KGV and PoW GAR during Op. Rheinubung

Discussions about the history of the ship, technical details, etc.
Steve Crandell
Senior Member
Posts: 630
Joined: Wed Feb 05, 2014 7:05 pm

Re: KGV and PoW GAR during Op. Rheinubung

Post by Steve Crandell » Wed Jan 27, 2016 11:34 am

Alberto Virtuani wrote: Why do you say KGV achieved 1 semi-salvo per minute ? The "green" PoW achieved almost 2 semi-salvo per minute at DS and I assume KGV could do at least in a similar way.....

Bye, Alberto
I was only repeating what I thought you said in the post I commented on. KGV was firing half salvos at Bismarck.

User avatar
Alberto Virtuani
Senior Member
Posts: 2230
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: KGV and PoW GAR during Op. Rheinubung

Post by Alberto Virtuani » Wed Jan 27, 2016 12:47 pm

@Steve Crandell:
Hi Steve, understood. Thanks for pointing out the mistake of mine.....
Bye, Alberto
"It takes three years to build a ship; it takes three centuries to build a tradition" (Adm.A.B.Cunningham)

dunmunro
Senior Member
Posts: 3294
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: KGV and PoW GAR during Op. Rheinubung

Post by dunmunro » Thu Jan 28, 2016 9:46 pm

I'll try and have my analysis finished by Sunday.

dunmunro
Senior Member
Posts: 3294
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: KGV and PoW GAR during Op. Rheinubung

Post by dunmunro » Mon Feb 01, 2016 8:29 am

dunmunro wrote:I'll try and have my analysis finished by Sunday.

Sorry, I've been very busy - I need about 4 hours of clear time to finish. Hopefully tomorrow.

User avatar
Alberto Virtuani
Senior Member
Posts: 2230
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: KGV and PoW GAR during Op. Rheinubung

Post by Alberto Virtuani » Mon Feb 01, 2016 8:37 am

@Dunmunro:
Hi Duncan, I'm sure we are all very interested to see the results of your analysis, but take all the time you need: luckily the war is over since 71+ years.... :wink:

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

dunmunro
Senior Member
Posts: 3294
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: KGV and PoW GAR during Op. Rheinubung

Post by dunmunro » Mon Feb 29, 2016 12:21 am

Alberto Virtuani wrote:@Dunmunro:
Hi Duncan, I'm sure we are all very interested to see the results of your analysis, but take all the time you need: luckily the war is over since 71+ years.... :wink:

Bye, Alberto
It is taking me longer than I expected, as it requires long periods of analysis. However here's a new fact never hithertoo revealed:

KGV's GAR states that she fired 660 rounds of 5.25in SAP. This number has been the standard figure given for her 5.25in expenditure but this figure (660) is incomplete as it neglects to mention 64 rounds of 5.25in HE that was also fired. The GAR does give the correct figure but one has to do some calculations to arrive at the correct number:

starboard battery = 70 rpg less S4 which only fired 12 = 502 rnds
Port battery = 29 rpg = 232 rnds
total = 734 less 10 rnds that were ordered but failed to fire
= 724

The Admiralty war diary states that KGV needed 660 rnds of 5.25in SAP and 64 rnds of HE to reammunition.

User avatar
Alberto Virtuani
Senior Member
Posts: 2230
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: KGV and PoW GAR during Op. Rheinubung

Post by Alberto Virtuani » Mon Feb 29, 2016 8:51 am

@Dunmunro:
Hi Duncan,
most interesting ! Thanks for these info.
Surprisingly port battery fired more shots than I was expecting (due to the battle geometry). I guess the port 5,25" battery was firing only around 10 o'clock for no more than 10 minutes.....

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

Cag
Senior Member
Posts: 577
Joined: Wed Sep 30, 2015 9:53 am

Re: KGV and PoW GAR during Op. Rheinubung

Post by Cag » Sat Mar 12, 2016 12:13 pm

Hi All,

I hope that I have put this post in the correct place, here rather than the Bismarck firing procedure thread as it concerns the PoW GAR but it does reference items posted in the Bismarck firing thread.

