PoW's gunnery VS BSM's gunnery

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

Moderator: Bill Jurens

User avatar
wadinga
Senior Member
Posts: 1864
Joined: Sat Mar 12, 2005 3:49 pm
Location: Tonbridge England

Re: PoW's gunnery VS BSM's gunnery

Post by wadinga » Sat Mar 16, 2019 9:03 pm

Hello All,

We have already established Conspiracy Theory and Revisionist can be accurately and rightly applied to the Controversial Theory being asserted as proven and correct.

Tendentious: expressing or intending to promote a particular cause or point of view, especially a controversial one. There is therefore nothing insulting in using tendentious to describe the assertions being made.
while I still find insulting the repeated usage of the word " tendentious ",
The word tendentious has only been used in two posts on this forum, last time in 2017 (also by me :wink: ) that is hardly "repeated".

Since one observation of the disruption caused by near misses is not enough to suggest a retraction of this assertion is in order:
Correct, but being under fire (while is a very dangerous situation) doesn't affect much own gunnery performances, except when a gunnery equipment is directly hit
here is another:

Busch
“Prinz Eugen” steers through the water columns of the impacts of the “Hood’s” heavy turret guns, a deluge pours down on the forecastle, the turrets, and the stand.
[page 151 start]
The Commander and runner leave the stand. The telescopes are temporarily covered with spray, and the Commander steps outside; he prefers to make his decisions with a clearer view.
With two clearly contradicting examples, one British, one German it is surely true to say that:
Correct, but being under fire (while is a very dangerous situation) doesn't affect much own gunnery performances, except when a gunnery equipment is directly hit
is both controversial and tendentious but also inaccurate based on these two witness accounts.


and confirmation of the variation in PG's rate of fire :

Busch
. The heavy cruiser’s rapid salvoes-for-effect send tremors throughout the ship.
Concentrating on the unlikely possibility that shots fired from PoW landed anywhere near either PG or Bismarck, at the end of the action Busch says:
The crew in the foretop cowl does not realize until after the battle that there were actually hits on their own cruiser. We found out, also later, that “Hood” had fired only on us, since the British admiral had ordered: “Division of fire from the left, ship against ship!”
No mention of shots from PoW landing anywhere near PG as photographed by Langemann and identified as being from Hood.

Busch describes in detail PoW's last shots in The Story of Prinz Eugen:
What they saw was this: the enemy was raising the four guns of his sole after turret two at a time, was firing and then lowering them to the loading position. At the same time he slewed suddenly hard to port only to turn back again immediately afterwards just hard to starboard.
Surely he might have made some observation about where these shots landed if they had been anywhere near the German ships.

As Bill has said:
At any rate, unless the turns involved were fairly steady, the chances of hitting during a turn were probably negligible.
and he was talking about someone using a proper fire control system not the "rudimentary" one available to Aylwin.

We need a precise quotation for this vague observation
(full-)salvo landing behind PG (ref. Busch)
All the best

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

Bill Jurens
Moderator
Posts: 606
Joined: Mon Oct 18, 2004 4:21 am
Location: USA

Re: PoW's gunnery VS BSM's gunnery

Post by Bill Jurens » Sat Mar 16, 2019 10:20 pm

OK, Gentlement, it's clearly time for both sides to begin backing off a bit. I did make a posting suggesting this earlier today, but for some reason -- this seems to happen about 10% of the time -- it never appeared, and I can see that since that time, things have gotten considerably more belligerent. My apologies for this -- I should have stepped in earlier, or kept better track of things over the last few hours.

Someone asked about the amount of heel in turns. It's complicated to estimate with any certainty because it's dependent upon a number of factors, e.g. ship speed and radius of turn, which are not constants even under ideal situations, and because a full analysis requires detailed knowledge of things like displacement, the metacentric height, and the moment of inertia of the waterplane. My first estimate, for a speed of about 25 knots and a turn radius of 500 yards, would be something like six degrees.

