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HF Dave
21-12-2011, 23:49
There are various references and pictures of this WWII radar site on the web, e.g. :

http://www.pixalo.com/community/landscape-photography/east-tilbury-radar-tower-40959.html

http://en.wikipedia.org/wiki/Coalhouse_Fort

But can anyone tell me which radar was actually used here? I don't think it was part of the Chain Home (and its various extensions) system (e.g. CHEL, CD/CHL), and was presumably operated by the Royal Navy rather than the RAF. I guess it must have been some kind of surface warning radar.

Carnaby
21-12-2011, 23:57
This reckons it was a Minefield Control Tower

http://www.southeast-defencephotos.com/gallery/index.php

HF Dave
22-12-2011, 11:17
This reckons it was a Minefield Control Tower

http://www.southeast-defencephotos.com/gallery/index.php

I'm pretty sure this description is incorrect. The control / observation tower is to the north of Coalhouse Fort (square building at TQ690769, SMR 10299), not right beside the Thames. The hexagonal radar tower was disguised as a water tower, and even marked as such on some maps.
Looking again at the SMR description (SMR 10296, location TQ 689763) it does talk about type NT 284 equipment.

HF Dave
22-12-2011, 11:37
Hmm... Type 284 was a gunnery surface radar (see http://www.kbismarck.org/forum/viewtopic.php?f=13&t=3567). So perhaps it was tested here before being fitted to Royal Navy ships.

HF Dave
22-12-2011, 21:43
Mike Osborne ('Defending Britain', pp.30-31) notes the similarity between this structure and the one at Beacon Hill Fort, Harwich (TM 262318). The latter is also hexagonal, but all three storeys are built of brick. Incredibly, the 21' antenna arrays are still in place. These were rotated manually to give bearing information.

See http://www.subbrit.org.uk/sb-sites/sites/b/beacon_hill_fort/index5.shtml and http://www.flickr.com/photos/radar666/3704636889/in/set-72157610372648506

Type 284 or a similar gunnery radar is looking a good candidate for East Tilbury.

HF Dave
01-10-2012, 20:57
A few photographs of the tower taken in September 2012. The upper storey would have housed the antenna (which may have been rotated manually) and the lower storey the other equipment.

10228

10229

10230

PETERTHEEATER
02-10-2012, 07:52
I can't see a connection from the base control room up to the scanner so to move it manually did someone have to climb the stairs?

Mike L
02-10-2012, 11:39
According to the 1985 guide to the Tilbury defences the radar tower was manned by Naval personnel and [I]may[I] have housed a type NT 284 instrument.
It also states that 'this radar is described in the War Office records of the period as having been established for minefield observation'.
There is a diagram in the guide of how the river-type minefield would have worked.

outkast
02-10-2012, 17:34
According to the 1985 guide to the Tilbury defences the radar tower was manned by Naval personnel and [I]may[I] have housed a type NT 284 instrument.
It also states that 'this radar is described in the War Office records of the period as having been established for minefield observation'.
There is a diagram in the guide of how the river-type minefield would have worked.

The minefield control tower is the one adjacent to the fort, the radar tower is out on the bank of the river.

HF Dave
03-10-2012, 12:32
I can't see a connection from the base control room up to the scanner so to move it manually did someone have to climb the stairs?

There was probably a mechanical connection going through one of the holes in the floor of the upper storey (but I must admit I didn't check the ceiling in the lower storey) which has subsequently been removed. Of course I'm not certain that the scanner was manually moved in this case, but I know the method was used on some early naval radar types.

Mike L
03-10-2012, 13:39
Outkast, I totally agree about the location of the minefield control tower but there still seems to be some confusion from the description in the guide.
Given that the radar tower is very close to the QF battery and the 284 seems to be a naval gunnery radar are the two related?

HF Dave
03-10-2012, 19:30
The minefield control tower is the one adjacent to the fort, the radar tower is out on the bank of the river.

Yes, about 750 yds north of the radar tower. It looks like a piece of Cubist abstract art:

10283

HF Dave
03-10-2012, 19:32
Outkast, I totally agree about the location of the minefield control tower but there still seems to be some confusion from the description in the guide.
Given that the radar tower is very close to the QF battery and the 284 seems to be a naval gunnery radar are the two related?

I think the QF battery was out of use by the time the radar was built. However the radar could have been used in conjunction with the minefield control tower. Just speculation on my part though.

Mike L
04-10-2012, 00:57
To be honest I haven't looked into this very much and I don't know where the minefield itself actually was.
A diagram in the 1985 guide shows a 'typical' river-type minefield with an observation tower on one bank and a sighting mast on the opposite bank. In the shallows at each bank a field of static 'mechanical mines' are shown with 'electro-contact observation mines' in the central channel. See attached diagram.
Given the obs posts at Tilbury the 'sighting mast' should be on the Kent bank of the Thames, this might give a location for the minefield. Does anyone know of such a sighting mast structure?
What I can't quite undestand is why a minefield defence radar would be positioned so far apart from the minefield observation post. Unless wireless was used the communication lines would be unneccessarily long. Also since the diagram seems to indicate 'line of sight' operation (not efficient at night I appreciate) would radar be a useful, if costly, addition?
Could the radar be associated with the nearby HAA battery?
Lots of questions, I look forward to hearing you opinions.

outkast
04-10-2012, 17:25
Outkast, I totally agree about the location of the minefield control tower but there still seems to be some confusion from the description in the guide.
Given that the radar tower is very close to the QF battery and the 284 seems to be a naval gunnery radar are the two related?