I Have a couple of questions, in the table shown in the BC firing procedure for the PoW salvo chart I am unsure about salvo 13 and 18. The ranges shown in the table are 16,150yds and 14,100yds and was just wondering where these came from as when I look at Enclosure IVa salvo 13 appears to be 16,450yds and 18 seems to be as salvo 17 at 14,100yds?

Also thanks to Antonio I have recalculated the three hits of PoW on Bismarck as suggested using the 220 course from salvo 9 and it seems that salvo 6 should not have hit the Bismarck as if Bismarck was on a 220 course it would have been at least 1000yds over?

Salvo 1 on the Enclosure IVa shows an estimated landing point of about 1625yds over Bismarck but this extends to over 2500yds when the 220 course is factored in. Enclosure IVa shows Bismarck on a steady course up to salvo 6 and then an almost half eliptical course there after.

Maybe someone could check my workings out as this seems odd that Bismarck was hit at salvo 6 that should not have hit anything?

Thank you
Best wishes
Cag.

Cag
Senior Member
Posts: 577
Joined: Wed Sep 30, 2015 9:53 am

Re: KGV and PoW GAR during Op. Rheinubung

Post by Cag » Wed Mar 16, 2016 2:36 pm

Hi All,

Just a quick tid bit of information. During my little bit of research regarding the amount of Gunnery practice of PoW I included an amount of time given for A turret firing a single round from each gun.

I was a little puzzled by this as it seemed odd, so after a little bit of delving in my stash of IWM photographs of PoW I found that the Admiralty Official Photographer, Lt Coote, asked for some shots of A turret firing which seems a plausible answer to the four shot A turret salvo?

Best wishes,
Cag.

dunmunro
Senior Member
Posts: 3294
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: KGV and PoW GAR during Op. Rheinubung

Post by dunmunro » Wed Oct 04, 2017 10:19 pm

After spending many hours on this, I find myself in the position of "merely disturbing the rubble" and the info on output stated earlier in the thread in my graphic table is about the best I can do with the information available.

My best estimate is that at salvo 49 ( 0920 )when A turret jammed, KGV had fired 196 x 14in rnds and had requested 207 x 14in rnds to fire for an output of 94.7%. I suspect that at 0908 ( salvo ~28 ) that KGV's output was nearly 100%.

User avatar
Alberto Virtuani
Senior Member
Posts: 2230
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: KGV and PoW GAR during Op. Rheinubung

Post by Alberto Virtuani » Thu Oct 05, 2017 9:10 am

Hi Duncan,
thanks for moving the discussion about KGV output here. :clap:

I know very well your attempt of analysis and I know also that there are not sufficient elements to determine the real output efficiency for KGV. We can only make an educated guess.

As I said above, there are 2 reasons why your assumption (based on Rodney's ordered shots) of 550 ordered shots for KGV cannot be realistic.

1) KGV gun n.4 in "Y" turret fired 49 actual shells. As the turret was not firing for at least 28 minutes during the battle, we should assume that it would have been able to fire 49+28+x(output loss for this gun cannot realistically be = 0%) shots during the battle, thus a total of around 80-85 salvos, that is 800-850 theoretical ordered shots (to which we have to subtract the shots not actually ordered due to a turret not bearing (28*4 = 112 for "Y" and "z" for the fore turrets, wooded for only a couple of minutes after 9:52). Thus, around 700 ordered shots.

2) If Rodney ordered 487 shots, KGV should have ordered not only 1,1 times more (accounting for the additional gun as per your assumption) but also 1,333 times accounting for her higher theoretical RoF achievable by design. In addition to the theoretical RoF, Rodney was turning 180° in front of Bismarck for many times, wooding all her turrets for at least 6 times, while KGV was turning less than Rodney, wooding mainly her "Y" turret only, except after 9:52.
Thus, again, a total of more than 700 ordered shots must be taken into account.

