River Plate: conflicting track charts

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Dave Saxton
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Re: AGS vs 3 cruisers

Post by Dave Saxton » Thu Feb 19, 2015 2:56 pm

alecsandros wrote:...

The actual results - 10 direct hits with 280mm guns and several damaging near misses - vs 2 hits by 203mm and 17 x 152mm indicate a substantialy more accurate gunnery for AGS.
Exeter's gunnery and firecontrol systems were disabled quickly and early. Reduced to four guns under local control as early 0623, and two guns on local control by 0634, Exeter really had no hope of scoring any further hits.

The two light cruisers were firing in unision using a common fire control solution early on. They were essentially firing 16 gun broadsides. This was when they did most of their damage. However the radio link between them broke down, forcing them to fire separately. From about 0640 the light cruiser fire was directed by Achilles' observation aircraft. It was later determined that the observer mixed up the shell splashes from the two cruisers, so his fall of shot corrections cancelled each other out, with one consistently shooting overs, and the other one consistently shooting short.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: River Plate: conflicting track charts

Post by alecsandros » Thu Feb 19, 2015 3:02 pm

... Yes but AGS also suffered damaging hits on her dorectors in the first 20 minutes of the battle. Wiyhout that damage she would have hit more often ...

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Re: River Plate: conflicting track charts

Post by Dave Saxton » Thu Feb 19, 2015 3:58 pm

alecsandros wrote:... Yes but AGS also suffered damaging hits on her dorectors in the first 20 minutes of the battle. Wiyhout that damage she would have hit more often ...
Indeed. One of the interesting comments made by Woodhouse was that AGS's 28 cm shooting remained very accurate throughout. The British were very impressed by the AGS's shooting. Yet we now know that AGS's firecontrol was impaired before 0640, loosing both the foretop optics and the radar. RPC problems for the forward turret were also encountered. It was not known until later that splinter damage to the director directing the 15 cm fire caused bearing track inaccuracy for the 15 cm fire. It is to the credit of AGS's crew that they worked through these problems under the stress of combat and were able to keep the heavy battery shooting so accurate. Yet how much more effective could the AGS had been if it could have maintained its pre-firecontrol damage shooting throughout? During the first 9 minutes, AGS consistently straddled and hit Exeter from ranges as great as 23000+ yards with rapidly changing rates. Impressive shooting indeed.

BTW, the key gunnery personal repatriated to Germany made up the key personal of the crew of the Tirpitz. The Chief Gunnery Officer on AGS, was Paul Ascher (of Jewish heritage) who became Luetjens' gunnery adviser on his staff, and who lost his life on the Bismarck.
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Re: River Plate: conflicting track charts

Post by Paul L » Fri Feb 20, 2015 1:49 am

I recall some one posting that the 6" secondaries on the AGS had no dedicated director , instead they had a sub plot from the main 11" Gun directors that could direct fire...if the staff had time. However since the 11" ballistics where no were near the 6" gun ballistics - this direction was not of much value.

The 88mm flak guns had a dedicated High Angle Director [HAD] and I suspected that the arrangement on the Hipper class was better since main battery had its own directors [fore and aft] and secondary flak had its own directors [2x on each side amid ship].
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Re: River Plate: conflicting track charts

Post by alecsandros » Fri Feb 20, 2015 8:27 am

Paul L wrote:I recall some one posting that the 6" secondaries on the AGS had no dedicated director , instead they had a sub plot from the main 11" Gun directors that could direct fire...if the staff had time. However since the 11" ballistics where no were near the 6" gun ballistics - this direction was not of much value.
... AGS had 2 directors for her main guns, the forward one being higher in the ship and usualy expected to direct the main battery. The aft one was usualy used to direct the secondary battery. The 105mm AA guns had directors of their own.

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Re: River Plate: conflicting track charts

Post by Paul L » Fri Feb 20, 2015 7:11 pm

Yes but its main task and training was firing the 11 battery. Its one of the explanations for the poor performance of the 6" guns.
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Re: River Plate: conflicting track charts

Post by Steve Crandell » Fri Feb 20, 2015 7:24 pm

Paul L wrote:Yes but its main task and training was firing the 11 battery. Its one of the explanations for the poor performance of the 6" guns.
Then you would have to say that for all of the German heavy ships. They all used one or more of the primary directors to control the secondary battery. I don't believe there was a dedicated secondary battery director for any of them.