I think we do have to return to the title of this thread, namely "PoW's gunnery vs BSM's gunnery. I assume from this that there is some attempt being made to determine exactly whose gunnery was 'better'. The fact that it's a very small sample, makes any assessment problematical, and the fact that there are, so far as I know, been no real firm definitions of exactly what 'better' might mean complicates things even further. Conditions were not experimental in nature, and this comparing one set of results to another is not really valid. One might, as a thought experiment, try to reverse the two opponents with regard to their tactical positions at the beginning of the engagement, and see if the results might be expected to come out differently. Or, as an alternative, try a sort of mental 'do-over' where one runs the engagement again right from the start. The results in either case are certain to be somewhat different, and in all likelyhood would be quite significantly different as sequential trials were run.

Whether or not the Bonomi/Virtuani reconstruction might be fairly characterized as 'revisionist' remains, at least in my mind, a debatable issue. Along those lines, we really have two questions to answer, viz:

a) Does the historical data available permit of any sort of detailed reconstruction at all?

and

b) If such a reconstruction were possible, might that be considered reliable enough to build a case suggesting that British leadership and tactical ability were egregiously inefficient and/or incompetent.

I do not think it appropriate at this stage to even begin to embark upon b) unless we can arrive at a fair consensus regarding the possibility that a) can be achieved, and -- should this be possible -- to determine exactly what the reconstruction of a) might look like in detail. So far as arguing about the 'table' at issue here, we might make further progress by asking ourselves exactly what the table is trying to tell us, and whether or not its accuracy, or lack thereof, is of any practical historical relevance. Basically, why do any of the actual table contents actually matter?

In any case, there is little to be gained by continuing this discussion if the parties involved continue to escalate the heat of the debate by making disparaging comments about those who disagree. Further, there is little point in trying to go back over the past dozen posts or so to try to determine who started, and/or who did the majority of the 'name calling'.

As Mr. Rico has suggested, we need to sometimes -- one hopes temporarily -- to simply agree to disagree at a certain point, abandon the specific point being argued, and seek to find another place from which to attack the problem where consensus is more likely, or has already been more nearly achieved. One needs to concentrate more on proving one's own case to be right, rather than concentrating on why the other person's case might be wrong. Lengthy point-by-point refutations sandwiched between preambles and summaries which are largely editorial in character are not getting us anywhere.

My previous message appears to have been lost. I hope that THIS message makes it through OK and will serve to stifle further passionate escalations.

Best from here, trying to keep a lid on things...

Bill Jurens

User avatar
Alberto Virtuani
Senior Member
Posts: 3438
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: PoW's gunnery VS BSM's gunnery

Post by Alberto Virtuani » Sat Mar 16, 2019 11:18 pm

Hello everybody,
Dunmunro wrote: "So lets compare all ship's gunnery up to 0602...oh wait we can't because...."
...No, we can use the data we have and these data produce the results in the following table.

PoW_BS_PG_Output_Comparison_McMullen_rounded.jpg
PoW_BS_PG_Output_Comparison_McMullen_rounded.jpg (56.43 KiB) Viewed 537 times

If Mr.Dunmunro disagrees about its meaningfullness, I'm ok with that. We agree to disagree.


Wadinga wrote: "The word tendentious has only been used in two posts on this forum...."
[material deleted by moderator Jurens]

[material deleted by moderator Jurens]
Wadinga wrote: "No mention of shots from PoW landing anywhere near PG"
...except that a shell fragment, later identified as 14", was found on the deck of the German cruiser... :lol:


Wadinga wrote: "We need a precise quotation for this vague observation : " (full-)salvo landing behind PG (ref. Busch)" "
He himself posted this "observation" (viewtopic.php?f=1&t=8491&start=180#p82475), I understand from Busch (quotation is very vague). He should be able to provide an explanation.

"a 15-inch salvo (or it may well have been a broadside, ie, all guns firing together) landed about 20 yards short of the quarterdeck.(E) It fell in the smooth 'slick' made by the skidding stern, exactly where that stern had been about three seconds before."

