If the RAF had been defeated in the Battle of Britain

[Shortround6]

The Bimarck's FLAK not being able to track 'biplanes' is a provable myth. It does obliquely link into the proctalgia fugax in this thread over the Dornier Do 215B2 that the Reich supplied the USSR in return for its cooperation and most particularly its Wheat and Oil.

I don't know what the Russians were looking for in Do 215B2 but the basic Do17 airframe dates to the end of 1934 (first flight) and the Russians certainly had opportunity to examine wrecked/shot down examples in Spain as 3 different versions were used there. Perhaps they wanted the latest model DB601 engine to go with the other examples they had purchased powering a few other planes (like He 100s)? in any case two light bombers weren't going to purchase a lot of oil or wheat.
Russians had problems with Naval fire control and during the 30s had purchased Naval fire control systems or parts from Italy. The sale of the heavy cruiser Lutzow would provide much more in the way of tonnage of goods that a pair of light bombers.

The FLAK systems for the Bismarck's 10.5cm and 15cm duel purpose guns was designed and capable of attacking fast small boats such as patrol boats either with a burst above the target or via direct fire. Obviously they'd be able to track a biplane.

Calling the 15cm guns dual purpose is certainly gilding the lily. I will grant that a number of navies used large caliber guns to shoot in the general direction of aircraft, Shooting battleship and cruiser main batteries into the water in front of torpedo bombers to cause large water spouts seems to have been a common tactic but nobody is really calling such guns or mounts dual purpose.
Having two different heavy AA guns with different ballistics on the same ship is only going to make the fire control problems harder. The Bismark already had a pretty good heavy AA set up, at least as far as guns went. The British had gone too far to the surface target side in the KG Vs with the 5.25in gun.

The 10.5cm ------------------was very good for the day.

The 2.0cm and 3.7cm was week and this was what may have let the Swordfish through.

The 3.7 cm guns had excellent ballistics. Fired at 45 degrees they had a 9000 yard range. By comparison the 40 Pom Pom was 5000 yards, 20 mm Oerlikon and 2.0cm C38 5300 yards, German FLAK 3.7cm 7100 yards. They were almost as good as the Boffors 40mm and its 11000 yard range.

Quoting max range for most of these Light AA guns (if not all) is nonsense. The effective range was often 1/4 to 1/3 of the max range. This is due to the times of flight and often primitive sights used.
Another factor is that most of them used tracer ammunition and used the tracer as part of a self destruct "mechanism". When the tracer was just about all burnt out it hit a delay pellet (slower burning composition) that lead to the HE cavity. When the flame reached the HE it detonated the shell well short of it's max range.
The max range is interesting in comparing the power of the gun and the shape of the shells (British 2pdr was poor on both counts) but in no way reflects on their actual use.

Their main weakness was that they were manually loaded semi automatic weapons so rate of was 30-60 rounds per minute.

This is not totally silly since higher firing rates would have blinded the gunners with flash and smoke and lead to guns over heating.

Trying to get even 30rpm out of this set up per barrel is pushing things. As the gun recoiled the breech blocks opened up and ejected the empty casing using cams/springs. Loaders shoved the new rounds into the chamber and the rim tripped a catch which released the spring loaded breechblock to close. Loaders have how long to reach back, grab another round and assume the position shown in the photo?

This 37mm gun was obsolete almost from the first day it was placed on deck.

Italians had a much better set up in 1932/33.

 

[Koopernic]

The Russians are pretty good with technology but Soviets were not so good because of their system just wanted latest advances in mass produced technology and stressed skin production to fill the gaps in.

Zeiss multicoated optics, gyroscope practice, ballistics data transmission, the supremely accurate mechanical ballistics computers, fuel injection.

FFS, the max range for AAA is a relative indicator. 50% for surface fire and 35% for AAA is a guideline.

The German Navy wanted to produce an auto loader for the SK3.7 but the effort went into the Geräte 58 5.5cm hit to kill weapon system instead.

