Naval History Forums

Jerry, if you can determine if the U-boat had a FuMO30 it would probably clarify the situation. Upon further study, what was later desiginated as FuMO30 could have been on the U-boat in question during 1942. In that case it had the broadband dipoles on the backside of the FuMO30 antenna mattress to serve its radar detector receiver rather than the Biscay Cross. In which case the KTB shorthand in that context probably is:
EM1= passive sonar monitoring
Em2= active radar surviellence and locating
EM3= passive radar detector monitoring

This is probably referring to the FuMG41Ggu (FuMO29) radar system given the 1942 dates. The FuMO29 consisted of 12 half wave dipoles arrayed around the front of the conning tower. This was a phased array scanning antenna system; meaning the radar beam was panned several degrees to the left or right electronically. It didn't need a rotating antenna to cover most forward and side sectors. (The GEMA radar system otherwise was not well suited to service aboard a U-boat, nonetheless. To fit in within the tight confines several key modules had to be omitted which degraded performance, and the combination of 8kw of radiated power and the low mounting height of the relatively small antenna, meant that the range to a destroyer was less than 8km -but it would be much greater to an aircraft) The 11 smashed antennas are probably referring to 11 of the 12 dipoles.

Given the 1942 date it is likely not any other electronic system aboard a U-boat. The Metox receiver would have probably used the FuMB-Ant-2 Honduras (Biscay Cross) for its antenna on a U-boat in 1942.

The rotatable mattress antenna for FuMO30 (which superseded the FuMO29 a few months later) consisted of only 8 full wave dipoles. It did have 4 broadband dipoles (FuMB-Ant-5 Samoa) on the backside of the Mattress, however.

These broadband dipoles could be used to serve any suitable radar detector receiver such as the Metox/Sadir, or Samos, as well as a Fanoe, or Wanze from mid 1943. These passive receivers may have been referred to as EMIII in KTB shorthand, given EMI =optical ranging, and EMII =ranging radar in several of the surface ship KTB entries? (In 1935 EM-I was referred to as Sonar by GEMA and NVA engineers, and EM-II was radar. However these acronyms were forbidden by the KM as early as 1937, with the term DeTe used for radar instead. By 1942 FuMG was the standard KM acronym for radar, but DeTe persisted and several surface ship KTB entries in 1941 and early 1942 referred to radar used for range finding as EMII)

All together the FuMO30 dipoles accounts for a total of 12 dipoles on the FuMO30 mattress. But why would they need to cover the dipoles on the mattress with a canvas? It was usually stowed within a compartment on the conning tower when not in use, unless it could no longer fit in the pocket due to the damage. Then covering it with a canvas may have been resorted to? Nonetheless once again the chronology of 1942 would seem to indicate FuMO29. The FuMO30 antenna array would more likely fit a 1943 chronology although a 1942 chronology could still be possible. A FuMO61 fit out could also be possible in 1943 but more likely not before 1944.

Hello, I am Jerry Mason, the administrator of the U-boat Archive website http://uboatarchive.net/ Thank you for this website and your interesting and informative posts. I have translated a KTB from U-507 http://uboatarchive.net/KTB507-3.htm which mentions the use of EM a number of times (see pages 12/14/18/20/22/28/83). I suspect that the EM 3 may be a prototype of Metox of perhaps a version of the FuMO 29 or 30 radar. The boat seems to operate the EM 3 in bad weather to prevent surprise by aircraft. A typical entry being "Because of bad visibility EM 3 operated, no indications." On page 83 the CO notes that "11 antennas for the EM 3 system were smashed in heavy seas. To hide from view a covering tarpaulin was used." Since it has been some time since the posts on the EM 3, I wonder if the authors have any more thoughts on what the EM 3 was. Best regards, Jerry

The bad news is that I don't know your e-mail. The good news is that the PM button is that link up there at the top of the page, right below the KBismarck.org banner where it says "You have 1 new message." Of course, if you'd prefer, you can always send an e-mail to my screen name @alltel.net .

Tiornu bonjour sorry cannot find the button to receive your PM. <<old horses ...you know. E-mail would be fine.

Erik, I have sent you a Private Message.

Hallo wadinga, Tiornu. To Wadinga yes, it was the xtal of the local oscillator which beats against the radar frequency to obtain an intermediate frequence. I cannot check further, I returned the german books to the library. I am waiting for your e-mail if you have one.

To Tiornu please e-mail to me, I have a question, OK?

wadinga wrote:Erik, RF and all,

I just discovered I have the Brennecke book "Pocket Battleship" on my own shelves, but a cursory run through reveals little specific on radar useage. There are examples of using the Seetakt to track merchant ship prey at night, and an intriguing example of confused ID, in thinking an iceberg was a Nelson class during the run for home. I haven't found anything yet in this English translation about detecting/not detecting British radar.


