Vanguard teleported in place of Bismarck

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Vanguard teleported in place of Bismarck

Postby alecsandros » Thu Aug 25, 2016 4:58 pm

... Part 4:
Brand new HMS Vanguard , comissioned May 12th 1946, is teleported exactly 5 years back in time, in Kiel, in place of KGM Bismarck.

The ship did not have the range of Bismarck, but it did have more range then the preceding KGV class, with about 20% extra fuel (from 4000 tons to 4800 tons), giving the possibility of attempting Rheinubung mission , IF a tanker could be provided on the evening of May 25th somewhere 1000km south to the southern exit of the Denmark Strait.

The ship departs Kiel , with Prinz Eugen, and goes to Denmark Strait at 24 to 27kts, burning 2400 tons of fuel in the process.

British cruisers Norfolk and Suffolk make radar and visual contact as historical, on May 23rd 19:30 hours, in fog.

Vanguard's advanced electronics and next-generation radars provide correct intel on the positino of HMS Norfolk and HMS Suffolk, but Luetjens helds fire, not knowing the identity of the targets (they could be American ships). When Norfolk exits a fog bank, identity is confirmed as British heavy cruiser, and aft 4 guns open fire on full radar direction.
As Norfolk hurries to get back in the fog bank, 4-gun straddles continously follow her inside the fog. 1 shell explodes near the forecastle, riddling the ship with splinters, killing many men. 1 minute later, a direct APC hit perforates the hull and expodes in the machinery room, killing almost everybody. On board Vanguard, technicians observe each 4-gun salvo clearly on the PPI radar scope, following each shell on the monitor, as it slams towars the cruiser, and also show the salvo splashes on the screen. Vanguard alters course to bring forward guns to bear. They fire, but the shock of the guns damages the main forward radar set. Target aquisition is sent to aft radar set, with reduced range of 25km (instead of 35km for the main radar). Firing continues on the damaged Norfolk from 14km, after a short 2 minutes lull. In 5 minutes, the cruiser receives 2 more direct hits, which explode inside. In 5 more minutes, 3 more hits, and Norfolk capsizes. However, in fog and twillight, Vanguard doesn't know NOrfolk is sinking, and continues to fire for 2 more minutes until target dissapears from radar screen. Ammo consumption so far - about 140 x APC shots, almost 50% of the total existing on board.

Second target is observed clearly on the PPI at 16km - it is Suffolk. Suffolk's radar beam is jammed by Vanguard's crew, and Suffolk doesn't know what's happening around her anymore. Norfolk's last, desperate transmission, is deciphered 10 minutes later on board Suffolk, which proceeds to pick up survivors. However, a 4-gun salvo errupts around her, through the fog (this tipe S.A.P projectiles, intended to damage the upper works and radars and directors). Suffolk makes evasion actions, and the folllowing salvos land to her stern. Vanguard consumes 50 more shots , one of which explodes close to Suffolk, riddling her with splinters, but not causing any meaningfull damage.

Seeing the deadly cat and mouse game lasts longer then he hoped for, and not knowing if he hit or sunk any of the targets, Luetjens proceeds south at ever increasing speed - target being 31kts.

In the mean time, Suffolk shut down her radar, which was anyway useless for the jamming reason (which was unknown to Suffolk's crew), and the crew modifies the operating frequency. Howver, when radar is switched on again, this frequency is also jammed, and radar shut down again. Suffolk sends her coordinates to Tovey, and stops to search for Norfolk in the fog. She finds the survivors about 30 minutes later, and starts picking them up until 22:00. After that, she proceeds south at 30kts, with radar turned on for the 3rd time (and not jammed anyumore, as distance if about 70km from Vanguard at this moment).

----

Vanguard builds speed up to 31kts at around 23:00, and mantains southern course.
Prinz Eugen is in the lead, to scan forward radar sector.

----

Holland dettaches his 6 DDs on a N-W search at 02:00, while he goes with Hood/PoW to the south at 29kts.

At 3:00, Vanguards's electronic nerve center pick up some tranmissions (radio) between Holland's force, but the message can not be deciphered. Some triangulation of the source offers some possibility of enemy chatter emanating 50 to 200km to the east of Vanguard. Not enough info for anything. As Holland's radars are switched off, Vanguard does not pick up any emissions , and with Vanguards' main radar offline, the enemy force is first picked up at 33km from Prinz Eugens GHG set (as historical).