I repeat: what's the relation between a (full-)salvo landing behind PG, and 2 isolated splashes (PG film) falling close to Bismarck, on PG starboard beam, belonging to two different salvos ? :?:


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)

HMSVF
Member
Posts: 196
Joined: Sun Jun 17, 2018 10:15 am

Re: PoW's gunnery VS BSM's gunnery

Post by HMSVF » Sun Mar 17, 2019 12:09 am

Bill Jurens wrote:
Sat Mar 16, 2019 10:20 pm
OK, Gentlement, it's clearly time for both sides to begin backing off a bit. I did make a posting suggesting this earlier today, but for some reason -- this seems to happen about 10% of the time -- it never appeared, and I can see that since that time, things have gotten considerably more belligerent. My apologies for this -- I should have stepped in earlier, or kept better track of things over the last few hours.

Someone asked about the amount of heel in turns. It's complicated to estimate with any certainty because it's dependent upon a number of factors, e.g. ship speed and radius of turn, which are not constants even under ideal situations, and because a full analysis requires detailed knowledge of things like displacement, the metacentric height, and the moment of inertia of the waterplane. My first estimate, for a speed of about 25 knots and a turn radius of 500 yards, would be something like six degrees.

I think we do have to return to the title of this thread, namely "PoW's gunnery vs BSM's gunnery. I assume from this that there is some attempt being made to determine exactly whose gunnery was 'better'. The fact that it's a very small sample, makes any assessment problematical, and the fact that there are, so far as I know, been no real firm definitions of exactly what 'better' might mean complicates things even further. Conditions were not experimental in nature, and this comparing one set of results to another is not really valid. One might, as a thought experiment, try to reverse the two opponents with regard to their tactical positions at the beginning of the engagement, and see if the results might be expected to come out differently. Or, as an alternative, try a sort of mental 'do-over' where one runs the engagement again right from the start. The results in either case are certain to be somewhat different, and in all likelyhood would be quite significantly different as sequential trials were run.

Whether or not the Bonomi/Virtuani reconstruction might be fairly characterized as 'revisionist' remains, at least in my mind, a debatable issue. Along those lines, we really have two questions to answer, viz:

a) Does the historical data available permit of any sort of detailed reconstruction at all?

and

b) If such a reconstruction were possible, might that be considered reliable enough to build a case suggesting that British leadership and tactical ability were egregiously inefficient and/or incompetent.

I do not think it appropriate at this stage to even begin to embark upon b) unless we can arrive at a fair consensus regarding the possibility that a) can be achieved, and -- should this be possible -- to determine exactly what the reconstruction of a) might look like in detail. So far as arguing about the 'table' at issue here, we might make further progress by asking ourselves exactly what the table is trying to tell us, and whether or not its accuracy, or lack thereof, is of any practical historical relevance. Basically, why do any of the actual table contents actually matter?

In any case, there is little to be gained by continuing this discussion if the parties involved continue to escalate the heat of the debate by making disparaging comments about those who disagree. Further, there is little point in trying to go back over the past dozen posts or so to try to determine who started, and/or who did the majority of the 'name calling'.

As Mr. Rico has suggested, we need to sometimes -- one hopes temporarily -- to simply agree to disagree at a certain point, abandon the specific point being argued, and seek to find another place from which to attack the problem where consensus is more likely, or has already been more nearly achieved. One needs to concentrate more on proving one's own case to be right, rather than concentrating on why the other person's case might be wrong. Lengthy point-by-point refutations sandwiched between preambles and summaries which are largely editorial in character are not getting us anywhere.

My previous message appears to have been lost. I hope that THIS message makes it through OK and will serve to stifle further passionate escalations.

Best from here, trying to keep a lid on things...

Bill Jurens
Hi Bill, keep up the good work!


