German radar at North Cape

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Christian VII.
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Re: German radar at North Cape

Postby Christian VII. » Wed Jan 21, 2015 5:48 pm

Dave Saxton wrote:
Christian VII. wrote:Absolutely excellent info Dave, it all just makes more and more sense now. The radar capabilities of the Germans, US & British were obviously remarkably close throughout the war, esp. within the Naval scene.

On a side note: Dave do you know at what range that Gneisenau detected Renown with her Seetakt radar on the 9th of April in 1940?

25km.


The Seetakt was used both as area search & FC radar during this engagement, right? Did Gneisenau commence firing at once, or?

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Re: German radar at North Cape

Postby dunmunro » Wed Jan 21, 2015 8:26 pm

Christian VII. wrote:Absolutely excellent info Dave, it all just makes more and more sense now. The radar capabilities of the Germans, US & British were obviously remarkably close throughout the war, esp. within the Naval scene.



No, this is not true. KM radar had an early lead but by May of 1941 it was totally outclassed by RN radar and remained so throughout the war. Consider Bismarck and PoW in May 1941(note, not all PoW radar systems were fully operational but all were fitted or in the process of being fitted):


GS radars:

Bismarck/PoW
3? / 1

combined GA/GS radars
Bismarck/PoW
0/4

combined WA/GA/GS radars
Bismarck/PoW
0/1

short range GA radars
Bismarck/PoW
0/4

By August 1941 PoW was also fitted with a 10cm type 273 WS/GS radar.

By Sept 1941, when her radar suite was completed PoW totally outclassed Tirpitz and this state of affairs remained until the end of the war; Tirpitz never received a radar outfit as capable as that fitted to PoW in Aug 1941.

Dec 1943:

GS radars:

Scharnhorst/DoY
3? / 2

combined GA/GS radars
Scharnhorst/DoY
0/4

combined WA/GA/GS radars
Scharnhorst/DoY
0/1

short range GA radars
Scharnhorst/DoY
0/6

WS/GS radar with PPI display
Scharnhorst/DoY
0/1

There's simply no comparison between DoY and Scharnhorst; the KM ship was totally outclassed in radar capability.

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Dave Saxton
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Re: German radar at North Cape

Postby Dave Saxton » Wed Jan 21, 2015 10:06 pm

Christian VII. wrote:The Seetakt was used both as area search & FC radar during this engagement, right? Did Gneisenau commence firing at once, or?



This was the first time in history that radar had been used to locate an enemy warship at night. The weather was nasty and they had to close range to within the visibility limits to identify what the radar contact was. Look outs on Gneisenau mis-identified the Renown as the Nelson and the other contacts (9 destroyers) as possible cruisers. This lead Luetjens to believe he had stumbled into the Home Fleet. He had no choice but to turn away based on this knowlege. Meanwhile the British were able to spot and lay guns on the Gneisenau (who they thought was the Scharnhorst and the Scharnhorst the Hipper) because the Germans had the rising sun behind them. Gneisenau opened fire only after the Renown did. The range was about 16,000 yards. The Gneisenau scored almost at once, a even though the Renown was mostly hidden in the gloom to the west. The radar set fitted was an early model without lobe switching, so it was used to range the target while using night optics for bearing.

The Scharnhorst's radar set was out of order due to a tuning error by one of its operators. Scharnhorst's shooting was poor.

The Renown required 16 salvos to find the range, but the hit it finally scored hit the foretop, severing the electrical power to the radar set. Gneisenau then ceased fire and Gneisenau pulled away into the weather using its superior speed, breaking contact. The Scharnhorst suffered several machinery break downs and so was unable to pull away for some time. Renown and Scharnhorst traded salvos several times with out either scoring.

Seetakt was a multi-role radar system used for FC, surface search, and air warning.
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.