The guns could reasonably fire 30 rpm each. No point going beyond that till a director was in place and advances in flashless smokeless powder.. I would have added dials so that the 3.7cm guns could accept data from the main directors.

Most of the defensive work had to be done by the quad 2.0cm systems but note the SK3.7 could reach out way beyond the Pom Pom even if it was a low rate of fire.

The 3.7cm weapon of choice on land and sea became the 3.7cm FLAK 43 which fired 250 rpm from 8 round disintegrating clips fed continuously to a range of 7100 yards at 45 degrees. This is about twice the rate of the boffors albeit at less range.

No one had proper directors for their 3.7cm and 40mm Systems quite late. Most were angular rate gyro sights.

 

[tomo pauk]

Now when we will have the 'mis-informative' post rating?

The FLAK systems for the Bismarck's 10.5cm and 15cm duel purpose guns was designed ...

Deserved once.

Because of the Reichs agreements with the USSR the two tandem aft directors were removed from Bismarck (and another two from Prinz Eugen) and shipped to the USSR. There was no question of the Reich not meeting its agreements on time. Less capable biaxially units were installed and may have hurt Bismarck's Defense.

Twice.

The attack on the Bismarck was carried out in limited visibility and the Swordfish used clouds to hide from the Bismarck's FLAK. The Swordfish had radar.

Thrice.

The 2.0cm and 3.7cm was week and this was what may have let the Swordfish through.

The 2.0cm C38 FLAK in a quad mount was a very effective weapon but there were only two of these. The rest were more basic single and twin gun mounts. The C38 2.0cm had 5300 yards range at 45 degree elevation, which was slightly more than the RN 40mm Pom Pom. When fired from a quad mount 2 guns could maintain continuous fire while the other two were reloaded and cooled. Dozens were fitted to Tirpitz but Bismarck had inadequate numbers.

The naval 3.7 cm guns had excellent ballistics. Fired at 45 degrees they had a 9000 yard range. By comparison the 40 Pom Pom was 5000 yards, 20 mm Oerlikon and 2.0cm C38 5300 yards, German Luftwaffe/Army FLAK 3.7cm 7100 yards. They were almost as good as the Boffors 40mm and its 11000 yard range.

Several times earned the 'mis-information' post rating just in these paragraphs. In one sentence we have 'week' (weak) 2 and 3.7cm AA guns on Bismarck, yet in other sentences they sing, dance and cook. Amazing.

Their main weakness was that they were manually loaded semi automatic weapons so rate of was 30-60 rounds per minute.

This is not totally silly since higher firing rates would have blinded the gunners with flash and smoke and lead to guns over heating.

Main weakness and not totally silly for the same weapon? Gold dust.
Seems like the introduction of 40mm Bofors was a major step back for the British and USA, since the gunners were apparently blinded by flash and smoke. Same when Kriegsmarine introduced the fast-firing 3.7cm Flak.

 

[swampyankee]

Ship-based AAA was far less effective than the planners thought, in general.

THe WWI British blockade was not generally considered legal by the international comunity

The Blockade and Attempted Starvation of Germany

This was what Lord Devlin frankly calls "the starvation policy" directed against the civilians of the Central Powers (particularly Germany),2 the plan that aimed, as Winston Churchill, First Lord of the Admiralty in 1914 and one of the framers of the scheme, admitted, to "starve the whole population — men, women, and children, old and young, wounded and sound — into submission."3

The British policy was in contravention of international law on two major points.4 First, in regard to the character of the blockade, it violated the Declaration of Paris of 1856, which Britain itself had signed, and which, among other things, permitted "close" but not "distant" blockades. A belligerent was allowed to station ships near the three-mile limit to stop traffic with an enemy's ports; it was not allowed simply to declare areas of the high seas comprising the approaches to the enemy's coast to be off-limits.

