German radar at North Cape

Warship design and construction, terminology, navigation, hydrodynamics, stability, armor schemes, damage control, etc.
Serg
Member
Posts: 107
Joined: Mon Jun 20, 2005 6:23 am
Location: Russia

German radar at North Cape

Post by Serg » Sat Jun 11, 2011 2:55 pm

I have some questions after reading "German capital ships and raiders in WW2" vol2 (from Scharnhorst to Tirpitz).

Well, German gunnery "improved in speed and accuracy, until, between 17000 and 20000 yards DoY frequently straddled and there were many near misses."
According to p15 (sinking of Scharnhorst)
The reported improvement of the enemy's fire in the later stages was PROBABLY due to some or all of the following: ... cessation of radar jamming when DoY mainmast was hit, and the jamming set put out of action.
For me quite interesting to know was British jammers really effective against German naval radar or not? Maybe this is answer on question why Scharnhorst was blind up to 12000 yardes. That might be true that DoY used jammer immediately after fixing Scharnhorst on radar.

And another side of story. German battle cruiser Scharnhorst, interrogation of survivors p10
"Jammer: Several survivors have referred to a Jammer carried on board, although it is not clear whether this was used in connection with enemy W/T or radar traffic. One survivor said that their own radar could not be used when it was switched on."
Does this ship have an antiradar set or not. According to last statement it does?

Here goes p19 where we read about
Gunnery radar: no useful details of the particular gunnery radar arrangement of the Scharnhorst were obtained, but it appears that there were two sets, probably fitted with beam-splitting with a possible accuracy of plus or minus one to two mils (3-6 minutes) (Note - This bearing accuracy, if true, would be of a high order comparable with that obtained with 274 and the later US low angle gunnery radars).
But it is well known that the admiral Frezer asserted in his action report "There is no doubt that, despite its shortcomings, British radar is still far superior to any yet encountered in German ships, and that this technical superiority and the correct employment of the gear enabled the Home Fleet to find, fix, fight and finish off Scharnhorst." I wonder is it tactics to improve morale like with German guided bombs?

User avatar
Karl Heidenreich
Senior Member
Posts: 4808
Joined: Thu Jan 12, 2006 3:19 pm
Location: San José, Costa Rica
Contact:

Re: German radar at North Cape

Post by Karl Heidenreich » Sat Jun 11, 2011 3:26 pm

The Germans had a very good radar equipment. THe Scharnhorst at North Cape had it shut down in order to avoid the British to detect it'ss transmision and fix their location. Let's remember that DoY didn't found target only with radar, they use traditional optical help in order to fire against Scharnhorst, which on the other side was crippled by a lucky hit early in the combat.
An appeaser is one who feeds a crocodile, hoping it will eat him last.
Sir Winston Churchill

User avatar
Dave Saxton
Supporter
Posts: 2953
Joined: Sat Nov 27, 2004 9:02 pm
Location: Rocky Mountains USA

Re: German radar at North Cape

Post by Dave Saxton » Sat Jun 11, 2011 4:16 pm

The British had jamming equipment but there's a report that mentions that it wasn't effective at North Cape because it wasn't operated correctly. The British had developed noise jamming to be used against Seetakt, because the coastal Seetatks (Calais B) had began blind fire direction on coastal convoys in Sept 1940. The jamming was first used in Feb 1941 when a coastal convoy was being hammered by Seetakt directed blind fire from coastal artillery near Dover. As soon as the jamming started the Germans ceased fire. The Germans responded by making Seetakt frequency agile. They could adjust the wave length over a narrow range and side step the jamming.
One survivor said that their own radar could not be used when it was switched on."
Its possible that as the Germans began the fight, their radar was partially jammed but it did not remain so adjusting the frequency. The Germans would oft times pretend that the jamming was effective so that the enemy would continue to believe it was effective. (The Allies did the same in response to German jamming, at least in the Med). Seetakt's sister radars, the Freyas, were routinely attempted to be jammed, or so thought during air raids, but after the war it was found that the Freyas usually side stepped the jamming. The GEMA radar was not easily jammed because it responded to echo pulses that were encoded with a frequency modulation. The Germans also had jammers and it was used during the Channel Dash against British 150cm radar.