My personal analysis of what has been presented is pretty simple. Personally I think that there is no comparison between Bismarck and HMS Prince of Wales (IMHO). Bismarck managed to range in on HMS Hood in a very short period of time and managed to hit her with a devastating blow within minutes. Bismarck is then able to ship target to HMS Prince of Wales (aided by the unfortunate Admiral Holland's close battle formation) and manages to land 5 hits on her in a matter of minutes. HMS Prince of Wales manages 3 hits prior to Hood's destruction and nothing after. Now HMS Prince of Wales had to under take some swift manoeuvring to avoid what was left of HMS Hood which cannot have helped her fire control, she then gets hit by both Bismarck and Prinz Eugen in a matter of minutes and then turns away from the action so it's no great surprise. My (personal) opinion on HMS Prince of Wales's performance is that she did ok whilst she had a free hand. A lot of time and money had been spent on her to perform the action she undertook, she had modern fire control, she radar (which may or may not have been used). If I had been her designer I would hope that she would have got some hits in.Thats what she was designed to do.

I don't think however she put in an exceptional performance given the circumstances up till 06:00. she wasn't being fired upon (and I acknowledge Mr Virtuani's opinion on this). If she had managed to get 1 or possibly 2 hits after 06:00 I think that the case for saying she put in a good performance is more solid (your the expert on these matters! I bow to your expert knowledge). If anything I think that her performance is indicative of a ship that still isn't properly "run in",she did ok when the going was good, problems arose when she ended up on the receiving end. Which isn't surprising if you account for the "human factor". McMullen was concentrating at the task at hand - he was in the zone, he may well not of have been aware of what was happening around him. That is not an unusual phenomena. IMHO a battleship is more than a sum of its mechanical parts, it relies on the men working together to make it an effective machine. I bow to the far more knowledgable members of the board, but I wonder if whether errors in drill etc had a direct effect on the effective management of the battleship and its equipment itself. We know that the KGV class had issues with their main armament I seem to remember that KGV herself was at one point down to 25% of her potential firepower during the final action with Bismarck. KGV was a more experienced ship than HMS Prince of Wales.

I will hold my hands up and say that I lack the in depth knowledge of the more senior members,I'm here to learn. I don't know whether the figures presented are correct. I don't know whether they could ever be 100% accurate. My gut feeling is that is that there is a discrepancy between the quantitive figures and the qualitative factors. Yes,HMS Prince of Wales made 3 hits, yes she made a decent output(in pure numerical terms) but it doesn't tell the whole story, the hits need to be taken in context. She was unopposed with a free reign, when she came under serious pressure the cracks emerged. Personally I don't think that this is an unusual situation with an inexperienced and new ship/crew but I acknowledge that this may not be the opinion of others.

Bill Jurens
Moderator
Posts: 606
Joined: Mon Oct 18, 2004 4:21 am
Location: USA

Re: PoW's gunnery VS BSM's gunnery

Post by Bill Jurens » Sun Mar 17, 2019 12:32 am

I regret that in the interests of keeping productive discussion alive, I have been forced to take the unusual step of deleting certain commentary posted by Mr. Virtuani in a previous post. The posting has been modified to show that deletions have been made.

Although in this case only Mr. Virtuani was involved, ALL members should be reminded that keeping a civil and respectable tone in correspondence is not only desired, it's required.

Bill Jurens

Bill Jurens
Moderator
Posts: 606
Joined: Mon Oct 18, 2004 4:21 am
Location: USA

Re: PoW's gunnery VS BSM's gunnery

Post by Bill Jurens » Sun Mar 17, 2019 12:58 am

@HMSVF:

Thank you for your comments. I have already commented that in the case of Prince of Wales, where some fairly detailed records survive, shooting appears to have been relatively poor near the beginning of the action. So far as I know, there are no reliable records listing the time or sequence of the hits received aboard Bismarck, so it is difficult to make any comment that does not involve excessive conjecture.

My perception, looking at quite literally thousands of gunnery practices is that success or failure during any particular exercise is based to a very large extent upon the performance of personnel rather than equipment. It's notable in that regard, that during pre-war gunnery practices, captains of USN ships very rarely complained that their relatively poor performances were due to bad equipment, but did complain a fair amount that other ships had, by one means or another, managed to put together experienced and efficient fire control teams. In the case of Bismarck and Prince of Wales, my suspicion is that a fair percentage of the individuals involved, at least at the lower levels of responsibility, were quite inexperienced on either side, and that neither ship had had a chance to properly work out the bugs in their main batteries before the Denmark Strait battle began. I am not sure that either ship had had a chance to do any extensive practice shooting at all.