This is what Britain did on November 3,1914, when it announced, allegedly in response to the discovery of a German ship unloading mines off the English coast, that henceforth the whole of the North Sea was a military area, which would be mined and into which neutral ships proceeded "at their own peril." Similar measures in regard to the English Channel insured that neutral ships would be forced to put into British ports for sailing instructions or to take on British pilots. During this time they could easily be searched, obviating the requirement of searching them on the high seas.

This introduces the second and even more complex question: that of contraband. Briefly, following the lead of the Hague Conference of 1907, the Declaration of London of 1909 considered food to be "conditional contraband," that is, subject to interception and capture only when intended for the use of the enemy's military forces. This was part of the painstaking effort, extending over generations, to strip war of its most savage aspects by establishing a sharp distinction between combatants and noncombatants. Among the corollaries of this was that food not intended for military use could legitimately be transported to a neutral port, even if it ultimately found its way to the enemy's territory. The House of Lords had refused its consent to the Declaration of London, which did not, consequently, come into full force. Still, as the US government pointed out to the British at the start of the war, the declaration's provisions were in keeping "with the generally recognized principles of international law." As an indication of this, the British admiralty had incorporated the Declaration into its manuals.

Do also remember that once the Haber process was industrialized, production of food could have been increased, as nitrate-based fertilizers could have been produced. The German government gave little priority to agricultural production, so the nitrates weren't used for fertilizer, farm laborers were taken out of fields, as were draft animals. It was a classic guns-vs-butter conflict, and guns won , so the German people starved. I'm sure, though, that Ludendorff never missed a meal.

The UK was a net importer of food, and the entire u-boat campaign was intended to starve Britain.

 

[Greyman]

I've read several times about Swordfish radar being used against the Bismarck - is this false for sure?

 

[Shortround6]

I don't know but I can offer a compromise.
How many of the attacking Swordfish had functioning radar?

The RAF had trouble keeping radar functioning in the Fuselage of a Blenheim. Flying around in rain squalls/clouds with an open cockpit plane with the radar of the time means what percentage of sets (even assuming that ALL aircraft had radar) are working at the time of the attack? And what was the range?

The fact that some aircraft of the attack group needed help with the direction to fly in doesn't actually prove that there was radar on planes or that there was no radar.

 

[pbehn]

According to the Bismark site some but not all Swordfish on Victorious and Ark Royal had ASV RADAR.

 

[tyrodtom]

I should have read the encounter reports closer.
3 Swordfish from the HMS Victorious ,had Mk I ASV radar, and a unknown number of the Ark Royal's Swordfish was also equipped.

Apparently each flight of 3 had one radar equipped aircraft.
Some, or all, flights lost contact with each other in the clouds and confusion.

 

[parsifal]

THe WWI British blockade was not generally considered legal by the international comunity

The Blockade and Attempted Starvation of Germany

This was what Lord Devlin frankly calls "the starvation policy" directed against the civilians of the Central Powers (particularly Germany),2 the plan that aimed, as Winston Churchill, First Lord of the Admiralty in 1914 and one of the framers of the scheme, admitted, to "starve the whole population — men, women, and children, old and young, wounded and sound — into submission."3

The British policy was in contravention of international law on two major points.4 First, in regard to the character of the blockade, it violated the Declaration of Paris of 1856, which Britain itself had signed, and which, among other things, permitted "close" but not "distant" blockades. A belligerent was allowed to station ships near the three-mile limit to stop traffic with an enemy's ports; it was not allowed simply to declare areas of the high seas comprising the approaches to the enemy's coast to be off-limits.

This is what Britain did on November 3,1914, when it announced, allegedly in response to the discovery of a German ship unloading mines off the English coast, that henceforth the whole of the North Sea was a military area, which would be mined and into which neutral ships proceeded "at their own peril." Similar measures in regard to the English Channel insured that neutral ships would be forced to put into British ports for sailing instructions or to take on British pilots. During this time they could easily be searched, obviating the requirement of searching them on the high seas.