Prinz Eugen starts having machinery trouble, and speed is slowly brought to 28kts on both German ships, starting 05:00.

At 5:30, almost simoultaneous visual and GHG contact is made. Targets unknown. 2 enemy ships coming at high speed in intercept manouvre.

At 5:50, they are identified as capital ships on board Vanguard, and as light cruisers on board Prinz Eugen.

Hood fires from 23km, Prince of Wales follows from 22.5km, Vanguard replies immediately with radar-guided fire from 22km, Prinz Eugen 2 minutes later from 20.5km.
Vanguards 381mm/L42 shells have a time of flight of 40 seconds at 20km versus Bismarck 30 seconds at same range, giving more time needed to assess range. Radar helps , but with target coming at 1.2km/minute, visual observation is mandatory to efficiently utilize the dwindling supply of APC rounds. Only 160 rounds are available after the nocturnal firings done on Norfolk/Suffolk, or 20 broadsides - 10 minutes of firing at max rate of fire !

Vanguard's fire is accurate, and first hit on HOod is made at 5:57, on the foretop. Prince of Wales hits Vangurad in the forecastle, triggering flooding, and in the underwater historical position, causing little trouble, as most of the explosion is contained by the deeper armor belt. Prinz Eugen strikes Hood 2 times, causing fires. Prinz Eugen shifts fire to Prince of Wales.

Vanguard strikes Hood at 6:01 in the 170mm portion of the main armor belt, the shell is fuzed and passes through. Howver, it does not have the perforating power of German 380mm/L52, and it has a 0.025sec fuze delay, meaning it explodes before reaching the after magazines. The force of the explosion is contained by the bukheads, allthough local damage is felt.

Hood switches fire to Vanguard at 6:02. Prince of WAles is at 14km distant, and hits Vanguard's crane. Prinz Eugen hits Prince of Wales 2 times, knocking out 1 aft rangefinder and 1 secondary turret.

Vanguard concentrates on Hood with all main guns. At 6:03, 2 x 381mm shells strike Hood in a succession of 20 seconds, one exploding inside the main con tower, killing everyone, the second jamming and exploding low order between the aft main turrets, which are non-operational.

Prince of Wales strikes Vanguard from 12km with a rare double-hit: 1 destroys 1 forward main turret, the other glances from 1 forward barbette and is deflected, wobbling and fuzed, towards the foretop, near which it explodes, sending deadly shrappnel through the windows, killing Lindemann and some others near him. Main radar is destroyed permanently by the force of the blast.

Hood correctly aquires the target from her aft command position, and lands 1 x 381mm hit in the tip of the forecastle, wihch takes on more water.

Vanguard's rear turrets fire at maximum rate of fire from 13km on Hood, with perfect radar ranges offered by the second radar set. Hood suffers 4 hits in 2 minutes, one of which goes through the upper deck and explodes very near to the aft magazines, the force of the blast forcing enough red hot splinters in the powder magazines to trigger a catastrophic explosion at 6:06. Hood explodes and sinks.

In the mean time, Prince of WAles batters Vanguard with 3 more x 356mm shots, 1 thorugh the stern, destroying 1 shaft and the shaft alley, and causing 1000tons of flood, 1 through the funnel, riddling the bridges with deadly splinters, and 1 through the aft con tower, which kills the 3rd gunnery officer, Baron von Mullencheim von Reichenberg - on duty in that time and place. He does not live to wirte what could have become to be one of the best, and most confusing, naval histories of the XXth century. amazingly, the aft radar still continues to function.

Vanguard switches fire to Prince of Wales - which accumulated 8 x 203mm shots until then, and has 1000tons of water inside.

Vanguard fires with 6 x 381mm guns against 10 x 356mm guns. Vanguard receives another shot underwater, exploding against beneath the armored belt, against hte bulkhead. Flooding starts at 6:08, and endagers one of the machinery rooms.
Prince of Wales suffers 2 x 203mm shots and 1 x 381mm shots, which hit her bridge, killing everyone including Capt Leach.
She loses her FC solution, and, with the aft con tower previously wrecked by 1 x 203mm shell, she is without effective command for some 2 minutes, in which she suffers 4 x 381mm shots, causing great damage and 3000tons of water (total) of flooding. The Brtisih BB is making a smoke screen. Vanguard has almost expended all APC ammo on board, in a 20 minutes battle with the 2 capital ships. Prinz Eugen consumed 210 x 203mm shots. Prinz Eugen launches torpedoes vs PoW, none of witch hit.