The Scharnhorst first began their fight against the Duke of York using the night optics rather than the radar, or possibly in combination with radar ranging and optical bearing and spotting. Hence they fired star shell to be used with the night optics. The night optics required some artificial light. The night optics would not have been effective as the range increased much beyond 11-12km, forcing the Scharnhorst to rely more and more on its remaining radar set alone. Hence as the range increased the Scharnhorst ceased to fire star shell indicating it had switched over to full radar control. One notes that the Scharnhorst's shooting was much improved as the range increased beyond the effective range of the night optics rather than falling off. This can't be contributed to SH firing on enemy gun flashes. Its very accurate shooting from beyond 17k proves its radar directed shooting was very effective and remained effective.
Gunnery radar: no useful details of the particular gunnery radar arrangement of the Scharnhorst were obtained, but it appears that there were two sets, probably fitted with beam-splitting with a possible accuracy of plus or minus one to two mils (3-6 minutes) (Note - This bearing accuracy, if true, would be of a high order comparable with that obtained with 274 and the later US low angle gunnery radars).
The 1940 redesign of Seetakt introduced a form of lobing, nick named Radattel Peilung. It provided a bearing accuracy of 1/10 of degree so the above was absolutely correct. These features were used with German radar aboard major warships from late 1941 providing blind fire capability. Also in 1943 an improved fine ranging system was introduced which provided a range accuracy of 25 meters and a resolution for range of 10 meters regardless of the range. The German RDFC was as good as Allied late war RD FC.

The Scharnhorst in the weeks prior to North Cape was equipped with the most update firecontrol set (FuMO26) at the foretop position and a series of radar tests and blind fire gunnery exercises were carried out in the Fjords. Unfortunately for the Germans, the new radar set at the foretop was destroyed by a direct hit from the Norfolk in the first Skirmish leaving SH 1/2 blind and only with the older radar aft. Of course once this happened the British had a significant overall radar advantage through the remaining combat scenarios that day as observed by Fraser.
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.

User avatar
Karl Heidenreich
Senior Member
Posts: 4808
Joined: Thu Jan 12, 2006 3:19 pm
Location: San José, Costa Rica
Contact:

Re: German radar at North Cape

Post by Karl Heidenreich » Sat Jun 11, 2011 4:56 pm

Dave Saxton:
because the coastal Seetatks (Calais B) had began blind fire direction on coastal convoys in Sept 1940
That's three years before the North Cape action and four years before the over dimensioned firing of the Iowas over Nowaki. Quite interesting if you consider the myth that only the allies did developed blind fire capability (which never showed in facts, by the way).
An appeaser is one who feeds a crocodile, hoping it will eat him last.
Sir Winston Churchill

dunmunro
Senior Member
Posts: 3541
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: German radar at North Cape

Post by dunmunro » Sat Jun 11, 2011 7:20 pm

I think the biggest factor in Scharnhorst's gunnery was that DoY ran out of flashless powder for her 5.25" guns, and Scharnhorst was then able to optically range and train on the 5.25" muzzle flash.

User avatar
Dave Saxton
Supporter
Posts: 2953
Joined: Sat Nov 27, 2004 9:02 pm
Location: Rocky Mountains USA

Re: German radar at North Cape

Post by Dave Saxton » Sat Jun 11, 2011 7:41 pm

Quite interesting if you consider the myth that only the allies did developed blind fire capability (which never showed in facts, by the way).
Well for blind fire to surface targets you need to locate the target precisely for distance and for bearing and you can develop an accurate firing solution. The Allied firecontrol radars could perform those functions and so were capable of blind fire. Most navies that developed radar directed blind firecontrol capabilities tended to use the radar attained ranges combined with optical bearing and spotting unless the circumstances dictated that they could not use the optics at all. Only in such cases they would have to use full radar fire direction.


The Duke of York was apparently also using radar combined with optics at North Cape, and illuminated the Scharnhorst with star shell, until the battle range outstripped the usefull range of its optics. It then went over to full radar directed fire using its Type 284M until it began to have difficulty in spotting the fall of shot. This was why the DoY was forced to cease fire at about 6:24 PM with the range at 19.5km.

Spotting shell splashes with radar is mainly a function of the signal to noise ratio and the resolution for range. The Type 284M actually had good resolution for range of 150 meters so the inability to spot shell splashes after awhile is puzzling.

