More on KGV Class main armament problems

Discussions about the history of the ship, technical details, etc.

Moderator: Bill Jurens

Bill Jurens
Moderator
Posts: 643
Joined: Mon Oct 18, 2004 4:21 am
Location: USA

Re: More on KGV Class main armament problems

Post by Bill Jurens » Mon Jun 24, 2019 4:32 pm

For some reason -- at least from here -- the forum appears to have been shut down for a period, but is back up again. That is the good news.

The bad news is that having read the previous flurry of commentary, I share expressed concerns regarding what appears to represents a slide back into a much more argumentative, and -- almost by definition -- a much less productive discussion.

I do not at this stage have the time to go over all of the immediately previous correspondence in order to pass judgement upon, and redact if appropriate, what amounts to a flurry of aggressive 'sniping' at other correspondents. I may do that later, if and as time permits.

Again, correspondents are requested to refrain from unnecessary editorializing and 'sniping' at other participants. Some members, for whatever reasons, appear to be much more susceptible to this sort of problem than others. STAY ON TOPIC!

I will be reading future correspondence carefully.

Any further commentary which includes aggressive and potentially insulting personal commentary will be deleted IN ITS ENTIRETY. Until further notice, I will in general no longer 'line edit' in order to delete specific phrases, etc. -- one offensive comment will be sufficient to dump the entire entry. Comments can, of course, be resubmitted with the offensive commentary deleted, but posters will hereafter have to do that themselves, and risk deletion of their commentary again. Should offensive commentary continue, I will ban members if and as appropriate. If this does not work, I will shut down the thread.

Members posting commentary should therefore err on the side of caution. If you think there is the possibility that one of your comments will be interpreted as argumentative, then you are probably right. If you don't have to say it, then perhaps don't say it at all.

Bill Jurens
as moderator.

User avatar
wadinga
Senior Member
Posts: 1906
Joined: Sat Mar 12, 2005 3:49 pm
Location: Tonbridge England

Re: More on KGV Class main armament problems

Post by wadinga » Mon Jun 24, 2019 4:55 pm

Fellow Contributors,

Can we at least agree that those shots which PoW got away were reasonably well directed? I have never disputed that, although one must remember that no-one in PoW knew at the time they had scored any hits at all.
Does the Ordnance Directors say PoW fired poorly ? No, they said the problems
Does this imprecise wording attempt to differentiate between the accuracy of shooting and separately, below par output? I really can't tell. "Fired" means both accuracy and output, and if one former gunnery officer thinks having already achieved a 25% failure rate when some guns have fired only 9 shots, most fewer, and some one only, is indicative of
minor
problems, then he is at odds with Sir Dudley Pound who specifically asked about these problems in a special memo, and the other two most senior gunnery experts who responded to him.
Please don't try to invent evidence, when having none.
My evidence has been presented, some has not.
and this is simply a (s[
Unfortunately the rest of this pearl of wisdom has disappeared, the text loss problem is still happening.

All the best

wadinga
"There seems to be something wrong with our bloody ships today!"

Bill Jurens
Moderator
Posts: 643
Joined: Mon Oct 18, 2004 4:21 am
Location: USA

Re: More on KGV Class main armament problems

Post by Bill Jurens » Mon Jun 24, 2019 5:32 pm

regarding target sizes, Dunmunro wrote:
"Target size = Bismarck = 251 x 36 = 9036m2 and PE = 212 x 22 = 4664m2. These numbers overstate the actual target surface area but the proportions will remain much the same, and we can see that Bismarck is a much larger target. If Hood had engaged Bismarck she had a much higher probability of hitting. in the same vein 3 gun salvos (from PoW) are 50% larger than two gun salvos (Hood).
Perhaps Bill Jurens can offer an opinion on the above paragraph?"
This represents a fairly intricate computation, and the ratios would, of course, vary somewhat with differences in target angle, angle of fall, and the basic shape of the ship itself. The USN, and likely other large navies as well, did extensive studies of this sort of thing, and developed a collection of often fairly intimidating algorithms to extract these sorts of ratios.