Hi Mike, I dont know if it adds to the confusion somewhat, but located at bowater farm about 2 miles north of coalhouse is a HAA site, this was original an four gun site, later four 9 inch guns were added, when carrying out some research about the place I came across a bit of text that mentioned bowater as being a site that was kept on after the war for testing ordanance fired from the 9 inch guns, also the guns could be used in a dual role such was thire range, they could hit anything coming up the river as well as aircraft passing overhead.
it could be possible that the radar towers use was connected with this testing phase of the bowater guns?

Just a thought, I may be way off beam.

outkast
04-10-2012, 17:27
To be honest I haven't looked into this very much and I don't know where the minefield itself actually was.
A diagram in the 1985 guide shows a 'typical' river-type minefield with an observation tower on one bank and a sighting mast on the opposite bank. In the shallows at each bank a field of static 'mechanical mines' are shown with 'electro-contact observation mines' in the central channel. See attached diagram.
Given the obs posts at Tilbury the 'sighting mast' should be on the Kent bank of the Thames, this might give a location for the minefield. Does anyone know of such a sighting mast structure?
What I can't quite undestand is why a minefield defence radar would be positioned so far apart from the minefield observation post. Unless wireless was used the communication lines would be unneccessarily long. Also since the diagram seems to indicate 'line of sight' operation (not efficient at night I appreciate) would radar be a useful, if costly, addition?
Could the radar be associated with the nearby HAA battery?
Lots of questions, I look forward to hearing you opinions.

both Cliffe and shornmead fort are on the opposite side of the river, its possible the sighting mast may have been on one of those.

although little remains of shornemead, quite bit remains of Cliffe.

PETERTHEEATER
05-10-2012, 10:24
Hi Mike, I dont know if it adds to the confusion somewhat, but located at bowater farm about 2 miles north of coalhouse is a HAA site

Now that confused me! Bowater Farm is just under a mile to the northwest of Coalhouse Point. The HAA site is recorded by Dobinson as Buckland. The '9 inch guns' would have been 9.2 inch. Four were installed Medway/Thames in WW1 but reduced to two by WW2 but where, I know not. If they were located at Bowlands Farm there should have been substantial foundations prior to construction of the HAA Battery.

EDIT: Add

If you look at the HAA site in Google Earth and 'rollback' the view to 1999, at least two of what appear to be 9.2 inch gun positions are to the right of the later HAA emplacements unless these are for when the original 3.7 inch HAA guns were replaced with 4.5 inch HAA?

See also a 1961 OS Map to 2500 scale on Old Maps website.

outkast
05-10-2012, 15:38
Hi Peter, I quick google serch brought up this, I will try and find the more thorough description I originaly found some years back.

Second World War heavy anti aircraft battery TN13. Eight concrete gun emplacements with their connecting roads and vehicle parks, magazine and command post. The battery forms two groups of anti-aircraft artillery. The earlier group comprises four octagonal emplacements of concrete conered by asphalt, which measure some 16 metres across. Inside the emplacements, the ten bolts which fixed the guns to the ground survive, as do the ammunition lockers against the walls. Between the middle two emplacements is a rectangular magazine building. At the rear of the group is a larger building which formed a command post and which included height and range-finding equipment, although this no longer survives. The group houses 4.5 inch guns from the mid-1940 to 1944. To the east is a second group of four emplacements, these examples comprising a deep circular pit, with an adjoining sunken engine room to the west or south west. A gun turret, which no longer survives, capped the circular pit, and housed a 5.25 inch gun. This group superseded the 4.5 inch guns in 1944 and continued in use until after the war. This anti-aircraft battery is the last surviving example in this area of Essex. Scheduled.

I have visited the site and eight gun pits survives along with a magazine and command bunker, four of the pits are of the early type and four of the later.

Mike L
05-10-2012, 19:02
Wow, this seems to get more confusing!
I have copied this from the 1985 guide to the Coalhouse Fort and East Tilbury artillery defences:


Air attacks on Britain were on a scale more vast and sustained than in the First World War and one of a ring of anti-aircraft batteries defending the eastern approaches to London was built at Bowaters Farm about 1200 yards to the west-north-west of Coalhouse Fort. It originated in August 1939 as a site for mobile 3.7-in. guns (maximum ceiling 41,100 ft} in sandbagged emplacements. The guns were initially manned by a Unit of Territorials. Then by mid1940 four permanent emplacements for 4.5-in. guns (maximum ceiling 44,010 ft.) with a central command post and other buildings were constructed. Further emplacements for 4 X 5.25-in, remotely-controlled and radar-directed guns (maximum ceiling 55.6000 ft.) were added later. The emplacements, magazines and other buildings still exist as a fine example of a type-site. The guns saw much action against enemy raiders and on one occasion the batters- was dive-bombed and on another hit by incendiary- bombs. The battery was Supported by nearby searchlights for night firing. In 1941 a single light projector, together With sound-location equipment to detect the noise of enemy aircraft at long range, was stationed on the jetty at Coalhouse Point. It was defended by a Lewis -gun but was strafed by enemy fighters on several occasions. There was another light on the old river wall near to the north caponier of Coalhouse Fort.

