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Clay Blair's "hitler's U-Boat War" Two Volume Set.


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#41 Rick

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Posted 05 February 2020 - 0926 AM

German maritime engineering failure

 

https://digitalcommo...599&context=etd

 

Some links:

 
 
 
 

Edited by Rick, 05 February 2020 - 0945 AM.

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#42 Stuart Galbraith

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Posted 05 February 2020 - 0933 AM

Yes, that would have cost us dear off Norway if they had got those right.


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#43 Chris Werb

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Posted 05 February 2020 - 1455 PM

Stuart, if you read Blair, you'll see the Germans were very imaginative and opportunistic in sending U-boats all over the place - they did the Indian Ocean much earlier than 1944 for example. However, the farther away you send them, the longer they take to get there and back and the more you have lay on tanking, resupply etc. which imposes further virtual attrition of your combat potential.  There aint no such thing as a free lunch.


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#44 Chris Werb

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Posted 05 February 2020 - 1457 PM

 

I was aware of the torpedo failure, which was a lucky break for us (similar to the one the Japanese had with USN torps early on). I hadn't seen that treatise though - very informative! Thank you.


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#45 Stuart Galbraith

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Posted 07 February 2020 - 0303 AM

Stuart, if you read Blair, you'll see the Germans were very imaginative and opportunistic in sending U-boats all over the place - they did the Indian Ocean much earlier than 1944 for example. However, the farther away you send them, the longer they take to get there and back and the more you have lay on tanking, resupply etc. which imposes further virtual attrition of your combat potential.  There aint no such thing as a free lunch.

I know that Chris, but its worth remembering, in further climes even the deck gun become useable again. With the lack of aircover and convoying, even prize rules would probably work.


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#46 Rick

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Posted 07 February 2020 - 0433 AM

At the time it occurred, it appears the "Battle for the Atlantic" in the early years was not going as well as the Royal Navy had hoped for. It appears though that technology won it for the Allies with radio direction finding, radar, and especially the airplane turning the tide. These were discoveries  that both navies could not have foreseen but one on which the RN put for more time, effort, and talent into once they were discovered. Naturally enough of course.


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#47 Chris Werb

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Posted 07 February 2020 - 1914 PM

At the time it occurred, it appears the "Battle for the Atlantic" in the early years was not going as well as the Royal Navy had hoped for. It appears though that technology won it for the Allies with radio direction finding, radar, and especially the airplane turning the tide. These were discoveries  that both navies could not have foreseen but one on which the RN put for more time, effort, and talent into once they were discovered. Naturally enough of course.

 

With what we know about what was possible with the technologies of the time, what turned out to be viable technical advances almost all favoured the Allies rather than the Axis in the North Atlantic. There was simply no counter the Germans could come up with against MACs, escort carriers and VLR aircraft, for example. As they started to deploy effective DCs, centimetric ASV, Leigh lights, rocket harpoons and homing torpedoes, things only ever got worse. Even without all those things, a hundred more early model Liberators would almost certainly have decisively turned things against the U-boats in the Atlantic, at least a year earlier. Even if the Germans deployed air search radars on subs as the US did, the sub would still have to dive and keeping them underwater effectively mission killed them. The radar would have provided something else to DF as well.


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#48 Jeff

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Posted 08 February 2020 - 1739 PM

I'm always struck by how drastically things changed in May of '43. The corner had been turned by then but the results were like flipping a light switch that month. How the Germans kept sending U-boats out after that was astonishing. They were getting murdered for no reason other than "doing their part". It kept Doenitz in Hitler's good graces, but it didn't do much for the lives of the U-boat crews.


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#49 RETAC21

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Posted 09 February 2020 - 0648 AM

I'm always struck by how drastically things changed in May of '43. The corner had been turned by then but the results were like flipping a light switch that month. How the Germans kept sending U-boats out after that was astonishing. They were getting murdered for no reason other than "doing their part". It kept Doenitz in Hitler's good graces, but it didn't do much for the lives of the U-boat crews.

 

There was that, but also it was the only strategy that may help the Germans, they tried different approaches, like sending U boats to other areas, a coastal campaign and sending them against the Murmansk run, but it was also important to keep the allies focused on the battle of the Atlantic to avoid those resources appearing elsewhere, such as supporting naval invasions in Italy or Greece or stregthening the defence of the Artic convoys.