Vanguard starts having big trouble with nearly 3500tons of water coming through 5 underwater holes. Pumping capacity appears lower then flooding capacity. The ship slows to 20kts, then to 15kts, while a list of 10 degrees settles, making firing impossible. Prince of wales retreats at 18kts, then 12kts, to the east, calling assistance from Suffolk and the 6 DDs.
Prince of Wales has 300 dead and wounded on board, 6 main guns functional, and only 4 secondary guns , and with no rangefinder or radar in function. She proceeds to repairs.
----

Luejens is desperate seeing his prize ship badly damaged after 12 hours of the initial spotting from the enemy. Furious of his fauly intel which told him all enemy capital ships were at anchor in Scapa, with fuel leaking out, with only 1200 tons of burnable fuel left, and with Prinz Eugen having fuel and machinery trouble of her own, the Admiral decides to turn back through the D.S. at 7:00AM.
Speed 16kts to perform repairs. Flooding is stopped, but ship retains 3 degrees list to starboard and 3 degrees down by the bow. Only 6 main guns in function, with 16 x APC shells left. 100 dead and wounded. Prinz Eugen is in the rear.
----

Unknown to him, Tovey is coming hard from the east at 27kts. The 6 DDs that Holland dettached do not see Luetjens's ships. They go to aid PoW, along with Suffolk.

vanguard appears safe until 15:00, when search a/c from Victorious find her to the souther edge of the Denmark Strait, some 30km off the thick fog banks. At the speed at which Vanguard is going, it would take 1.5 hours to enter fog. Victorious is 300km to the east, 2.5 hours off a possible Swordfish torpedo attack. KGV is 5 hours off gun range.

Pursuit starts - Tovey coming hard from the south, on the trails of Luetjens. Delta speed is 10kts, then 7kts as Vanguard builds back to 20kts steady speed.

In the night of May 24/25th, at around 03:00, Vanguards radar picks up enemy radar emissions triangulated at 40 to 60km south. It's KGV with Repulse , Victorious and several cruisers (the DDs were left behind not being able to catch up).

At 3:15, it becomes clear that the enemy is coming with a delta speed of 10km/h, and would be in gun range in less then 3 hours. However, Luetjens hopes to lose them in the fog and to jam their radars - which he does during the night.

At 6:00, KGV passes at 12km east of Vanguard without spotting her. All radar equipment is non functional and nobody knows why.

at 9:00AM, KGV is low on fuel and so is Repulse. They are in the northern zone of the Denmark Strait, with Victorious, which conducts air searches, once out of the fog banks. KGV uses her floatplanes to extend search area. At 12:00, Vanguard is discovered 40km south of Tovey.

The British attack with 9 Swordfish, which are badly shaken by the radar-controlled AA guns of Vanguard: 3 Swordfishes are destroyed, 4 damaged, none hits the target.

At 14:00, Tovey charges with KGV in the lead, Repulse close behind. First shot is fired by Vanguard from 24km.
Prinz Eugen follows at 21km. KGV replies at 20km, Repulse at 20km as well.

Vanguard strikes KGV in the base of the funell at 14:10, range 18km, with a 381mm SAP shell, causing speed drop to 18kts, then 10kts. 2 more x 381mm shots hit KGV - 1 glancing off the armored belt, another destroying the 2 x 356mm gun turret.

In the mean time, Prinz Eugen strikes Repulse 2 times, and Repulse strikes Vanguard with a crippling near-miss salvo, which destroys all radar antenas and kills 20 men.

Only P.E. remains with radars operational, adn hits Repulse again, underwater, triggering a slow flood of 500tons of water in the machinery room. Speed falls to 21kts.

Vanguard suffers 1 x 381mm hit in a aft main barbette, which is barely perforated, with the projectile suffering low-order explosion wchich sends hot fumes inside the barbette's ammo elevator, scalding everybody alive and jamming the elevator in place. Vanguard remains on 4 x 381mm guns. Wild manouvreing take her off Repulse's aim, but the own shooting is confused as well.

Luetjens orders smoke to be done by both ships.

