Best U.S. cruisers at the river Platte

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Re: Best U.S. cruisers at the river Platte

Post by tommy303 » Sat Jul 28, 2012 10:16 pm

I agree with Duncan. You are stacking the cards heavily in favor of the US cruisers to such a point that AGS has no real way of winning aside from some extraordinary good luck.

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Re: Best U.S. cruisers at the river Platte

Post by steffen19k » Sun Jul 29, 2012 2:22 am

This reminds me of a what if scenario about a single M1 tank at the Battle of the Bulge...

All I'm going to say is, if you were gonna do it right, use the ships the Navy had available in 1939, as they were equipped in 1939.

USS Salt Lake City, USS Omaha and USS Milwaukee would be my picks.
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Re: Best U.S. cruisers at the river Platte

Post by Guesser » Sun Jul 29, 2012 6:45 am

The information I have read is that they had Brooklands and Late New Orleans, even Wichita could have been available although I don't think there would have been any enticements that would have pried the latter from the US navy.

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Re: Best U.S. cruisers at the river Platte

Post by ede144 » Sun Jul 29, 2012 9:19 pm

alecsandros wrote:
ede144 wrote: I wonder how would this work? The US ships had no immunity against the 11' of AGS. Secondly due to a splinter damage the range keeper of the 5.9' guns did not work correct. This was luck for the RN and one could not expect same happens all time.
Third The US Navy ships did not have torpedoes. So Langsdorf would not do man overs to prevent torpedo attacks. Fourth The US Navy of this time was not well known for good shooting.
Hi Ede,
The previous posters mentioned that the US cruisers would have much more artillery available, and of superior quality...
In a normal, battle line engagement, the deluge of fire would take it's toll on Graf Spee... On the other hand, if Langsdofrf would decide to mantain the range as long as possible, and open fire from 20-22km, things may turn out very differently...
That's exactly the point. The US Navy 8" 55 Mark 9 had a range of 29100m. The German SK/C 28/55 had 36400m. As the accurcy of a gun get's worse when you get to max range, one could assume that the chance of a hit for AGS is approx 10% against the US cruisers of 1-2%. Give a rate of fire for AGS of 2/gun/minute, you can expect hits after 2-3 minutes after begin of the battle. How many hits can a ship stand if it has no immunity zone?

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ede

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Re: Best U.S. cruisers at the river Platte

Post by tommy303 » Sun Jul 29, 2012 10:52 pm

Another problem which might have reared its ugly head was the defects in the fuzing of US base-fuzed shells. US fuzes were very complex, incorporating as they did several bore safeties, besides the usual detents, whose moving parts were required to slide into position for the fuze to complete arming. It was found that fumes from the ammonium picrate bursting charges of the shells penetrated the fuze assembly and corroded the internal parts. This was not evident from the outside and resulted in an extremely high dud rate until the problem was diagnosed in late 1942 and corrective measures taken in mid 1943.

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Re: Best U.S. cruisers at the river Platte

Post by Dave Saxton » Mon Jul 30, 2012 9:21 pm

Another factor of the time frame, given Langsdorf maintaining longer battle ranges, is that Graf Spee has effective radar. Graf Spee's radar set operated on a wave length of 60cm with range to another panzerschiff (cruiser) of 25km. More importantly, it was well suited to provide exact range to target data for the fire control systems.
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Re: Best U.S. cruisers at the river Platte

Post by Lutscha » Thu Aug 02, 2012 6:40 am

Dave, was the Radar usable for gunnery on GS? I know it could be used for gunnery and even for blind fire later on, but IIRC from the AVKS 700 the AVKS modified BS' FC sytem to integrate the Seetakt for gunnery purpose. Was this done for GS as well?

