Kriegsmarine surface ships are more aggressive in the Atlantic.

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Richard Anderson
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Re: Kriegsmarine surface ships are more aggressive in the Atlantic.

Post by Richard Anderson » 08 Mar 2023 18:49

Carl Schwamberger wrote:
08 Mar 2023 16:00
There were post war records found of Abwehr agents that survived in the US into the war. One into 1945. They provided a thin trickle of information on weather reports from open sources and ships they could observe docking and departing east coast harbors. How useful that was I cant say. Successful intelligence is seldom based on the 'Golden Message', but rather on endless reading and analysis for bits and fragments. So, whatever the Abwehr obtained from the US agents had some sort of utility at least for background.
Two Abwehr agents. Simon Koedel and his daughter Marie. Arrested in October 1944, but is unlikely that their espionage activities extended beyond December 1941.

The two landed in Maine in 1944, Colepaugh and Gimpel, used their Abwehr funds to live it up in New York City until they were both arrested in December 1944.
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Carl Schwamberger
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Re: Kriegsmarine surface ships are more aggressive in the Atlantic.

Post by Carl Schwamberger » 09 Mar 2023 00:40

Laidlas Farrago trawled through the Abwehr message records he found in US Army archives and found a few others. One the Abwehr identified as A3778 Farrago matched to a "German merchant" the FBI claimed to have run as a double agent, N98. Farrago indirectly casts a lot of doubt on the usefulness of FBI counter espionage records, but judged this a match to the Abwehr records & likely a doubled spy. Another a Walter Koehler, was also claimed as a double agent by the FBI. however Farrago found that a large portion of the messages recorded by the Abwehr did not match those in the FBI files. The FBI files indicated a Walter Koehler had been on their watch list from when he confessed to the US consul agent in Lisbon & they took him into custody when he arrived in the US Portuguese flagged ship. Evaluations made by the new SS managers after the Abwehr was taken over in 1944 rated Koehler as highly reliable with a accuracy rating of his message on a ratio of 3-1. Farrago crosschecking FBI to Abwehr records found the FBI claimed 115 messages sent by Koehler from 7 February 1943 tp 26 April 1945, but 231 messages recorded by the Abwehr as received. Farrago interviewing suviving Abwehr managers two decades later found one who remembered a "Dutchman" Walther Koehler who had been in a program for training agents to double as a cover for other operations. He also identified this Walter Koehler as a German spy in the US circa 1917 1918. Since the 'extra' messages under Koehlers case file don't match or reflect the FBI material Farrago speculates that Kohler somehow managed to send traffic unmonitored by the FBI, or perhaps there was another agent the Abwehr identified with Koehlers indentity. This is supported in that the Abwehr message records indicated two different cyphers used for the messages from Koehler. Farrago does not record when the last useful message was sent from the Koehler source, but does say the last message on 27 April was one of the FBI compositions.

Most of the non FBI material sent by Koehler was the names of ships observed on the New York docks, departures, arrivals, and ship types. Plus what weather reports that filtered past the security controls.

Simon Koedel seems to have gone dark from some time in 1941. Farrago does not identify any Abwehr messages as from him after 1941. Since there was a collapse of the broad array of German spy networks in the US in 1941 this is not unusual. Farrago also identifies him as a Imperial German Army Captain and a active agent in the US during the Great War.

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Re: Kriegsmarine surface ships are more aggressive in the Atlantic.

Post by Peter89 » 09 Mar 2023 07:16

Carl Schwamberger wrote:
08 Mar 2023 16:09
I think that the only way this would have worked was by occupying Tunisia. You cannot have a supply run through a country you don't control. As that request was turned down again and again, there was no point using it.
The French did allow a token amount of iIalian material via Tunisia. Less than 100,000 tons over two years. That effort illustrated the limits. While the ports of Tunis & Bizerte were relatively high capacity the railway running south to Sfax was not. It had some limits & a typical army size transport of 50,000 to 100,000 tons daily was not possible. The greater problem was the rail terminated at Sfax. The material had to be sent on by automotive transport to Tripoli, along a paved but low capacity automotive road. Or by coastal freighter/barge.
Well, 50-100,000 tons DAILY would certainly got the Germans to Cape Town :)

The Suez base was about 5000 t/d, the Axis in North Africa received about half that amount.
"Everything remained theory and hypothesis. On paper, in his plans, in his head, he juggled with Geschwaders and Divisions, while in reality there were really only makeshift squadrons at his disposal."

