PoW's gunnery VS BSM's gunnery

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

Moderator: Bill Jurens

Bill Jurens
Moderator
Posts: 620
Joined: Mon Oct 18, 2004 4:21 am
Location: USA

Re: PoW's gunnery VS BSM's gunnery

Post by Bill Jurens » Sat Apr 06, 2019 1:44 am

Northcape has suggested this thread be closed as futile. Because the discussion still seems fairly lively and has remained at least tolerably civil, I will allow it to remain open for now.

Bill Jurens.

User avatar
Alberto Virtuani
Senior Member
Posts: 3455
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: PoW's gunnery VS BSM's gunnery

Post by Alberto Virtuani » Sat Apr 06, 2019 7:19 am

Hello everybody,

ignoring the provocations and the (already explained) errors in calculating average values proposed above,
Bill Jurens wrote: " One can know what's wrong, without knowing what's right."
..and what's wrong, please ?

To say something is wrong (we speak about points 1), 2), 3) and 4) a person should be able to explain why, else such a statement is just denial and the figures have to be accepted and digested, inconvenient as they can be, as explained by Adm.Santarini.

BS vs PoW gunnery performances.jpg
BS vs PoW gunnery performances.jpg (63.32 KiB) Viewed 543 times

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: 198
Joined: Sun Jun 17, 2018 10:15 am

Re: PoW's gunnery VS BSM's gunnery

Post by HMSVF » Sat Apr 06, 2019 12:19 pm

Alberto Virtuani wrote:
Sat Apr 06, 2019 7:19 am
Hello everybody,

ignoring the provocations and the (already explained) errors in calculating average values proposed above,
Bill Jurens wrote: " One can know what's wrong, without knowing what's right."
..and what's wrong, please ?

To say something is wrong (we speak about points 1), 2), 3) and 4) a person should be able to explain why, else such a statement is just denial and the figures have to be accepted and digested, inconvenient as they can be, as explained by Adm.Santarini.


BS vs PoW gunnery performances.jpg


Bye, Alberto



A quick question.

If POW output loss was 26% lost shots vs 14% due to mechanical problems/human error how come she is able to match Bismarcks ROF? Or is this based on on the remaining 74% ? POW had 10 x 14inch guns, so if all were fully functional she should have in theory delivered 10 shells to Bismarcks 8. From what I can gather each gun could let off 2 rounds a minute so are we talking about comparison of fire between POW firing 7 or 8 out her 10 against Bismarcks 8?

If fully functional a KGV should have had a higher number of shells delivered by virtue of her caring a larger number of guns?


In regards to POW damage v Bismarck doesn't that come down to luck and design differences between the two ships?

HMSVF
Member
Posts: 198
Joined: Sun Jun 17, 2018 10:15 am

Re: PoW's gunnery VS BSM's gunnery

Post by HMSVF » Sat Apr 06, 2019 12:33 pm

dunmunro wrote:
Fri Apr 05, 2019 9:00 pm
Alberto Virtuani wrote:
Fri Apr 05, 2019 8:27 pm
Hello everybody,
Dunmunro wrote: "that means that Bismarck was scoring hits at the rate of about 3/min on PoW"
Wrong.
Bismarck scored hits between minute 6:00 and minute 6:02, therefore 1.5 hit per minute, that is very high, but absolutely not impossible in such a situation, where the range was becoming very effective.
PoW couldn't hit in return due to the avoiding maneuvers and then to the hard turn away. Had she kept engaging on a steady course she would have probably scored hits as well immediately after 6:02. At 6:03 she would have been in a very good situation with the false "torpedo alarm" that forced the German ships to turn hard.
You stated that the first 38cm hit on PoW was at "...6:00:50..." not 0600, and if the last hits were scored at ~0602 then the hits were scored within ~70 seconds.

Seems incredibly tight to me. From reading the Navweaps site the german the performance figures for the shell are as follows

10,940 yards (10,000 m): 13.9 seconds
21,870 yards (20,000 m): 32.0 seconds.