And, we must remember, as I pointed out before, we are in reality dealing with a very small sample. It was not uncommon to find that ships shooting very well on one target run might perform abysmally on the next one done. Usually, this was due to some unforseen breakdown in equipment or coordination, and the rhythm once lost, can be very difficult to pick up again.

What we see, often, is a missed shot or two due to some difficulty in loading, etc., as happened aboard Prince of Wales when her shell transfer mechanisms jammed. Equally common, but much less frequently recorded in detail, are difficulties in fire control, where a fuze blows rendering part of the communication system inoperative, even if only for a few seconds, or someone drops their pencil on the deck, meaning that for twenty seconds or so nobody is actually properly putting corrections into the fire control computer, so that what someone thinks is the spotting correction for salvo four is actually the correction for salvo three.

A lot also has to do with just plain luck. Sometimes you just get a lucky streak where even though your mean point of impact is way over the target, for some reason three shells in the salvo just happen to fall short, and you get two hits, while the next ship in line puts the m.p.i. right on the button, but fires a 'donut', i.e. a salvo where almost nothing actually comes down where the m.p.i. actually is.

Trying to assess the relative quality of Bismarck's firing vs that of Prince of Wales and Hood is, in my opinion, trying to decide which of three players is the better one after three hands of 'blackjack'. You can do it of course, but you probably can't do it very reliably

Bill Jurens.

Bill Jurens
Moderator
Posts: 606
Joined: Mon Oct 18, 2004 4:21 am
Location: USA

Re: PoW's gunnery VS BSM's gunnery

Post by Bill Jurens » Sun Mar 17, 2019 1:16 am

While I'm on a roll (rant?) I might as well comment a little bit more on the heel of Prince of Wales during the turn around the wreck of Hood. Presumably all agree that such a turn occurred, although the precise nature of the turn, recorded only anecdotally, is difficult to assess. There are three major factors involved. The first is speed. As the degree of heel is proportional to V^2, even a small change in speed can change the amount of heel fairly dramatically. The problem is that we really don't know the precise speed at any point in the turn; although we can roughly estimate what we think it might have been, it's still only an estimate. The second is the radius of the turn; the tighter the radius the greater the heel will be. That tends to be roughly a proportional relationship, i.e. halving the radius will roughly double the angle of heel. The third revolves around the stability of the ship, which in turn revolves around the distances between the center of buoyancy, the center of gravity. and the metacenter. In the case of Prince of Wales, we really (or at least I really...) don't know the precise metacentric height, which is largely a function of displacement and the distribution of weight. Nor do we really have a good idea of the position of the center of buoyancy, which is some function of draft. Basically, the greater the metacentric height, the less the heel will tend to be.

Using reasonable estimates for the variables involved, i.e. a metacentric height of about seven feet, a radius of turn of about 500 yards, and a speed of something like 25 knots, one tends to get heel values in the vicinity of 5-8 degrees. So far as gunnery is concerned this would probably result in a negligible change in range, and an error in deflection -- assuming the computers could keep up at all in a turn, which is doubtful -- of about 200 yards. In other words, what one would tend to see, if gunnery were maintained during a turn of that sort, would be salvos still falling at at about the same range, but well off in deflection, usually in the direction of the turn, i.e. if one were turning to starboard and firing over the bow, the deflection errors would tend to be heavily to the right.

Bill Jurens.

User avatar
Alberto Virtuani
Senior Member
Posts: 3438
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: PoW's gunnery VS BSM's gunnery

Post by Alberto Virtuani » Sun Mar 17, 2019 9:19 am

Hello everybody,
Bill Jurens wrote: " I have been forced to take the unusual step of deleting certain commentary posted by Mr. Virtuani in a previous post. "

[Text deleted by the Administrator. If users have any problem with the moderation of this forum, they should complain off-line, not here]
Bill Jurens wrote: "shooting appears to have been relatively poor near the beginning of the action."
...but more effective anyway than Bismarck's shooting, as PoW hit at the sixth salvo after 3 minutes fire, while the first reported hit from Bismarck on Hood (the spotting top one) occurred some time after the boat deck hit, thus at least 3,5 if not 4 minutes after Germans opened fire, while PoW's first hit was obtained from a longer distance too.


