Bismarck at DS with better radar

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JAG
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Bismarck at DS with better radar

Postby JAG » Fri Aug 21, 2015 7:40 pm

When I first read that the KM could have adopted lobe switching very early in the development stage this came immediately to my mind, what if Bismarck had a better radar when she ran into the RN cruisers?

As it is, I do not know why the RN cruisers actually survived the first encounter, the German radar should have made certain that any blundering RN cruiser would have been received by immediate and accurate salvos as soon as in visual range. Were they off in order to not provide warning by emitting?

And in that case, would a radar capable of using the already developed "radatel peilung" method have allowed B&PE to accurately blind fire on the cruisers?

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Re: Bismarck at DS with better radar

Postby Matrose71 » Sat Aug 22, 2015 1:40 am

Hello,

their was no Radar fault, both cruisers (Norfolk and Suffolk) were spotted at the entry of the Denmark Straight under 10000 yards!
It was only and only Lütjens fault to not open instantly fire and blow them out of the water!

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Re: Bismarck at DS with better radar

Postby Dave Saxton » Sat Aug 22, 2015 2:06 am

Bismarck's radars had Radattal Peilung. A careful reading of the AVKS report proves it without question. Bismarck and Prinz Eugen were equipped with the best radars available anywhere in the world at that time.

As to why Luetjens didn't take them under fire earlier, look to the experiences of the Scheer passing through the same strait. The Scheer encountered patrolling cruisers and tracked them on radar but held fire so it would not give itself away needlessly. The cruisers never saw the Scheer and they did not have radar. Luetjens would have known about this and had every reason to expect the enemy not to see him or be able to retain contact if they did given the conditions. It was the right decision if not for Suffolk's new Type 284 radar.

It is obvious that Radattal Pielung was in action against Vian's destroyers.

Brinkmann's later commentary indicate that the German radars were on. Brinkmann speculated that the German radar transmissions may have given them away.
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: Bismarck at DS with better radar

Postby JAG » Sat Aug 22, 2015 3:09 am

Thanks to both of you, it seems incredible to me that a CA could survive unscathed when a BB and a CA were, or at least should have been, waiting with guns loaded and trained on the radar contact, and once in visual range there was no reason to refrain from opening fire instantly.

IIRC Suffolk was seen to turn away so save for an incredible coincidence it was safe to assume they had been spotted. I even seem to recall that Lutjens also delayed opening fire on Renown during Wesser, so against Hood was actually the third time Lutjens delayed opening fire without good reason? Were there any delays against Norfolk?

Regarding lobe switching, I would have expected such a radar to be pretty much capable of blind fire (Im such an expert...), when was the KM finally capable of spotting fall of shell with radar?

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Re: Bismarck at DS with better radar

Postby Matrose71 » Sat Aug 22, 2015 3:26 am

There was not any cruiser to Scheer under 15000 yards, what is a very big differnce to 9000yards!

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Re: Bismarck at DS with better radar

Postby A Raven » Sat Aug 22, 2015 4:25 am

Did Bismarck track the Suffolk with her radar for the many hours after the battle, when Suffolk was using her 284 to track Bismarck?

Dave Saxton wrote:Bismarck's radars had Radattal Peilung. A careful reading of the AVKS report proves it without question. Bismarck and Prinz Eugen were equipped with the best radars available anywhere in the world at that time.

As to why Luetjens didn't take them under fire earlier, look to the experiences of the Scheer passing through the same strait. The Scheer encountered patrolling cruisers and tracked them on radar but held fire so it would not give itself away needlessly. The cruisers never saw the Scheer and they did not have radar. Luetjens would have known about this and had every reason to expect the enemy not to see him or be able to retain contact if they did given the conditions. It was the right decision if not for Suffolk's new Type 284 radar.

It is obvious that Radattal Pielung was in action against Vian's destroyers.

Brinkmann's later commentary indicate that the German radars were on. Brinkmann speculated that the German radar transmissions may have given them away.

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Re: Bismarck at DS with better radar

Postby Dave Saxton » Sat Aug 22, 2015 2:36 pm

A Raven wrote:Did Bismarck track the Suffolk with her radar for the many hours after the battle, when Suffolk was using her 284 to track Bismarck?