For the 2 above reasons (perfectly matching) and having fired ONLY 339 actual shells, I suspect that KGV was having a very poor output efficiency (on May 27) of largely less than 50% in total and, logically, of no more than 80% in the first minutes of the engagement, perfectly in line with PoW at DS and with the "weak" design of the 14" guns turrets). However, again, both our hypothesis are pure speculations, lacking a KGV detailed salvo plot.


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

dunmunro
Senior Member
Posts: 3294
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: KGV and PoW GAR during Op. Rheinubung

Post by dunmunro » Thu Oct 05, 2017 9:39 am

Alberto Virtuani wrote:Hi Duncan,
thanks for moving the discussion about KGV output here. :clap:

I know very well your attempt of analysis and I know also that there are not sufficient elements to determine the real output efficiency for KGV. We can only make an educated guess.

As I said above, there are 2 reasons why your assumption (based on Rodney's ordered shots) of 550 ordered shots for KGV cannot be realistic.

1) KGV gun n.4 in "Y" turret fired 49 actual shells. As the turret was not firing for at least 28 minutes during the battle, we should assume that it would have been able to fire 49+28+x(output loss for this gun cannot realistically be = 0%) shots during the battle, thus a total of around 80-85 salvos, that is 800-850 theoretical ordered shots (to which we have to subtract the shots not actually ordered due to a turret not bearing (28*4 = 112 for "Y" and "z" for the fore turrets, wooded for only a couple of minutes after 9:52). Thus, around 700 ordered shots.

2) If Rodney ordered 487 shots, KGV should have ordered not only 1,1 times more (accounting for the additional gun as per your assumption) but also 1,333 times accounting for her higher theoretical RoF achievable by design. In addition to the theoretical RoF, Rodney was turning 180° in front of Bismarck for many times, wooding all her turrets for at least 6 times, while KGV was turning less than Rodney, wooding mainly her "Y" turret only, except after 9:52.
Thus, again, a total of more than 700 ordered shots must be taken into account.

For the 2 above reasons (perfectly matching) and having fired ONLY 339 actual shells, I suspect that KGV was having a very poor output efficiency (on May 27) of largely less than 50% in total and, logically, of no more than 80% in the first minutes of the engagement, perfectly in line with PoW at DS and with the "weak" design of the 14" guns turrets). However, again, both our hypothesis are pure speculations, lacking a KGV detailed salvo plot.


Bye, Alberto
1) RN salvos were composed of 1/2 the guns able to fire (for example even numbered guns on one salvo and odd numbered guns on the other). The maximum number of guns ordered to fire per salvo was usually 5, when all three turrets could bear, or 3 if only the forward turrets could bear.

2) Theoretical RoF had little bearing on the salvo rate, which was set according to visibility, sea state, and the need to have well defined intervals between the salvos of different ships. If Rodney had replaced Hood at DS then her salvo rate would have matched PoW in order to fire into the correct time slots. It would not have been slower because her theoretical salvo rate of 3 per minute was still much greater than the requested salvo rate. Similarly KGV's salvo rate would not have varied much, if at all, from Rodney's.

There is no indication in the GAR of any serious loss of output from KGV until 0920.

User avatar
Alberto Virtuani
Senior Member
Posts: 2230
Joined: Mon Jul 08, 2013 8:22 am
Location: Milan (Italy)

Re: KGV and PoW GAR during Op. Rheinubung

Post by Alberto Virtuani » Thu Oct 05, 2017 10:01 am

Hi Duncan,
1) yes, I'm speaking of this procedure, that I discovered long time ago thanks to you. :clap:
When I write salvo, I intend semi-salvo. Still if gun n.4 in "Y" turret was able to fire 49 shots, a minimum of 80-85 ordered shots should be possible for it, that means 800-850 ordered shots in total (in the hypothesis that all turrets were always bearing). For sure 550 ordered shots are too few taking into account the 28 minutes when Y turret was wooded (out of 1 hour and half battle). :negative:

2) In any case, Rodney's salvo rate must have been much slower than KGV's due to the turns she was doing in front of Bismarck, from 9:17 till 10:15 totally wooding her all-fore turrets for 7 times. For both points above, I suspect the total ordered shots for KGV were more than 700.