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#50 Stuart Galbraith

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Posted 09 February 2020 - 0700 AM

I'm always struck by how drastically things changed in May of '43. The corner had been turned by then but the results were like flipping a light switch that month. How the Germans kept sending U-boats out after that was astonishing. They were getting murdered for no reason other than "doing their part". It kept Doenitz in Hitler's good graces, but it didn't do much for the lives of the U-boat crews.

I would have to check, but that was around the time they finally found a reliable break into 4 wheel Enigma if I remember rightly. Im sure there were many other technical advances showing up at the same time, but I think that was probably the main cause.


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#51 RETAC21

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Posted 09 February 2020 - 0903 AM

 

I'm always struck by how drastically things changed in May of '43. The corner had been turned by then but the results were like flipping a light switch that month. How the Germans kept sending U-boats out after that was astonishing. They were getting murdered for no reason other than "doing their part". It kept Doenitz in Hitler's good graces, but it didn't do much for the lives of the U-boat crews.

I would have to check, but that was around the time they finally found a reliable break into 4 wheel Enigma if I remember rightly. Im sure there were many other technical advances showing up at the same time, but I think that was probably the main cause.

 

 

https://uboat.net/te...gma_ciphers.htm

 

NAVAL ENIGMA Ciphers

prepared by Ralph Erskine

The main Enigma ciphers used by the U-boats are listed below. The Bletchley codename for a cipher is given first, with the Kriegsmarine name in brackets.

Dolphin (Heimische Gewässer, later Hydra)

Dolphin came into service at the beginning of the war. It was used by all U-boats (and ships) in "home waters" (an area which included the Atlantic) until 5 October 1941 (see Shark).

Bletchley broke Dolphin from 1 August 1941 until the end of the war.

Shark (Triton)

Used by the Atlantic and Mediterranean U-boats from 5 October 1941. Introduced because of fears about security, especially the threat from the British Secret Service, which was highly (but overly) respected by the Kriegsmarine. Shark used three-rotor Enigma (M3) until 1 February 1942, when it switched to the four-rotor version (M4).

Bletchley broke Shark in M3 form. The M4 version was only broken on three days before 13 December 1942. From then until the end of August 1943, it was generally broken, but quite often late. From September 1943 onwards, Shark was normally broken within about 24 hours.

Turtle (Medusa)

Used by the Mediterranean U-boats from June 1943 to October 1944. Turtle was broken from June 1943 onwards.

Narwhal (Niobe)

Used by the Northern U-boats (based in Norway) from 25 June 1944 to the end of the war. Narwhal was broken from September 1944.

[No British name] (Thetis)

The cipher for U-boats on tactical training exercises in the Baltic. Thetis was never broken.

Grampus (Poseidon)

Used by U-boats in the Black Sea from October 1943 to August 1944. Grampus was broken from October 1943.

Sunfish (Tibet)

Used by supply ships and U-boats in the Far East from September 1941. Sunfish was intermittently broken from August 1943.

Other naval Enigma ciphers

These included:

Barracuda (Neptun)

The cipher for fleet operations. Barracuda was used from May 1941. It was never broken.

Bonito (Eichendorff)

Used by the Small Battle Units Command (which covered midget submarines, such as Marder and Seehund) from March 1944 to the end of the war.

Bonito was first broken in May 1944, and generally solved from July 1944.

Sources
  • Der Schlüssel M Allgemeine Bestimmungen (M. Dv. Nr 32/3)
  • British Intelligence in the Second World War: Its Influence on Strategy and Operations,
    F. H. Hinsley, with E. E. Thomas, C. F. G. Ransom and R. C. Knight,
    volume 2 (London, 1981), Appendix 4; volume 3(1) (London, 1984), Appendix 3.

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#52 Chris Werb

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Posted 09 February 2020 - 1144 AM

 

I'm always struck by how drastically things changed in May of '43. The corner had been turned by then but the results were like flipping a light switch that month. How the Germans kept sending U-boats out after that was astonishing. They were getting murdered for no reason other than "doing their part". It kept Doenitz in Hitler's good graces, but it didn't do much for the lives of the U-boat crews.

I would have to check, but that was around the time they finally found a reliable break into 4 wheel Enigma if I remember rightly. Im sure there were many other technical advances showing up at the same time, but I think that was probably the main cause.

