Lutzow vs. US heavy cruiser

[dunmunro]

Your calculation of relative hitting power falls apart if the 8" shell hits a turret or other important area. If it does, the turret will be knocked out the same as a turret on the cruiser. What you seem to be saying is the AGS was a superior ship and all the worlds navies were stupid because they should have stopped building 8" cruisers and instead build 11" cruisers with six guns. I simply don't believe that and I don't believe AGS is going to be as effective as you think at long range. For example, she got very few hits on either British cruiser in their engagement in spite of a long battle and expending a lot of her ammunition. The historical results simply don't support your theory.

In fact the building of such ships was outlawed by treaty. I'm not saying that a USN 8" CA couldn't win, just that the odds favour the PB. It was no accident that the RN had to use 3 ships to counter GS, and even then it was touch and go. The RN cruisers were able to damage GS's FC early on and the 3 to 1 odds forced Langsdorf to continually shift his fire and both sides had to resort to salvo chasing to avoid being overwhelmed.

[hammy]

Tactically , Henry Harwood's handling of his squadron at the Battle of the River Plate was less than ideal .
Peeling Exeter away on her own initially ( " Exeter to investigate " ) was likely to get her identified sooner than necessary , because she was one-of-a-kind with a distinctive silhouette , and would be very likely to be therefore selected by G S as her first target , as the main threat to her , being the strongest enemy present .
Manouvering Ajax and Achilles together as a division is just what Holland was to do later with Hood and PoW at Denmark Strait , with the same result ; - Graf Spee could shift fire rapidly between these two targets because the firing solutions had been made unecessarily easy for her .
Had all three of the British cruisers been manoevering independently and using their speed advantage to close the range or retire at will , and dodging in and out of smoke screens then G S would be taking more hits and in the confusion her fire control would be in trouble with three targets to plot .
Of course HH had no VHF radio to talk to or direct his fellows , and opted for control instead .
I recall that someone flew off a Seafox spotter plane to aid the gunnery by spotting the fall of shot , but I never heard that it affected events at all .

Exeter was by way of being an experimental type . Like her half sister York , she was intended to do the distant water cruiser jobs but at a much more economic rate than the bigger County class Washington treaty ships .
It is unlikely that a Zara or New Orleans would be such a "tin-clad" .

[dunmunro]

Tactically , Henry Harwood's handling of his squadron at the Battle of the River Plate was less than ideal .
Peeling Exeter away on her own initially ( " Exeter to investigate " ) was likely to get her identified sooner than necessary , because she was one-of-a-kind with a distinctive silhouette , and would be very likely to be therefore selected by G S as her first target , as the main threat to her , being the strongest enemy present .
Manouvering Ajax and Achilles together as a division is just what Holland was to do later with Hood and PoW at Denmark Strait , with the same result ; - Graf Spee could shift fire rapidly between these two targets because the firing solutions had been made unecessarily easy for her .
Had all three of the British cruisers been manoevering independently and using their speed advantage to close the range or retire at will , and dodging in and out of smoke screens then G S would be taking more hits and in the confusion her fire control would be in trouble with three targets to plot .
Of course HH had no VHF radio to talk to or direct his fellows , and opted for control instead .
I recall that someone flew off a Seafox spotter plane to aid the gunnery by spotting the fall of shot , but I never heard that it affected events at all .

Exeter was by way of being an experimental type . Like her half sister York , she was intended to do the distant water cruiser jobs but at a much more economic rate than the bigger County class Washington treaty ships .
It is unlikely that a Zara or New Orleans would be such a "tin-clad" .

In fact Harwood attempted to use Concentration fire where both ships would be controlled by one ship via a special radio link. Unfortunately this did not work well, and the aircraft spotting was partially to blame! The problem with open order manoeuvring is that it rapidly becomes impossible to determine whose's salvos are whose, especially with two identical 6" CLs firing at the same target, because as they change range, you often have a situation arising where both ship's salvos arrive more or less simultaneously. Tovey's open order formation caused KGV's gunners to spot on Rodney's shell splashes for much of the early part of the action and the constant arrival of each others salvos, at random intervals, must have been a real headache for Rodney and KGV's gunners. This could have been avoided had KGV and Rodney advanced on Bismarck in close formation with a constant interval between each ships salvos, and this was what Holland had planned to do, to maximize his firepower.