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Re: Kriegsmarine surface ships are more aggressive in the Atlantic.

Post by Carl Schwamberger » 09 Mar 2023 16:00

Opps. Should have been 5,000 to 10,000 tons daily
& a typical army size transport of 5,000 to 10,000 tons daily was not possible.

glenn239
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Re: Kriegsmarine surface ships are more aggressive in the Atlantic.

Post by glenn239 » 09 Mar 2023 18:22

Peter89 wrote:
07 Mar 2023 19:11
I have doubts about that. A Fw 200 cruising at 330 km/h can do different things than the Graf Zeppelin II at 110 km/h. It's not as simple as "3 times of that".
I wonder if a Zeppelin could have done air to air refuelling? Max speed of the GZ was 73kt. Stall speed of an HE-111 in landing configuration was 67kt. That's a pretty thin margin, but I wonder if they could have got the stall speed down to more like 60kt?
The first raid on Bordeaux-Merignac took place on the night of November 22–23, 1940, and saw 32 bombers destroy four hangars and two Fw 200s on the ground.
Right, if based on the coast of France they'd be highly vulnerable. In Central Germany, not so much.
I seriously doubt that it could be the case in 1939-1941, when the opportunity existed at all.
The radar signature of a big convoy of ocean going merchant ships was enormous.

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Re: Kriegsmarine surface ships are more aggressive in the Atlantic.

Post by glenn239 » 09 Mar 2023 18:25

Orwell1984 wrote:
07 Mar 2023 18:58
Until reliable and consistent weather reporting is available to them, this plan is a non-starter.
All good points, provided that civilian zeppelin safety standards were no different than wartime military standards, that the Atlantic Ocean never had extended periods of good weather, that the German weather service was non-existent, and that a 70kt Zeppelin cannot outrun a 15kt storm front.

Peter89
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Re: Kriegsmarine surface ships are more aggressive in the Atlantic.

Post by Peter89 » 10 Mar 2023 06:32

glenn239 wrote:
09 Mar 2023 18:22
Peter89 wrote:
07 Mar 2023 19:11
I have doubts about that. A Fw 200 cruising at 330 km/h can do different things than the Graf Zeppelin II at 110 km/h. It's not as simple as "3 times of that".
I wonder if a Zeppelin could have done air to air refuelling? Max speed of the GZ was 73kt. Stall speed of an HE-111 in landing configuration was 67kt. That's a pretty thin margin, but I wonder if they could have got the stall speed down to more like 60kt?
A way more practical solution to that problem is to carry some internal fuel tanks.
glenn239 wrote:
09 Mar 2023 18:22
The first raid on Bordeaux-Merignac took place on the night of November 22–23, 1940, and saw 32 bombers destroy four hangars and two Fw 200s on the ground.
Right, if based on the coast of France they'd be highly vulnerable. In Central Germany, not so much.
If they'd be based in Central Germany, it would take them about a day and a half to get into the operation zone, and the same time to float home, severly limiting their usefulness.
glenn239 wrote:
09 Mar 2023 18:22
I seriously doubt that it could be the case in 1939-1941, when the opportunity existed at all.
The radar signature of a big convoy of ocean going merchant ships was enormous.
No, I meant that the suitable radar might not have been available in 1939-1941. The FuG 200 Hohentwiel arrived to the KG 40 in 1942. Prior to that, good visibility allowed to spot a convoy at 15-20 km, but bad visibility (which was quite frequent over the Atlantic) reduced it to half.
"Everything remained theory and hypothesis. On paper, in his plans, in his head, he juggled with Geschwaders and Divisions, while in reality there were really only makeshift squadrons at his disposal."

glenn239
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Re: Kriegsmarine surface ships are more aggressive in the Atlantic.

Post by glenn239 » 10 Mar 2023 18:07

Peter89 wrote:
10 Mar 2023 06:32
If they'd be based in Central Germany, it would take them about a day and a half to get into the operation zone, and the same time to float home, severly limiting their usefulness.
Aloft time would be roughly 120 hours. Distance from Munich to Nantes is about 8 hours flying time.

Assuming the RAF did manage to bomb a Zeppelin in Germany, then it would presumably be scrapped, which is exactly what they did with the things anyways.
glenn239 wrote:
09 Mar 2023 18:22
No, I meant that the suitable radar might not have been available in 1939-1941. The FuG 200 Hohentwiel arrived to the KG 40 in 1942. Prior to that, good visibility allowed to spot a convoy at 15-20 km, but bad visibility (which was quite frequent over the Atlantic) reduced it to half.
This is a Zeppelin, not an airplane. The radar can weigh 10,000kg. I'm thinking maybe a Freya might be adaptable to the task.