They attempt withdrawal to the south-east, in hope of night to set in and to avoid enemy ships.

But KGV builds back speed in 1 hour at 22kts, Repulse matches speed, and they go after them.

At 17:00, they come into horizon line - vanguard goes to full 25kts, but fuel supply is dwindling. Hopes of using some of the theoretically non-burnable fuel are not realistic, and Luetjesn discovers he has only 100 tons of burnable fuel left.

Without hope of aid from Luftwaffe or Uboats in that latitude and longitude, and with the enemy coming after him, he decides to make a last stand with all guns to bear.

At 17:30, Vanguard opens fire with HE shells - the only ones left. They produce high columns of water and cause great splinter casualties, knocking out most radars and directors on board KGV from 24km range. KGV accelerates to 24kts, and opens fire soon after from 23km. Prinz Eugen fires on Repulse. Repulse targets Prinz Eugen.

In the following 10 mintues, KGV receives 2 x 381mm shots which lodges 1 main tuirret into place and the aft funnel completely, speed drops again to 15kts. However, Vanguard suffers 2 x 356mm shots - 1 exactly at the base of the main tower, killing Luetjens and everybody inside. The second - exploding in the crew mess hall, killing 100 men instantly.

Repulse is hit 3 times , and loses (temporarily) 1 main turret. Prinz Eugen is hit amidships by 1 x 381mm shell which perforates inside the machinery room and explodes, bringing speed down to 20kts.

---

Both forces had sufferd loses, Prinz Eugen is hit again and loses her main radar. Repulse suffers 1 more x 203mm shot , which devastates her radio room and all her aerials - she cannot transmit or receive orders anymore.

KGV plants 2 x 356mm shots in vanguard, destroying her funnel and causing fires amidships. The ship starts to slowdown, crew morale breaks down.

Prinz Eugen attempts to cover vanguard - and fires on KGV, to draw her aim. She succeeds, and both British BBs focus on her. In 15 minutes, Prinz Eugen receives 4 big shell hits, and starts to sink.

Vanguard's command is taken over by anotehr senior officer, which attempts to reorganize the firing of the 4 main guns. He succeeds in straddling KGV at 18:03, splinters showering the ship.

Burning, KGV fires on local control. Repulse's fires are more controlled, and her 3rd turret is brought back to action from 11km range.

From 18:05 to 18:15, Vanguard is hit 8 times, and loses all main battery and control positions. The ship is listing heavily, but is not sinking.

Repulse comes to 6km, planting several broadsides into her, causing great damage to the upper works.

Still, she doesn't sink.

KGV and Repulse are very low on fuel, and at 19:00 they retreat to Iceland, leaving Vanguard to her fate (scuttling).
Survivors are taken by Victorious and the cruisers. They are over 2000 survivors from Prinz Eugen and Vanguard, which are interned in the British isles.

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Re: Vanguard teleported in place of Bismarck

Postby Dave Saxton » Thu Aug 25, 2016 8:59 pm

On board Vanguard, technicians observe each 4-gun salvo clearly on the PPI radar scope, following each shell on the monitor, as it slams towars the cruiser, and also show the salvo splashes on the screen.


Vanguard's Type 274 and Type 275 fire control radars could not do that circa 1946. The Type 273Q surface warning had been superseded by the crappy Type 293/277 and it could not using the Skyatron either.
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: Vanguard teleported in place of Bismarck

Postby Dave Saxton » Wed Aug 31, 2016 12:20 am

Just in case anybody is puzzled by above post, it was made based upon the known operating properties of Type 274 and Type 275.

Type 274 could not spot the fall of shot. The reason it could not was because the radar beam was not scanned. Therefore, unless the shot fell within the beam, that was less than 1 degree wide, Type 275 could not see the splash. With a beam less than 1 degree wide the shot would almost always fall outside the radar's field of view.

For this reason, a special radar was fitted after 1947 to spot the fall of shot for Type 275, but only to the foretop set. The aft set did not receive this capability. The spotting radar fitted was Type 930 and Vanguard was the only warship fitted with this particular radar type. It was based on an Army radar used for coastal artillery spotting. Since it was not designed for warships originally, it proved very difficult to fit on Vanguard and proved very unreliable in the harsh marine environment. It was easily damaged by gun blast because it used mechanical scanning and mounting struts.

