10 moments that changed the course of the war at sea

From the Washington Naval Treaty to the end of the Second World War.
Byron Angel
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Re: 10 moments that changed the course of the war at sea

Post by Byron Angel »

paul.mercer wrote: Gentlemen,
In the book 'Scharnhorst' by Alf R Jacobsen, he states that 'In the course of the next 27 minutes DoY pumped more than 200 heavy shells at Scharnhorst from distances as short as 4000 metres, strangely only seven or eight of them appear to have sored hits'
I am not a gunnery or radar expert, but this seems to me to be pretty rotten shooting, KGv & Rodney were shooting at this sort of range in the end and from the pictures taken by Ballard & Co they seem to have blown most of Bismarcks superstructure away, so what was wrong?

..... Much of DoY's shooting consisted of "blind" fire, i.e. - under full radar control, without the target being optically visible. Her FC radar could provide excellent range data, but was relatively poor at defining deflection. Salvoes would be fine for range but many/most would miss for deflection. Similar blind fire issues affected US and other FC radars of the period as well. USN night firing practice was ideally to have range controlled by by the FC radar, but gun train controlled by the big optical range-finder in the director tower.

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alecsandros
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Re: 10 moments that changed the course of the war at sea

Post by alecsandros »

Byron Angel wrote:
paul.mercer wrote:
..... Much of DoY's shooting consisted of "blind" fire, i.e. - under full radar control, without the target being optically visible. Her FC radar could provide excellent range data, but was relatively poor at defining deflection. Salvoes would be fine for range but many/most would miss for deflection. Similar blind fire issues affected US and other FC radars of the period as well. USN night firing practice was ideally to have range controlled by by the FC radar, but gun train controlled by the big optical range-finder in the director tower.

B
.. and the sea state was worse at NOrth Cape then it was during Bismarck's final battle, IIRC.. thus even with a good firing solution, salvo trajectory would be constantly deflected by the movement of the ship on heavy seas.
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Dave Saxton
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Re: 10 moments that changed the course of the war at sea

Post by Dave Saxton »

Byron Angel wrote:..... Much of DoY's shooting consisted of "blind" fire, i.e. - under full radar control, without the target being optically visible. Her FC radar could provide excellent range data, but was relatively poor at defining deflection. Salvoes would be fine for range but many/most would miss for deflection. Similar blind fire issues affected US and other FC radars of the period as well. USN night firing practice was ideally to have range controlled by by the FC radar, but gun train controlled by the big optical range-finder in the director tower.

B
Hi Byron,
Duke of York fired using radar ranging and used star shell to observe the fall of shot. Then as the range increased to beyond the effective range of star shell it could not spot the fall of shot. It was asking over the radio any other RN warship to spot the fall of shot and report it to Duke of York. ADM220/27 has some interesting critisms of Type 284M for blind fire operation, chief among these being the inability to spot the fall of shot. It wasn't the ability to spot for range so much as the ability to spot for bearing.

The way Type 284M worked was, that the presentation was by A-scope, which only presented range data (A -scopes can be very precise for range measurement though). They knew if the antenna was aimed at the correct bearing by if the trace flickered or not. The trace flickered if the bearing track was off, but held steady if the antenna aim was correct. The actual bearing accuracy claimed was amazing, however. It was as good as 0.08*! Among the problems listed in ADM220/27:
Range less than max range of guns.
Fluctuacting pips during bearing fix making it difficult to use.
Inability to spot the fall of shot
The resolution for both range and bearing being not fine enough

ADM220/27 has some interesting points about ranging inaccuracies by using extremely short pulse width, using Mk13 as the example.
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.
paul.mercer
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Re: 10 moments that changed the course of the war at sea

Post by paul.mercer »

alecsandros wrote:
Byron Angel wrote:
paul.mercer wrote:
..... Much of DoY's shooting consisted of "blind" fire, i.e. - under full radar control, without the target being optically visible. Her FC radar could provide excellent range data, but was relatively poor at defining deflection. Salvoes would be fine for range but many/most would miss for deflection. Similar blind fire issues affected US and other FC radars of the period as well. USN night firing practice was ideally to have range controlled by by the FC radar, but gun train controlled by the big optical range-finder in the director tower.