This introduces the second and even more complex question: that of contraband. Briefly, following the lead of the Hague Conference of 1907, the Declaration of London of 1909 considered food to be "conditional contraband," that is, subject to interception and capture only when intended for the use of the enemy's military forces. This was part of the painstaking effort, extending over generations, to strip war of its most savage aspects by establishing a sharp distinction between combatants and noncombatants. Among the corollaries of this was that food not intended for military use could legitimately be transported to a neutral port, even if it ultimately found its way to the enemy's territory. The House of Lords had refused its consent to the Declaration of London, which did not, consequently, come into full force. Still, as the US government pointed out to the British at the start of the war, the declaration's provisions were in keeping "with the generally recognized principles of international law." As an indication of this, the British admiralty had incorporated the Declaration into its manuals.

As I said, the british were not saints. moreover the 1856 paris agreements were not dead in 1914, but had been superceded, primarily because in the intervening years new technologies, notably submarines and long range surface raiders made the accord obsolete. in any event , the 1856 agreement had been superceded by a series of conventions which we collectively call or refer to as the Geneva conventions, or the hague conventions. Those conventions have been periodically updated over the years, the last being in 1987 I think. In any event, by 1914 the 1856 agreements had been superceded, by the hague agreements, and this allowed both close and distant blockades, the right to board search and detain neutral ships, the right for a naval power to declare certain areas a "declared area" (a war zone), and to control and restrict the imports of any nation within that area.

The British were confronted with rather a nasty surprise when the Germans decided to conduct worldwide mercantile warfare and then unrestricted attacks on merchant shipping, dispensing entirely with the niceties of stop and search.

The nation most opposed to the imposition of the blockade was the US. It was not "generally regarded as illegal, except by them and the free trade propnents. That believe largely evaporated after the germans started sinking their ships indiscriminately.

In WWII the issue of unrestricted mercantile warfare did bed down pretty quickly, but we are not talking about unrestricted warfare on an opponent, or even a neutral not working for ones own side. We are talking about why the Germans had a hard time with their exports. That hard time in part stems from their treatment of their own friends and trading partners not in the way they conducted operations against the allies. The german behaviour againt the European shipping market was so bad that despite the obvious threats from German U-boats those shipping companies thought it a safer, better deal to work for the allies rather the Germans. the germans proceeded to lose most of their own shipping during Norway, and after that were forced to play nicer towards the remaining neutrals and their ships

 

[Juha2]

Hi, most of the gains seem to come from the increase in FTH,

If the over Dornier Do 215 Managed 465km/h on the DB601Aa producing 1100hp at a FTH of 3700m/12200ft.

...

Hello Koopernic
thanks for the answer and calculations.

Juha

 

[Koopernic]

I don't think I can even begin to comprehend what you are trying to say Tomo. Just say it directly rather than try satire.

The Bofors system worked because by the time it was introduced widely it was aimed by remote control and had good Ballistics. The Pompom had mediocre ballistics. As noted by reports of the Sinking of PoW and Repulse nearly a year latter they had a very limited effect compared to a pair of Boffors on the foredeck.

Firing away with multiple AAA with gunners located at 37mm/40mm caused problems with blast and smoke. That's one reason no one had a 50mm anti aircraft gun.

Whatever the limitations of the German Naval 3.7 cm mount and ROF it had good ballistics and was stabalised. I imagine it eventually received a gyro sight. They also never replaced them in Tirpitz or Prinz Eugen despite having the excellent 3,7cm FLAK 43 and earlier FLAK 37 I would assume they preferred to have the extra range and ability to fire continuously.

In terms of fire power relative to deck space the quad FLAK worked because it was not so large and didn't produce so much blast it needed to be aimed remotely.

Some of the better FLAK directors were removed from Bismarck and Prinz Eugen to complete Lützow which had been sold to the USSR.

 

[tomo pauk]

My opinion is that you are trying too much in painting German hardware in best colours, stating the performance figures and abilities that are either calculated or plainly wrong.