Type 275 was a conical scanning radar so it could not be used to spot the fall of shot. From a RN document:

the set has two inherent disadvantages. Firstly it has no spotting tube as the conical scanning system of Type 275 is fundamentally unsuitable for working a B scope.....


Conical scanning is suited to tracking and targeting aircraft but is quite unsuitable for surface targeting.

According to the same document neither fire control set was equipped with PPI indicators. The document lists all the PPI indicators fitted to HMS Vanguard and these sets are not included. PPI indicators were only used for Vanguard's air warning and surface warning radars and their associated combat information centers. These air warning and surface warning radars did not possess the required resolution to provide the type of spotting described in the above article.

Hence all the work to eventually fit Type 930.

The following may be useful in tweaking the above hypothetical scenario: A May 1946 test shoot with the firing of 26 15" broadsides and 23 5.25" broadsides revealed that the antennas of both the Type 274 and Type 275 were very susceptible to damage by gunfire shock and that significant improvements would need to be made to prevent the fire control radars from being easily knocked out by gunfire blast during combat.

Other tests indicated that there were severe interference problems among the various radar sets, and also between the various radio sets and radar sets on the Vanguard.
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: Vanguard teleported in place of Bismarck

Postby alecsandros » Wed Aug 31, 2016 11:41 am

Many thanks for the clarifications David.

My intention was to offer an alternative Rheinubung mission, with the Vanguard being considered a very advanced BB in terms of electronics.

But , with such different capabilities of the electronics systems, Vanguard wouldn't behave much better then Bismarck did, intelligence and counter-intelligence wise (except those cool radar jammers :D ), during the hypothetical Rheinubung. It also appears that the 1946 radar capabilities of Vanguard were less then those of 1943 Duke of York (during the battle of North Cape).

However, in the light of your informations , I think the "hypothetical" should be made more hypothetical, either by teleporting the 1947 Vanguard, or modifying the 1946 Vanguard to keep on board 1943/1944 British radar suites existing on the battleships that served in the war during those times.

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Re: Vanguard teleported in place of Bismarck

Postby Dave Saxton » Wed Aug 31, 2016 2:41 pm

alecsandros wrote: It also appears that the 1946 radar capabilities of Vanguard were less then those of 1943 Duke of York (during the battle of North Cape).



Well Vanguard's radars were far more advanced technically, but with the advancement it became more difficult to apply that more advanced technology in practice. It was also a text book case of a bureaucracy over reach. The ASE bureaucracy, which over saw radar in the RN, demanded that some of these new radars they had developed be fitted despite the protestations of the fleet.

Duke of York had only one PPI indicator at the time of North Cape. It was used for the Type 273Q surface warning set.

The new Type 277/293 sets, which replaced Type 273 on British heavy ships, were designed to work with a new 3 dimensional display system call the Skiatron. Unfortunately the radars sets themselves performed poorly. The primary literature is full of complaints about Type 277/293. The max range, even with larger and larger antennas was less than 28,000 yards.

The previously mentioned RN documents describes Type 274:

This is the most accurate fire control radar in existence and it is unlikely that there will be any development of a replacement gunnery surface set for the control of surface gunnery. Little improvement could be obtained by the use of more modern techniques than those included in Type 274 and the advance in GS sets will almost certainly be radar for guided missiles.

Type 274 in (only) HMS Vanguard is, however, the first set of this type to be fitted with auto-follow arrangements. The addition of auto follow completes the advance of facilities for accurate surface fire control by radar.

In conjunction with the Mk X AFTC auto follow permits the production of really smooth and accurate range and bearing plots and a consequent quick calculation of enemy rates.

The use of auto follow does not in itself reduce the effect of radar spot wander (echo paint wander). The important feature of the use of auto follow is the complete system possesses characteristics which are accurately calculable, repeatable and free from operator idiosyncrasies.....The use of auto follow in conjunction with the Mk X table has a further important advantage. It is possible to derive the inclination of the target by means of an mechanism controlled by the speed -along and speed across shafts. When following is automatic the correlation between jitter in speed along and speed across is maintained and this allows a shorter smoothing of the time constant to be used in obtaining target inclination.


It was far more advanced than DoY's Type 284M. It just could not spot the fall of shot by itself. The reason it did not scan its radar beam was because scanning radar is easy to jam. So Type 274's design reflected the new late war and post war realities of radar counter measures and counter counter measures. Scanning may have messed up the above mentioned auto follow feature as well.