So that leaves around 40 (ish) seconds to realise that Hood has sunk, take that in, switch target to POW and fire (assuming that guns were loaded and ready when Hood sunk (assuming that this is when she actually disappeared as opposed to the moment she suffered the catastrophic damage - surely Schneider would have waited in the the second instance to see just how badly damaged Hood was before switching to POW). Isn't this where Bismarcks gunnery record would be invaluable?

User avatar
Herr Nilsson
Senior Member
Posts: 1386
Joined: Thu Oct 21, 2004 11:19 am
Location: Germany

Re: PoW's gunnery VS BSM's gunnery

Post by Herr Nilsson » Sat Apr 06, 2019 1:25 pm

Alberto Virtuani wrote:
Sat Apr 06, 2019 7:19 am
Hello everybody,

ignoring the provocations and the (already explained) errors in calculating average values proposed above,
Bill Jurens wrote: " One can know what's wrong, without knowing what's right."
..and what's wrong, please ?

To say something is wrong (we speak about points 1), 2), 3) and 4) a person should be able to explain why, else such a statement is just denial and the figures have to be accepted and digested, inconvenient as they can be, as explained by Adm.Santarini.


BS vs PoW gunnery performances.jpg


Bye, Alberto
As I‘ve already tried to explain: using the same little information for PoW in your table we have for Bismarck, it’s impossible to get McMullens figures. In the reverse conclusion the figures we get from the table for Bismarck are wrong in any case.
Regards

Marc

"Thank God we blow up and sink more easily." (unknown officer from HMS Norfolk)

User avatar
Alberto Virtuani
Senior Member
Posts: 3455
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: PoW's gunnery VS BSM's gunnery

Post by Alberto Virtuani » Sat Apr 06, 2019 1:41 pm

Hello everybody,
HMSVF wrote: "is this based on on the remaining 74% ?"
Yes, correct but only for # shells delivered /minute and effective RoF. For actual RoF the output loss is irrelevant.
Of course KGV (as well as Nelson) class ships were "designed" to deliver more shells than a ship with 8 guns.
HMSVF wrote: "Seems incredibly tight to me. "
Correct again, but the whole battle was incredibly tight in time compared to a classical battle: Hood exploded after 5 minutes fire only, PoW was hit within 1 minute and retreated 40 seconds after having been hit. The whole battle lasted around 16 minutes in total, including the last salvos fired behind the retreating PoW.
If we consider the first hit from PoW at 5:56:20 till the last on PoW just after 6:02, we have ONLY 360 seconds that determined the whole battle (and the further operation).


Herr Nilsson wrote: "..using the same little information for PoW in your table we have for Bismarck, it’s impossible to get McMullens figures. In the reverse conclusion the figures we get from the table for Bismarck are wrong in any case."
No, both methods are correct (and they actually approximately match in both cases):
1) in the first case we need to "assume" Bismarck "ordered shots"/"salvos" to just get to a perfect calculation as per McMullen methodology (and whatever assumption you choose, we get comparable results, try and tell us your "proposed" values, as a certain number of shots/salvo were actually fired anyway). OR
2) in the second, we just normalize PoW output without ANY assumption and this calculation (albeit approximate vs McMullen precise calculations) is fully valid for the effective average values (btw, you have never explained why in your opinion this is wrong...).
Just choose your preferred one (conclusions don't change at all, as logical, because at the end Bismarck fired only 93 shells).


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: 198
Joined: Sun Jun 17, 2018 10:15 am

Re: PoW's gunnery VS BSM's gunnery

Post by HMSVF » Sat Apr 06, 2019 4:48 pm

Alberto Virtuani wrote:
Sat Apr 06, 2019 1:41 pm
Hello everybody,
HMSVF wrote: "is this based on on the remaining 74% ?"
Yes, correct but only for # shells delivered /minute and effective RoF. For actual RoF the output loss is irrelevant.
Of course KGV (as well as Nelson) class ships were "designed" to deliver more shells than a ship with 8 guns.
HMSVF wrote: "Seems incredibly tight to me. "
Correct again, but the whole battle was incredibly tight in time compared to a classical battle: Hood exploded after 5 minutes fire only, PoW was hit within 1 minute and retreated 40 seconds after having been hit. The whole battle lasted around 16 minutes in total, including the last salvos fired behind the retreating PoW.
If we consider the first hit from PoW at 5:56:20 till the last on PoW just after 6:02, we have ONLY 360 seconds that determined the whole battle (and the further operation).