 

[pbehn]

From reading the accounts the Bismark had no difficulty at all in laying accurate AA fire against an individual plane it just couldn't track a dozen targets at once. It was surprised by some attacks while it drove others off.

 

[pbehn]

Doing a bit of browsing on the net, the mission report/account just says ASV RADAR but the two sites below show the ASV mk XI fitted to a Swordfish, the radome is between the wheels where the torpedo would go so it was a choice of either or.

quote
ASV Mk.XI
The ASV Mk.XI was a centrimetric radar intended for the TBR (torpedo bomber and reconnaissance) aircraft of the Fleet Air Arm, the component of the Royal Navy that operated carrier aircraft. It was also known known as ASVX and therefore it sometimes has been called, erroneously, ASV Mk.X.

ASV Mk.XI could be fitted between the main wheel legs of a Fairey Swordfish. In addition to the bulky radome, a Leigh light could be fitted. The radome made the the carrying of torpedoes or large depth charges impossible, so when the target was a ship the Swordfish was accompanied by other aircraft without radar. Against submarines, the radar-equipped Swordfish Mk.III was armed with eight rockets on underwing launches, and also carried flares to illuminate any U-boat it found. Fired at 600 yards, the rockets easily penetrated a submarine's hull.
This radar was also carried by the Fairey Barracuda Mk.III.

ASV Mk.XI had a maximum range of about 60km against ships, and in good conditions and at low altitude (2000 feet) it could detect a surfaced submarine at about 20km. But it could detect a schnorkel only in very calm seas and at distances below 8km. It gave bearings with an accuracy of about 2 degrees.
unquote.
Fairey Swordfish - Aircraft - Fighting the U-boats - uboat.net
British ASV Radars - Technical pages - Fighting the U-boats - uboat.net

 

[Koopernic]

Doing a bit of browsing on the net, the mission report/account just says ASV RADAR but the two sites below show the ASV mk XI fitted to a Swordfish, the radome is between the wheels where the torpedo would go so it was a choice of either or.

quote
ASV Mk.XI
The ASV Mk.XI was a centrimetric radar intended for the TBR (torpedo bomber and reconnaissance) aircraft of the Fleet Air Arm, the component of the Royal Navy that operated carrier aircraft. It was also known known as ASVX and therefore it sometimes has been called, erroneously, ASV Mk.X.

ASV Mk.XI could be fitted between the main wheel legs of a Fairey Swordfish. In addition to the bulky radome, a Leigh light could be fitted. The radome made the the carrying of torpedoes or large depth charges impossible, so when the target was a ship the Swordfish was accompanied by other aircraft without radar. Against submarines, the radar-equipped Swordfish Mk.III was armed with eight rockets on underwing launches, and also carried flares to illuminate any U-boat it found. Fired at 600 yards, the rockets easily penetrated a submarine's hull.
This radar was also carried by the Fairey Barracuda Mk.III.

ASV Mk.XI had a maximum range of about 60km against ships, and in good conditions and at low altitude (2000 feet) it could detect a surfaced submarine at about 20km. But it could detect a schnorkel only in very calm seas and at distances below 8km. It gave bearings with an accuracy of about 2 degrees.
unquote.
Fairey Swordfish - Aircraft - Fighting the U-boats - uboat.net
British ASV Radars - Technical pages - Fighting the U-boats - uboat.net

The radar used by the Swordfish was the ASV Mk IIN operating at 1.5m. No microwaves in service yet. The RAF version was simply the ASV Mk II.

There would have been no radar dish, just dipole arrays.

Good luck with finding a photo of one on a Swordfish though plenty on Wellingtons etc. Usually one array scanned out along the wings to look sideways and another directly forward.

Probably helped aim the torpedoes as well.

 

[parsifal]

ASV radar had begun to be fitted to Swordfish in early 1941, and some of 825 squadron (of HMS Victorious were embarked onto the new carrier during her shakedown preprations, arriving on the 15 May, fitted with ASV radar. In the first attack on the DKM Bismarck, the attack formation of 9 a/c was split into three groups of three aircraft, for some of these subflights, all three a/c delivered, or attempted to deliver a torpedo onto the target.