I totally agree however with Mr.Jurens regarding "luck" impact that can in some way cover any deficiency in gunnery with just one lucky hit. That's why we have to take any comparison between PoW and BS as very dependent on luck regarding who hit first (my comment above), hit rate (HMSVF post above), effectiveness of hits, damage inflicted, etc..
The only figures that are much less dependent on luck are the ones related to the output efficiency and the RoF and the "annoying table" (download/file.php?id=3422) is a comparison regarding these parameters (the ones chosen by McMullen to report PoW performances), based on what we know about the battle, clearly showing that PoW (at least in terms of average effective RoF) had a gunnery performance that was in no way inferior to Bismarck.


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)

User avatar
wadinga
Senior Member
Posts: 1864
Joined: Sat Mar 12, 2005 3:49 pm
Location: Tonbridge England

Re: PoW's gunnery VS BSM's gunnery

Post by wadinga » Sun Mar 17, 2019 1:06 pm

Fellow Contributors,

Strangely it has been said as proof of PoW's accuracy of gunnery when firing at the Bismarck that:
...except that a shell fragment, later identified as 14", was found on the deck of the German cruiser.
I am not quite sure why hits on the other vessel this would prove the assertion, but in my copy of Busch the Story of Prinz Eugen P 52
The Chief Engineer Korvettenkapitan Graser produced the fragment of the firing base of a 12 inch shell, which he had found on the Boat Deck, on the port side behind the funnel. It was a longish piece of jagged steel with copper-red rings upon it. It had come from the Hood.
Despite the inability to establish the calibre correctly, there is no suggestion it was 14 inch and no suggestion it came from any other vessel than Hood.

Curiously, the later book (1958) is less dimensionally accurate than his German language book of 1942 (although possibly somewhat less "celebratory", what with losing the war etc) which says:
Das Sprengstuck stammt einwandfrei von einer 38cm-cm-Granate der "Hood" p190 Ersten Gefecht
The KTB itself is self contradicting over the calibre with multiple crossings out and as it was produced on arrival in Brest it may be that German information on British shells was sketchy then (May 1941). What is obvious is that it was expected to have come from Hood because that was the only ship that was shooting at them. I think we may assume later sources are more accurate.

Additionally there is another curious statement based on some confusion:
I understand from Busch (quotation is very vague). He should be able to provide an explanation.
I presume "he" is me. I quoted Brooke:
a 15-inch salvo (or it may well have been a broadside, ie, all guns firing together) landed about 20 yards short of the quarterdeck.(E) It fell in the smooth 'slick' made by the skidding stern, exactly where that stern had been about three seconds before.
but it has been misinterpreted as being from Busch. Since the wall of water occurred when Aylwin was supposed to be delivering his phenomenally-accurate shots it was cited as another example of what makes accurate gunnery hard when under fire and the extreme unlikeliness that the shots photographed landing near PG were from PoW at all but instead were from Hood ten minutes earlier as Langemann and Busch state. I would have thought someone prepared to denigrate both Brooke and Busch in general, except when citing the latter as a precise source (a mast), would have been familiar with their writings by now.

It has been said:
as I present facts supported by evidences, while other forum members prefer to rely on accounts written on books (dramatically exaggerated), such as Brooke's and Busch's texts, both very much "celebratory" and/or "propaganda" texts, instead of reading the official gunnery reports available.
I am now precluded from commenting on the "evidences" ( I assume the "mathematical analysis" presented ) but I think it unfair to denigrate the accounts of eye witnesses like Busch and Brooke. They have minor errors no doubt, and as responsible researchers we can combine and synthesize various accounts and identify those points which may be at error.

