Kriegsmarine radars

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richtea
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Kriegsmarine radars

Post by richtea » Fri Feb 18, 2011 12:39 pm

No doubt this has been asked before, but can someone explain why the kriegsmarine were reticent in using radar ?
I'm thinking in particular about Scharnhorsts last sortie, in perpetual near darkness in an arctic winter surely radar could have helped the Scharnhorst find JW55B.
By 1943 the RN was using radar for target acquisition, range finding and anti-aircraft fire.
yet the Germans seemed to use radar in a far different way.
Could this be admiral Beys lack of big ship knowledge ?
being a destroyer man perhaps he did not realise the advantage radar gave him.
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Richard
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Re: Kriegsmarine radars

Post by RF » Fri Feb 18, 2011 6:09 pm

I assume you are talking about using the radar the KM ships had, not about the development of shipboard radar itself. Most German ships used radar sparingly for fear of betraying their position.
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Re: Kriegsmarine radars

Post by richtea » Fri Feb 18, 2011 10:21 pm

Thanks RF,
that's one of the reasons that i had read about.
I was thinking more on the lines of
German destroyer radar was very unreliable, Bey was primarily a destroyer man.
did he let this cloud his judgment on the use of radar on Scharnhorst.
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Re: Kriegsmarine radars

Post by dunmunro » Fri Feb 18, 2011 11:15 pm

richtea wrote:No doubt this has been asked before, but can someone explain why the kriegsmarine were reticent in using radar ?
I'm thinking in particular about Scharnhorsts last sortie, in perpetual near darkness in an arctic winter surely radar could have helped the Scharnhorst find JW55B.
By 1943 the RN was using radar for target acquisition, range finding and anti-aircraft fire.
yet the Germans seemed to use radar in a far different way.
Could this be admiral Beys lack of big ship knowledge ?
being a destroyer man perhaps he did not realise the advantage radar gave him.
Regards
Richard
Scharnhorst did use her FC radars for surface search, and the KM had been using FC radar for this purpose from 1939. The RN began using aerial warning radars (type 280/279) for target acquisition and FC/AAFC in 1939/40. However, the KM never deployed specialised WA and WS radars.

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Re: Kriegsmarine radars

Post by Dave Saxton » Sat Feb 19, 2011 3:39 am

richtea wrote:No doubt this has been asked before, but can someone explain why the kriegsmarine were reticent in using radar ?
I'm thinking in particular about Scharnhorsts last sortie, in perpetual near darkness in an arctic winter surely radar could have helped the Scharnhorst find JW55B.
By 1943 the RN was using radar for target acquisition, range finding and anti-aircraft fire.
yet the Germans seemed to use radar in a far different way.
Could this be admiral Beys lack of big ship knowledge ?
being a destroyer man perhaps he did not realise the advantage radar gave him.
Regards
Richard
It is often stated on the internet that the KM practiced a radar silence doctrine. This is not exactly correct. Actually the final Scarnhorst sorti was the only combat example of the German heavy warships maintaining a radar silence tactic. In all other cases they used radar and usually quite skillfully. There was no official doctrine, but it was up to the discretion of the admiral or captain.

Prior to 1942 the KM could use active radar rather carefree (and they did) because everybody else was so technically backward in terms of radar by comparison. From 1942 they could no longer use active radar so carefree because the enemy was catching up in terms of radar knowlege technique. It would often depend on the nature of the mission. A KM warship on offensive duty could prematurely give away its position by the careless use of active radar and the Germans were very aware of this fact. The Allies by contrast did not usually risk a mission kill by giving themselves away through careless use of active radar, so they had less to loose through careless use. We know that during some of the Tirpitz's 1942 sorties, that permission usually had to be asked for and received of the commanding officer to switch on the active radars. On New Years Eve 1942 Capt. Stange of the Luetzow ordered the active radars switched on for two minutes every ten minutes. After the British had given themselves away through their own radar emissions, Stange then switched on his ship's active radar and used it hence forth. After the loss of the Scharnhorst, the OKM issued printed guidelines to assist ship commanders on this difficult question.