The absence of any serious problem up to 9:20 just means an output around 80% - max 90% for any battleship under any condition. It does not exclude the usual, frequent misfires and minor problems. For sure your 100% is unrealistic.

In any case, we are just speaking of our personal views, there are not enough elements to come to any proved conclusion for KGV gunnery efficiency on MAy 27. PoW output at DS (75%) is instead a fact and it was just not exceptional, but not so bad to justify a disengagement. Leach was honest NOT listing any actual loss of output as the reason for the disengagement in his report but only adding his own doubts about the reliability of the guns and of the crew......


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

dunmunro
Senior Member
Posts: 3294
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: KGV and PoW GAR during Op. Rheinubung

Post by dunmunro » Thu Oct 05, 2017 11:24 am

Alberto Virtuani wrote:Hi Duncan,
1) yes, I'm speaking of this procedure, that I discovered long time ago thanks to you. :clap:
When I write salvo, I intend semi-salvo. Still if gun n.4 in "Y" turret was able to fire 49 shots, a minimum of 80-85 ordered shots should be possible for it, that means 800-850 ordered shots in total (in the hypothesis that all turrets were always bearing).

2) In any case, Rodney's salvo rate must have been much slower than KGV's due to the turns she was doing in front of Bismarck, from 9:17 till 10:15 totally wooding her all-fore turrets for 7 times. For both points, I suspect the total ordered shots for KGV were more than 700.

The absence of any serious problem just means an output around 80% - max 90% for any battleship under any condition. It does not exclude the usual, frequent misfires. For sure 100% is unrealistic.

In any case, we are just speaking of our personal hypothesis, there are not enough elements to come to any proved conclusion for KGV on MAy 27. PoW output at DS (75%) was just not exceptional, but not so bad to justify a disengagement. Leach was honest NOT mentioning the loss of output as the reason for the disengagement but only adding his own doubts about the reliability of the guns and of the crew......


Bye, Alberto
1) The maximum KGV RoF was 1.7 salvos/minute or .85 rnds per minute but average RoF was less than that due to visibility and ship turning - Rodney averaged 1.3 salvos/minute or .65 rnds/gun/minute (113 salvos in 87 minutes). KGV's B2 gun jammed after firing 40 rnds at ~0944. Fire was ordered for another ~28 minutes during which a maximum of 24 (.85 rds/min) or 18 (.65/rnds) could have been fired by B2 gun, so that gives a maximum of 64 to 58 possible rnds which equals a maximum of 128 salvos or 116 salvos using the average salvo rate from 0944 to ceasefire at 1014, but there were also periods after 0944 when the A and B turrets were wooded due to turns and so 113 salvos for KGV (as per Rodney) is just about correct, and only about 100 of these would have been with 5 gun salvos. Rodney fired from 0847 to 1014 while KGV fired from 0848 to 1021, but she ceased fire for 9 minutes from 1009 to 1018, so Rodney fired for 87 minutes and KGV for 84 minutes. At 0920 when KGV's A turret jammed (having fired an average of 23 rnds/gun), I estimate that KGV fired 49 salvos while Rodney's GAR records 46 salvos at 0920.

2) Rodney's 16in turrets could traverse at 4degs/sec while KGV's could only manage 2degs/sec, consequently both ships lost about the same number of salvos due to turns.

Rodney's GAR reports that she maintained 90% output for the first 30 minutes versus my estimate of ~95% for KGV.

alecsandros
Senior Member
Posts: 4000
Joined: Wed Oct 14, 2009 2:33 pm
Location: Bucharest, Romania

Re: KGV and PoW GAR during Op. Rheinubung

Post by alecsandros » Thu Oct 05, 2017 11:57 am

For perspective ,
We should add that most WW2 battleship gun battles were short (10-15 minutes), thus making KGV's record during a 30-min interval , and in an Arctic storm , all the more remarkable.

Post Reply