Application of a ‘quick ‘n dirty’ algorithm predicts that for a 90 degree target angle, and an angle of fall of of 45 degrees or so – the projected areas would appear to be in the ratio of about 1.6:1. This is in satisfying, but perhaps fortuitous, agreement with an analysis of illustrations given in ONI 204, which for target angles of 90 degrees and angle of fall of 15 degrees, yields a ratio of 1.56:1. The measured projected areas are, incidentally, 4469 and 2862 m^2 respectively.

Bill Jurens

User avatar
Alberto Virtuani
Senior Member
Posts: 3486
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: More on KGV Class main armament problems

Post by Alberto Virtuani » Mon Jun 24, 2019 5:49 pm

Hello everybody,
Wadinga wrote: "Can we at least agree that those shots which PoW got away were reasonably well directed? "
Well, we can agree that the 55 PoW fired shells in 9 minutes were fairly well directed.

However, the 93 shells delivered by Bismarck in 14 minutes (pending a better estimation of her fire action that I have not seen yet) were possibly even better directed (only if we assume 6 hits for Bismarck, I think 5 is a more cautionary assumption). For sure they were not more in quantity, keeping in mind that PoW aft turrret was wooded for the first 8 salvos (see effective # shells/ minute, computed using McMullen methodology download/file.php?id=3463). Thus I tend to state (in fair agreement with Santarini) that PoW RoF was very good, her output loss was not good but precision was good.

The output problems (25% output loss) vs 15% of PG and (most likely 14% of Bismarck) were significative but not so much larger of the ones of any battleship in action and still with 10 guns available, the ship was able to deliver a good quantity of shells.
E.g. at Gaudo, Vittorio Veneto loss of output was only 11%, but the RoF was awfully slow, 29 salvos in 23 minutes (due to bad visibility conditions and much higher, almost extreme, range), with 94 actually fired shells.



Bye, Alberto
Last edited by Alberto Virtuani on Mon Jun 24, 2019 6:06 pm, edited 1 time in total.
"It takes three years to build a ship; it takes three centuries to build a tradition" (Adm.A.B.Cunningham)

"There's always a danger running in the enemy at close range" (Adm.W.F.Wake-Walker)

User avatar
Alberto Virtuani
Senior Member
Posts: 3486
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: More on KGV Class main armament problems

Post by Alberto Virtuani » Mon Jun 24, 2019 6:04 pm

Hello everybody,
@ Bill Jurens:
thanks for the precise calculation of the target areas.

However, due to the actual position of the hits received by Bismarck, putting PG instead of BS (fixing the amidship point), the first and second would have hit also PG (just at the extreme bow), while the only debatable is the third one that could have hit or not (it's too difficult for me to graphically superimpose BS and PG silhouettes to verify whether PG could have avoided the third shell). Also, a few areas will possibly result void in BS and full in PG profile once superimposed, making possible (even if most unlikely) that other shell(s) that passed through BS voids could have hit PG....


Bye, Alberto
"It takes three years to build a ship; it takes three centuries to build a tradition" (Adm.A.B.Cunningham)

"There's always a danger running in the enemy at close range" (Adm.W.F.Wake-Walker)

dunmunro
Senior Member
Posts: 3905
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: More on KGV Class main armament problems

Post by dunmunro » Mon Jun 24, 2019 6:12 pm

Bill Jurens wrote:
Mon Jun 24, 2019 5:32 pm
regarding target sizes, Dunmunro wrote:

"Target size = Bismarck = 251 x 36 = 9036m2 and PE = 212 x 22 = 4664m2. These numbers overstate the actual target surface area but the proportions will remain much the same, and we can see that Bismarck is a much larger target. If Hood had engaged Bismarck she had a much higher probability of hitting. in the same vein 3 gun salvos (from PoW) are 50% larger than two gun salvos (Hood).
Perhaps Bill Jurens can offer an opinion on the above paragraph?"

This represents a fairly intricate computation, and the ratios would, of course, vary somewhat with differences in target angle, angle of fall, and the basic shape of the ship itself. The USN, and likely other large navies as well, did extensive studies of this sort of thing, and developed a collection of often fairly intimidating algorithms to extract these sorts of ratios.

Application of a ‘quick ‘n dirty’ algorithm predicts that for a 90 degree target angle, and an angle of fall of of 45 degrees or so – the projected areas would appear to be in the ratio of about 1.6:1. This is in satisfying, but perhaps fortuitous, agreement with an analysis of illustrations given in ONI 204, which for target angles of 90 degrees and angle of fall of 15 degrees, yields a ratio of 1.56:1. The measured projected areas are, incidentally, 4469 and 2862 m^2 respectively.