According to Baron von Muellenheim, the Bismarck command knew from radar and passive sonar that Suffolk had joined Norfolk and Prince of Wales to the north east before the Bismarck made the move west to break contact.

The arrangement with Prinz Eugen about what sectors to cover with each ship's radars that existed before the battle, may have continued after the battle?

The photos of Bismarck taken from the Prinz Eugen when it changed positions with Bismarck twice following the battle are interesting. The early photo shows all three radars trained on the direction of Prince of Wales, but following photos show the conning tower set and the foretop set always pointing in the same various directions together. Seetakt at that time could combine two or more sets to operate as one unit. They may have been slowly rotating around and around with the still photos capturing them at various positions. (By combining them they may have been able to bring which ever forward set that had been knocked out when Bismarck fired at Norfolk back on line.) However, the aft set is always trained to the direction of Suffolk in these series of photos.
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: Bismarck at DS with better radar

Postby Dave Saxton » Sat Aug 22, 2015 2:56 pm

JAG wrote: when was the KM finally capable of spotting fall of shell with radar?


It could always spot the fall of shot at least for range. In the AVKS report it is recommended that the fine range presentation and also the fine bearing presentation of Bismarck's radars be given scalar reference points make spotting the fall of shot and correcting the MPI easier. During the wee hours of the morning, during June 1941, a coastal Seetakt set was used to direct blind fire of an 11-inch shore battery. According to the record, the method of spotting the fall of shot and then correcting to obtain hits using the radar alone was used at a range of 33km.

One of the interesting things about the AVKS report is that Bismarck's crew was very green and not well trained in the use of the radars or the operation of the rotating rangefinder assemblies that the radar sets were mounted to. Some of Bismarck's apparent non use of its radar capabilities and the primary use of optics could be due to the level of training of the personal. For example, Baron von Muellenheim was a gunnery officer on Bismarck but he knew very little about the radars on a technical level and was unaware of the fine bearing modules, although he knew they could be used to find the exact range of target if it could not be seen with the 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.

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Re: Bismarck at DS with better radar

Postby Steve Crandell » Sat Aug 22, 2015 5:58 pm

That's interesting, because the US Mark 3 could only spot 16" shell splashes out to about 20,000 yds. When you say they can "always" spot them, that implies range was not an issue at all.

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Re: Bismarck at DS with better radar

Postby A Raven » Sat Aug 22, 2015 6:58 pm

By the time of the Bismarck affair, the RN were using blind fire by radar types 279 and 281 against unseen surface targets, and by types 284 and 285, also against unseen surface targets and against unseen low flying aircraft. The first writing that I can find (so far) date from around October/November 1940, and relate to actions in the Mediterranean.
When did the Germans begin to use radar directed blind fire against UNSEEN surface targets and against UNSEEN air targets? The word UNSEEN is key.
When did the Germans first fit radar receivers onto warships?
Thank you.


Dave Saxton wrote:
A Raven wrote:Did Bismarck track the Suffolk with her radar for the many hours after the battle, when Suffolk was using her 284 to track Bismarck?


According to Baron von Muellenheim, the Bismarck command knew from radar and passive sonar that Suffolk had joined Norfolk and Prince of Wales to the north east before the Bismarck made the move west to break contact.

The arrangement with Prinz Eugen about what sectors to cover with each ship's radars that existed before the battle, may have continued after the battle?

The photos of Bismarck taken from the Prinz Eugen when it changed positions with Bismarck twice following the battle are interesting. The early photo shows all three radars trained on the direction of Prince of Wales, but following photos show the conning tower set and the foretop set always pointing in the same various directions together. Seetakt at that time could combine two or more sets to operate as one unit. They may have been slowly rotating around and around with the still photos capturing them at various positions. (By combining them they may have been able to bring which ever forward set that had been knocked out when Bismarck fired at Norfolk back on line.) However, the aft set is always trained to the direction of Suffolk in these series of photos.

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Re: Bismarck at DS with better radar

Postby JAG » Sat Aug 22, 2015 8:49 pm

Dave Saxton wrote:
JAG wrote: when was the KM finally capable of spotting fall of shell with radar?