A radar tower, built by 1941. still stands on the river wall about three hundred yards upstream of the Q.F. battery. It was manned by naval personnel and may have housed a type N.T. 284 instrument. This radar is described in the War Office records of the period as having been established for minefield observation.

The Second World War Anti-aircraft Gun Site (TQ 678.771)
The site, located at Bowaters Farm on rising around over-looking the marsh, consists of eight concrete gun emplacements, connecting road, and vehicle parks, magazines and a command post, together with various ancillary buildings and a barracks, all surrounded by a perimeter fence. The emplacements are in two distinct groups, the southernmost one being for 4 X 5.25-in. heavy anti-aircraft guns and the other for 4 X 4.5-in. anti-aircraft -guns. The site began in 1939 as a battery for 3.7-in. guns in sandbagged emplacements.
Each of the emplacements for the 5.25-in. guns consists of a deep circular pit which contained a gun turret and, linked by a short access cable tunnel, an annexed under-ground engine room. In the pits can be seen the circular fixing plates for the base of the guns and the ready-use ammunition recesses. In the engine room are the concrete engine beds, and various related wall and ceiling fixtures.
The other four emplacements are more simple, comprising a concrete enclosure wall, pierced by two entrances and embanked with earth on the outside. Their interiors contain six ammunition lockers butting on to the wall and in the centre can be seen ten holding-down bolts for the gun pedestals. In one or two of the emplacements painted numbers - presumably bearings - are still discernible on the exterior walls of the ammunition locker, together with place-names such as Tilbury and Shell Haven to give an instant general directional reference. Between Nos 2 and 3 emplacements is a magazine divided into five compartments, each dividing wall having a painted rectangle on which holdings were recorded. There is a large separate magazine adjacent to the east perimeter fence of the site.
The command post has been altered since its original construction and this obliterated the positions for the predictor and height range-finding equipment. To the rear of this building is a powerhouse.
The barracks are of red brick with, despite wartime urgency, fine red-tiled roofs. They line the entrance road on the north side of the site. Private property.

Radar Tower, Second World War, Coalhouse Point (TQ 689. 763)
Hexagonal tower consisting of a lower brick building supporting an upper concrete structure on a metal frame. The lower building contained the power plant, electrical equipment and radar screen, together with living and sleeping accommodation for naval personnel. The aerial array was mounted in the upper structure. On the beach to the west side of the tower is the demolition debris from what may have been two concrete Defence Electric Light Emplacements of earlier date.


So no mention of 9 or 9.2in guns and no definative statement on the use of the radar tower.
The HAA battery is shown below and the location is as the map previously posted.
I have posted a similar question on WW2Talk so there might be some input from there soon.

Mike L
05-10-2012, 21:09
Found this:
http://www.pastscape.org/hob.aspx?hob_id=1375139&sort=2&type=&rational=a&class1=None&period=None&county=None&district=None&parish=None&place=&recordsperpage=10&source=text&rtype=monument&rnumber=1378614

Seems they aren't sure either!

PETERTHEEATER
06-10-2012, 04:10
We are drifting a bit now but I think that it is safe to say that there were no 9.2 inch guns on this site.

I don't know whether radar was used as part of the direction of the 5.25 operated by the Royal Artillery. By late war the proximity fuze was in use so standard range finders (on-site) would still have been in use.

To me, it is more likely that the Radar Tower in question was for tracking potential targets at night or in poor visibility to enable attack using command detonated mines in the river as per Post 14.

Pity the Brennan torpedo installation in Cliffe Fort on the opposite bank was obsolete:)

outkast
06-10-2012, 19:31
We are drifting a bit now but I think that it is safe to say that there were no 9.2 inch guns on this site.

I don't know whether radar was used as part of the direction of the 5.25 operated by the Royal Artillery. By late war the proximity fuze was in use so standard range finders (on-site) would still have been in use.

To me, it is more likely that the Radar Tower in question was for tracking potential targets at night or in poor visibility to enable attack using command detonated mines in the river as per Post 14.

Pity the Brennan torpedo installation in Cliffe Fort on the opposite bank was obsolete:)

I think you are proberly right, it was a long time ago and my memory aint what it used to be, friend of mine wrote a book on the brennan torpedo instalations.

When I was a kid the stair were still climbable, from memory there is very little in the room at the top, I do have some pics of whats in the lower rooms, if I can find them i will post them up.

Mike L
06-10-2012, 19:47
I have been trying to find out a bit more about the radar. There is a radar tower at Beacon Hill fort, Harwich which was constructed about the same time (although they clain it is the earliest RDF tower) and it too is hexagonal but is a solid walled 3 storey building. The radar equipment is still there (or most of it) and it is open to the public on odd days.
That radar is apparently a type 287, which I haven't found much about yet, and apparently used for gunnery direction, mostly protection against E-Boat attacks.
My first thought was that the type 284 reportedly at Tilbury seemed a strange choice as it was the same sort fitted to cruisers (eg Sheffield, tracking the Bismark) and perhaps a type 271, which was smaller and hand operated might be the sort fitted - not so sure now. Some of the radar sets have very high power output so the generating set required would have to be very large. Surprisingly little detail of radar towers in Defence of Britain and finding more detail is proving a bit difficult.

outkast
06-10-2012, 20:28
only one I can find at the moment of the interior of the coalhouse tower
http://gi131.photobucket.com/groups/p300/QGVJK1C0F3/047.jpg

this one I took at beacon hill fort

http://gi131.photobucket.com/groups/p300/QGVJK1C0F3/247.jpg

Mike L
07-10-2012, 01:14
Some useful information here:
http://www.rnmuseumradarandcommunications2006.org.uk/PAGE%2019.htm

Takes a bit of searching through the pdf files but the file:
RADAR FROM THE FIRST SET UNTIL THE END OF WW2.pdf
seems to give quite a good summary of usage of radar equipment in ship and shore based applications.
Still not sure it answers any of the questions related to this thread but I will keep looking.
A visit to the radar tower at Harwich (when it is open) might answer many questions.

