River Plate: conflicting track charts

[Dave Saxton]

There has been numerous references recently to the River Plate battle. The common wisdom is that Langsdorf recklessly charged right in throwing away his advantages and getting himself in a mess. Churchill included a track chart that looks much like this:


Most charts in most secondary literature are variations on this theme. There are several problems with this track chart, the greatest being that it doesn't match the movements of AGS reported by the German documents at all. The AGS movements were:

0552: Enemy in sight from the foretop , range 31,000 meters (34,000 yards). One cruiser (correctly identified as Exeter) and (incorrectly) two destroyers, proceeding at 14 knots on course 060T.

0614 Langsdorf decides to attack and calls for full speed. The resulting smoke from the diesels is seen by the enemy. This was the first the British knew of AGS's presence.

0615 AGS turns on to course 097T

0617 After completing its turn AGS opens fire on Exeter from a range of 20,600 meters ( 22,500 yards).

0617-0623 Exeter makes a 225* turn to starboard coming around on to course 275T. AGS follows Exeter through its turn with its fire, straddling it repeatably, and scoring 4 direct hits, and three damaging near misses. Exeter straddles with its salvos numbers three and four, and scores two deck hits on AGS.

0626-0631 AGS turned to its port to course 060T and then to 005T to stop Ajax and Achilles from crossing its T. AGS shifts fire to the light cruiser, since it is believed that Exeter is incapacitated.

0634 AGS turns additionally to port, coming to course 320T. It shifts the fight from starboard to port and shifts fire back to Exeter, scoring three more direct hits. AGS is hit in the foretop by a 6" shell from about 16,000 meters battle range. This hit knocks out its foretop firecontrol station. foretop rangefinder, and radar set.

0638 AGS turns to course 283 and lays a smoke screen against Ajax and Achilles which are on its port quarter at 16km range.

I tried to scan a copy of the geftchskizze but I couldn't get in a presentable size on the scan. Here is my own drawing of the gefetchskizze to scale and reported speeds:



From this is it is apparent that Langsdorf never let the battle range fall into a short range battle up to his turn away at about 0640 hours. Some 40 minutes later, the British had closed the range (AGS to Ajax), to about 7,000 meters, by using their superior speed, aided by a series of turns by AGS. The range then increased to 13 miles as AGS continued to retire to the westward and the British fell back to shadow. However, AGS still straddled the British cruisers from that range and the British fell back further to 31,000 meters.

There are problems with the German chart as well, but it is much more correct than most.

[Steve Crandell]

I was just thinking as I read again of AGSs FC top hit how often that seems to happen. It seems to me that hits like that are ironically a result of inaccurate fire by the enemy ... on for line, but way over for range. If the fire was straddling, I don't think you would ever get hits on the main top FC position.

[Dave Saxton]

True, particularly in the case of short range fire. This can be seen in the photos of the Bismarck's final battle. Shell splashes can be seen hundreds of yards beyond or short of the Bismarck. Shells that would have passed just over the Bismarck by a few meters would have traveled some distance before striking the sea beyond. Or fired to shoot through the hull a few meters above the waterline, or at the water line, they may strike the sea quite some distance short of the target. Compounding the difficulty was very heavy seas. A minute error in angle of departure, can result in large variations for the point that the shells finally impact the sea. The amount of scatter for range as a result of dispersion can also be very great at short range.

In cases of steeper angles of fall, the allowable error for range, and dispersion, and still being able to hit the target anywhere becomes much smaller. For example, the hit on AGS's foretop had angle of fall of about 24*. It would have hit the sea only about 30 meters beyond the target.

One of the two deck hits scored by Exeter on Graf Spee also illustrates this. This shell, a dud, passed through the foretop, a bit lower down than the 6" hit, before striking the deck on the other side of the superstructure. The angle of fall for this to happen had to be rather steep. This would indicate that the German chart showing Exeter turning away to start its turn around to course 275T was correct, and the range of the hits scored by both AGS and Exeter up to 0626 hours was greater than 22,500 yards.

[Thorsten Wahl]

german scetch


zoomable
https://plus.google.com/u/0/photos/1136 ... 4337291328

[Dave Saxton]

Thanks Thorsten. This is mostly the same as the one published by Rasenack, but not exactly the same. Rasenack claims his is directly from the KTB. Rasenack's doesn't show Exeter coming to a north west course, but steady on 275* until its turn away at about 0638 hours.

British accounts describe Exeter going out of control and going off course to its starboard, after the 11" HE hit on B turret also took out the command bridge and the conn. The out of control pennant was hoisted but the next hit cut the mast down. An officer making his way to another battle station noticed from Exeter's wake that is was turning in a circle to starboard, and got word to the back up helmsman to bring the course back to 275T, as ordered by Capt. Bell before he departed to set up command in the after position. This sketch does show Exeter coming around to a north west course for a period. A map drawn by Eric Grove also shows a meandering course of Exeter, but is more exaggerated than the German chart, and shows (incorrectly in my opinion) Exeter turning to its port instead of to its starboard at the start of the battle.