Bill Jurens

Bill, thanks.

So if PoW was shooting at PE, we could multiply the 3 hits obtained against Bismarck by (1.56/1 = .64) to account for target area, which yields 1.92 hits and then by (2/3 = .67), to account for reduced salvo size, to give an adjusted 1.3 hits. It seems likely that Hood's FC was damaged just about when she opened her A arcs so this countered any advantage obtained by the 4 gun salvos. If PoW only fired 10 salvos, we would then multiply the 1.3 hits by (10/18 = .56) to account for total number of salvos fired, and the total probability of number of hits = .7 so we can see that shooting at PE led to a much smaller probability of hits. Conversely, if Hood had engaged Bismarck she had a much higher probability of hitting.

We can also see that Hood's radar gave her accurate ranging from the beginning and would have done so for PoW as well.

Edited to better explain the reasons for each multiple.
Last edited by dunmunro on Mon Jun 24, 2019 6:29 pm, edited 1 time in total.

User avatar
Alberto Virtuani
Senior Member
Posts: 3486
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: More on KGV Class main armament problems

Post by Alberto Virtuani » Mon Jun 24, 2019 6:24 pm

Hello everybody,
Dunmunro wrote: "So if PoW was shooting at PE, we could multiply the 3 hits obtained against Bismarck by (1.56/1 = .64) to account for target area, which yields 1.92 hits and then by (2/3 = .67), to account for reduced salvo size, to give an adjusted 1.3 hits...."
No, we could not.
Please read my post (viewtopic.php?f=1&t=8556&start=225#p84096) and try to superimpose the two profiles with the actual hits sustained by Bismarck.... The reasoning would be correct only statistically, not with the actual hits.

Can someone explain me Mr.Dunmunro calculations (what are exactly the 2/3 and 1/3 adjustments ? What 's "reduced salvo size" ?) ? Sorry for my ignorance but I don't see how they can be correct mathematically (without any intent to insult, of course)...


Bye, Alberto
Last edited by Alberto Virtuani on Mon Jun 24, 2019 6:37 pm, edited 5 times in total.
"It takes three years to build a ship; it takes three centuries to build a tradition" (Adm.A.B.Cunningham)

"There's always a danger running in the enemy at close range" (Adm.W.F.Wake-Walker)

dunmunro
Senior Member
Posts: 3905
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: More on KGV Class main armament problems

Post by dunmunro » Mon Jun 24, 2019 6:26 pm

Salvo chasing.

This is from the CO's report of Renown's action against S&G:
During this and subsequent periods I took advantage of the agility of the modern fire control now fitted in RENOWN to alter course within small limits as necessary to prevent the enemy establishing hitting.
The above was probably due to salvo chasing. Unfortunately we don't have a similar report for PE.

User avatar
Alberto Virtuani
Senior Member
Posts: 3486
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: More on KGV Class main armament problems

Post by Alberto Virtuani » Mon Jun 24, 2019 6:29 pm

Hello everybody,
Dunmunro wrote: "Salvo chasing......Unfortunately we don't have a similar report for PE."
we have all we need in the PG KTB + battlemap, without any need for suppositions (that can be applied to Bismarck as well in case it was done by PG, changing nothing).


Bye, Alberto
"It takes three years to build a ship; it takes three centuries to build a tradition" (Adm.A.B.Cunningham)

"There's always a danger running in the enemy at close range" (Adm.W.F.Wake-Walker)

Bill Jurens
Moderator
Posts: 643
Joined: Mon Oct 18, 2004 4:21 am
Location: USA

Re: More on KGV Class main armament problems

Post by Bill Jurens » Mon Jun 24, 2019 7:23 pm

To be honest, I am not entirely clear what we are trying to prove (or disprove) in this discussion.

That being said, my opinion the sample size is so small, the testimony describing fall of shot, etc. so incomplete and contradictory, the actual number and sequence of shots fired so indeterminate, and the geometric situation so uncertain as to render anything other than very very general conclusions to be reached -- or rather more accurately postulated.