Mike L
08-10-2012, 15:25
Have left email enquiries at the RN radar and communications museum and 'the garrison' based to Coalhouse fort, no replies so far.

HF Dave
10-10-2012, 20:25
English Heritage Pastscape record (monument no. 1375139) states of the Coalhouse radar tower, "it is thought that this is one of only three of its kind surviving in the country."

Beacon Hill RDF tower (see #24 above) is obviously one of these, and presumably the other one is at Newhaven Fort (Sussex) though is somewhat different in design:

http://www.pastscape.org/hob.aspx?hob_id=1424027
http://www.flickr.com/photos/50619197@N07/5661622785/

HF Dave
10-10-2012, 20:32
That radar is apparently a type 287, which I haven't found much about yet, and apparently used for gunnery direction, mostly protection against E-Boat attacks.

This isn't really consistent with the ASWE documentation from the 1940s which describes the 287 as an obsolete surface warning set, not a gunnery direction set.

There's an awful lot of information in the old documents on that website, and it is not easy to search for specific items. But, like you I've not been able to specifically find anything relating to Coalhouse radar tower. Good luck with the other potential sources.

HF Dave
10-10-2012, 20:41
Just for further interest... Coalhouse Fort was HMS St. Clement (or Clements) from 1943-46, a combined operations base. Probably no link to the radar, but it may have been known by that name earlier, and I just keep hoping to find a document mentioning radar type xxx tested at HMS St. Clement!

Mike L
10-10-2012, 22:11
I haven't heard from 'the garrison' yet but had this in my emails today:

Hello and thank you for your enquiry sent to Bill Legg, the Curator of the Royal Navy's Museum of Radar and Communications. Bill has forwarded it to me to answer. Until I relocated away from Hampshire, I was Bill's librarian and archivist at the Museum.

The first thing I have to say is that we deal only with our core subjects, namely naval things, and your subject is covered by army things, specifically, in WW2 at those location, the artillery regiments. Fortunately, National Archives apparently has a file which will interest you covering Beacon Hill Fort [apply for/order WO [which stands for War Office] 192/212, but I regret to inform you that despite a search of their database plus that of the Imperial War Museum, I can find no reference to Coal House Point.

The army at Beacon Hill Fort would have had easy access to naval personnel serving with the Fleet at Harwich, and the Dover Patrol were frequent visitors to the Thames, so there was an opportunity for those in the Tilbury areas to liaise with the navy.

I note that the radar "tower" at Tilbury was erected approximately half a mile away from the Fort, and wondered whether that "tower" was a stand-alone edifice or whether it was a Maunsell Tower, sunk into the sea bed just off shore? The Thames NAVAL Maunsell's [the ARMY also had their own type of Maunsell's] certainly had RDF and were well equipped to deal with surface targets and with aerial targets. The "tower" at Beacon Hill appears to have been built on terra firma not far from the gun-housing.

You say that you think that both had either a Type 287 or a Type 284 naval radar fitted. The Type 284 was a big ships [cruiser and above] surface gunnery radar [GS] with a shore-fitted variant either as a static fit [S] or as a mobile [T] available. However, the Type 287, a Warning of Surface Craft [WS] radar, was already obsolete when war broke out in 1939, so I doubt whether this would have been fitted in either area. After the Battle of the River Plate, no RN ships was fitted with the Type 287. The Type 284 [M4, P3, P4 where M = first major modification and P = second major modifications and the figure suffixes show the number of 'tweaks' to each modification] was a 50cm radar operating in 'L Band' with any frequency within the band 390 to 1550 mc/s [MHz today]. The other radars of the war years used 10cm, 3cm, 1.25cm and 6mm, the latter operating in the 50,000 mc/s band. The Type 284 was replaced in the navy by the much more reliable Type 275. Going back to the National Archives, they have details of the Type 284 radar equipment with can be ordered by visiting ADM [which stands for Admiralty] 220/1542. I regret that by the time the Museum website was written in 2006, the handbook for this piece of kit had been entrusted to the NA for national posterity, and was unavailable directly by any naval authority.

Whilst the internet has details of the Maunsell Tower, there is no real clear picture of the Naval version, although the army version get a pretty good showing. I have therefore sourced this picture for you from the IWM database.

You can clearly see the RDF antenna on the very top of the rig, and this appears to be HA [High Angle] and I would have thought control radar for the bofors or pom poms. The legs of these monsters were not hollow, providing instead accommodation and storage space for the crew. This picture shows a model of the Maunsell.

I sincerely hope that this helps in some way, although I know that it is far from the answer desirable. It makes good common sense to believe that radar was employed for in 1940/41, it was a reasonably well established 'weapon' of war - no new site would have been constructed without it.