It is very interesting to consider Bill's observations on heel.
There are three major factors involved.
I would like to respectfully add a significant fourth: duration of turn ie total number of degrees of course change. It has been suggested that "violent heeling" can result from as little as 10 degrees of course change. I would be interested to hear further comment on this assertion.

All the best

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

User avatar
Alberto Virtuani
Senior Member
Posts: 3438
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: PoW's gunnery VS BSM's gunnery

Post by Alberto Virtuani » Sun Mar 17, 2019 2:13 pm

Hello everybody,

Wadinga wrote: "Despite the inability to establish the calibre correctly, there is no suggestion it was 14 inch and no suggestion it came from any other vessel than Hood."
I admit I have always "blindly" trusted the PG film captioning on Hood website (http://www.hmshood.com/history/denmarkstrait/film.htm):

Brinkmann_splinter.jpg
Brinkmann_splinter.jpg (11.7 KiB) Viewed 414 times

Does anybody knows whether the shell fragment was analyzed and attributed with some certainty to a 14" or a 15" shell?


Wadinga wrote: "I quoted Brooke:"
thanks for clarifying. Quotation was done without specifying the source and after having mentioned Busch and Lagemann just before....

I see the point now, the "water wall" would have prevented Alwin from delivering quite precise shots at Bismarck.
However, as Bismarck is firing with the turrets surely bearing much aft of her beam when we see the splashes (download/file.php?id=3251), the images are taken after 6:04, thus the shells cannot be Hood shells. They are from PoW salvo 20 and 21, whatever Brooke (quite dramatically) wrote later.
An alternative, credible, battlemap would be needed to counter this fact, and I have not yet seen any here.


Wadinga wrote: "we can combine and synthesize various accounts and identify those points which may be at error"
A wise suggestion, that should be applied by the author, "in primis".
For sure Busch is in error when captioning the splash photo (see above for demonstration), being simply impossible, but when his reported distance of Suffolk matches perfectly the geometrical reconstruction done by Antonio "a priori" and is further confirmed by Ellis autobiography, I guess we can "identify" his account as reliable in this circumstance.


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)

User avatar
José M. Rico
Administrator
Posts: 915
Joined: Sat Oct 16, 2004 10:23 am
Location: Madrid, Spain
Contact:

Re: PoW's gunnery VS BSM's gunnery

Post by José M. Rico » Sun Mar 17, 2019 4:04 pm

Just to remind you all that If any user has a problem with the moderation of this forum they should complain off-line, not here.
Comments of that kind will be removed from the board.

Bill Jurens
Moderator
Posts: 606
Joined: Mon Oct 18, 2004 4:21 am
Location: USA

Re: PoW's gunnery VS BSM's gunnery

Post by Bill Jurens » Sun Mar 17, 2019 5:07 pm

My thanks to Mr. Rico for taking the time to delete some personal commentary which I (and likely others) might have found offensive. It's probably better that way.

I am sure that most readers realize that the intent of deleting commentary is not to muzzle discussion, but to prevent the posting of belligerent and/or offensive commentary, which in the end is almost always counter-productive, and -- because it tends to drive away more reasonable, and often more knowledgeable, commentators -- can quickly degrade the forum as a whole. Sadly, as my mother was fond of saying, it's often true that "It's the empty drum which makes the most noise..."

As an aside, constructively intended and reasonably-phrased commentary on my performance as moderator and my opinions regarding various technical issues, is now and will remain, welcome.

Best to all. And I do mean ALL.

Bill Jurens.

Bill Jurens
Moderator
Posts: 606
Joined: Mon Oct 18, 2004 4:21 am
Location: USA

Re: PoW's gunnery VS BSM's gunnery

Post by Bill Jurens » Sun Mar 17, 2019 5:29 pm

Wadinga wrote:

"It has been suggested that "violent heeling" can result from as little as 10 degrees of course change. I would be interested to hear further comment on this assertion. "

A good deal, I suppose, might depend upon one's idea of 'violent'. In general, because the course changes rather slowly at the beginning of a turn, and the radius remains high, the heeling moment comes on quite gradually. The heel increases as the radius of the turn gets tighter, but because the speed of the ship is also falling at the same time, these two effects somewhat cancel one another out.