I concur that Bey's lack of big ship experience was likely a factor in his poor application of his ship's radar capabilities. The SH was actually well equipped in terms of active radar capability. We now know that the SH was equipped with a FuMO26 in the weeks before the sorti, and that it was extensively tested and trained on for the use of blind fire direction by SH commanding officer in the fjords. This radar was a highly capable set specilizing in accurate blind fire direction, and with a BB to BB range well exceeding 30km. SH may have also been equipped with Hohentwiel K surface warning set with a detection range to destroyers of 36km. The FuMO26 was destroyed by a direct hit before it could be used.
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Re: Kriegsmarine radars

Post by Dave Saxton » Sat Feb 19, 2011 4:04 am

dunmunro wrote:Scharnhorst did use her FC radars for surface search, and the KM had been using FC radar for this purpose from 1939. The RN began using aerial warning radars (type 280/279) for target acquisition and FC/AAFC in 1939/40. However, the KM never deployed specialised WA and WS radars.
Seetakt was multirole radar adept at airwarning and surface warning as well as gunlaying. Actually Seetakt is in reference to Sea Tactical which is general tactical use, such as air warning and surface warning.
The British by contrast had by May 1941 almost a dozen different kinds of shipborne radar installed, but it was not until the 10cm type 271 (and 273) appeared, with sea trials in March and April 1941, that they had a surface-search set competitive with Seetakt.. (L Brown)


When Seetakt was first introduced in 1936 Fleet Command wanted it to be mainly a surface search radar hence the designation: Seetakt. But Naval Ordnance also saw how it could revolutionize gunlaying at sea and the basic design was heavilly biased to such capabilities. If it was used for gunlaying as the primary mission it was more properly referred to as Seeart for Sea Artillery. The earlist models were operational in 1937.
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: Kriegsmarine radars

Post by Dave Saxton » Sat Feb 19, 2011 4:27 am

richtea wrote: German destroyer radar was very unreliable,
Actually German naval radar, including sets used on destroyers, was very reliable, for a given time frame, especially considering the vacuum tube technology available during WWII. It was extra heavy duty in construction and modular in design. The second series of design was designed to be easily maintained and repaired at sea. The Scharnhorst's aft radar (the destroyers used the same basic radar modules) illustrates how durable the GEMA radar had become by 1943. It stayed in operation right up until almost the very end, if not the end, and had endured by that time hours of continous operation, and the relentless concussion of heavy guns in close proximity, and the pounding of a heavy artic storm, and the pounding of direct hits on their own ship from the enemy.

A more likely reason Bey did not carry over an attitude of utilizing radar from his destroyer experience, is the typical range attainment from a destroyer to another destroyer due to the relatively low antenna mounting height and the small size of the target in comparison to a large warship. Another factor of the German radar on destroyers was the nature of the antenna mounting which wasn't stabalised against pitch and roll (not so on the big ships). In rough seas it could be very difficult to use on the destroyers.
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: Kriegsmarine radars

Post by Thorsten Wahl » Sun Feb 20, 2011 6:22 pm

Kriegsmarine destroyer captains were instructed to search for signs of use of radar at the enemy at least since 1940.
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Re: Kriegsmarine radars

Post by richtea » Sun Feb 20, 2011 9:43 pm

Thank you ALL for the replies,
they have helped me to try and understand why admiral Bey did not use the one tool that
could have helped him to find JW55B.
Obviously once the covering cruisers destroyed his radar he was almost certain to fail.
Yet he still tried another sweep to the north.
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Richard
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Re: Kriegsmarine radars

Post by celticmarine10 » Mon Feb 21, 2011 3:39 am

Its obvious that the British had better radar. I'm no expert, but the radar used on surface vessels of the kriegsmarine doesn't seem to have been too reliable. Look at Bismarck. A single Salvo from her guns put her Radar out of action. Whats worse is that German radar most often could not be repaired at sea.
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Re: Kriegsmarine radars

Post by tommy303 » Mon Feb 21, 2011 5:50 pm

A single Salvo from her guns put her Radar out of action. Whats worse is that German radar most often could not be repaired at sea.
Shock of gunfire putting radar out of action was not just a German problem, but a problem for anyone else at the time that used radar at sea on a warship. Early sets of all nations were fragile, due in part to vacuum tube technologies, and if a more complicated problem developed which put the radar out of action, it was often only in port that it could be fixed in many cases. This was not always the case with German radars, particularly on larger ships. The electronics were modular and if a fault developed, one could replace the offending module with one from the store of spares, provided of course that the basic set itself was not destroyed completely by battle damage. On small vessels like destroyers, the number of spares carried might have been limited, as would have been the number of radar specialists on board, so it was possible in their case a break down would have required port side repairs more often than not. I really don't know; however on the big ships, repair of the set was possible at sea provided the fault was simple enough and could be traced to one of the modules. Repair of the aerial might have required more than available on board. The biggest problem, I believe, was recalibrating the set once a new module was in place and working. During Graf Spee's cruise, the radar broke down a number of times due to harmonic vibration from the diesels, but each time the set was repaired and brought back on line.