As I leave you, I just want to say that the Harwich area is much better known to the main stream navy [which includes us] than was the Thames areas, other than of course Sheerness and Chatham. If you read paras five and six [both short] of this page http://www.godfreydykes.info/JUST_SOME_OF_MY_FAVOURITE_NAVY_PICTURES.htm you get a good idea of how Beacon Hill fitted in with the planned defence of the area.

With my best regards and also of course, with Bill regards

Sincerely

Godfrey [Jeff] Dykes


I have replied attaching more information about the Tilbury tower.
So it does seem the type 284 radar set is unlikely to have been used as I guessed (lucky guess!) but little more seems to be known at the moment. If anyone is going to TNA might be worth looking at the documents mentioned, although apparently related to Harwich rather than Tilbury.

outkast
10-10-2012, 22:51
just to confuse things even more, at least two guns taken from HMS hood were installed on top of one of the casements at coalhouse, the emplacement for these is still there, could there have been a connection with the radar used?

Mike L
10-10-2012, 23:10
It's still confusing.
The 1985 guide states it MAY have had a NT284 radar which seems both vague and quite specific, then suggests other documents (War Office records) state that it was for minefield observation.
The email from Godfrey states the 284 was (as I have found elsewhere) a cruiser gunnery radar.
It seems to me that possibily Tilbury could have had a type 287 radar (as apparently at Harwich) which was a 'warning of surface craft' type. This would seem more appropriate for a minefield defence radar but why position it so far away from the minefield control tower?
I have heard of the Hood's guns being fitted but, again, why place a radar tower so far away from the guns?
More research needed methinks.

outkast
11-10-2012, 16:36
Hi Mike, topography may have plaid a part in its location, coalhouse sits in the pefrect position to defend the river, any vessels coming down the river would have to negotiate a long sweeping bend, they would have been eposed to the guns from coalhouse fort, east tilbury battery, cliffe fort and partly shornemead fort, the arc of fire for the above was quite broad, they may have picked the location as it would give them the best possible radar sweep of the river wiothout being in the arc of any of the guns sited at the above.

outkast
14-10-2012, 21:27
looks like there may be another tower of similar design at tollesbury

http://img.photobucket.com/albums/v134/drsugfit/general%20pics/TowerWW11Tollesbury.jpg

outkast
14-10-2012, 22:06
some info on the above tower

http://unlockingessex.essexcc.gov.uk/uep/custom_pages/monument_detail.asp?content_page_id=89&monument_id=1034528&content_parents=61,80

Mike L
14-10-2012, 23:39
Great find Outkast!
So the type 287 is mentioned there in relation to minefield defence as well. Brilliant.
I have asked a contact (on WW2Talk) who is going to TNA on Thursday to have a quick look at the WO and ADM documents mentioned earlier. I will also mention the Tollesbury site to him. If there seems to be a lot of useful information in them I might visit TNA myself to copy them, however from Godfrey's email reply these files seem to relate to type 284 radar so might not be relevant.
So far all I have found is that the type 287 radar was considered obsolete at the outbreak of WW2, it had a 21 foot dia aerial array and some spare aerial 'pig trough' components are stored at Beacon Hill fort.
We might be getting somewhere!

Mike L
17-10-2012, 19:13
On the 'Chain home photographs' thread mbriscoe has replied to my query:

"Radar At Sea" has ..

"In addition, 9 type 287 (modified type 284) were set up ashore covering controlled minefields in port approaches"

"In passing, it is worth mentioingh that an early model of type 271 was sent to the Army at ARDE, installed in two GL Mk2 trailers with two 2 metre paraboloid aerials, and, manned by the Army, set up on 19 July 1941 on the SOuth Foreland just North of Dover, 330 feet above sea level alongside the naval type 287 set (a 50cm type 284 with a large aerial for use ashore).
Reference given as ADM 220/78. Chief Supt ADRE, report on Typoe 271X, no date but forwarded to CSS by DSD 15 Augg 1941. But that probably refers to the first part of the bit I quoted rather than the 287.

In the Appendix
Type 287
Minewatch
50cm
about 600 MHz
15 kW
To sea 1941
284 adapted for minewatching ashore

There was also the 288(1) which was a 284 adapted for Armed Merchant Cruisers and 288(2) which was a 284 adapted for training ashore.

The 284 has same frequency and power and to sea 1940 as main armament directors.


So that answers a few questions. I am now wondering if the 'modified' type 284 is actually a 284 with the 'pig trough' solid antenna and designated 287. Does that make sense?.

HF Dave
17-10-2012, 20:33
On the 'Chain home photographs' thread mbriscoe has replied to my query:

[I]"Radar At Sea" has ..

"In addition, 9 type 287 (modified type 284) were set up ashore covering controlled minefields in port approaches"



Fantastic. Thanks to Mike and Outkast for providing so much information. If there were 9 of them used around the British coast, I wonder where they all were...