Type 275 was light years better for AA directing than the previous Type 285M. However, it changed the DP secondary into essentially an AA only battery if radar directed. We know that by late war, AA was far more important than anti- destroyer anyway, though.

Also listed in the document is the inclusion of 3cm Type 262 light flak directing radar. (Other sources mention that Type 262 never became fully operational by the time it was superseded with by newer systems in the late 1950s) Vanguard was a deadly AA platform compared to WWII warships, nonetheless.
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: Vanguard teleported in place of Bismarck

Postby Dave Saxton » Wed Aug 31, 2016 3:17 pm

alecsandros wrote:
It also appears that the 1946 radar capabilities of Vanguard were less then those of 1943 Duke of York (during the battle of North Cape).



Today we tend to imagine the Duke of York's radars were more capable at North Cape than they actually were. Type 284 used only an single A-scope indicator. It could track shells in flight for range. It could also spot shell splashes (for range only) if the shell fell beyond or short 150 meters from the target. This ability was largely because it had a much wider beam compared to Type 274. However, the wider beam also means inferior comparative bearing discrimination.

The Royal Navy did not seem to put the same emphasis on spotting the fall of shot as the USN did. The RN did not consider radar spotting essential for blind fire. Nonetheless, Duke of York was hampered at N. Cape by Type 284M's poor capabilities to spot the fall of shot. Duke of York was asking other warships to report its fall of shot because it could not spot the fall of shot accurately enough using radar.
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: Vanguard teleported in place of Bismarck

Postby alecsandros » Wed Aug 31, 2016 3:36 pm

... But still Duke of York straddled consistently throughout the night, so her systems did produce good solutions after all.

In the scenario above, do you think Vanguard could have obtained full blindfire solution and hit Norfolk in the fog repeatedly ? I originally thought it could, now reading your assesment it appears less likely to be so - at least in the way I imagined it.

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Re: Vanguard teleported in place of Bismarck

Postby dunmunro » Wed Aug 31, 2016 7:25 pm

Dave Saxton wrote:Just in case anybody is puzzled by above post, it was made based upon the known operating properties of Type 274 and Type 275.

Type 274 could not spot the fall of shot. The reason it could not was because the radar beam was not scanned. Therefore, unless the shot fell within the beam, that was less than 1 degree wide, Type 275 could not see the splash. With a beam less than 1 degree wide the shot would almost always fall outside the radar's field of view.

For this reason, a special radar was fitted after 1947 to spot the fall of shot for Type 275, but only to the foretop set. The aft set did not receive this capability. The spotting radar fitted was Type 930 and Vanguard was the only warship fitted with this particular radar type. It was based on an Army radar used for coastal artillery spotting. Since it was not designed for warships originally, it proved very difficult to fit on Vanguard and proved very unreliable in the harsh marine environment. It was easily damaged by gun blast because it used mechanical scanning and mounting struts.

Type 275 was a conical scanning radar so it could not be used to spot the fall of shot. From a RN document:

the set has two inherent disadvantages. Firstly it has no spotting tube as the conical scanning system of Type 275 is fundamentally unsuitable for working a B scope.....


Conical scanning is suited to tracking and targeting aircraft but is quite unsuitable for surface targeting.

According to the same document neither fire control set was equipped with PPI indicators. The document lists all the PPI indicators fitted to HMS Vanguard and these sets are not included. PPI indicators were only used for Vanguard's air warning and surface warning radars and their associated combat information centers. These air warning and surface warning radars did not possess the required resolution to provide the type of spotting described in the above article.

Hence all the work to eventually fit Type 930.

The following may be useful in tweaking the above hypothetical scenario: A May 1946 test shoot with the firing of 26 15" broadsides and 23 5.25" broadsides revealed that the antennas of both the Type 274 and Type 275 were very susceptible to damage by gunfire shock and that significant improvements would need to be made to prevent the fire control radars from being easily knocked out by gunfire blast during combat.

Other tests indicated that there were severe interference problems among the various radar sets, and also between the various radio sets and radar sets on the Vanguard.