Herr Nilsson wrote: "..using the same little information for PoW in your table we have for Bismarck, it’s impossible to get McMullens figures. In the reverse conclusion the figures we get from the table for Bismarck are wrong in any case."
No, both methods are correct (and they actually approximately match in both cases):
1) in the first case we need to "assume" Bismarck "ordered shots"/"salvos" to just get to a perfect calculation as per McMullen methodology (and whatever assumption you choose, we get comparable results, try and tell us your "proposed" values, as a certain number of shots/salvo were actually fired anyway). OR
2) in the second, we just normalize PoW output without ANY assumption and this calculation (albeit approximate vs McMullen precise calculations) is fully valid for the effective average values (btw, you have never explained why in your opinion this is wrong...).
Just choose your preferred one (conclusions don't change at all, as logical, because at the end Bismarck fired only 93 shells).


Bye, Alberto
Yes, correct but only for # shells delivered /minute and effective RoF. For actual RoF the output loss is irrelevant.
Of course KGV (as well as Nelson) class ships were "designed" to deliver more shells than a ship with 8 guns
Good afternoon all,


Is it irrelevant though? The KGV class were designed around 10 guns, the whole raison d'être of the using the 14 inch gun was that they could carry more than say a 8 or 9 x 15 inch vessel and deliver a hail of fire (the initial design was for 12 x 14inch but they couldn't square the armour protection within the 35000 ton nominal limit). In effect POW has turned into a 7/8 x 14 inch battleship, which was not the desired outcome, she should have had a much higher rate of fire than Bismarck by definition of her larger number of main armament barrels. She didn't for a variety of reasons including drill errors and mechanical breakdowns.Losing a quarter of your of your available push doesn't really strike me as being fully effective.That the crewman of the POW (with the help of Vickers employee's) managed to keep up a reasonable rate of fire does them credit, but I'm sure that I would want all 10 guns firing shells at the enemy rather than wondering whether you may manage 7 or 8. I just think that the figures need to be taken in context.

Yes, probably POW managed to loose off roughly the equivalent of Bismarck, however she should have been putting out more.



Best wishes



HMSVF

User avatar
Alberto Virtuani
Senior Member
Posts: 3455
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: PoW's gunnery VS BSM's gunnery

Post by Alberto Virtuani » Sat Apr 06, 2019 5:11 pm

Hello everybody,
HMSVF wrote: "Is it irrelevant though?"
Yes it is, of course ONLY in the calculation of the average actual RoF, that would have been exactly the same either had all PoW guns fired perfectly (0% output loss) or just half of them had been in action (50% output loss). This figure only impacts the average effective RoF and the # shells fired / minute.

HMSVF wrote: "She didn't for a variety of reasons including drill errors and mechanical breakdowns."
as well as Prinz Eugen (15% output loss) that lost more than 1 gun for the whole battle: so what ?
Bismarck (that, in my assumption, based on total probable fired salvo had a loss of 14%) lost as well 1 gun out of 8. This is absolutely normal for any battleship when firing big guns (and "assuming" Bismarck was almost perfect (96 shots for 93 shells) the actual RoF would be ridiculously low compared to PoW, while the effective would not change significantly).
PoW lost more than the German ships, but more than compensated, having 10 guns vs 8.


Bye, Alberto
Last edited by Alberto Virtuani on Sat Apr 06, 2019 5:50 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)

HMSVF
Member
Posts: 198
Joined: Sun Jun 17, 2018 10:15 am

Re: PoW's gunnery VS BSM's gunnery

Post by HMSVF » Sat Apr 06, 2019 5:31 pm

Alberto Virtuani wrote:
Sat Apr 06, 2019 5:11 pm
Hello everybody,
HMSVF wrote: "Is it irrelevant though?"
Yes it is, of course ONLY in the calculation of the average actual RoF that would have been exactly the same had all PoW guns fired perfectly (0% output loss) or just half of them had been in action (50% output loss). This figure only impacts the average effective RoF and the # shells fired / minute.