The early versions of ASV used did not allow a torpedo to be carried by those aircraft fitted with ASV radar, yet most accounts suggest all aircraft were carrying a torpedo in this first attack.


Some elements of the account therefore seem to be at odds with known facts, yet just as forcefully, most observers are of the opinion that without the assistance of ASV radar, this attack would never have developed.

The following account is from the following site:

http://www.kbismarck.com/article2.html


"Realistically, the prospects for the attack were not good. The squadron was ill-prepared for its assignment, several of the pilots having only made their first carrier landing on the 19th, and they had not made even a single squadron attack in training. Under the prevailing weather conditions, eight-tenths cloud cover at 1,500 feet with intermittent rain squalls, a visual search was like looking for the proverbial 'needle in a haystack', but the squadron's new ASV radar was expected to make the difference. At 2327 ASV contact was established on a contact some 16 miles ahead of the formation and Bismarck was sighted briefly through a gap in the clouds only to be lost again seconds later. Descending below the clouds with his squadron, Esmonde located the cruisers still shadowing, and HMS Norfolk directed the aircraft towards their target some fourteen miles ahead on the starboard bow.

At 2350 hours a further ASV contact was made and Esmonde again led his squadron below the cloud cover to begin his attack. Unexpectedly, the contact proved to be the United States Coast Guard cutter Modoc, peacefully pitching and rolling in the heavy Atlantic swell. Unfortunately Bismarck, then only six miles to the south, spotted the aircraft and the vital element of surprise was lost. When the Swordfish finally closed to deliver their torpedo attack, they were met by a 'very vigorous and accurate' barrage of heavy and light AA, which tagged Esmonde's Swordfish (5A) at a range of four miles. Though Swordfish 5M lost contact in the dense cloud covering the area, the remaining eight aircraft pressed home their attack with elan.

At exactly midnight Esmonde led the first sub-flight into a simultaneous attack. His starboard lower aileron was hit almost immediately, and he abandoned his original intention to attack from starboard, deciding to drop there and then, whilst he was still in a good position on the target's port beam and Bismarck was nicely silhouetted against the glow of the setting sun. Both he, and Sub-Lieutenant(A) Thompson, in 5C, released on Bismarck's port bow from an altitude of 100'. The third member of the flight, Lieutenant MacLean, in 5B, got separated in the descent through the clouds and attacked separately, but also on the port side. Proving that his ship handling skills were superb, Captain Lindemann artfully dodged all three "fish".

The three Swordfish of the second sub-flight were led in by Lieutenant Gick. Approaching from starboard, he was not satisfied with the approach angle, and elected to pull back into the clouds and work his way round to a better position. The remainder of his flight continued on however, Lieutenant (A) Garthwaite in 5G dropping on Bismarck's starboard bow and Sub-Lieutenant(A) Jackson, in 5H/V4337 from her starboard quarter, but again Lindemann avoided the deadly missiles.

Moments later, the two Swordfish remaining in the third sub-flight appeared on the Bismarck's port quarter, and amid a hail of AA fire, Lieutenant(A) Pollard, in 5K, and Sub-Lieutenant(A) Lawson, in 5L released from a good angle but, again, to no avail. Meanwhile, Percy Gick, in 5F, now appeared low down on the water on the enemy's port bow. His sudden appearance caught the Germans by surprise, and there was no avoiding his torpedo, which plowed into Bismarck amidships, exploding on her armour belt".

CV Ark Royal received a number of ASV equipped swordfish 18 and 19th May, with the arrival of aircraft transport HMS Furious with a load of hurricane, Fulmar IIs and Swordfish fresh from England. The hurricanes were destined for Malta but the carrier aircraft were for the Ark Royal.

Again it should not be in dispute that the Ark Royal was carrying ASV equipped Swordfish. From the same site…..