 

 

The allies were also deploying escort carriers and MACs in significant numbers and had finally (sort of) gotten it together on deploying VLR aircraft - both carrier and VLR aircraft had much better depth charges, rockets and homing torpedoes. Escort and support groups were becoming plentiful with better training, better cooperation with aircraft, better sensors and weapons. It got to the point that some convoys were deliberately sailed into known u-boot patrol lines to flush them out and provide targets, particularly to air.  In return the Germans (who did not believe we had broken Enigma, were using HF/DF to anything like the extent we were and were unaware of centimetric radar) tried a variety of things - the T-5 anti escort homing torpedo, arming u-boats with lots of 2cm and 3.7cm Flak guns and telling them to sail in groups and fight it out with aircraft on the surface, sonar and radar decoys and a new radar detector (that also could not detect centimetric radar). None of that worked against the overwhelming numerical and technological strength and increasing competence of the allies in the air and at sea. That and shortly thereafter they Germans definitively lost the ability to decode our convoy comms. They were fucked and, as Jeff pointed out, they were sent to their deaths simply to cause virtual attrition in numbers of sailings by the enforced maintenance of the convoy system and to tie up allied resources in tracking them down and killing them.


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#53 Stuart Galbraith

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Posted 09 February 2020 - 1200 PM

I'm always struck by how drastically things changed in May of '43. The corner had been turned by then but the results were like flipping a light switch that month. How the Germans kept sending U-boats out after that was astonishing. They were getting murdered for no reason other than "doing their part". It kept Doenitz in Hitler's good graces, but it didn't do much for the lives of the U-boat crews.

I would have to check, but that was around the time they finally found a reliable break into 4 wheel Enigma if I remember rightly. Im sure there were many other technical advances showing up at the same time, but I think that was probably the main cause.
 
https://uboat.net/te...gma_ciphers.htm
 


NAVAL ENIGMA Ciphers
prepared by Ralph Erskine

The main Enigma ciphers used by the U-boats are listed below. The Bletchley codename for a cipher is given first, with the Kriegsmarine name in brackets.
Dolphin (Heimische Gewässer, later Hydra)
Dolphin came into service at the beginning of the war. It was used by all U-boats (and ships) in "home waters" (an area which included the Atlantic) until 5 October 1941 (see Shark).
Bletchley broke Dolphin from 1 August 1941 until the end of the war.
Shark (Triton)
Used by the Atlantic and Mediterranean U-boats from 5 October 1941. Introduced because of fears about security, especially the threat from the British Secret Service, which was highly (but overly) respected by the Kriegsmarine. Shark used three-rotor Enigma (M3) until 1 February 1942, when it switched to the four-rotor version (M4).
Bletchley broke Shark in M3 form. The M4 version was only broken on three days before 13 December 1942. From then until the end of August 1943, it was generally broken, but quite often late. From September 1943 onwards, Shark was normally broken within about 24 hours.
Turtle (Medusa)
Used by the Mediterranean U-boats from June 1943 to October 1944. Turtle was broken from June 1943 onwards.
Narwhal (Niobe)
Used by the Northern U-boats (based in Norway) from 25 June 1944 to the end of the war. Narwhal was broken from September 1944.
[No British name] (Thetis)
The cipher for U-boats on tactical training exercises in the Baltic. Thetis was never broken.
Grampus (Poseidon)
Used by U-boats in the Black Sea from October 1943 to August 1944. Grampus was broken from October 1943.
Sunfish (Tibet)
Used by supply ships and U-boats in the Far East from September 1941. Sunfish was intermittently broken from August 1943.
Other naval Enigma ciphers
These included:[/size]
Barracuda (Neptun)
The cipher for fleet operations. Barracuda was used from May 1941. It was never broken.
Bonito (Eichendorff)
Used by the Small Battle Units Command (which covered midget submarines, such as Marder and Seehund) from March 1944 to the end of the war.
Bonito was first broken in May 1944, and generally solved from July 1944.
Sources
  • Der Schlüssel M Allgemeine Bestimmungen (M. Dv. Nr 32/3)
  • British Intelligence in the Second World War: Its Influence on Strategy and Operations,
    F. H. Hinsley, with E. E. Thomas, C. F. G. Ransom and R. C. Knight,
    volume 2 (London, 1981), Appendix 4; volume 3(1) (London, 1984), Appendix 3.