Any armour that any cruiser could carry would be of little use against 11" AP shells, and probably (at least at a low obliquity impact) against 11" base fused shells as well, and a PB is also well armoured especially on her turrets. A retreating PB keeping its A arcs open would present its belt armour inclined at ~55 degrees and this would probably give it a partial immune zone from about 20k yds or more, although the decks would still be vulnerable.

Let's replace Lutjen's and Holland's force with a PB and a USN CA, and remove the other forces involved.

We have the PB recognizing the CA at about 26K yds and presumably it would then turn and retreat at 26 knots* but keep its A arcs open and open fire. The CA works up from 29 to 31 knots and steers directly for the PB to close the range. I'm guessing that this gives a closing speed of about 10 knots, meaning that the CA has about a 20min run where the PB will have a large advantage in effective firepower, and this is where the CA is at its greatest disadvantage.

* In a random encounter where both ships are moving at say 15 knots, the PB's diesel engines will allow it to accelerate much more quickly than a steam turbine driven ship, and it will rapidly open the range for the first 30mins or so. Here I have postulated that both ships are moving at high speeds.

[Bgile]

Well, if you are correct and the 11" gun on GS has a good chance to kill a CA at 25,000 yds, then the CA would do best to refuse combat. I just don't understand why six 11" guns have a better chance to hit than nine 8" guns. I have the impression that 18,000 yds is max effective range of 6", and you are arguing that 8" is only 20,000 yds.

[dunmunro]

Well, if you are correct and the 11" gun on GS has a good chance to kill a CA at 25,000 yds, then the CA would do best to refuse combat. I just don't understand why six 11" guns have a better chance to hit than nine 8" guns. I have the impression that 18,000 yds is max effective range of 6", and you are arguing that 8" is only 20,000 yds.

The USN 6", for example, has a max range of 26100 yds, and 18/26.1 = .69. 8" max range = 30050 yds x .69 = 20730 yds. 11" max range = 39900 yds x .69 = 27500 yds. Of course optical FC becomes problematic at that 27500 yds, but depending on conditions might still be effective, although radar ranging becomes useful.

Of course if the CA can engage at closer ranges, and we replace Exeter with a USN CA at River Platte then the CA might be able to overwhelm the PB before being shot to pieces as Exeter was.

While reviewing the AP performance of the PB 11", I realize now, that it is considerably worse than Scharnhorst's 11" guns and the belt and turret armour of a USN CA might confer a wide immune zone against the PB gun. This complicates the process of trying to sort out what would happen in an encounter.

[Bgile]

What you say really does make sense, and you make a good case based on the ballistics of the 11" gun.

I would point out that at really long range, deck hits become more likely and the flat trajectory becomes less relevant. Just where that occurs I'm not sure, and cruisers have a relatively narrow beam so the effect would be less important than when your target is a ship with a wide beam.

[Byron Angel]

I would point out that at really long range, deck hits become more likely and the flat trajectory becomes less relevant. Just where that occurs I'm not sure, and cruisers have a relatively narrow beam so the effect would be less important than when your target is a ship with a wide beam.

..... The crossover point for indicence of side versus deck hits for a target ship of typical transverse cross-sectional proportions is about 15 degrees angle of fall.


Byron

[Gary]

The turret faces and the tower of AGS would stand up well to 8 inch fire but I dont know about the rest of the ship.

Harwood did ok at River Plate considering what he had - 2 Leanders and the Junkyard dog (Exeter)

Whilst I'm a fan of the little Leander (look at the records of Ajax and Orion), its not large enough or equipped with enough firepower to take on a pocket battleship.
Exeter carried a large spare parts locker which she seemed to go through at a silly rate and she only mounted 6 guns to the Counties 8.
If Harwood had had Cumberland backed up by 2 Town class, history may have been different

But at the time of the River Plate action, how much did the British know about the Pocket batleships and their armour thickness?

[Bgile]

I would point out that at really long range, deck hits become more likely and the flat trajectory becomes less relevant. Just where that occurs I'm not sure, and cruisers have a relatively narrow beam so the effect would be less important than when your target is a ship with a wide beam.

..... The crossover point for indicence of side versus deck hits for a target ship of typical transverse cross-sectional proportions is about 15 degrees angle of fall.


Byron

That's useful information, but what is a typical ship? Battleships and cruisers usually have much different length to beam ratios, and their long range profile to incoming shells is therefore different.

If we can use that example with respect to the US 8"/55 cal gun firing a 335 lb shell, the point you are referring to occurs at about 15,000 yds.