Mike L
17-10-2012, 21:02
That's what I was wondering Dave. If we can assume the 3 in Essex, all covering estuaries and probably controlled minefields, that leaves 6 probably in similar locations - any ideas?
IF the 287 has a 21 foot diameter antenna it requires a good size housing but not necessarily the hexagonal style used in the Essex sites.
Looking at a map of the east and south coast of England the possibilities seem to be:
Medway/Sheppey
Portsmouth/Southampton
Poole
Exmouth
Plymouth
Falmouth
I haven't included Folkstone and Dover as they are harbours rather than estuaries but they could be possibilities.
North of Essex Great Yarmouth, the Wash and Grimsby then not much until Hartlepool and Newcastle upon Tyne.

cptpies
18-10-2012, 08:54
This thread has kicked off a similar one on the PSG forum. The Defence of Britain survey didn't record any of these sites but I have added all three to the eDoB database. I would be very interested to know if any more crop up. Since they seem to be associated with controlled minefields I would add Burnham on Crouch and Oban to the above list both of which have large minefield control towers and possibly anywhere else with an XDO post.

Dartmouth
Torquay
Folkestone
Sheerness
Blyth
Leven
Cromarty
South Ronaldsay

mbriscoe
18-10-2012, 10:17
Never heard any suggestion of a radar associated with the XDO at Oban (http://canmore.rcahms.gov.uk/en/site/185071/details/gallanachmore+xdo+post/) or Cromarty (http://canmore.rcahms.gov.uk/en/site/173677/details/south+sutor+xdo+post/). There was a CHL (http://canmore.rcahms.gov.uk/en/site/138980/details/cromarty+south+sutor+chain+home+low+radar+station/) on the hill above Cromarty XDO and a fire control radar at North Sutors (http://canmore.rcahms.gov.uk/en/site/139009/details/north+sutor+coast+battery/) but the fire control radar at South Sutors (http://canmore.rcahms.gov.uk/en/site/138983/details/south+sutor+coast+battery+radar+site/) is nearer to the XDO (can't remember looking at that structure but access to the site is difficult now) but from the description was just associated with the gun battery.

Mike L
19-10-2012, 00:46
Doing a bit of googling for possible other sites and this popped up:
http://www.kenthistoryforum.co.uk/index.php?topic=409.0
The last reply refers to a type NT 284 at Fan Bay near Dover. This is the same radar reputedly used at Tilbury.
I was starting to think the NT 284 was possibly redesignated 287 but I am not so sure now!

PETERTHEEATER
19-10-2012, 04:16
You guys are getting some mileage out of this one! Fascinating stuff; keep going for I am following the trail.

cptpies
19-10-2012, 12:33
Fan Bay became a CHL/CHEL site so the 284 may have been the first radar installed there. Nothing remains there now.

outkast
09-11-2012, 18:09
adding more info.

This is a pic taken of the radar inside the tower at beacon hill, its taken using a fisheye lense but note the hole in the roof and the circular mounting.
http://img.photobucket.com/albums/v134/drsugfit/beaconhill.jpg

The biulding below is on the front of newhaven fort
http://img.photobucket.com/albums/v134/drsugfit/DSC_0072.jpg

This is a pic of the inside, note the hole in the roof and circular mounting.
http://img.photobucket.com/albums/v134/drsugfit/newhavenradar.jpg

From memory the same two features appear in the tower at coalhouse.

Mike L
17-11-2012, 23:45
Hi all, just received a reply from the RAF Air defence Radar Museum:

I am writing this from home for the RAF Air Defence Radar Museum.
We have found a reference to the Navy 287 radar in Appendix B, entitled "Radar Techniques", in the School of Anti-Aircraft Artillery Handbook, probably dated 1951. In the chapter entitled "List of Royal Navy Radar Equipments" there are 32 Navy radars listed, including the Type 287 as follows:

"Type 287 radar. A 50cm shore-based radar for watching minefields. Its details are the same as the Navy
282, 284, 285 radars except for the aerial
287 Aerial: Two "pig troughs" each with 24 dipoles, mounted on tower. Power gran (?) 200".


Navy Type 284 for comparison.
"Frequency: 52 to 49cm (580 to 605 Mc/s). Max Vis Range: 12 miles. Peak Power: 60KW to 100 KH.
Puilse width: 1 to 2 us. PRF: 500. Power Supply: 180V cs and 110 V/220 DC. No. of operators: 3.
Aerial: Common T/R. 24 horizontal centre-fed dipoles in line with parabolic cylindrical reflector. Also known as the Pig Trough.

Display: A-scope. Mks M3/M4 with electronic marker scale and mechanical painter. Mks P3/P4 with electronic notch marker with separate expanded strobe time-base".

Number of operators: 3. Display: 'A' Scope. M3/M4 Mks electronic marker scale and mechanical pointer.

P3/P4 Mks electronic notch marker with separate expanded strobe timebase


We hope that the above may be of some use. Please note that the Copyright remains with the Ministry of Defence.

Curator of Documents
RAF Air Defence Radar Museum


So it would appear we were thinking along the right lines most of the time!

Mike L
18-11-2012, 01:22
Just looking at this a bit closer the photo outkast has posted in #45 seems to show the correct 'double pigtrough' type 287 aerial but without the dipoles fitted. There are however 24 pairs of holes in each of the 'pigtroughts' and the dipoles would have been short vertical rods fitted between each pair of holes. The 284 would have had a similar 24 dipole array but in a single parabolic reflector if I am reading it correctly. As for the rest of the technical stuff it's largely gibberish to me!

HF Dave
19-11-2012, 21:45
"Type 287 radar. A 50cm shore-based radar for watching minefields. Its details are the same as the Navy
282, 284, 285 radars except for the aerial
287 Aerial: Two "pig troughs" each with 24 dipoles, mounted on tower. Power gran (?) 200".