"Meanwhile, Ark Royal fitted two ASV-equipped Swordfish with long-range tanks and sent them off at 1200 to maintain contact until relieved. At 1154 Bismarck broke her long silence, reporting that she was being shadowed by an enemy 'Land plane'. Thereafter, and until 2320 that night, Ark Royal's Swordfish, working in pairs, maintained a vigil over Bismarck, keeping her under continuous observation".

"Coode found he was four miles ahead and to leeward of the target. Realizing that a slow approach against the wind would be suicidal, he re-entered the cloud to close in and try another angle. This left the second sub-flight, to 'open the ball'. Lieutenant D. F. Godfrey-Faussett (2B) having lost Coode in the clouds, led the second sub-flight up to 9,000 feet where they ran into some icing problems before descending on the ASV's attack bearing. He and Sub-Lieutenant(A) K. S. Pattisson (2A) were both caught in an intense AA barrage that hit both aircraft as they made their run in from the Bismarck's starboard beam, but both survived the storm of 'shot and shell'. Meanwhile, Sub-Lieutenant(A) A. W. D. Beale (2P) having lost touch with the other two, returned to Sheffield to get a new range and bearing to the enemy. "

 

[pbehn]

I have no idea really about the various marques of the RADAR but I suspect the early marques while not having a radome did have a huge heavy set and power needs that meant carrying a ASV and a torpedo would be a bit of a problem.

 

[Koopernic]

I have no idea really about the various marques of the RADAR but I suspect the early marques while not having a radome did have a huge heavy set and power needs that meant carrying a ASV and a torpedo would be a bit of a problem.

The builder of this Tamiya model says the ASV is on the interplane struts:

Both these Baracuda also appear to have an ASV Mk.IIN on the upper wing surfaces and a microwave pod on the rear aircraft only. I note how the Royal Navy didn't seem to think it was worthwhile to arm the observer.

To me it looks like the two yagi arrays sent pulses alternately 45 degrees to each side. By comparing pulse return strengths a rough idea of direction could be formed.

The Admiralty probably lightened it's version. This 1.5m RAF Radar did the yeomans work with versions used on sloops and corvets to warn of aircraft and provide radar ranging.

The Swordfish were able to use clouds to minimise the Bismarck's ability to use its heavy FLAK and maybe used the radar to track Bismarck from within the clouds.

Bismarck's light FLAK was weak, more in the sense of location, sweep angles that were noted already but had not been put into effect.

This thread has the core insights. It's worth reading the AKVDS report. Bismarck hadn't been worked up properly.
No Swordfish shot down by Bismarck - Naval History Forums

The capacity to deal with this kind of attack probably required full blind fire capability. Such a radar was the Euklid FuMO 231, some 6 delivered and possibly installed on destroyers in construction in 1945 or late 1944. A lot of great RN radars to do this job as well but only in 1944 as far as i can see.

This is a shore based multipurpose Seetakt called flakleit-g. Note the height finding aerial and also optical range finder.

0

Something like this was installed on Prinz Eugen in 1943 but then removed.

This is her 1944 setup. The height finding owls ears have disappeared. The FuMO 81 Berlin-S is a microwave set with 4 PPI scopes. Mostly issued to mine sweepers and torpedo boats. Note how small the microwave units are. The FuMO 26 is the standard blindfire capable Radar for ranging and engaging surface targets. The question is how did the Kriegsmarine restore its height finding ability. At least one expert says they used the phase shifting technology from Wassermann radars to find height. I'm not so sure.

 

[pbehn]

Koopernic, it is all a mystery to me. The rocket firing Swordfish required metal underwings and came in in 1943. The centimetric RADAR radomed Swordfish also came in in 1943. I cant see any really conclusive proof that a Swordfish could carry both a torpedo and ASV

 

[Greyman]

I note how the Royal Navy didn't seem to think it was worthwhile to arm the observer.

The Barracuda had a twin Vickers K mounted in the rear cockpit with 5 magazines per gun. The hoods are just closed in that photograph so they might be carried and not visible.