As far as I can make out Brennecke's book on Bismarck has not been translated into English! Does anyone know otherwise? Amazes me that some of the contentious, poorly researched stuff we have seen written lately gets into print and yet a book on Bismarck, written relatively soon after the war, by a German officer who researched with witnesses doesn't get printed in English to reach a world readership.

All the best
wadinga

This is a common problem with books written in Germany before around 1960, they are out of print, cannot be obtained, aroused no outside interest and so remained largely unknown.

I do know that some transcripts were provided for the US Naval Institute Proceedings in the 1950's which might include this book, have you tried looking in this area?

wadinga wrote:Erik, RF and all,

I
It mentions "quartz" spares being delivered by u-boat in early 1941 prior to the run for home.


All the best
wadinga

I believe this piece of equipment was specifically requested by Scheer's officer responsible for the radar, as the funkmaat transmitting the request had a problem with the encoding letters for quartz so it was some time before the receiving station could make sense of the message.

Tiornu wrote:I won't divert the discussion into a castle topic, but I do love castles. I am a writer, and I often use fantasy medieval settings.
There are no medieval castles in Missouri! And Claudius never sent his men quite this far west....

Have you been to Britain?

We have lots of castles here.

dar Bonjour Wadinga, If yoy send me an e-mail I'll answer by e-mail on the dope about your question. erik ( ludwig.f9lt@wanadoo.fr )

Hallo Sean, yes I know RDF, used it prewar.

Only introduced Brinkmann to show to RF there wer ongoing discussions about radar.

The main point in my answer to RF is that in May 1941 Krancke was the only captain in the GN who had first hand real time experience of using radar during an encounter with an RN ship. Of course he could not give any info about how to use the R600. That was the domain of B-Dienst who should advise Admiral Bismarck. Erik

I won't divert the discussion into a castle topic, but I do love castles. I am a writer, and I often use fantasy medieval settings.
There are no medieval castles in Missouri! And Claudius never sent his men quite this far west....

Erik, RF and all,

I just discovered I have the Brennecke book "Pocket Battleship" on my own shelves, but a cursory run through reveals little specific on radar useage. There are examples of using the Seetakt to track merchant ship prey at night, and an intriguing example of confused ID, in thinking an iceberg was a Nelson class during the run for home. I haven't found anything yet in this English translation about detecting/not detecting British radar.

It mentions "quartz" spares being delivered by u-boat in early 1941 prior to the run for home.

It seems to me that Krancke would have valuable general knowledge of use and reliability of the Seetakt/EM II/FuMo system under operational conditions, which could be added to that from Operation Berlin. However I am still hazy about how much could be detected at sea from British radar transmissions using ordinary general purpose receivers, even against the comparatively low frequency systems like 279, 79 & 281. So Erik can you explain more on "He also showed that one could determine the presence of enemy radar also without having an R600. " His conclusion was apparently that there was no British radar at sea, but how can you say that because you detected no transmissions there were none?

As far as I can make out Brennecke's book on Bismarck has not been translated into English! Does anyone know otherwise? Amazes me that some of the contentious, poorly researched stuff we have seen written lately gets into print and yet a book on Bismarck, written relatively soon after the war, by a German officer who researched with witnesses doesn't get printed in English to reach a world readership.

Brinckmann goes on about an imaginary British long range passive sonar even better (apparently) than his GHG in his War Diary. He imagines and speculates about a dedicated device to pick up radar transmissions, although we now know only Bismarck had the one and only prototype R600, and this suggests it was so secret even Brinckmann didn't know it even existed. His comments on radio/radar silence were surely written after consultation with Henning von Schultz, his B-Dienst officer who expressed himself so appalled when they heard Lutjens' long transmission, knowing Bismarck was in the clear.

Langsdorff would undoubtedly have valued Seetakt if he was groping his way home through snowstorms and British patrols in the Denmark Strait, but he never got the chance.

All the best
wadinga

E.Ludwig wrote:Do you have information about the Graf Spee's orders. I read it somewhere but forgot to make a note. Au revoir, Erik

I'm not aware that radar featured much with Graf Spee, Rasenack for example seemed only to consider the Seetakt to be relevant for gunnery ranging.
Of course Harwood didn't have radar and given the excellent visibility on the day of the battle radar wouldn't have been needed anyway.

Matters might be very different if Graf Spee had tried to break out from Montevideo at night and if the British ships did have radar.