If I were provided a more precise idea of exactly what we are attempting to establish in this discussion, it is possible that I might be able to provide a more useful answer.

Might someone provide that? It might be that we are fighting more about the question itself than the answer thereto...

Bill Jurens

User avatar
Alberto Virtuani
Senior Member
Posts: 3486
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: More on KGV Class main armament problems

Post by Alberto Virtuani » Mon Jun 24, 2019 7:42 pm

Comment deleted as excessively argumentative in tone. [WJJ].
Last edited by Alberto Virtuani on Mon Jun 24, 2019 7:47 pm, edited 1 time in total.
"It takes three years to build a ship; it takes three centuries to build a tradition" (Adm.A.B.Cunningham)

"There's always a danger running in the enemy at close range" (Adm.W.F.Wake-Walker)

User avatar
wadinga
Senior Member
Posts: 1906
Joined: Sat Mar 12, 2005 3:49 pm
Location: Tonbridge England

Re: More on KGV Class main armament problems

Post by wadinga » Mon Jun 24, 2019 7:45 pm

Fellow Contributors,

It has been said:
The output problems (25% output loss) vs 15% of PG and (most likely 14% of Bismarck)
Accepting for a moment the guesstimate value for Bismarck and the principle of entropy within mechanical systems, if PoW achieved 25% failure with only 55 shells, Bismarck achieved approx. half that failure rate whilst firing nearly twice as many shells, and PG a similar rate to Bismarck whilst firing almost four times as many shells as the British ship, it is clear that PoW's system was seriously less reliable than either of her opponents.

Someone may consider PoW's problems minor minor, but in a handwritten memo, reproduced above, the First Sea Lord, Sir Dudley Pound clearly did not, and specifically questioned what was causing these problems and what was being done about them, from the two most senior officers concerned with RN gunnery. He received specific opinions that PoW had worse problems than KGV, from both men and both cited the short time since commissioning.

As such their comments completely justify Leach's actions in withdrawing from the action against two vessels suffering a fraction of the failures PoW was experiencing. Leach was aware of the failures occurring during the action, was aware of those which had preceded the action and as a Gunnery expert himself, knew they were unlikely to get better.
However, the 93 shells delivered by Bismarck in 14 minutes (pending a better estimation of her fire action that I have not seen yet)
I wonder how we might identify a better estimate Since the current one is pure guesswork, all other permutations are equally likely and equally unlikely.

This opinion:
(only if we assume 6 hits for Bismarck, I think 5 is a more cautionary assumption).
is completely at odds with Santarini's concluding table 20 where he gives only one hit by Bismarck.
Thus I tend to state (in fair agreement with Santarini)
This observation entirely contradicts Santarini and therefore his conclusions.

All the best

wadinga
"There seems to be something wrong with our bloody ships today!"

User avatar
Alberto Virtuani
Senior Member
Posts: 3486
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: More on KGV Class main armament problems

Post by Alberto Virtuani » Mon Jun 24, 2019 7:55 pm

Commentary deleted as excessively argumentative in tone. [WJJ]
"It takes three years to build a ship; it takes three centuries to build a tradition" (Adm.A.B.Cunningham)

"There's always a danger running in the enemy at close range" (Adm.W.F.Wake-Walker)

User avatar
Alberto Virtuani
Senior Member
Posts: 3486
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: More on KGV Class main armament problems

Post by Alberto Virtuani » Mon Jun 24, 2019 9:31 pm

Comment deleted due to inappropriate commentary. {WJJ]
Last edited by Alberto Virtuani on Mon Jun 24, 2019 9:54 pm, edited 4 times in total.
"It takes three years to build a ship; it takes three centuries to build a tradition" (Adm.A.B.Cunningham)

"There's always a danger running in the enemy at close range" (Adm.W.F.Wake-Walker)

User avatar
Alberto Virtuani
Senior Member
Posts: 3486
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: More on KGV Class main armament problems

Post by Alberto Virtuani » Mon Jun 24, 2019 9:33 pm

....
Last edited by Alberto Virtuani on Mon Jun 24, 2019 10:20 pm, edited 1 time in total.
"It takes three years to build a ship; it takes three centuries to build a tradition" (Adm.A.B.Cunningham)

"There's always a danger running in the enemy at close range" (Adm.W.F.Wake-Walker)

Post Reply