B
.. and the sea state was worse at NOrth Cape then it was during Bismarck's final battle, IIRC.. thus even with a good firing solution, salvo trajectory would be constantly deflected by the movement of the ship on heavy seas.
I see what you mean about the weather, but it was'nt exactly flat calm during the final engagement with Bismarck and gunnery officers are supposed to practice and be able to make hits in all weathers, surely 4000m should be almost point blank for a modern battleship like DoY, seven or eight hits out of two hundred does'nt seem very good shooting to me despite the conditions.
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Re: 10 moments that changed the course of the war at sea

Post by Byron Angel »

Dave Saxton wrote:
Byron Angel wrote:..... Much of DoY's shooting consisted of "blind" fire, i.e. - under full radar control, without the target being optically visible. Her FC radar could provide excellent range data, but was relatively poor at defining deflection. Salvoes would be fine for range but many/most would miss for deflection. Similar blind fire issues affected US and other FC radars of the period as well. USN night firing practice was ideally to have range controlled by by the FC radar, but gun train controlled by the big optical range-finder in the director tower.

B
Hi Byron,
Duke of York fired using radar ranging and used star shell to observe the fall of shot. Then as the range increased to beyond the effective range of star shell it could not spot the fall of shot. It was asking over the radio any other RN warship to spot the fall of shot and report it to Duke of York. ADM220/27 has some interesting critisms of Type 284M for blind fire operation, chief among these being the inability to spot the fall of shot. It wasn't the ability to spot for range so much as the ability to spot for bearing.

The way Type 284M worked was, that the presentation was by A-scope, which only presented range data (A -scopes can be very precise for range measurement though). They knew if the antenna was aimed at the correct bearing by if the trace flickered or not. The trace flickered if the bearing track was off, but held steady if the antenna aim was correct. The actual bearing accuracy claimed was amazing, however. It was as good as 0.08*! Among the problems listed in ADM220/27:
Range less than max range of guns.
Fluctuacting pips during bearing fix making it difficult to use.
Inability to spot the fall of shot
The resolution for both range and bearing being not fine enough

ADM220/27 has some interesting points about ranging inaccuracies by using extremely short pulse width, using Mk13 as the example.


..... You raise a good point, Dave, regarding the the practical utility of FC radar at night, which I equate with the range at which fall of shot could be detected/spotted. This range appeared to differ according to the caliber of the firing battery. In the Guadalcanal campaign, open fire ranges were largely dictated by this factor. Based upon my readings, USN Mk 3/4 FC radars circa 1942 could spot shell splashes at approximately the following ranges:

5in - 12,000 yds
6in - 13,000 yds
8in - 14,000 yds
14-16in - 20,000 yds

- i.e. ranges more or less varied as the square root of the gun caliber.

Surigao Strait suggests the Mk 8 circa 1944 performed slightly better, given that fire was opened by the BBs at 23,000 yards.


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alecsandros
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Re: 10 moments that changed the course of the war at sea

Post by alecsandros »

paul.mercer wrote:
I see what you mean about the weather, but it was'nt exactly flat calm during the final engagement with Bismarck and gunnery officers are supposed to practice and be able to make hits in all weathers, surely 4000m should be almost point blank for a modern battleship like DoY, seven or eight hits out of two hundred does'nt seem very good shooting to me despite the conditions.
Actualy DoY fired 446 shells throughout the engagement, IIRC, at ranges of 10-18km.

During Bismarck's final battle, the sea state was bad, but my impression is that at NOrth Cape it was much worse...
pg55555
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Re: 10 moments that changed the course of the war at sea

Post by pg55555 »

.

So many things.

Re. Nightfighters ;

1: "The proof of the pudding ....." the British using NON "state of the art" radar had the ability to hunt the German fighters, that is fact.

