correct firing bearing, you can't distinguish overs from unders in your straddles so you don't have the information needed to make firing solution corrections. Also, because of the great inertia of battleships, speed variations are much harder to make than course changes. Thus, your targeting bearing guesses are more likely to be accurate than your targeting range guesses. Therefore, dispersion in range is less important because your aiming point's range is more likely to be wrong anyway.

As for the historical example of West Virginia shooting at Yamashiro in the Surigao Strait battle, the fact that it was the first salvo is significant. Since Yamashiro didn't know that the battleline was there, she wouldn't yet be moving evasively. Therefore, your firing solution was probably as good as it ever would be. Anyway, I'm not sure that this would prove anything. She was part of a six battleship battleline so, as a counter arguement, I could just say that the other five didn't hit with their first salvos.

I assume that you were talking about me as the "he" that had put together a "battleship simulator". I have done nothing of the sort. I referred to a naval database. It has about 22,000 ships in it with most of them having multiple version to cover refits (Renown had the most with 16 versions). It also has 713 aircraft. The range of dates for both ships and aircraft is from 1920 to 1945. The database is quite powerful. For example, I can have it search for all British light cruisers with six to eight 6" guns, four to six 21" torpedo tubes, built between 6/33 and 4/35, and sunk between 4/41 and 7/41 in some specified area of the Mediterranean by a combination of Italian ship torpedoes and gunfire but not submarine torpedoes nor bombs. Anyway, about the "battleship simulator". What I have instead are the orders of battle for 335 battles of all types (surface, carrier, convoy, air, or whatever). 77 of them have animated battle maps that you can step through minute by minute seeing the movement of ships, torpedo tracks, smoke screens, and who is firing at whom (primary and secondary gunfire). For carrier battles, you see instead the movement of aircraft searches, strikes, and CAP. Those animated maps, however, aren't a simulator but rather a documentation of historical battles. What I do have is "power calculator" for groups of ships and planes. The groups of ships can either be the two sides of an actual battle or groups just custom created. For each ship, it calculates the power of that ship for the type of battle, its capability in a surface, ASW, or AA battle. After summing the powers for each group, the ratio of the sums indicates which side is likely to win the battle. For convoy ASW battles, there is another variable; the size of the convoy determines how many escorts are needed to patrol the perimeter. Less escorts allow gaps that subs can exploit; more escorts free some of them to pursue subs to destruction in hunter/killer operations. The power sum of the escort is decreased/increased to reflect this.

Back to our two ships, I merely compared the surface power calculations for the two ships. The ratio of South Dakota to Richelieu is 1.169:1 so South Dakota is 17% better. Since you mentioned Surigao Strait, I'll give that battle's ratio too. The 6 battleships, 8 cruisers, 36 destroyers, and 39 PT-boats ratio to the Japanese 2 battleships, 3 cruisers, and 8 destroyers was 2.879:1 so the Allies had a 188% advantage.

Since we are discussing my database, I want to make an appeal for help in making more animated maps. Has anyone seen battle tracks for any of the following battles?

10/20/40 Attack on convoy BN.7
12/25/40 Hipper versus convoy WS.5A
02/03/41 Attack on convoy BN.14
04/16/41 Tarigo convoy
04/30/42 Defense of convoy QP.11
05/02/42 Sinking of Edinburgh
10/14/42 Sinking of Komet
02/29/44 Le Malin and Le Terrible in an Adriatic sortie
04/29/44 Two German TBs T24 and T27 versus Haida and Athabaskan
03/18/45 German TA.24, TA.29, and TA.32 versus Lookout and Meteor

Thanks, Keith
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Re: Richelieu vs. South Dak

Post by lwd »

Keith Enge wrote:I think that some of the discussion here is confusing dispersion and accuracy. Dispersion is the scatter pattern around your aiming point. Accuracy is the deviation of the center of your dispersion pattern from the aiming point. Accuracy is very important; if you can't center your dispersion pattern on your aiming point, you might as well be shooting blindfolded. Dispersion, as I assert, is much less important because the target isn't likely to be at your aiming point.
But dispersion is a measure of how big of area the shells are scattered over. If dispersion a has CEP is twice as big as bthen your chance of hitting a ship anywhere in the CEP area for as is ~half what it would be for b. Now if the ship is outside the CEP area then the P(H) for a may indeed be greater for a than b but that means you've screwed up your figing solution or your pattern is "too tight".
mentioned "offset salvo firing". This is, in essence, intentional dispersion; you are scattering your shells to cover a larger area because you are unsure where your target will be in that area. This, therefore, would seem to support my arguement that dispersion isn't particularly important if you purposely add your own artificial dispersion. Using your example, Richelieu moves 617 meters but can change course by plus or minus 30 degrees. Since the cosine of 30 degrees is 0.5, you get plus or minus 308.5 meters in range (your 310 meters). Therefore, to cover all of the places that the target could be, you need offset salvo firing of plus and minus 308.5 meters or a dispersion radius of 308.5 (which is quite a large dispersion, reinforcing my point that dispersion isn't important).
I disagree. The point here is that you are firing on shorter intervals and with updated fire control solutions. For instance when shooting at Nowaki it was pointed out that the Japanese skipper would wait until he saw the guns fire and then maneuver radically. If a turret is firing ever 20 seconds or so any then there are at least two turret salvoes in the air at any point and he is likely to maneuver into one if he doesn't keep turning in the same direction. If he does then he becomes predicatable and also looses effective speed.