Spotting for bearing is enhanced by a narrower beam- up to point. It is easier to attain a narrow beam with a shorter wave length. The late war British 274 however, produced such a narrow beam that the shells from a salvo pattern would fall outside of the beam and so it could not spot the fall of shot.
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.

User avatar
Dave Saxton
Supporter
Posts: 2953
Joined: Sat Nov 27, 2004 9:02 pm
Location: Rocky Mountains USA

Re: German radar at North Cape

Post by Dave Saxton » Sat Jun 11, 2011 7:58 pm

dunmunro wrote: ...and Scharnhorst was then able to optically range and train on the 5.25" muzzle flash.
Considering the battle range and the accuracy of the shooting at the time in question, the Scharnhorst would had to of had some pretty amazing optics.
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.

Serg
Member
Posts: 107
Joined: Mon Jun 20, 2005 6:23 am
Location: Russia

Re: German radar at North Cape

Post by Serg » Sat Jun 11, 2011 10:13 pm

Karl Heidenreich wrote:The Germans had a very good radar equipment. THe Scharnhorst at North Cape had it shut down in order to avoid the British to detect it'ss transmision and fix their location. Let's remember that DoY didn't found target only with radar, they use traditional optical help in order to fire against Scharnhorst, which on the other side was crippled by a lucky hit early in the combat.
It seems so. Then according to British chronology Scharnhorst ceased fire at 18.20 range 20000 and DoY at 18.24 range 21400. If a range was limited only by radar spotting there was minor difference in the quality.
Dave Saxton wrote:The Germans also had jammers and it was used during the Channel Dash against British 150cm radar.
Thanks,
but again I need something cleared up. I know about jamming of British coastal radars during channel dash but nothing about german 'ship to ship' jamming. Does Scharnhorst have shipborne jammer set (or antiradar device) at that time?
dunmunro wrote:I think the biggest factor in Scharnhorst's gunnery was that DoY ran out of flashless powder for her 5.25" guns, and Scharnhorst was then able to optically range and train on the 5.25" muzzle flash.
Are you sure that DoY fired 5.25 up to 20000 yards? What spotting method she used?

Serg
Member
Posts: 107
Joined: Mon Jun 20, 2005 6:23 am
Location: Russia

Re: German radar at North Cape

Post by Serg » Sat Jun 11, 2011 10:17 pm

BTW, why DoY ceased fire? I read two versions. The former you can find in Death of Scharnhorst by Winton. He states on p120 that at 18.24 "Type 284 radar developed a defect". It also confirmed by Tarrant in his 'KG5 class battleships' p207. But it seems that defect take place prior to 18.16, when DD's try to spot 14" salvos. Second version belongs to Howse (Radar at sea) which explained the order to cease fire as "because shell splash observation by radar became difficult". Who is right?

dunmunro
Senior Member
Posts: 3541
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: German radar at North Cape

Post by dunmunro » Sun Jun 12, 2011 3:15 am

This is what The Loss of the Scharnhorst by AJ Watts has to say:

NOTES TO BRITISH GUNNERY

On board the flagship, HMS Duke of York, it was found necessary to alter the 5.25" turrets that were firing starshell as the third turrets on the port and starboard side ran out of this type of ammunition. The amount of flashless cordite in the 5.25" turrets was also limited and after a while the turrets had to resort to using full flash cordite. This provided an excellent aiming point for the Scharnhorst's gunners which was made full use of. It was found that when the 5.25's checked fire, the accuracy of the Scharnhorst's gunfire deteriorated. It was also noted that the full flash cordite on the 5.25 's also caused some discomfiture to the 14" guns crews. The forward HA/LA directors were use to control the 5.25" turrets firing SAP while the after directors controlled those firing starshell.

The three 6" cruisers were all armed with flashless cordite but the Norfolk had only full flash cordite for her 8" guns. Again this proved to be quite a hazard, the Scharnhorst being able to range on the cruiser with deadly effect. The blinding effect of the fully flashed cordite on the Norfolk forced her to use blind fire for her guns while the Belfast and Sheffield at times used visual fire, occasionally being able to obtain rather indistinct points of aim.