2: The British found that the German system of Ground Intercept integration was a wonder of complexity, accuracy and skill. But also, time and resource wasting and inefficient.

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Naval Radar ;

A: Do NOT believe all the silly "wargame" claims for USN fire control (whether radar or non-radar controlled). There is a ridiculous ability to only "see" the best figures. This was noted during WW2 by the British. There is a 1944 paper on a tour of US naval radar facilities where a pair of British experts disagreed with a lot of what was being stated (considering 1940s British language quite strongly). The US claimed wonderful abilities, whilst the British considered them to have ignored both the actual radar performance and many factors in "the fire control solution" including wind effects and gun wear. Modern commentators tend towards extending incomplete and minimal statistics to ridiculous conclusions.

B: Despite any WW2 era claims, radar was NOT well suited for maximum performance in anything other than calm seas, and optimal performance (indeed any performance) demanded good maintenace. The same paper as above noted that RN radar sometimes was "too" accurate as different scans of the radar would bounce off different aspects of large targets thus feeding differing distances into the fire control tables. Even in the 1950s with the next generation of post-war radars the RN regarded Soviet raiding cruisers as a danger, it was only with better quality (especially re. electronic jamming) airborne radar in the late 1950s that the RN could relax. Compare this with the incredibly Blase attitude from most modern commentators on WW2.

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B:

C:
Francis Marliere
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Re: 10 moments that changed the course of the war at sea

Post by Francis Marliere »

pg555,

Could you please elaborate your comments on naval radar ? I may be mistaken (English is not my native language and I sometimes misunderstand), but they are not validated by neither "common wisdom" nor publication (especially "Fast Battleship Gunnery during World War II: A Gunnery Revolution" (Warship International Vol. 42, No. 2, and Part 2 in Vol. 43, No.1) by Bill Jurens and Brad Fischer).

Best,

Francis Marliere
Hartmann10
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Re: 10 moments that changed the course of the war at sea

Post by Hartmann10 »

Hello to all:
Hartmann10 wrote:
Among with the US Navy night fighters and also the RAF night fighters. It was the only way to make an effective defence at night. I don´t see any different way to deal with the problem: The "SM", "SP" (both Navy radar sets) and "SCR-584" radar sets were used in this way, even when the main use of the "SCR-584" was the gunlaying. Also some British sets were used in this way in the "Baby Blitz" of 1944.
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That's interesting about the USN use of GCI techniques, Javier. I don't see a better way to deal with the problem either.
Yes, David. I have a document concerning the use of these radars from carriers to guide the fighters to the enemy, and also, the modification for surveillance and fighter direction against kamikazaes of the destroyer pickets with SP and SP-1M sets (all of "Gearing" class, and some of Destroyer Escorts). I can send you via Mail the info.
So many things.

Re. Nightfighters ;

1: "The proof of the pudding ....." the British using NON "state of the art" radar had the ability to hunt the German fighters, that is fact.
¿? :shock: Who has said that Britsh Night Fighters used non state of the art radars? If you don´t know, the AI MK X set is only a "cropped" (lightweight) US SCR 720 radar, with one of the two displays modificed according to the needs of the RAF. Even more, the USAAF delayed more than half a year the entry of the P-61 "Black Widow in service because of the desperate pledges of Churchill to Roosevelt concerning the SCR 720. During half a year allmost all the SCR 720 sets manufactured were sent to the RAF, so the USAAF had a highly specialised Night Fighter, the P-61 "Black WidoW" useless in Great Britain because of It didn´t have radar sets installed.
Even more, the RAF, used far more of 20 years the AI MK X set (the US SCR 720) after the war because they didn´t have anything better.
The centimetric sets designed by the RAF scientist were too complex to develope and/or excellent for laboratory, but not well suited for combat conditions. That is a fact. The MK VIII set was fastly retired by this reason. The main reasons were the overly complex spiral scanning and automatic target adquisition. The Germans made an automatic lock on system which was very effective and capable, the "Elfe", capable of being coupled to a wide variety of different radar sets.
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Hartmann10
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Re: 10 moments that changed the course of the war at sea