Thanks for that, it's later than I remember. I do remember they were using the settings of the weather forecast at some remote site that was putting part of the system in neutral.

Have you read the High Sebag Montefiore book on naval Enigma? It's really good.
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#54 RETAC21

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Posted 09 February 2020 - 1230 PM

 

 

 

I'm always struck by how drastically things changed in May of '43. The corner had been turned by then but the results were like flipping a light switch that month. How the Germans kept sending U-boats out after that was astonishing. They were getting murdered for no reason other than "doing their part". It kept Doenitz in Hitler's good graces, but it didn't do much for the lives of the U-boat crews.

I would have to check, but that was around the time they finally found a reliable break into 4 wheel Enigma if I remember rightly. Im sure there were many other technical advances showing up at the same time, but I think that was probably the main cause.
 
https://uboat.net/te...gma_ciphers.htm
 


NAVAL ENIGMA Ciphers
prepared by Ralph Erskine

The main Enigma ciphers used by the U-boats are listed below. The Bletchley codename for a cipher is given first, with the Kriegsmarine name in brackets.
Dolphin (Heimische Gewässer, later Hydra)
Dolphin came into service at the beginning of the war. It was used by all U-boats (and ships) in "home waters" (an area which included the Atlantic) until 5 October 1941 (see Shark).
Bletchley broke Dolphin from 1 August 1941 until the end of the war.
Shark (Triton)
Used by the Atlantic and Mediterranean U-boats from 5 October 1941. Introduced because of fears about security, especially the threat from the British Secret Service, which was highly (but overly) respected by the Kriegsmarine. Shark used three-rotor Enigma (M3) until 1 February 1942, when it switched to the four-rotor version (M4).
Bletchley broke Shark in M3 form. The M4 version was only broken on three days before 13 December 1942. From then until the end of August 1943, it was generally broken, but quite often late. From September 1943 onwards, Shark was normally broken within about 24 hours.
Turtle (Medusa)
Used by the Mediterranean U-boats from June 1943 to October 1944. Turtle was broken from June 1943 onwards.
Narwhal (Niobe)
Used by the Northern U-boats (based in Norway) from 25 June 1944 to the end of the war. Narwhal was broken from September 1944.
[No British name] (Thetis)
The cipher for U-boats on tactical training exercises in the Baltic. Thetis was never broken.
Grampus (Poseidon)
Used by U-boats in the Black Sea from October 1943 to August 1944. Grampus was broken from October 1943.
Sunfish (Tibet)
Used by supply ships and U-boats in the Far East from September 1941. Sunfish was intermittently broken from August 1943.
Other naval Enigma ciphers
These included:[/size]
Barracuda (Neptun)
The cipher for fleet operations. Barracuda was used from May 1941. It was never broken.
Bonito (Eichendorff)
Used by the Small Battle Units Command (which covered midget submarines, such as Marder and Seehund) from March 1944 to the end of the war.
Bonito was first broken in May 1944, and generally solved from July 1944.
Sources
  • Der Schlüssel M Allgemeine Bestimmungen (M. Dv. Nr 32/3)
  • British Intelligence in the Second World War: Its Influence on Strategy and Operations,
    F. H. Hinsley, with E. E. Thomas, C. F. G. Ransom and R. C. Knight,
    volume 2 (London, 1981), Appendix 4; volume 3(1) (London, 1984), Appendix 3.


Thanks for that, it's later than I remember. I do remember they were using the settings of the weather forecast at some remote site that was putting part of the system in neutral.

Have you read the High Sebag Montefiore book on naval Enigma? It's really good.

 

 

Agreed, good read


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#55 Ken Estes

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Posted 09 February 2020 - 1419 PM

 

 

I'm always struck by how drastically things changed in May of '43. The corner had been turned by then but the results were like flipping a light switch that month. How the Germans kept sending U-boats out after that was astonishing. They were getting murdered for no reason other than "doing their part". It kept Doenitz in Hitler's good graces, but it didn't do much for the lives of the U-boat crews.

I would have to check, but that was around the time they finally found a reliable break into 4 wheel Enigma if I remember rightly. Im sure there were many other technical advances showing up at the same time, but I think that was probably the main cause.