So it would appear we were thinking along the right lines most of the time!

So that, with all the other contributions above, just about answers my original question. Many thanks.

HF Dave
10-12-2012, 20:29
Just a few more photos of the radar tower...
This first one is looking up at the under-side of the upper storey. Notice that in the middle there is a small circular hole (presumably for the antenna spine) with a rusted metallic rectangular surround:

10818

There are actually two doorways into the lower storey, one on the NE side, and one on the SW side. There is a spread of large concrete and brick blocks on the SW side, suggesting that there was originally a forebuilding (the maps also seem to indicate that this could be the case). The SW doorway only goes into a small room, completely isolated from the rest of the floor. There remains a rusted metal panel on the wall, looking like some kind of switchgear /distribution panel (as provided in Outkast's photo earlier in the post, and also below):

10819

10820

The NE entrance is used to access the rest of the lower floor (although I wasn't athletic enough to try). One of the sides looking out over the Thames are two very domestic looking windows high up, and a smaller square opening lower down. The brick arch visible within looks rather like a fireplace, but it may just be the top of a doorway / alcove.

10821

HF Dave
10-12-2012, 20:43
Going back to the minefield theme for a minute, close to the control tower (beside Coalhouse Fort and inland from the radar tower) is a small concrete blockhouse right next to the moat. It looks like a pillbox but has no gun loopholes. This photo shows the minefield control tower and the other building in the background:

10823

It may have been used to house junctions for the minefield cabling as inside are three wooden racks and square holes in the concrete below them where presumably the cables entered the building. Could the one on the right have gone to the control tower, and the other two (directly ahead in the photo) gone off to the minefield?

10822

Mike L
21-08-2013, 23:57
An old thread now I know but a new member on WW2Talk (sceen name petersberg) recently posted this answer to a similar thread there:

Just spotted your website. Thought I'd chip in as members were asking for more info.

Tollesbury, Coalhouse Fort and Harwich (hexagonal) radar towers were all built for completion on 1 April 1941, by the Admiralty, to house 50-cm Type 287 RDFs (radars) which were to "watch" over the nearby "observation" minefields. All functioned till about mid-1943, when said mines were lifted. The basic idea was that the radars would only be switched on in the event of a serious intrusion into Blackwater, Thames and Harwich Harbour by raiders or invaders, and would then plot the positions of enemy ships so that the British mines (moored in groups of three or four) could be detonated underneath them along electric cables starting onshore.

The 287 had detecting ability at sea level and an exceptionally narrow (approximately 5-degree) horizontal lobe or beam, enabling it to perform this task--because it was derived from the shipboard gunnery Type 284.

It was not, except perhaps in some experiments, used to guide artillery fire--the siting of the stations overlooked only the nearby harbour mouths and not any distance out to sea. Each 287 station had a naval crew (ratings only) of six to eight.

The published books on this are a bit misleading and incomplete. The 287 crews did not sit watching their screens all day and plotting and reporting shipping (that would have involved far more personnel), but were there to put their sets on and locate intruders over the mines during alerts and/or low visibility.

I see that one of my books (Battle of the East Coast 1939-45) mentioned in other posts. Very kind of someone, but when I wrote that 18 years ago I only knew what the radars were for and not about their equipment and precise operational capability--or lack of.

The official Nat Archive papers which deal with these come under Controlled Minefields, Nore Command manpower, and Army unit war diaries. The published books only take us so far and 3 are in error:

1)One saying the 287s were used for seaward E-boat tracking and coast artillery

2)Another saying they were to guide Allied ships through minefields--imagine a ship threading its way into the Port of London through LIVE British mines!

3)Another saying every minefield had its radar--on smaller rivers, such as the Crouch, Colne and Deben, there was none.

In a November 1940 Admiralty file a List A and a List B of proposed harbour RDF posts are given. One list is for these specifically minefield sites, the other for radars with wider functions (including coast artillery, low-level air-raid detection and E-boat tracking) which was never built because superseded by upgraded Army and RAF 10-cm coast defence equipment.

Every single mention of the Coalhouse and other 287 radars, Army and Navy, gives them as "Observation Minefield".

I can pass on the file reference nos. if anyone is keen.

Forgot to add. I have photocopies of polar diagrams (detection lobes) and other technical data for Types 284 and 287. The significant difference is that the 287 has a narrower lobe, enabling it to narrow down the plot sufficiently to justify blowing the mines, which, of course, could only be detonated the once!

The mines weren't blown from the radar room, but from a control tower, some distance away, linked to it by phone. In most places control towers are still standing.

I know the family of the officer who commanded the set-up at Harwich/Felixstowe, and have some photos of the control towers and personnel there.

I would just tip off members that the owner of the Tollesbury radar tower, whom I also a know, had a family tragedy recently and might not be happy to have military history buffs showing up on his land.


So that seems a pretty good confirmation of what we had suspected/discovered several months ago.