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Re: Best U.S. cruisers at the river Platte

Post by Keith Enge » Thu Aug 02, 2012 4:28 pm

Francis -
If you want French ships against AGS, don't propose Algerie and La Galissoniere. Why not use ships that were actually tasked with that duty. Among the nine groups that the British and French created to hunt and counter the pocket battleships were a group consisting of Dupleix and Foch (their responsibility was the western Atlantic). This would have been a bloody battle with both sides able to penetrate each other at all ranges. However, German secondaries could penetrate at all ranges too while the 90mm French secondaries could not. Nevertheless, I still would favor the French but they too would be badly hurt.

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Re: Best U.S. cruisers at the river Platte

Post by Dave Saxton » Thu Aug 02, 2012 11:49 pm

Lutscha wrote:Dave, was the Radar usable for gunnery on GS? I know it could be used for gunnery and even for blind fire later on, but IIRC from the AVKS 700 the AVKS modified BS' FC sytem to integrate the Seetakt for gunnery purpose. Was this done for GS as well?
With the introduction of the 1940 models the radars could be directly linked to the fire control system via selsyns. To better utilize such capability is probably why the upgrades to FC alluded to were made. This type of automatic data transfer was being used for optical rangefinder data and optical bearing data from WWI on German ships according to Freidman.

They way Seetakt worked while being used for firecontrol was that the selected target pip was placed in the center of the fine range indicator which contained the zero mark, with a selected amount of range short and long of the target pip. The radar operator needed only to hold the pip on the zero mark and the range was automatically measured and recorded on gauges. From 1940 such data transfer could occur auomatically. However, even before the introduction of the fully automatic data transfer for radar, the radar derived range data could be manually inputed into the firecontrol systems.

Seetakt could always be used for firecontrol even from the prototype stage. When the first prototype was demonstrated in Sept 1935 it showed a bearing accuracy of 0.10* and Naval Ordnance became very involved with directing further development, with the view of optimizing it for firecontrol. Naval Ordnance required a range accuracy of 50 meters and a bearing accuracy within 0.20* of Seetakt from 1936 to use it for firecontrol puropses. Such bearing accuracy was obtained via lobe switching. However, the first production models did not activate the lobe switching features. The radars were used for ranging the targets in conjunction with optical bearing early in the war and at the time of River Platte. This method was of course the prefered method by everybody-even late war-as long as the target could be seen.

The new 1940 versions of Seetakt introduced a new phased array scanning method of lobing with a bearing accuracy within 0.10* and could be used for blind fire applications. As far as be confirmed at this point, this capability was first activated on Tirpitz in late 1941. However we have to explain Bismarck's accurate night shooting against Vain's destroyers with out using any artifical light aids.
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Re: Best U.S. cruisers at the river Platte

Post by Dave Saxton » Thu Aug 02, 2012 11:58 pm

Lutscha wrote:.... Was this done for GS as well?
A strong case can be made that AGS was benefitting from radar ranging early in the historical battle. AGS's early shooting is described as uncannily accurate, but this accuracy was not sustained throughout the action. The radar would have been lost, at least temporarly, when the 6" shell burst high in the foretop tower.
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Re: Best U.S. cruisers at the river Platte

Post by Lutscha » Fri Aug 03, 2012 7:15 am

Its imprressive, how the Seetakt from 1936 compares to the Type 274 from 1944 (94m/0,05°) accuracy. Thanks Dave, so much for superior allied RFC...

Karl will be delighted. :D

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Re: Best U.S. cruisers at the river Platte

Post by RF » Fri Aug 03, 2012 7:52 am

Keith Enge wrote:Francis -
Among the nine groups that the British and French created to hunt and counter the pocket battleships were a group consisting of Dupleix and Foch (their responsibility was the western Atlantic). This would have been a bloody battle with both sides able to penetrate each other at all ranges. However, German secondaries could penetrate at all ranges too while the 90mm French secondaries could not. Nevertheless, I still would favor the French but they too would be badly hurt.
Assuming that those 5.9 inch guns were actually properly working.....