 

 

The allies were also deploying escort carriers and MACs in significant numbers and had finally (sort of) gotten it together on deploying VLR aircraft - both carrier and VLR aircraft had much better depth charges, rockets and homing torpedoes. Escort and support groups were becoming plentiful with better training, better cooperation with aircraft, better sensors and weapons. It got to the point that some convoys were deliberately sailed into known u-boot patrol lines to flush them out and provide targets, particularly to air.  In return the Germans (who did not believe we had broken Enigma, were using HF/DF to anything like the extent we were and were unaware of centimetric radar) tried a variety of things - the T-5 anti escort homing torpedo, arming u-boats with lots of 2cm and 3.7cm Flak guns and telling them to sail in groups and fight it out with aircraft on the surface, sonar and radar decoys and a new radar detector (that also could not detect centimetric radar). None of that worked against the overwhelming numerical and technological strength and increasing competence of the allies in the air and at sea. That and shortly thereafter they Germans definitively lost the ability to decode our convoy comms. They were fucked and, as Jeff pointed out, they were sent to their deaths simply to cause virtual attrition in numbers of sailings by the enforced maintenance of the convoy system and to tie up allied resources in tracking them down and killing them.

 

Another key was the ability to inflict serious losses in the Bay of Biscay with all types of aircraft using centimeter wave airborne radar.

 

The ahead thrown weapons greatly increased surface ship lethality vs subs.


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#56 Chris Werb

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Posted 11 February 2020 - 1335 PM

 

 

 

I'm always struck by how drastically things changed in May of '43. The corner had been turned by then but the results were like flipping a light switch that month. How the Germans kept sending U-boats out after that was astonishing. They were getting murdered for no reason other than "doing their part". It kept Doenitz in Hitler's good graces, but it didn't do much for the lives of the U-boat crews.

I would have to check, but that was around the time they finally found a reliable break into 4 wheel Enigma if I remember rightly. Im sure there were many other technical advances showing up at the same time, but I think that was probably the main cause.

 

 

The allies were also deploying escort carriers and MACs in significant numbers and had finally (sort of) gotten it together on deploying VLR aircraft - both carrier and VLR aircraft had much better depth charges, rockets and homing torpedoes. Escort and support groups were becoming plentiful with better training, better cooperation with aircraft, better sensors and weapons. It got to the point that some convoys were deliberately sailed into known u-boot patrol lines to flush them out and provide targets, particularly to air.  In return the Germans (who did not believe we had broken Enigma, were using HF/DF to anything like the extent we were and were unaware of centimetric radar) tried a variety of things - the T-5 anti escort homing torpedo, arming u-boats with lots of 2cm and 3.7cm Flak guns and telling them to sail in groups and fight it out with aircraft on the surface, sonar and radar decoys and a new radar detector (that also could not detect centimetric radar). None of that worked against the overwhelming numerical and technological strength and increasing competence of the allies in the air and at sea. That and shortly thereafter they Germans definitively lost the ability to decode our convoy comms. They were fucked and, as Jeff pointed out, they were sent to their deaths simply to cause virtual attrition in numbers of sailings by the enforced maintenance of the convoy system and to tie up allied resources in tracking them down and killing them.

 

Another key was the ability to inflict serious losses in the Bay of Biscay with all types of aircraft using centimeter wave airborne radar.

 

The ahead thrown weapons greatly increased surface ship lethality vs subs.

 

 

Especially as the Germans were unaware of centimetric ASV radar until long after its introduction. The increase in lethality of unguided AS weapons was staggering. Obviously, you have to look at weapon as part of a weapon system as it was necessary to locate the submarine in three dimensions and launch projectiles to coincide with it.  The Squid was directly linked to the recorder on the Sonar which provided accurate range and depth data on the target and continuously updated the fuses until launch - some accounts say it actually fired the mortar. In one account I read, a typical DC pattern early in the war, directed by ASDIC of the period had about a 2% chance of killing a typical u-boat in deep water. Twin squid, used on Loch class frigates, with its attendant 144/147 sonar combination (also used with Hedgehog on some vessels) yielded a kill rate of 60% per salvo. Obviously, DCs would have an improved chance if used in combination with that sonar suite too, but post war trials apparently found that Squid was still nine times more effective than depth charges (presumably hydrostatic fused cylindrical rather than the much improved American tear drop shaped, fast-sinking magnetic fused ones).


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