Post by Hartmann10 »

Sorry, I sent the message before than I liked.
2: The British found that the German system of Ground Intercept integration was a wonder of complexity, accuracy and skill. But also, time and resource wasting and inefficient.
Well, that is an opinion. The Germans could have said the same from the USAAF or the RAF systems. That´s a very subjetive, not objetive opinion, as It is not based on facts or hard data.
I have the whole encycopedia of the MIT radar Lab, the 28 volumes, written between 1947 and 1949, and in the first they describe the functioning mode of the combined GCI RAF/USAAF in British soil. I can assure You that it was pretty similar to the Luftwaffe system (the most striking thing is that the search radars were all of British origin, but the gunlaying radars wereallmost entirelly of USA origin, the superb SCR 584 (the GL 3 A was in fact the lend lease SCR 584 radar set).
pg55555
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Re: 10 moments that changed the course of the war at sea

Post by pg55555 »

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USN interception/GCI techniques were those adopted from the UK via the visit of HMS Victorious.

The UK's views on German techniques were based on the post-war study of the system in operation. Fantastic radar systems which were expensive, and slow and inefficient because of the way the radars guided fighters - the UK system used "ordinary" radars and general guidance.

MOST of the Mosquito nightfighter intruders did NOT use the Mark X until very late war because they did not want it to fall into German hands (it was used over the UK and gradually over the Channel) - that's why I said half a generation behind.

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sandym
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Re: 10 moments that changed the course of the war at sea

Post by sandym »

paul.mercer wrote: I see what you mean about the weather, but it was'nt exactly flat calm during the final engagement with Bismarck and gunnery officers are supposed to practice and be able to make hits in all weathers, surely 4000m should be almost point blank for a modern battleship like DoY, seven or eight hits out of two hundred does'nt seem very good shooting to me despite the conditions.
I think seven or eight hits out of two hundred is pretty good, considering the weather conditions and the relatively primitive electronic aids to gunnery, plus the myriad of human factors.

Us keyboard warriors with vast technilogical reach and instant access to 'knowledge' are always so quick to criticise and mythologise what went before.

We are also dreadful at turning naval events into ship versus ship events, whereas, in fact, they were fallible and frail humans against fallible and frail humans.
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Dave Saxton
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Re: 10 moments that changed the course of the war at sea

Post by Dave Saxton »

I recently accessed an RAF paper on electronic warfare and radar during WWII and up through the 1960s. It turns out that the standard RAF Airborne AI radar used during the war also used antler antennas.

This radar was the Mk-IV used by the Mossys over occupied territory. Its performance was some what inferior to the German Lichtenstein. But the MK-VIII which featured a dish antenna inside the nose cone was not cleared for use over enemy territory until mid 1944.

The night raids over Nuernburg during March 1944 which resulted in huge bomber losses for the British and the with draw of the Sterling bomber from combat service, caused a revaluation of the restrictions on Mk-VIII. The true performance of MK-VIII was only marginally better than the German and in service British AI radars, with a detection range of 3-6 miles if the target was dead ahead - and if the altitude was also at least 15,000 feet. The field of view was only a few degrees but it did not have the huge ground return problem of MK-IV. Its introduction to combat did not turn the tables much in the airborne radar war because of the on going "Monica Disaster."

Monica was a 10cm radar that warned if a German night fighter was on the tail of the British aircraft and could be used to assist the fire of the tail gunner. The Germans used Monica emissions to home in on the target, usually taking it by surprise and shooting it down! It took the British until late 1944 to determine what was happening and Monica was ordered switched off.

Some British night fighters were allowed to continue to use Monica for the "Whiting Manouver". The tactic was to use Monica to lure in a German night fighter and then attempt to turn on to the tail of the German and acquire the target on the Mk-VIII radar.

At the end of the war, the American 3cm AI radar (known to the British as MK-X) was also introduced on the Mossy. MK-X required an a strange elongated nose cone, however.
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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