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Re: River Plate: conflicting track charts

Post by tommy303 » Fri Feb 20, 2015 7:53 pm

The AGS had three day action, low angle gunnery control positions--upper level of the conning tower on the navigation bridge with two directors, foretop GCT on the tower mast with two directors, and the after FCT with one director. Each position had a rangefinder, although the forward one had a shorter base length than the foretop and aft rangefinders.

The usual protocol when closed up for action was for the foretop position to control the main armament since it had the best all round view and longest line of sight to the horizon. Control of the 15cm guns was assigned to the forward command post in the conning tower with one director controlling the port battery and one the starboard battery. The after fire control tower was kept as a reserve for the other two should circumstances arise.

That said, any of the low angle directors could be used with either main or secondary batteries by connecting it up with the appropriate gunnery plotting room.

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Re: River Plate: conflicting track charts

Post by Dave Saxton » Sat Feb 21, 2015 2:41 pm

Thanks Tommy,

The reason for the poor performance of the middle artillery is given by Rasenack:
Ein kleiner granatsplitter ist durch den steurbord zielgeber gegangen. Zum Gluck ist die Optik heil und auch das getriebe nur wenig beschadigt, so das bis zum abend auch dieser ausfall beseitigt werden kann. Diesen schaden hatte man wahrend des gefechtes uberhaupt nicht bemerk. Da aber durch die beschadigung des kein kippwinkel an die batterie war, hatte die mittelartillerie sehr schlecht am ziel.


Meaning in general, assuming my German is not too bad; that a small shell splinter entered the starboard director (of assume the forward conning tower FC station). But as luck would have it, the optic was left intact and the director function but little impaired, so the damage remained unknown until late in the evening. The casualty was not noticed by the operator during the battle at all. However, the director did not provide the proper fine bearing angle alignment to the battery, resulting in very poor on target performance.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: River Plate: conflicting track charts

Post by Dave Saxton » Sat Feb 21, 2015 3:00 pm

tommy303 wrote: The after fire control tower was kept as a reserve for the other two should circumstances arise.

That said, any of the low angle directors could be used with either main or secondary batteries by connecting it up with the appropriate gunnery plotting room.
An example of this flexibility, is that after the 6" shell knocked out the foretop firecontrol station, the foretop range finder, and the radar, the aft station took over, and the 28 cm shooting continued to be, according to the British, highly accurate.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: River Plate: conflicting track charts

Post by Steve Crandell » Sat Feb 21, 2015 5:52 pm

Dave Saxton wrote:
tommy303 wrote: The after fire control tower was kept as a reserve for the other two should circumstances arise.

That said, any of the low angle directors could be used with either main or secondary batteries by connecting it up with the appropriate gunnery plotting room.
An example of this flexibility, is that after the 6" shell knocked out the foretop firecontrol station, the foretop range finder, and the radar, the aft station took over, and the 28 cm shooting continued to be, according to the British, highly accurate.
That is exactly what would happen in a warship with the director in the rangefinder cupola as in pretty much every other warship in the world. One apparent problem with the German system is it was possible for the rangefinder to be mistakenly taking ranges to a different target from the one the ship was shooting at.

Also, if one of the optic devices was damaged and it's bearings were offset, the guy next to the operator would probably notice it immediately though his own optic device and say "why aren't you on the target anymore?".

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Re: River Plate: conflicting track charts

Post by Paul L » Sat Feb 21, 2015 8:32 pm

That kind of error seems common. At the same time the German secondaries were being misdirected the British Light cruiser fire was also being miss directed by their spotter plane that mistook one ships shell splashes for the other and corrected accordingly.
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Re: River Plate: conflicting track charts

Post by Steve Crandell » Sun Feb 22, 2015 2:01 am

Paul L wrote:That kind of error seems common. At the same time the German secondaries were being misdirected the British Light cruiser fire was also being miss directed by their spotter plane that mistook one ships shell splashes for the other and corrected accordingly.
Yes, that was a serious problem with spotter aircraft, and one reason they weren't used very often once radar spotting became reliable enough to more or less depend on.

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Re: River Plate: conflicting track charts

Post by Dave Saxton » Mon Feb 23, 2015 2:42 pm

Steve Crandell wrote: One apparent problem with the German system is it was possible for the rangefinder to be mistakenly taking ranges to a different target from the one the ship was shooting at.
Looking at Schmalenbach's schematics, once the target was designated both the appropriate director and the appropriate rangefinder were put on target and controlled by the computer/operators. It could be any rangefinder and any director, or any radar.

Once Berlin radar became available in 1944, primary target designation came from using the PPIs.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: River Plate: conflicting track charts

Post by dunmunro » Mon Feb 23, 2015 7:25 pm


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