An alternative River Plate battle involving only French cruisers against AGS would be interesting. The location of the battle presumably would be different, say off French West Africa, which means that South American harbours would not be available for AGS to run to.
If the French tackled AGS on opposite flanks as Harwood attempted, I think that the French could sink AGS, particulary if the 5.9's aren't being directed and AGS has nowhere to run to.
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Re: Best U.S. cruisers at the river Platte

Post by RF » Fri Aug 03, 2012 7:57 am

Dave Saxton wrote:
Lutscha wrote:.... Was this done for GS as well?
A strong case can be made that AGS was benefitting from radar ranging early in the historical battle. AGS's early shooting is described as uncannily accurate, but this accuracy was not sustained throughout the action. The radar would have been lost, at least temporarly, when the 6" shell burst high in the foretop tower.
Yes, the radar was good to start with, but the AGS still wasn't able to dispose of Exeter as quickly as Bismarck did with Hood. In other words the gunnery didn't benefit that much from the radar, it didn't turn defeat into victory which would have been if Exeter was sunk from radar targetted gunnery before Ajax and Achilles were in range.....
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Re: Best U.S. cruisers at the river Platte

Post by Byron Angel » Fri Aug 03, 2012 11:22 am

Dave Saxton wrote: This type of automatic data transfer was being used for optical rangefinder data and optical bearing data from WWI on German ships according to Freidman.

..... The evolved German WW1 system, incorporating real-time electro-mechanical transmission of range data from multiple range-finder positions into the Mittlungs Apparat (an automatic electro-mechanical range averaging and range rate computer) did include a manually operated FTP link to transfer range rate output from the Mittlungs Apparat into the FC computer. It was without question an excellent system, but was not at that early point in time a completely automated one.

B

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Re: Best U.S. cruisers at the river Platte

Post by Dave Saxton » Fri Aug 03, 2012 2:13 pm

The evolved German WW1 system, incorporating real-time electro-mechanical transmission of range data from multiple range-finder positions into the Mittlungs Apparat (an automatic electro-mechanical range averaging and range rate computer) did include a manually operated FTP link to transfer range rate output from the Mittlungs Apparat into the FC computer. It was without question an excellent system, but was not at that early point in time a completely automated one
Good to know. Thanks Byron.
Lutscha wrote:Its imprressive, how the Seetakt from 1936 compares to the Type 274 from 1944 (94m/0,05°) accuracy. Thanks Dave, so much for superior allied RFC...

Karl will be delighted. :D

Although early Seetakt was capable of fine accuracy, in practice it was somewhat dynamic. In a 1944 OKM document overviewing radar development it is stated that the range accuracy could "suffer" if too wide of range was displayed on the fine range indicator (in other words if it wasn't zoomed in enough There was a limit to how far it could be zoomed in and still hold the target with the early models). The typical range accuracy of the early models such as equipped AGS was 100 meters, so Naval Ordnance found 100 meters range accuracy wanting! Naval Ordnance complained about the fine ranging system early in the war.

Nonetheless, the fine ranging system was progressively improved to the point that by 1943 the typical range accuracy was 25 meters regardless of the range to target. By 1944 Naval Ordnance loved Seetakt's fine ranging system so much that they wanted to retain its features in new radars. The range accuracy attainable was impressive by even late war Allied standards. By way of comparison, the USN MK8 had a range accuracy of 0.10% of the range plus or minus 15 yards. So at 30,000 yards battle range the range accuracy was 45 yards for Mk8. Very impressive but not as good as Seetakt.

The real advantage of Seetakt's unique fine ranging system was resolution for range, however. The resolution for range was always within 100 meters, and could be as fine as 10 meters, which made it ideal for spotting the fall of shot relative to the target. Or to pickup targets against a land back drop.

The bearing accuracy available from lobe switching was only available if lobe switching was used. Up until 1941 the KM did not usually employ lobe switching features on shipboard Seetakt sets. The resolution for bearing was always a few or more degrees due to the decimetric wave length.

Regarding Type 274, it featured truely outstanding resolution for bearing, of less than 1*. This extremely narrow beam width, however, made it so it could not spot the fall of shot by itself.
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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