PETERTHEEATER
22-08-2013, 14:10
Thanks for adding that Mike, very interesting.

cptpies
23-08-2013, 13:43
This clears up the confusion nicely. But also begs the question where is/was the XDO post that should have been associated with the tower? The ones at Beacon Hill and Coalhouse Forts still exist.

outkast
23-08-2013, 16:24
There was a very interesting discussion about these towers on the pillbox study group, I have also noticed a similar structure as the room at the top of the towers at both Newhaven fort and on the cliff tops near dover castle,

the one at Newhaven
http://www.bing.com/maps/?v=2&cp=sfxb6fh0400z&lvl=20&dir=270&sty=b&eo=0&q=newhaven&form=LMLTCC

the one at dover
http://www.bing.com/maps/?v=2&cp=shn4v8h39fys&lvl=19.48&dir=359.27&sty=b&eo=0&q=dover&form=LMLTCC

could these also be associated with radar, being on the cliff top would have negated the need for them being perched on a tower.

cptpies
23-08-2013, 18:10
The Dover one is listed on the DoB as a pillbox but I haven't seen an image of it to confirm that embrasures exist in it. The Newhaven structure is for the GL radar I believe, but I can't remember the source of that info, I've been there a number of times so probably picked it up from an information board.

Mike L
26-08-2013, 14:23
Two more very useful posts from 'petersberg' on WW2Talk:

The XDO--or, rather, Minefield Control Posts on Essex coast were as follows:



Blackwater field-- in small concrete tower at Bradwell, on opposite side of water from Type 287 RDF tower at Tollesbury. Came under HMS Nemo, Brightlingsea--speciifically Lt Martin RNVR



Harwich field--in small concrete pillbox right on the corrner by the Harwich breakwater



Felixstowe field--in XDO structure just south of Landguard Fort. Both these came under HMS Badger, Harwich--Lt de Neumann RNVR.



Coalhouse--I don't know but it can be looked up in same Admiralty minefield files as others.



Hwch and Fstwe still stand, Bradwell possibly--haven't checked lately. Coalhouse ?



Incidentally each TYpe 287 tower had a power generator in the base. The Tollesbury one was certainly THE power source, as electricity didn't extend to the site. Harwich and Coalhouse ones may have been standbys as there was public supply very nearby. The 287 aerial arrays were hand-turned from the floor below. The 287 receiver screen was a old-style "Type A", just showing a fixed horizontal trace and range--the bearing was just determined by manually pointing the aerials at the "target" in the minefield. There was, of course, no heightfinding.





Hello Mike L and cptpies.



Yes, Bradwell was linked to Tollesbury by phone line. There was also a minefield and control tower in the Colne mouth--the control was in the pillbox on the roof of No 1 (St Osyth Pt) Martello Tower--still there. But there was no radar there and the Tollesbury one didn't reach that far. Same on the Crouch--pointy-topped control tower (still there) and minefield, but no "RDF".



To investigate this at the Nat Archive quite a lot of time and effort is needed. There is a jigsaw (a well-fitting one!) and no one comprehensive account.

This applies nationally (for South and West coast as well as East)...

See:1) Army Command files (Eastern, Southern, etc) for lists of "VULNERABLE POINTS". In these the 287 posts are listed, with map refs, usually in groups: The May 1943 Eastern Cmd VP list is the clincher because it lists the 3 Essex RN RDFs as "Observation Minefield (287)"

2)Admiralty files on minefields., especially controlled and observation ones, and on local defences, e.g--ADM 199/535, 542, 823 (include excellent minefield charts + lists

of proposed control and RDF posts. Also ADM 1/10762--this is about a SECOND proposed set of harbour defence RDF stations which was not built, but in passing refers to a "List A" of 287 positions (without using term "Type 287" or specifications

3)ADM 1/4781 and WO 199/2538 give us the manning, role and proposed shut-down of the Tollesbury tower--very useful

4)WO 199/994 briefly mentions Army tests for using the Harwich tower to guide coast artillery fire, but in so doing explains that it is already an RN minefield RDF tower (dated October 1941).

5)ADM 1/13136 discusses the lifting of observation mines and the shutdown of one or two RDF posts, including Coalhouse and Harwich

6)J F Coales and F A Kingsley's books on WW2 naval radar explain the general development of the 284-type ship radar and mention fact that 287 was based on it--include technical diagrams. Also mentioned bu US author Friedman BUT HE IS UNRELIABLE on this.

7)ADM 220/1468--RN Radar Polar Diagrams--includes 284 and 287 and enables comparison.



About 30 years ago I did a lot of research on the East Coast naval bases and interviewed officers who mentioned the minefields and radars. (Published a couple of books in the 1990s mentioning the set-up).

More recently I met the dauighter of Lt de Neumann RNVR, who commanded the Harwich, Felixstowe and Deben minefields.



I must add that ideally one needs to be versed in the wider technical history of WW2 British RDF. One or two website contributors and musuem curators are using key terms too loosely, or from a modern rather than early 1940s angle--even apparently simple words like plot, track, range, beam, frequency and pulse can be tricky.

The fact that the Type 287 had one of the highest frequencies of any operational 1941-period British RDF does not mean it had some super-detecting ability, super-long range, or unique frontline role. It had one limited, emergency, role--and throughout its history never resulted in one mine being blown or one enemy ship being sunk!



Hope this helps. I got onto all this again recently because I visited the Harwich RDF tower, where the mounting and reflectors of a 287 were found and re-erected. The tower is identical to the Tollesbury one, and though rather different from Coalhouse Ft, has the same hexagonal shape and had the same role.





I posted a map and 'HF Dave's photo of the Coalhouse minefield control tower on the thread on WW2Talk for petersberg's information (hope you don't mind Dave!).