Serg
Member
Posts: 107
Joined: Mon Jun 20, 2005 6:23 am
Location: Russia

Re: German radar at North Cape

Post by Serg » Sun Jun 12, 2011 8:32 am

dunmunro wrote:This is what The Loss of the Scharnhorst by AJ Watts has to say:
...when the 5.25's checked fire, the accuracy of the Scharnhorst's gunfire deteriorated
Thanks, I did not have this book yet. The context clearly indicates that DoY's 5.25 checked fire before Scharnhorst. Seems Watts at least partially wrong here because according to report "between 17,000 and 20,000 yards DoY frequently straddled and there were many near misses." The Scharnhorst ceased firing at 20,000 yards.
Jamaica ceased fire when the range had opened to 18,000 yards. According to Hughes-Hallett his blind fire was of "doubtful value". Probably 5.25" ceased fire even below this range?

Serg
Member
Posts: 107
Joined: Mon Jun 20, 2005 6:23 am
Location: Russia

Re: German radar at North Cape

Post by Serg » Sun Jun 12, 2011 9:56 am

Well, if we look on problem from the opposite direction. What is the maximum range of the german 150mm and british 5.25" illuminating shell? I guess it lay somehow between 17,500 (152mm japanese star shell) and 11600 yards (130mm russian star shell) I.e optical spotting will be useless beyond this range?

dunmunro
Senior Member
Posts: 3541
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: German radar at North Cape

Post by dunmunro » Sun Jun 12, 2011 11:26 am

Serg wrote:Well, if we look on problem from the opposite direction. What is the maximum range of the german 150mm and british 5.25" illuminating shell? I guess it lay somehow between 17,500 (152mm japanese star shell) and 11600 yards (130mm russian star shell) I.e optical spotting will be useless beyond this range?
The 5.25" starshell uses a number 215 time fuze, with a maximum 80sec time of flight, and recommended burst height of 2200 ft (733 yds). Since the typical maximum range of a 5.25" shell is about 23000 yds (including an allowance for reduced MV due to barrel wear), the maximum range for a 5.25 starshell would be about 22k yds. However, the maximum useful range is probably less than that, because night optics probably have trouble even with starshell illumination past some maximum distance.
Last edited by dunmunro on Sun Jun 12, 2011 11:49 am, edited 1 time in total.

dunmunro
Senior Member
Posts: 3541
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: German radar at North Cape

Post by dunmunro » Sun Jun 12, 2011 11:47 am

Serg wrote:
dunmunro wrote:This is what The Loss of the Scharnhorst by AJ Watts has to say:
...when the 5.25's checked fire, the accuracy of the Scharnhorst's gunfire deteriorated
Thanks, I did not have this book yet. The context clearly indicates that DoY's 5.25 checked fire before Scharnhorst. Seems Watts at least partially wrong here because according to report "between 17,000 and 20,000 yards DoY frequently straddled and there were many near misses." The Scharnhorst ceased firing at 20,000 yards.
Jamaica ceased fire when the range had opened to 18,000 yards. According to Hughes-Hallett his blind fire was of "doubtful value". Probably 5.25" ceased fire even below this range?
According to Watts, DoY checked 14in fire at 21400 yds at 18:24, and was using blindfire by radar control at that point. Scharnhorst checked fire at 18:20, at 20k yds, just as DoY scored her last, but fatal 14in hit.

Serg
Member
Posts: 107
Joined: Mon Jun 20, 2005 6:23 am
Location: Russia

Re: German radar at North Cape

Post by Serg » Sun Jun 12, 2011 1:32 pm

dunmunro wrote: Since the typical maximum range of a 5.25" shell is about 23000 yds (including an allowance for reduced MV due to barrel wear), the maximum range for a 5.25 starshell would be about 22k yds.
Thanks again!
Can you confirm that the British 5.25 starshells had the same muzzle velocity as SAP or HE shell i.e 2600 fps?
As far as I know starshells used special reduced charges which give reduced muzzle velocity.
dunmunro wrote:According to Watts, DoY checked 14in fire at 21400 yds at 18:24, and was using blindfire by radar control at that point. Scharnhorst checked fire at 18:20, at 20k yds, just as DoY scored her last, but fatal 14in hit.
Yes, it seems all sources agreed with this data but more interesting when DoY checked 5.25in fire. And when Scharnhorst checked her 150mm fire. All sources somehow missed it.

Post Reply