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Re: Kriegsmarine surface ships are more aggressive in the Atlantic.

Post by Peter89 » 10 Mar 2023 19:38

glenn239 wrote:
09 Mar 2023 18:22
No, I meant that the suitable radar might not have been available in 1939-1941. The FuG 200 Hohentwiel arrived to the KG 40 in 1942. Prior to that, good visibility allowed to spot a convoy at 15-20 km, but bad visibility (which was quite frequent over the Atlantic) reduced it to half.
This is a Zeppelin, not an airplane. The radar can weigh 10,000kg. I'm thinking maybe a Freya might be adaptable to the task.
Seems to be a long shot for me. But in any case, the Luftwaffe showed little to no interest in developing a maritime recon or naval aviation arm. Had there been any serious emphasis on this service branch, the development of radars for aircrafts would take place anyway. Thus the zeppelins, quite unsuitable for this kind of mission, would be scrapped as in OTL.

Mind you, the Condor crews used binoculars to spot the convoys up until 1942. Thus they missed more convoys than they found. This is how the Germans thought of the task.
"Everything remained theory and hypothesis. On paper, in his plans, in his head, he juggled with Geschwaders and Divisions, while in reality there were really only makeshift squadrons at his disposal."

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Re: Kriegsmarine surface ships are more aggressive in the Atlantic.

Post by Orwell1984 » 11 Mar 2023 15:19

glenn239 wrote:
09 Mar 2023 18:25
Orwell1984 wrote:
07 Mar 2023 18:58
Until reliable and consistent weather reporting is available to them, this plan is a non-starter.
All good points, provided that civilian zeppelin safety standards were no different than wartime military standards, that the Atlantic Ocean never had extended periods of good weather, that the German weather service was non-existent, and that a 70kt Zeppelin cannot outrun a 15kt storm front.
Lots of big assumptions and dice rolling here.

Given that zeppelins are even more affected by weather than regular aircraft, it's not just safety that is a concern but the actual ability to operate that is also important.

A brief survey of the transatlantic service the Germans did run shows the North Atlantic trips were fraught with weather issues, damage to the vessels themselves, etc. [source Airships.net history of zeppelin operations detailed throughout the site]

This was the case with as complete weather reporting as was available at the time.

This scenario posits success with a fraction of the access to weather information.

This is why the South Atlantic route was prefered.

The North Atlantic may have great periods of weather. But without accurate weather reporting, how are you going to know? Roll the dice each time?

The existence of the German weather service is important but that's one half of the weather reporting equation. You need timely reports from both sides. In the northern hemispherse, weather systems mostly move from west to east. The Germans understood this. That's why they used the reports from the US weather service (on the west side of the Atlantic) during their peace time Zeppelin operations which they got in real time through radio communication. Without this source and without any real time substitute, again, this is a huge risk with an expensive, irreplaceable piece of equipment.


The Germans knew they needed weather reports from the Western side of the Atlantic for accurate forecasting. Hence the weather stations they set up in Canada ( Weather Station Kurt, Labrador, 1943, operational length - one month)

Allied weather reporting was always more accurate than German during WW2 precisely because they could rely on a wider and bigger reporting system having stations in North America, Iceland and Greenland.

The best history of German weather reporting is Wekusta by John Kingston which outlines the constant challenge the Germans had getting accurate weather reports in WW2. Another of his books Even the Birds Were Walking does a good job of covering the issue of weather reporting from the British side, illustrating the advantages the Allies held.

Just a general note on weather in the North Atlantic.
Tropical storms have one-minute maximum sustained winds of at least 39 mph (34 knots, 17 m/s, 63 km/h), while hurricanes have one-minute maximum sustained winds exceeding 74 mph (64 knots, 33 m/s, 119 km/h). Most North Atlantic tropical storms and hurricanes form between June 1 and November 30.
Some historical data on storms in the NA (it needs to be understood that this information is available due to as near as complete access to weather information was available, something our Zeppelin crew would not have access to)

http://tropical.atmos.colostate.edu/Rea ... thatlantic

Of course the above is all possibilities and historical averages. Nothing that definitely will happen.
But with weather reporting, you can take into account these situations if they occur. And mitigate them.

Without the reports you'd be flying blind.

As our poor Zeppelin crew would be in the scenario outlined.

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