East Tilbury radar tower

A bit of an interesting debate going on at AIX about the use of a WW2 radar tower near Coalhouse fort at East Tilbury, Essex.
It may have been related to a river minefield, one of the batteries of guns or even associated with the nearby Bowater Farm HAA battery.
Except from the 1985 guide to the East Tilbury 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.


Does anyone have further information?

 

Try contacting Jonothan Catton, chairman of The Garrison, a WW2 Royal Artillery living history group at The Garrison | Welcome to The Garrison He has quite a bit of knowledge of Coalhouse Fort and its history

 

Thanks for that suggestion Doug, I will give it a try.

 

No reply so far from Jonathan Catton but I received this from the former librarian and archivist of the Royal Navy Radar and Communications 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 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.


I am surprised the museum were not aware of the Tilbury tower and have sent them such information as I have about it. Now getting down to the 'nitty gritty' of trying to identify what radar was used and what for.
The type 284 radar I had already identified as a large ship gunnery type from other online sources so it would not appear to be the type used in a shore location. The type 287 (used at Harwich) seems a better bet. The towers at Tilbury and Harwich are similar (hexagonal 3 storey structures) albeit the Tilbury tower is an 'open' lattice structure at first floor wheras Harwich is solid brick, and they were built around the same time. Until I get a chance to visit Kew to see the WO and ADM files mentioned above I think I am a bit stuck.
Unless we have any radar experts here?

 

Now been advised of the third 'radar tower' in the Essex area. This one is on the SEAX Essex history register and is described as a 'Naval watchtower'.
It is located in Tollesbury and the construction looks almost identical to the Beacon Hill Harwich radar or RDF tower. Crucially both are reported to have been equipped with type 287 RDF sets (although these were reputedly obsolete at the start of the war) and appear to be associated with river minefield defence.

From SEAX report:
A six-sided, brick-built tower stands by the former route of the railway line to Tollesbury Pier and the River Blackwater approximately half a mile to the S.E. "Survey of Pillboxes and WW2 Defence Sites in Tollesbury, Essex," 1995, records that it was built in 1940 and was a Naval Watchtower used as a control centre for mines in the River Blackwater and its environs. <1>"The Battle of the East Coast (1939-1945)" records that in Essex controlled minefields, with individually connected mines, were laid at Harwich, Lower Hope Reach (on the Thames) and Holehaven, and on the rivers Crouch (see SMR 10004), Blackwater and Colne. <2>The site has not been visited. This site is on private property and access to the area is only with the express permission of the owner. SITE ASSESSMENT 2009: No documentary records have been discovered relating specifically to this tower but it is apparent that one of its main purposes was as a control tower for a minefield laid across the River Blackwater. It would, therefore, have fulfilled the same function as the purpose-designed tower (SMR 10004), now a Scheduled Monument, which looked out across the River Crouch. However, there is another tower of this type, or very similar, extant at Beacon Hill Fort, Harwich (SMR 54). This is described in a RCHME, 1997, report as a Type 287 Radio Direction Finding tower built in 1940-1. <3>

 

A member on AIX has also posted this:
"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 it would appear we might know of the location of 2 or 3 of the 9 x 287s where are the others?

 

Just received an email 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 Tecniques", 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 Derfence Radar Museum"


So that seems to confirm the previous information and some of the guesses too!

 

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.

Anyway, good website and I hope to keep logging on!

 

petersburg,
Superb answer, thanks very much for clearing this matter up.
If you can post the TNA file refs I might have a look at them next time I am at Kew.

 

The XDO posts at Coalhouse and Beacon Hill are still extant, the info above strongly suggests there should have been one associated with the Tollesbury tower too but none is extant or recorded as having been present. Does anybody know otherwise?

 

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.

 

petersberg,
The tower still exists at Tilbury, see attached picture and map.
The red dot on the map is the approximate location of the tower and the red arrow indicates the approximate direction from which the photo was taken.
The map is an annotated scan of the map in the Coalhouse Fort guide book, the photo was posted by AIX member 'HF Dave'.

 

Thanks Petersburg. So it would seem the Bradwell post would have been the one that cooperated with the Tollesbury tower.

 

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.

 

Thanks petersberg,

If I get time when I am next at TNA I will look up those files.

Interesting (if widely misunderstood) little part of Britain's early war defences.

 

Petersburg, In the interests of completeness do you have a location for the Bradwell XDO post? It no longer appears to exist according to the DoB and SEAX despite most of the pillboxes still being extant along the sea bank.

 

Hello cptpies...

A Nov 1940 Admiralty file proposing the various sites just says "by Bradwell Quay", and what with the power station and yachting there has of course been a lot of redevelopment there.
The previous July the proposal was (quote) "on land belonging to Mr Watts of Weymark's Farm". It was built by Taylor Woodrow's Colchester builders' branch.

The nice chart of the Blackwater minefield I have does not show control tower or RDF tower.
It might show up on Army's Eastern Command (XI Corps) Vulnerable Point lists, separately listed from the Tollesbury RDF tower.

From West Mersea I spotted a small structure across the water on the open shore east of Bradwell itself, which from there looked like the Crouch Control Tower east of Burnham, but I was so far away I couldn't see it properly--could be something else.

Do let me know if you do find it. The Crouch one has a photo online, for comparison.

P

 

Just looked at another photocopied Adm. doc. I have here, dated August 1940.
You should find this of use, but there could have been a change of plan...
The proposal was that the Bradwell minefield control AND RDF station should be "on the seawall" at 51o44'46"N, 0o53'62"E "within half a mile of Bradwell Quay". The cabling for the mines diid indeed come ashore at that point.
Of course the radar was actually put over at Tollesbury, but if they stuck to the other part that will give you a good fix.
Incidentally this is the earliest reference to an Essex minefield RDF I can find. Bear in mind the setup wasn't finished till about 1 April 1941--the minelayers were based locally in the March.

 

Thanks Petersburg but I think your longitude is a little off, you can't have 62 seconds, should it be 52? that would put just offshore of the powerstation. I'm wondering if one of the seawall pillboxes was used rather than build a dedicated tower, although visibility form one of those wouldn't have been ideal.