HMSVF wrote: "She didn't for a variety of reasons including drill errors and mechanical breakdowns."
as well as Prinz Eugen (15% output loss) that lost more than 1 gun for the whole battle: so what ?
Bismarck (that, in my assumption, based on total probable fired salvo had a loss of 14%) lost as well 1 gun out of 8. This is absolutely normal for any battleship when firing big guns (and "assuming" Bismarck was almost perfect (96 shots for 93 shells) the actual RoF would be ridiculously low compared to PoW, while the effective would not change significantly).
PoW lost more than the German ships, but more than compensated, having 10 guns vs 8.


Bye, Alberto
Good afternoon all,


But she was designed to fire 10 not 7 or 8. That she matched a ship armed with 8 guns (firing occasionally only 7) is all well and good but she didn't do as she was designed. I think this is all contextual. Yes she did well with the guns that she was able to service, yes with the 7 or 8 guns that she was able to fire she matched a ship armed with 8 guns (I believe that the 14 inch were designed for 2rpm, Navweaps has the German 15 inch as 2 to 3 rpm). In the context of how well did she fire at Denmark Strait, the net result was that she didn't operate as planned and it wasn't just down to drill error, which you rightly point out can occur in any vessel mounting large guns.

Its a bit like tying a boxers arm behind his back, but congratulating him for keeping up a similar number of punches as his two armed opponent. Commendable,but he would probably been more effective with both arms.


Best wishes


HMSVF

dunmunro
Senior Member
Posts: 3902
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: PoW's gunnery VS BSM's gunnery

Post by dunmunro » Sat Apr 06, 2019 10:32 pm

Bill Jurens wrote:
Thu Apr 04, 2019 6:04 pm
Mr. Virtuani presented a listing a few memos ago in which he wrote:

"7) PoW was initially heavily handicapped by having only the fore turrets bearing for the first 8 salvos, and despite that, she hit first."

I'd be interested in knowing how the sequence and timing of hits, particularly on Bismarck, has been established. So far as I know, there is no really detailed narrative from Bismarck that addresses this, nor for that matter any specific information which might exclude the possibility of one or more hits from Hood.

So to assert that PoW "hit first" would seem to be problematical.

I'd again repeat my previous question regarding the examination of the Denmark Strait German film, i.e. I would be interested in knowing precisely how the timing was established. Particularly when there is no sound attached, and there are no things such as people moving in the picture to give some visual indication of appropriate speeds, it's quite conceivable that the film could have been significantly increased in the editing room, and in fact one might even expect this sort of chicanery in what amounted to a propaganda film. If sound is being recorded, the speeding up the film also alters the pitch of spoken speech etc., and although we can tolerate a certain amount of this without being able to detect it, we can pick it up quite easily, so jiggering sound film is (or was) a bit more difficult. With modern technology this problem is much more easily cured. We have, for some reason, a fairly high tolerance for speed errors in film presentation, even when familiar objects are being depicted, with errors of 20% or so quite difficult to detect unless the items in the frame are quite familiar. Motion pictures shown on television are quite routinely -- and undetectably -- sped up or slowed down by surprising amounts to make them fit into the rather regular clock schedule needed there, vs a motion picture presentation where overall presentation time is only loosely fixed.

Bill Jurens
I've been wondering about another aspect of that film as well; the film being shown on youtube seems to show 16x9 formatting, but I would have thought that the original was filmed in 4x3 format as that was the most common format of that era.

Bill Jurens
Moderator
Posts: 620
Joined: Mon Oct 18, 2004 4:21 am
Location: USA

Re: PoW's gunnery VS BSM's gunnery

Post by Bill Jurens » Sun Apr 07, 2019 2:02 am

Without seeing the original negatives, etc., it's difficult to tell. Technically, we don't even know if the filming was done in 16mm or 35mm format, although these were (usually) about the same aspect ratio. (As I recall, one was about 1.34:1 while the other was about 1.37:1, but that's just recollection.) 16 x 9 is, of course, about 1.777:1. We really don't know, for sure, the frame rate either, and if light levels were low, the camera may have been 'undercranked' in order to allow sufficient exposure time, as the films of the time were really very slow by current standards. I suspect, but am not sure, that the format was 35mm...