It could always spot the fall of shot at least for range. In the AVKS report it is recommended that the fine range presentation and also the fine bearing presentation of Bismarck's radars be given scalar reference points make spotting the fall of shot and correcting the MPI easier. During the wee hours of the morning, during June 1941, a coastal Seetakt set was used to direct blind fire of an 11-inch shore battery. According to the record, the method of spotting the fall of shot and then correcting to obtain hits using the radar alone was used at a range of 33km.


Thank you Dave, that about settles it doesnt it? Were any hits obtained?

One of the interesting things about the AVKS report is that Bismarck's crew was very green and not well trained in the use of the radars or the operation of the rotating rangefinder assemblies that the radar sets were mounted to. Some of Bismarck's apparent non use of its radar capabilities and the primary use of optics could be due to the level of training of the personal. For example, Baron von Muellenheim was a gunnery officer on Bismarck but he knew very little about the radars on a technical level and was unaware of the fine bearing modules, although he knew they could be used to find the exact range of target if it could not be seen with the optics.


From what Ive read it seems the KM wanted "foolproof" radars that could be operated and maintained with little or no training in order to maintain secrecy, hence the late introduction of lobe switching, but the approach does seem odd to say the least if you end with half-trained operators and caretakers...

So, the OP then should more appropriately read:

"Bismarck at DS with fully trained radar personnel"

I still think the ships should have been ready to open fire in the direction of the radar contact and do so as soon as the CA came into sight, with better use of radar far more salvos could have been accurately fired and maybe allow the ships to escape.

Did PE open fire?

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Re: Bismarck at DS with better radar

Postby Dave Saxton » Sat Aug 22, 2015 11:49 pm

Steve Crandell wrote:That's interesting, because the US Mark 3 could only spot 16" shell splashes out to about 20,000 yds. When you say they can "always" spot them, that implies range was not an issue at all.


By saying it could always spot the fall of shot I'm countering some of the secondary literature's incorrect readings that early Seetakt could not spot the fall shot. I'm referring to time periods.

I have not seen any list that specifies it could spot main battery splashes to X range and no more. We do have the primary document that reports that the coastal Seetakt was used to spot the fall of shot at 33km. It may of had more range than a ship board set because of antenna height.

British ASE documents point out that the ability to spot shell splashes is a function of signal to noise ratio. Seetakt had a better signal to noise ratio than Mk3. This is simply a matter of the physics of radar. Seetakt had a bandwidth matched to pulse width which greatly improves the signal to noise ratio required for detection (this principle was not known to the Allies until they examined a captured Wuerzburg). Seetakt also operated at a frequency below the area that receiving pentode vacuum tubes become increasingly noisier. Beginning at 400mhz these vacuum tubes becoming more and more noisier as the frequency increases. This was why the wavelength was changed to ~80cm. It lowered the noise floor.

The British addressed this problem with their 600mhz radars (50cm) partly by using grid grounded triodes instead of pentodes. Centimetric radars required solid state chrystal devices in place of vacuum tubes. They were just as noisy as pentode vacuum tubes at 50cm but didn't get any noisier with decreasing wavelength. The way to improve spotting range with centimetric radars was to increase the echo signal relative to the noise. This was done by going to 3cm wavelength in most cases because the reflectivity of water droplets to 3cm wavelength is great. The British ASE tested the American Mk8 and MK13 (ASE #41). The range for main battery spotting of 10cm Mk8 was found to be less than 30k, but 3cm MK13 was at least 30,000 yards. Mk8Mod3 is a MK8 converted to MK13.

The reason the British Type 274 could not spot shell splashes was because of none of the above. It's transmitted beam (which was not scanned) was so narrow that the shells would almost always fall outside the beam. In 1947 Vanguard's Type 274 got an additional spotting set added on. It was 3cm.
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: Bismarck at DS with better radar

Postby Dave Saxton » Sat Aug 22, 2015 11:57 pm

JAG wrote:Thank you Dave, that about settles it doesnt it? Were any hits obtained?


Yes.

Did PE open fire?


No.
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: Bismarck at DS with better radar

Postby dunmunro » Sun Aug 23, 2015 10:06 pm

Dave Saxton wrote:
The reason the British Type 274 could not spot shell splashes was because of none of the above. It's transmitted beam (which was not scanned) was so narrow that the shells would almost always fall outside the beam. In 1947 Vanguard's Type 274 got an additional spotting set added on. It was 3cm.