[alecsandros]

Well, if you are correct and the 11" gun on GS has a good chance to kill a CA at 25,000 yds, then the CA would do best to refuse combat. I just don't understand why six 11" guns have a better chance to hit than nine 8" guns. I have the impression that 18,000 yds is max effective range of 6", and you are arguing that 8" is only 20,000 yds.

Hello,
We must also take into account the relative probable damage that the US/Germ ships would suffer. It's obvious 9 guns > 6 guns, but a 118kg-152 kg shell with a 1,7 - 2,3 kg bursting charge (US AP 8") < 300kg, 6,6 kg bursting charge of the Graf Spee. After all, Exeter was a smoking wreck after receiving 3 direct hits (and one near miss).

[Legend]

The American ship does have one advantage... due to their fairly high rate of fire they could shoot off many more rounds per minute than the two of the Deuschland Class. The Baltimore class for instance, could fire off 4,000lbs more ammo in one minute than the Lutzow.

Baltimore: 3,015lbs(Broadside) x 4(RoF) = 12,060 lbs/min

Lutzow: 3,996(Broadside) x 2(RoF) = 7,932 lbs/min


If however it was a Northampton, New Orleans, or Portland class, then it would only be a slight advantage in firepower, only around a 2,000 lb difference.

Another question if I may, did the US cruisers of the time have the technological capability with their radars and other targeting systems, have the capability to both maneuver and fire at the same time? If they did than they could constantly swerve and change course, making it much much harder for the Germans to gain an accurate firing solution.

[hammy]

" Junkyard dog " is a little bit harsh on Exeter as a design , Gary . Had she been armed with the 6 inch triple mounts and not the 8 inch twins , she would be just another standard RN cruiser .

And " Smoking Wreck " was not exactly her condition when she turned away Alexandros . The hits forward had ripped up her forward gunhouses and fragment damage had damaged her bridge and knocked out systems there , but then she was a tinclad , hardly built with fighting heavyweight warships in mind .

ANY cruiser getting an 11 inch shell hit , all 660 pounds of it , is going to stagger a bit .

As regards the problem of several ships shooting against the same target muddling up whose splashes were whose , this had been solved , in conditions of fair or better optical observation by the French Navy , who used dye indicators in their big shells to stain the splashes different colours for different ships .
There is a funny story about some French battleship operating with a British counterpart , asking the Brit " What colour will you be shooting ? " ..... ( ? ? ? ) " Not Understood " signals back the Brit . " O K , you fire white then " says the Frenchman .

[dunmunro]

The official account of the action lists at least six 11in hits on Exeter and several near misses:

http://funsite.unc.edu/hyperwar/UN/UK/L ... /37989.pdf

It makes for a very interesting read.

[lwd]

...
Basically the 11" gun will be at least as accurate at 25k yds as the 8in at 20k, and will tend to maintain at least a 5k yd advantage, in terms of accuracy at longer ranges.

If you are basing in on the charts it looks more like almost rather than at least. That chart's for one gun extrapolating the relative performance of the 11" gun compared to the 8" gun from a single chart is highly problematic.

The RN and USN 8" have almost identical ballistics.

For some elastic enough definition of "almost" perhaps but not in my book.

. .... I would say that the 11in is probably more than twice as accurate as the 8in at 25k yds.

Even if it is which I'm far from convinced of at this point. The higher rate of fire and more guns mean that the C is likely to get more hits sooner.

Additionally, the PB skipper can opt to keep his A arcs open and use all 6 guns, while the CA skipper will have to close his A arcs to minimize the time at long ranges, thus reducing his firepower by a 1/3.

Or not. Of course if he does he can maneuver to make himself a harder target and with only 6 guns the P(H) falls off pretty quickly for the 11" gun as well.

the 11 shells are also much more destructive than a 8" having a much larger burster ranging from 14.5lbs for the AP to 35lb for the base fuzed HE, while the USN 335lb a8" AP was only 5 lb, so a single 11" hit is probably equivalent to 3 to 5 8" hits in terms of destructive potential.

The problem with this is more hits give a better chance of hitting something important. This is exerbated by the plunging effect.

Fighting a PB would be a very tough proposition for any any Allied CA ....

Now that I can agree with.

[alecsandros]

The official account of the action lists at least six 11in hits on Exeter and several near misses:

http://funsite.unc.edu/hyperwar/UN/UK/L ... /37989.pdf

It makes for a very interesting read.

A good read, indeed. But I only counted 5 direct hits on Exeter..