Christian VII.
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Re: German radar at North Cape

Postby Christian VII. » Wed Jan 21, 2015 10:32 pm

dunmunro wrote:
Christian VII. wrote:Absolutely excellent info Dave, it all just makes more and more sense now. The radar capabilities of the Germans, US & British were obviously remarkably close throughout the war, esp. within the Naval scene.



No, this is not true. KM radar had an early lead but by May of 1941 it was totally outclassed by RN radar and remained so throughout the war. Consider Bismarck and PoW in May 1941(note, not all PoW radar systems were fully operational but all were fitted or in the process of being fitted):


GS radars:

Bismarck/PoW
3? / 1

combined GA/GS radars
Bismarck/PoW
0/4

combined WA/GA/GS radars
Bismarck/PoW
0/1

short range GA radars
Bismarck/PoW
0/4

By August 1941 PoW was also fitted with a 10cm type 273 WS/GS radar.

By Sept 1941, when her radar suite was completed PoW totally outclassed Tirpitz and this state of affairs remained until the end of the war; Tirpitz never received a radar outfit as capable as that fitted to PoW in Aug 1941.

Dec 1943:

GS radars:

Scharnhorst/DoY
3? / 2

combined GA/GS radars
Scharnhorst/DoY
0/4

combined WA/GA/GS radars
Scharnhorst/DoY
0/1

short range GA radars
Scharnhorst/DoY
0/6

WS/GS radar with PPI display
Scharnhorst/DoY
0/1

There's simply no comparison between DoY and Scharnhorst; the KM ship was totally outclassed in radar capability.


But now you're talking about the number of radars used on the ships, and this has nothing to do with the capability of the radar sets used.

As Dave points out KM radar was just as capable as RN radar in terms of range, accuracy & bearing. That having been said the RN ships might have been fitted with more radar sets by 1943 but, correct me if I'm wrong, the Germans were starting to equip their ships with more radar from then on as well.

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Re: German radar at North Cape

Postby Dave Saxton » Wed Jan 21, 2015 10:37 pm

dunmunro wrote:
Christian VII. wrote:Absolutely excellent info Dave, it all just makes more and more sense now. The radar capabilities of the Germans, US & British were obviously remarkably close throughout the war, esp. within the Naval scene.



No, this is not true. KM radar had an early lead but by May of 1941 it was totally outclassed by RN radar and remained so throughout the war.



Christian is correct here.

The Bismarck was equipped with three multi-role FuMO27 sets. In the firecontrol mode FuMO27 was far superior to POW's early model Type 284. It was also superior in the surface search role to any set the POW carried in May 1941.

Brown commenting on the importance of Type 271 wrote:

The British had by May 1941 almost a dozen different kinds of radar installed but it was not until when the 10cm type 271 appeared, with sea trials in March and April 1941, that they had a surface search set competitive to Seetakt.


So for the two most important roles of radar at sea, Bismarck had superior radar capability in May 1941.

Going into 1942 FuMO27 remained slightly superior to Type 284M and was about equal to Type 273P in the surface search mode.

FuMO26 was unquestionably superior to Type 284M in the firecontrol mode and could match the range of Type 273Q (without a PPI).

During 1944, Tirpitz was not only equipped with FuMO26, but also FuMO81 Berlin, FuMO63 Hohentwiel, and FuMO213 Wuerzburg. This suite was hardly outclassed by 1944 British radar suites. Moreover, the British were starting to replace the excellent Type 273Q with the poor performing Type 277 which was outclassed by FuMO81.
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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Re: German radar at North Cape

Postby dunmunro » Thu Jan 22, 2015 12:45 am

Christian VII. wrote:
But now you're talking about the number of radars used on the ships, and this has nothing to do with the capability of the radar sets used.

As Dave points out KM radar was just as capable as RN radar in terms of range, accuracy & bearing. That having been said the RN ships might have been fitted with more radar sets by 1943 but, correct me if I'm wrong, the Germans were starting to equip their ships with more radar from then on as well.