These training films suggest that type 274 could spot for range and line:


3308.—Instructional Film—Radar Spotting
(G.D. 0125/45.—21 Jun. 1945.)
A series of instructional films on “ Radar Spotting ” is being made by the
Royal Naval Film Section, in collaboration with H.M.S. “ Excellent ” . It is
intended th a t these filing should supersede P a rt 6 of the Royal Naval Instructional
Film “ Radiolocation—(A. 74*) ” which is now out of date and will subsequently
be withdrawn.
2. The production of the following films is now in hand :—
Series A. 16 mm. silent film entitled “ Radar Spotting
Part I Type 274, Spotting Tube, how to spot for range.
Part H Type 274, Spotting Tube, how to spot for line.
Part IH Type 275, Ranging Tube, how to spot for range.
Part IV Type 284, Spotting Tube, how to spot for range.
Part V Type 273, with Panel L.17 or L.18, how to spot for range.
Series B. 16 mm. silent film entitled “ Radar Fall of Shot—Practice films ”for use with
Cinema Radar Fall of Shot Teacher
Pa rt I Type 274, Spotting for range.
P a rt I I Type 274, Spotting for line.
P a rt I I I Type 2_75, Spotting for range.
Pa rt IV Type 284, Spotting for range.
P a rt V Type 273, Spotting for range.
Series C. 35 mm. Sound Instructional Film entitled “ Radar Spotting ”
3. Details of Films.—Series A shows a series of single and multi-gun salvos
fired at moored practice target, carrying Radar reflectors whose Radar response
effectively simulates a surface target.
These films have been made with the object of enabling detailed instruction
to be given to spotting operators in range and line spotting. They have been
made without sound track to expedite completion and distribution, but edited so
th a t each film is a complete record of one particular series of firings as seen on one
type of Radar set display. The fall of shot has been recorded by the visual camera
simultaneously with a photographic record of the displays on the 274, 275, 284 and
273 Radar sets.
They are capable of projection upon any 16 mm. sound film or silent film
projector.
The general sequence for the five parts of this series is to show each salvo
first, as the visual spotting officer saw it, then as the spotting operator saw it on his
display (and how he measured the M.P.I. of the salvo), then the actual fall of the
salvo as recorded by a Rake Marking camera. Thus the spotting operator, in
addition to seeing the fall of the shot on his Radar display, obtains a visual picture
of the fall of the shot in correct relationship to the target for range and line, which
should enable him to conceive a better appreciation of his problem under the more
realistic conditions of firing a t an enemy ship.
4. Series B. Radar Fall of Shot—Practice Films.—These films provide a
number of photographed practice runs of the Radar displays of the 274, 275, 284
and 273 Radar sets, which, when projected on to the screen face of the teacher,
the construction of which is described below, give a realistic impression of salvos
fired a t a ship target.
I t should be noted th a t these films are for practice purposes only and should
be shown after the spotting operator has received preliminary instruction from the
“ Radar Spotting ” films, Parts I to V.
The display shows exactly the echo of the salvo and the target as seen on a real
tube, and the spotting operator, by calling out to the instructor his appreciation
of the M.P.I. of the salvo, should obtain good practice in accurate spotting both for
lines and range on the 274 set, and for range in the 275, 284 and 273 sets. The
correct position of the M.P.I. for each salvo will be issued in the form of a “ Crib ”
for the use of the instructors.
5. Series C 35 mm. Instructional Film “ Radar Spotting ” .—This film is to be a
comprehensive instructional sound film dealing with all. aspects of spotting fall of
shot by means of the various Radar sets. I t will deal with the principles involved
advantages and limitations of Radar spotting and show the drill and procedure to
be used for all equipments. ( A.F.OS. 3282—3433/45 21 June 1945)

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Re: Bismarck at DS with better radar

Postby JAG » Mon Aug 24, 2015 2:41 am

Dave Saxton wrote:
JAG wrote:Thank you Dave, that about settles it doesnt it? Were any hits obtained?


Yes.

Did PE open fire?


No.


Thx, could you please provide more details on the engagement? Target? Sunk? It was a Calais B?


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