I would not be even slightly surprised to see that the film seen on television or on Youtube, etc., has been cropped, edited, and otherwise variously distorted etc. in order to accommodate the convenience of the editors of the platform involved. Television and Youtube etc. are intended for entertainment, not analysis. As a matter of fact, so were contemporary newsreels, etc...

So for serious work, I would rate the analytical value of the films as seen on television or the internet as very low; better than nothing, but not by much...

Bill Jurens.

User avatar
Alberto Virtuani
Senior Member
Posts: 3455
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: PoW's gunnery VS BSM's gunnery

Post by Alberto Virtuani » Sun Apr 07, 2019 7:38 am

Hello everybody,
HMSVF wrote: "the net result was that she didn't operate as planned.... it wasn't just down to drill error"
Yes, as well as Prinz Eugen surely did not and Bismarck most probably did not (depending on salvos ordered).
I feel we should compare the actual performances on May 24, not the "theoretical design" performances (that are never met in action, AFAIK).

The "big" 14" turrets problem was the fact that KGV vessels (not only PoW and not because she was green) were prone to jam their (complex) feeding mechanisms when turning hard while firing and operating the rings. On PoW this problem occurred however only after and due to Leach's decision to disengage.




Regarding the PG film,
I think (together with the photos) it's one the main sources of information we have.
We can correctly debate about format, speed, exposure, etc. however the evident starboard turn of PG at its very beginning allows with certainty to time the start of the film at around 6:04, when PG turned according to her official battlemap (see here for full demonstration viewtopic.php?f=1&t=8491&start=435#p82759).
The rest of the action (once removed the insertion of Hood explosion) is consecutive without any interruption, therefore the only "debatable" aspect is the precise timing of the Bismarck turn back to port at the end of the film (viewtopic.php?f=1&t=8335&start=375#p82424), depending on the film speed.


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)

pgollin
Senior Member
Posts: 354
Joined: Sat Jan 11, 2014 12:01 pm

Re: PoW's gunnery VS BSM's gunnery

Post by pgollin » Sun Apr 07, 2019 2:39 pm

Alberto Virtuani wrote:
Sun Apr 07, 2019 7:38 am

...... The "big" 14" turrets problem was the fact that KGV vessels (not only PoW and not because she was green) were prone to jam their (complex) feeding mechanisms when turning hard while firing and operating the rings. ......


So you discount the problem with the interlocks that the gunnery report identified as the major problem ?

.

User avatar
Alberto Virtuani
Senior Member
Posts: 3455
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: PoW's gunnery VS BSM's gunnery

Post by Alberto Virtuani » Sun Apr 07, 2019 8:26 pm

Hello everybody,
pgollin wrote: "So you discount the problem with the interlocks that the gunnery report identified as the major problem ?"
How many shots did PoW miss during the 9 minutes director controlled battle due to this "major" problem (out of the total 19 missed shots), based on the PoW GAR ?


I was not referring to all the "minor" (when summed up, of course relevant) problems (most of them solved however in few salvos) happened during the first 18 salvos, but to the really "serious" one (at salvo 20) that, while turning very hard, caused an hinge tray to be buckled, jamming the shell ring (and putting out of action, had the battle lasted longer an entire quadruple turret for hours). Of course also this major problem may be considered one of the problems with interlocks as well...

This was the weak point of KGV class turrets, that made them unreliable: due to the same identical reason, a quadruple turret was put out of action for 30 minutes (and another one was close to jam as well "on several occasions") on May 27 on board KGV as well.


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)

Byron Angel
Senior Member
Posts: 1036
Joined: Sun Mar 06, 2011 1:06 am

Re: PoW's gunnery VS BSM's gunnery

Post by Byron Angel » Mon Apr 08, 2019 3:30 am

This argument that hard turns were the principal agent of the 14-in quadruple turret's unreliability is unconvincing to say the least. IIRC, in none of the surface engagements fought by KGV class battleships during the war did firing efficiency reach even 80 percent - which in itself was an unacceptable figure; someone please correct me if I am wrong on this point.

B

Locked