The situation can be a bit unstable at the very beginning or the very end of a turn. When the rudder is first put over, especially if the rudder is put over sharply, the ship has not yet begun to turn at all, so the force acting outward through the center of gravity is zero, but the force on the rudder is pushing the bottom of the hull outwards. This results in a short period where the heel is actually towards the inside of the turn, followed by a transition, gradual or otherwise, to a situation where the heel is directed outward. During this same period the rudder forces often cause the ship to bodily (and briefly) move in a direction opposite to the intended turn, i.e. putting the rudder hard over for a turn to starboard can actually result in a small transient overall movement to port.

At the end of the turn, especially if the turn is very rapid, and stability is low, returning the rudder to a zero position, or reversing it, can result in a situation where the rudder force pushing the lower hull outboard -- and thus somewhat mitigating the outboard heel due to centrifugal/centripetal issues -- is removed or even reversed. This can result from a brief panic when the crew notices that the heel is excessive and feel that the ship is nearly ready to capsize outboard, and therefore zeros or reverses the rudder. Ironically, that action can, and has, led to precisely the capsize it was intended to prevent. The best solution in cases like this is often to cut power, which of course cuts speed, and which in turn reduces the heeling moment considerably.

So one might expect to see short transient unexpected changes in heel during the period of rudder activation. Usually, compared to the overall general heel that might be experienced in a turn, these transients, which are usually quite small, can be neglected.

The fact that all of this is often being simultaneously affected by hydrodynamic effects such as wave motion, and other issues such as wind, renders a definitive answer, except in rather unusual or dramatic situations, difficult.

Bill Jurens

dunmunro
Senior Member
Posts: 3887
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: PoW's gunnery VS BSM's gunnery

Post by dunmunro » Sun Mar 17, 2019 9:22 pm

Alberto Virtuani wrote:
Sat Mar 16, 2019 11:18 pm


Wadinga wrote: "No mention of shots from PoW landing anywhere near PG"
...except that a shell fragment, later identified as 14", was found on the deck of the German cruiser... :lol:

This is the quote from PE's war diary (p.42):
"...Personally, | observed nothing of the enemy's countermeasures. According to reports from the officers in position at the main antiaircraft battle station, a number of heavy caliber salvos impacted in the immediate proximity of the ship. Two [salvoes] struck 100-150 meters forward of the bow, one about 50 meters off port forward, which put the decks heavily awash, and quite a few impacts hit astem in 'the wake. Later, [salvo] impacts were observed [that came] from the heavy cruiser stationed to starboard, but they landed 4-5,000 meters short. A piece of shrapnel from a heavy caliber shell was found on the portside boat deck. It showed the telltale marks of two guide rings [1] and was, according to data tables in a technical bulletin on weapons intelligence, not [2] from the Hood, but it was instead attributed to a ship of the King George class."

[1] driving bands...
[2] 'with' crossed out and 'not' substituted in the Admiralty and NARA copies.
It is interesting that the shell fragment was not identified as 14in from a measurement of it's circumference, which would have been definite, but by the presence of two driving bands, which may or may not have been a correct determination, depending on the accuracy of kM intelligence.

As we've discussed in the past, an AP shell should have it's fuze activated upon striking water and then the shell will detonate shortly thereafter. The explosion can then send splinters a considerable distance from the point of detonation, so this doesn't imply a near miss. As the range closes the shells strike the water very obliquely and the detonation might occur close to the surface, or even in the air.

If there were 14in shells falling close to PE, they might well have come from Aylwin's local control fire via Y turret. Perhaps he targeted PE instead of Bismarck?

Bill Jurens
Moderator
Posts: 606
Joined: Mon Oct 18, 2004 4:21 am
Location: USA

Re: PoW's gunnery VS BSM's gunnery

Post by Bill Jurens » Mon Mar 18, 2019 4:17 am

For what it's worth, my information on British 14" and 15" bullets was that they used single driving bands, i.e. a single driving band seat. The Germans in contrast, seem to have preferred to use two driving bands.

Bill Jurens

Locked