No, it isn't just numbers of radars but overall radar capability.

Sept 1941.
Number of long range (~20nm) WS/GS sets:
PoW/Tirpitz
1 / 0

Number of long range (~100nm in WA mode) WA/WS/GA/GS sets:
PoW/Tirpitz
1 / 0

number of dedicated secondary armament GA/GS
PoW/Tirpitz
4 / 0

number of dedicated short range GA radars:
PoW/Tirpitz
4 / 0

WS and WA sets could provide continuous all round surveillance without detracting from gunnery - Tirpitz could not do this.
PoW had dedicated GA/GS radars slaved to the secondary and tertiary directors - Tirpitz did not.

Whether or not the characteristics of one particular radar was marginally better than another serves only to obscure the fact that the RN had a far superior overall radar capability.

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Re: German radar at North Cape

Postby Dave Saxton » Thu Jan 22, 2015 1:31 am

Kind of like saying that the Mig-23, Mig-27, and Mig-29 presents an over all greater capability than the multi-role F/A-18?
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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Re: German radar at North Cape

Postby dunmunro » Thu Jan 22, 2015 2:18 am

Dave Saxton wrote:Kind of like saying that the Mig-23, Mig-27, and Mig-29 presents an over all greater capability than the multi-role F/A-18?


I'm not familiar with those aircraft.

Here's an example from real life. In Dec 1943 HMS Glasgow (and HMS Enterprise) engaged a force of KM destroyers that were attempting to escort blockade runners through the Bay of Biscay.

Glasgow's WS/GS type 273 was used to provide the CO with an overall tactical appreciation of the situation (and to augment the type 284). Her WA/GA/GS type 281 was used to provide continuous all round air and surface surveillance. Her GS type 284 was used to provide ranging data to the main armament. Her GA/GS type 285 radars were used to provide ranging data to the secondary armament. During the battle the Luftwaffe intervened and engaged Glasgow with air launched guided missiles. Glasgow detected the aircraft (and missile)with her WA radar and engaged it with accurate GA radar ranged long range AA fire and also engaged the missile with her GA short ranged radar CIWS; during this attack Glasgow continued to engage the KM surface threat with her dedicated GS radar ranged main armament.

Although Glasgow's radars in Dec 1943 were more modern and capable, PoW had essentially the same capabilities in Aug 1941.

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Re: German radar at North Cape

Postby Dave Saxton » Thu Jan 22, 2015 2:12 pm

As a practical matter, so many of these niche radars just didn't matter that much- most of the time. After Brown comments that the British had almost a dozen shipboard radars deployed, but it wasn't until Type 271 that the British at last had a surface search radar competitive with Seetakt he goes on:

In their hunt for the Bismarck only one shipboard radar set of the entire pack of hounds was effective...It remains a puzzle that a naval command that gave high priority to radar placed so little importance on surface search equuipment. The answer to the puzzle probably lies in Britian's approach to radar from the long long-wave side.


Long range air warning and a multitude of AA radars did little for the Prince of Wales off Kuantan. In the case of North Cape the only British radars that really mattered were Type 273 and Type 284. Off Guadalcanal the radars that really mattered were SG and Mk3.
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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Re: German radar at North Cape

Postby Dave Saxton » Thu Jan 22, 2015 2:30 pm

WS and WA sets could provide continuous all round surveillance without detracting from gunnery - Tirpitz could not do this.
PoW had dedicated GA/GS radars slaved to the secondary and tertiary directors - Tirpitz did not.


Sure it could. From Sept 41 through 1943 it had 3 separate active radars. Though 1944 it had six separate active radars. Tirpitz did not need dedicated radars for secondary directors. German firecontrol was not divided between main battery and secondary systems.
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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Re: German radar at North Cape

Postby Steve Crandell » Thu Jan 22, 2015 5:38 pm

Dave Saxton wrote:
WS and WA sets could provide continuous all round surveillance without detracting from gunnery - Tirpitz could not do this.
PoW had dedicated GA/GS radars slaved to the secondary and tertiary directors - Tirpitz did not.