A bigger argument against salvo chasing in my book is it also degrades the fire control solution of the firer and thus is most useful as a tactic when one has decided to either retreat or try and get in range for a torpedo attack or something similar.
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Re: Richelieu vs. South Dak

Post by Keith Enge »

lwd - A slight correction. You wrote that "If dispersion a has CEP is twice as big as b, then your chance of hitting a ship anywhere in the CEP area for a is ~half what it would be for b". This is wrong; a CEP is a radius but you will be scattering shells over an area. Therefore, if you double the radius, the area will increase by a factor of 2 squared. Thus, you will get one quarter of hits, not one half.
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Re: Richelieu vs. South Dak

Post by Mostlyharmless »

One question that puzzles me is why Massachusetts' 16” shell could get through Jean Bart's 150 mm armoured deck without even being slowed enough to explode before it passed through the 40 mm armoured deck into the (empty) 155 mm magazine. I have seen it suggested that French homogeneous armour contained too much sulfur with serious effects on the maximum elongation (referenced to German examination of French armour after 1940) or that Jean Bart was listing so that the effective angle of descent was steeper as suggested by a French report of an angle greater than 30 degrees. However, I have also read that the deck was made by joining sections with an overlap so that at the join there are two decks laminated together with only a total thickness of 150 mm. Unfortunately, I do not know how thick the two individual plates were nor if the hit was at such a join. Does anyone have a complete answer?

On the issue of the battle, as Richelieu's commander I would use my one undoubted superiority by increasing speed to over 30 knots away from South Dakota. That way I would also avoid the danger of my guns blowing up.
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Re: Richelieu vs. South Dakota

Post by alecsandros »

Yes, it's intriguing how a shell could defeat so much armor given the circumstances...
There was also another 406mm shell (the 5th strike) which perforated 16 + 18 + 8 + 13 + 15 + 100mm of steel on Jean Bart's stern, allthough I don't know if the steel was armor grade.

Another explanation I can think of for the large perforations would be barrell wear on Massachussets. After all, the ship fired abut 800 shells that day... About 90/gun... Or about 1/4th of the maximum recomended shots before replacing the gun. Barrel erosion would have slowly decreased initial shell velocity, which would have lead to a shorter range. To compensate, the barrels would have needed to be elevated slightly more... Which would mean that the descent and striking angle would also have been slightly bigger than expected at the given range (20-22km).
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Re: Richelieu vs. South Dak

Post by alecsandros »

Keith Enge wrote:I think that some of the discussion here is confusing dispersion and accuracy. Dispersion is the scatter pattern around your aiming point. Accuracy is the deviation of the center of your dispersion pattern from the aiming point. Accuracy is very important; if you can't center your dispersion pattern on your aiming point, you might as well be shooting blindfolded. Dispersion, as I assert, is much less important because the target isn't likely to be at your aiming point.
It depends on the salvo pattern. It's one thing to have 2 shells 600y off each other and the other 6 grouped around a 200y point, and another to have most of the shells in a circle or square or whatever at long distances from each other. Consistency, mentioned by Delycros, is also very important. If the salvos don't keep the shape, it's very difficult to hit anything... Richelieu, as I understand it, had both poor salvo dispersion and inconsistency.
Therefore, to cover all of the places that the target could be, you need offset salvo firing of plus and minus 308.5 meters or a dispersion radius of 308.5 (which is quite a large dispersion, reinforcing my point that dispersion isn't important).
It's certainly difficult to hit such a target at long range, but if your salvos are consistent and danger space sufficient, it's only a matter of time... Indeed, the danger space of the 406mm L45 shells wasn't that impressive...

As for the historical example of West Virginia shooting at Yamashiro in the Surigao Strait battle, the fact that it was the first salvo is significant. Since Yamashiro didn't know that the battleline was there, she wouldn't yet be moving evasively.
I was thinking about this also. At the time of the salvo impact, Yamashiro was engaging the forward screen of DDs and CAs, battling violently among them.
I don't know if it was doing evasion actions, but considering the number of DDs around, and the fate of Fuso (struck by several torpedoes 1 hour earlier) it is very likely that it was doing them...


=====
Congratulations for the database. It must have taken years to accomplish... Unfortunately, I don't have info about the battles you requested..

What I don't understand is " I merely compared the surface power calculations for the two ships". What does "power calculation" mean ?
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Re: Richelieu vs. South Dak

Post by lwd »

alecsandros wrote:...
As for the historical example of West Virginia shooting at Yamashiro in the Surigao Strait battle, the fact that it was the first salvo is significant. Since Yamashiro didn't know that the battleline was there, she wouldn't yet be moving evasively.
I was thinking about this also. At the time of the salvo impact, Yamashiro was engaging the forward screen of DDs and CAs, battling violently among them.
I don't know if it was doing evasion actions, but considering the number of DDs around, and the fate of Fuso (struck by several torpedoes 1 hour earlier) it is very likely that it was doing them...
Yamashiro had also taken at least one torpedo already I beleive and was rather constrained by the strait in it's movements. Given her situation I'm not sure how many relevant lessons can be gleaned from her loss.
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