Type 274 could spot for both range and Line (bearing) . It is true that the beam was narrow but even a one degree beam is typically wide enough to see the FoS since a one degree error in line was rare, especially given the very accurate range and target bearing that Type 274 could provide:
Image

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Re: Vanguard teleported in place of Bismarck

Postby dunmunro » Wed Aug 31, 2016 7:45 pm

Dave Saxton wrote:
alecsandros wrote:
It also appears that the 1946 radar capabilities of Vanguard were less then those of 1943 Duke of York (during the battle of North Cape).



Today we tend to imagine the Duke of York's radars were more capable at North Cape than they actually were. Type 284 used only an single A-scope indicator. It could track shells in flight for range. It could also spot shell splashes (for range only) if the shell fell beyond or short 150 meters from the target. This ability was largely because it had a much wider beam compared to Type 274. However, the wider beam also means inferior comparative bearing discrimination.

The Royal Navy did not seem to put the same emphasis on spotting the fall of shot as the USN did. The RN did not consider radar spotting essential for blind fire. Nonetheless, Duke of York was hampered at N. Cape by Type 284M's poor capabilities to spot the fall of shot. Duke of York was asking other warships to report its fall of shot because it could not spot the fall of shot accurately enough using radar.


DoY asked for other ships to report the FoS only when the range exceeded 20k yds. The rough sea state reduced the range that the FoS could be seen via type 284 radar.

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Re: Vanguard teleported in place of Bismarck

Postby alecsandros » Thu Sep 01, 2016 6:06 am

Many thanks David,
I see there in the diagram they refer to a "bright spot". Is that some sort of electronic pointer that coudl be moved by the operator on the radar screen to emphasize various areas ?

Also, we see in the digram usualy 1 large ellipsoid, depicting the target, and 1 smaller ellipsoid depicting shell splash.

If the firing ship fires 4 shots in a salvo, would the screen draw 4 smaller ellipsoids (possibly somewhat overlapping) ?

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Re: Vanguard teleported in place of Bismarck

Postby Dave Saxton » Thu Sep 01, 2016 1:54 pm

If Type 274 could adequately spot the fall of shot consistently then there would be no point in going to the trouble of developing and fitting Types 930, 931, 932.

Also in Admiralty documents among the short comings of Type 284 listed is often an inability, or a very poor ability, to 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.

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Re: Vanguard teleported in place of Bismarck

Postby dunmunro » Fri Sep 02, 2016 7:24 pm

Dave Saxton wrote:If Type 274 could adequately spot the fall of shot consistently then there would be no point in going to the trouble of developing and fitting Types 930, 931, 932.

Also in Admiralty documents among the short comings of Type 284 listed is often an inability, or a very poor ability, to spot the fall of shot.


There's big difference between an optimal ability to spot FoS and none at all. The Type 274 operator could determine if the MPI was to the left or right of the target but it was harder to estimate by exactly how much, although the narrow field meant that it could not be too far in either direction. Type 930 was an army radar developed for coastal guns but was ill suited to shipboard use. Type 931 was a Canadian radar similar to 930 but designed for shipboard use while 932 was the same radar built in the UK. The 930 series were designed to provide a quantitative measurement of the FoS MPI and to aid the Type 274 in acquiring the correct target.

Type 284 went through many permutations but DoY's type 284M3 could spot FoS and did so for most of the action.

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Re: Vanguard teleported in place of Bismarck

Postby Dave Saxton » Sat Sep 03, 2016 4:05 am

dunmunro wrote:
Dave Saxton wrote:If Type 274 could adequately spot the fall of shot consistently then there would be no point in going to the trouble of developing and fitting Types 930, 931, 932.

Also in Admiralty documents among the short comings of Type 284 listed is often an inability, or a very poor ability, to spot the fall of shot.


There's big difference between an optimal ability to spot FoS and none at all. The Type 274 operator could determine if the MPI was to the left or right of the target but it was harder to estimate by exactly how much, although the narrow field meant that it could not be too far in either direction. Type 930 was an army radar developed for coastal guns but was ill suited to shipboard use. Type 931 was a Canadian radar similar to 930 but designed for shipboard use while 932 was the same radar built in the UK. The 930 series were designed to provide a quantitative measurement of the FoS MPI and to aid the Type 274 in acquiring the correct target.

Type 284 went through many permutations but DoY's type 284M3 could spot FoS and did so for most of the action.


The need to piggy back on an Army radar to better spot the fall of shot speaks for itself.
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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