Sure it could. From Sept 41 through 1943 it had 3 separate active radars. Though 1944 it had six separate active radars. Tirpitz did not need dedicated radars for secondary directors. German firecontrol was not divided between main battery and secondary systems.


To use those radars, didn't the rangefinder have to be trained all around the ship to search for contacts? Didn't it have a much narrower beam than the usual surface search radars in use at that time?

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Re: German radar at North Cape

Postby dunmunro » Thu Jan 22, 2015 6:47 pm

Dave Saxton wrote:As a practical matter, so many of these niche radars just didn't matter that much- most of the time. After Brown comments that the British had almost a dozen shipboard radars deployed, but it wasn't until Type 271 that the British at last had a surface search radar competitive with Seetakt he goes on:

In their hunt for the Bismarck only one shipboard radar set of the entire pack of hounds was effective...It remains a puzzle that a naval command that gave high priority to radar placed so little importance on surface search equuipment. The answer to the puzzle probably lies in Britian's approach to radar from the long long-wave side.


Long range air warning and a multitude of AA radars did little for the Prince of Wales off Kuantan. In the case of North Cape the only British radars that really mattered were Type 273 and Type 284. Off Guadalcanal the radars that really mattered were SG and Mk3.


The type 281 was developed specifically to be a combined WA/WS set and the RN was just transitioning to the type 271/273 during the Bismarck action. Neither RN cruiser (Suffolk and Norfolk) had the latest radar outfit (although Suffolk was reasonably up to date with a type 279 and a type 284)- it could take many months before ships were released for a refit to have their radars upgraded.

PoW suffered radar failures before and during her last battle (so did Bismarck), but her radar suite worked "as advertised" during Operation Halberd.

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Re: German radar at North Cape

Postby Christian VII. » Thu Jan 22, 2015 10:23 pm

What was the exact performance of the FuMO 26 with the enlarged 3x6 m matress?

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Re: German radar at North Cape

Postby Dave Saxton » Fri Jan 23, 2015 9:45 pm

Christian VII. wrote:What was the exact performance of the FuMO 26 with the enlarged 3x6 m matress?

Range: 30km +30%
Range accuracy: 25m
Bearing accuracy: 0.10*
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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Re: German radar at North Cape

Postby Dave Saxton » Fri Jan 23, 2015 10:06 pm

Steve Crandell wrote:
Dave Saxton wrote:
WS and WA sets could provide continuous all round surveillance without detracting from gunnery - Tirpitz could not do this.
PoW had dedicated GA/GS radars slaved to the secondary and tertiary directors - Tirpitz did not.


Sure it could. From Sept 41 through 1943 it had 3 separate active radars. Though 1944 it had six separate active radars. Tirpitz did not need dedicated radars for secondary directors. German firecontrol was not divided between main battery and secondary systems.


To use those radars, didn't the rangefinder have to be trained all around the ship to search for contacts? Didn't it have a much narrower beam than the usual surface search radars in use at that time?



1942-43 They could use one for FC, while keeping the other two in all around search. Or 2 for FC and 1 for search..ect..The range finders could rotate conituously through 360* in the same direction. They did not need to reverse direction to prevent cabling from binding up, which I have seen claimed incorrectly on the internet. The possible rate of rotation depended if the RF traverse was synced to the master gyro or not. Controlled through the master gyro the rate of rotation was 1 rotation every 70 seconds. It could also be controlled manually with much higher traverse rates, or set to rotate continously at more rapid rates. The beam width of FuMO27 was the same as SG or Type 271.

In 1944 two additional radar sets, Berlin and Hohentwiel were mounted to the heads of masts. Berlin provided a continuous "sharply defined" 360* panoramic view on PPI indicators.
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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