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Re: Kriegsmarine radars

Post by RF » Mon Feb 21, 2011 6:30 pm

I would imagine that rough sea conditions would also mitigate against repairs to exposed radio/radar equipment as well, particulary in Arctic waters.

The Scheer I recall had to wireless home a request for a spare part to her radar equipment whilst in the South Atlantic, which was picked up from a supply ship on the homeward bound run.
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Re: Kriegsmarine radars

Post by José M. Rico » Mon Feb 21, 2011 7:46 pm

tommy303 wrote:
A single Salvo from her guns put her Radar out of action. Whats worse is that German radar most often could not be repaired at sea.
Shock of gunfire putting radar out of action was not just a German problem, but a problem for anyone else at the time that used radar at sea on a warship. Early sets of all nations were fragile, due in part to vacuum tube technologies, and if a more complicated problem developed which put the radar out of action, it was often only in port that it could be fixed in many cases. This was not always the case with German radars, particularly on larger ships. The electronics were modular and if a fault developed, one could replace the offending module with one from the store of spares, provided of course that the basic set itself was not destroyed completely by battle damage. On small vessels like destroyers, the number of spares carried might have been limited, as would have been the number of radar specialists on board, so it was possible in their case a break down would have required port side repairs more often than not. I really don't know; however on the big ships, repair of the set was possible at sea provided the fault was simple enough and could be traced to one of the modules. Repair of the aerial might have required more than available on board. The biggest problem, I believe, was recalibrating the set once a new module was in place and working. During Graf Spee's cruise, the radar broke down a number of times due to harmonic vibration from the diesels, but each time the set was repaired and brought back on line.
I would only like to add that during Bismarck's final battle, the King George V also had her radar broken down due to the blast of its own 14 inch guns.

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Re: Kriegsmarine radars

Post by Dave Saxton » Mon Feb 21, 2011 10:21 pm

From Harry von Kroge on the overall relaibility of GEMA radars:
The Calais earned a reputation as a most reliable ground radar, along with Freya. It's hasty introduction soon determined that models with higher capabilities were called for, but the GEMA sets were not to be beaten, because consequent evaluation of failures had removed the teething troubles. The robust construction and clean engineering had proved itself worth the large material outlay, and this applied equally to the sea-borne Seetakt sets. They were exposed to climatic and combat conditions that necessarily led to more failures than ground radar. The number of failures that were repaired and returned to service through replaced modules or direct repair went down markedly with the increase in the quality of the training of radar personal aboard ship. Here the robust construction and clean engineering proved effective. Until the 1944 invasion the Navy alone used about 2,000 GEMA radars of all types aboard ship and land....
The series II sets introduced in 1940 were designed specifically to be more easilly repaired and maintained at sea, based on war experience. With the series I sets, the biggest problem was the fragile TS1 transmitter triodes. Replacing this triode originally required factory or NVK technicians. Herr Erblsoeh (one of the GEMA owners) himself accompanied Graf Spee during the Spanish Civil War cruise as the radar tech. The series II models employed much improved TS6 triodes which proved to be much more reliable. Along with the series II models came easy to use testing and diagnostic equipment, so the radars could be re-calibrated and tuned quickly aboard ship. When the Luetzow finally began shooting at Barents Sea it was found that the shock of the guns was rattling one of the tubes and making it difficult for the operator to spot the fall of shot. They shut down the radar, pulled and replaced the offending module, and recalibrated the set, bringing it back into action in a matter of a few minutes. As I posted above regarding the durability of Scharnhorst's aft radar at North Cape the GEMA radar design began to exhibit fairly remarkable reliability (at least as far as vacuum tube technology can be) by mid war.
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: Kriegsmarine radars

Post by Dave Saxton » Mon Feb 21, 2011 10:45 pm

RF wrote:The Scheer I recall had to wireless home a request for a spare part to her radar equipment whilst in the South Atlantic, which was picked up from a supply ship on the homeward bound run.
The Scheer's radar failed after about 5 months of operation at sea while the Scheer was in the Indian Ocean. The failure was of a quartz crystal that set the timing of the Central Impulse Geraete. This was a strange failure mode very unlikely to happen. Kind of like if the quartz timer in your wrist watch quit working. Once a U-boat had delivered a new quartz the radar sprang back to life. Earlier, after the eccounter with HX84 it was suspected that the radar had been knocked out of calibration, but it was quickly put back in order, indicating the availability of testing and recalibration equipment. After using radar to dodge a patrolling cruiser while passing back through the Denmark St. the radar failed again. This was because the weather proof doors to one of the water proof module cases had been left open allowing moisture from a heavy fog to invade the case. Once the case was dried out the radar returned to service.
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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