This chart shows the hits scored by AGS on Exeter at about 0634 hours were from about 20,000 meters. I got the same result in a track chart I constructed.

It is fairly obvious that Exeter never closed range to 12,000 yards at any point. It did fire torpedoes and the torpedo crews thought the range was 12,000 yards, but they actually had no instrumentation still functioning to give them a precise range. It was a bad range guess at best. AGS was not aware that Exeter had fired torpedoes.

[Dave Saxton]

A German Naval Ordnance analysis dated Feb 5 1940 states that from the track chart (probably the exact one posted by Thorsten) Langsdorf made a mistake by turning north to stop Ajax and Achilles from crossing his T, while shifting fire to the light cruisers, instead of around to the west, or to the south and keeping the heat on Exeter.

Indeed a turn to the west or to the south would have been a brilliant tactical move. It would have closed range on Exeter and could have allowed him to quickly finish off the already hard hit Exeter, while catching the two light cruisers going the wrong way at high speed, reducing their threat for the time being. But it could of perhaps increased the risk to AGS of receiving torpedo hits from the Exeter.

[Paul L]

Definitely finish off Exeter and batter the other two cruisers since they have to rush to the aid of a sinking Exeter. That's the only way to ensure they can't shadow the AGS thus effecting an escape.

The point is not moot since the entire KM doctrine was riding on the out come of this first clash. This was the quintessential test of the notion that the KM was designed around...... 'defeat what you can't run away from '. Langsdorf shrank from his responsibility to the KM and his ship.

I am always reminded of what the skipper of the Ajax reported - he never understood why Langsdorf didn't just 'run them down' and finish off the last two cruisers. This was an opinion he held to his dying day.

[Steve Crandell]

How does one "run down" two cruisers that are faster than you are?

[Paul L]

How does one "run down" two cruisers that are faster than you are?

Simple you give them a compelling reason to stay.

Langsdorf just continues to close with the Exeter and torpedo her until she is sinking. Harwood will have no choice but to battle to the ailing cruisers side and in doing so subjects his other two cruisers to join Exeter crippled and limping away.

That is the only way he can escape his captures.

The tactic of 'defeating what you can't run away from' has obvious drawbacks.

[Steve Crandell]

How does one "run down" two cruisers that are faster than you are?

Simple you give them a compelling reason to stay.

Langsdorf just continues to close with the Exeter and torpedo her until she is sinking. Harwood will have no choice but to battle to the ailing cruisers side and in doing so subjects his other two cruisers to join Exeter crippled and limping away.

That is the only way he can escape his captures.

The tactic of 'defeating what you can't run away from' has obvious drawbacks.

I don't believe Harwood would sacrifice his other two ships and let AGS get away in order to save Exeter.

[Dave Saxton]

Go to 24:00 minutes and see Admiral Sir Charles Woodhouse's, Ajax's captain during the battle, comments on the battle. Most interesting:

https://www.youtube.com/watch?v=0rt6JDmJjYs

[Paul L]

How does one "run down" two cruisers that are faster than you are?

Simple you give them a compelling reason to stay.

Langsdorf just continues to close with the Exeter and torpedo her until she is sinking. Harwood will have no choice but to battle to the ailing cruisers side and in doing so subjects his other two cruisers to join Exeter crippled and limping away.

That is the only way he can escape his captures.

The tactic of 'defeating what you can't run away from' has obvious drawbacks.

I don't believe Harwood would sacrifice his other two ships and let AGS get away in order to save Exeter.

There in lays the problem. Lesser RN combatants had charged much tougher foes than Harwood faced at this point in the war. In the best tradition of the RN they attacked to save their fellow ships and crew. They don't have to sacrifice these ships, just get exposed to enough main battery fire to reduce the speed to below the AGS speed, thus allowing the PBS to escape shadowing.

[Steve Crandell]

You are actually suggesting that the British cruisers engage with the idea of getting their speed reduced so they can't shadow AGS? Really?

[Paul L]

You are actually suggesting that the British cruisers engage with the idea of getting their speed reduced so they can't shadow AGS? Really?

Of course not ,they would fight for as long as the had to.... any cut off point for engagement would be if Exeter sinks or all three ships are crippled and turn away from AGS , giving up the mission . At this point Langsdorf or his next in command would probably take that opportunity to make good an escape.

[alecsandros]

... On paper the cruisers had a significant advantage over Graf Spee.
3 distinct targets, totalling 6x203mm, 16x152mm and 24x102mm guns (34 of which could be brought to bear on one side of the ship), vs 6x280mm, 8x150mm and 6x105mm guns (13 of which could be brought to bear on one side of the ship).
26000 tons standard vs 13000 tons standard.
30-32kts speed vs 24-26kts speed.

Graf Spee could hope to score some critical hits with her powerfull main guns, firing 300kg shells. However 6 main guns (director controlled) could only hope to score a significantly smaller quantity of hits than 22 main guns (director controlled).

The German raider also had heavier armor, but with so many enemy guns in action against her, topside damage to critical soft systems was to be expected.

===

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.