Fighter Direction Tenders
GCI Radars (Neptune/Overlord)
Ground controlled interception radars in operation Neptune / Overlord. The Allied Invasion of France, June 1944.
Background
This accounts starts by introducing the organisation that made it all possible – the Telecommunications Research Establishment (TRE). TRE started as a small group of scientists within the Bawdsey Research Group under the British Air Ministry Research Group and was located at Orfordness, Suffolk, England. Here they worked on the development of a Chain Home (CH) radar which later was to be credited for the survival of the United Kingdom in the 1940 – Battle of Britain. They were relocated to the Isle of Purbeck at Worth Matravers, Dorset, in May 1940. In fear of a *”Bruneval style” raid on Dorset, TRE and its supporting Telecommunications Flying Unit (TFU) at RAF Station Hurn, moved on 25th May, 1942, to Malvern and Defford respectively. From here, TRE responded successfully to the questions “Can you do it?” and “When can we have it?” One of the many concerns of those planning the inevitable invasion of the Continent, was the need of forward warning and control radar. This equipment must be in a position prior to the beach landings of Allied forces – thus the concept evolved of installing suitable radar equipment on floating vessels in the Channel. These vessels became known as Fighter Direction Tenders (FDTs).
The two Ground Controlled Interception (GCI) radar systems installed on the FDTs were developed by TRE – Air Ministry Experimental Station (AMES) Type 11 and Type 15. The Type 15 radar antenna was developed at Worth Matravers and built at Christchurch in December 1940. The AMES Type 11 system was developed by TRE, following the Bruneval raid. It had many similarities to the sophisticated German “Wurzburg” radar system, parts of which were captured during the raid.
This section covers the development of FDTs and their use in the invasion of the Continent. Reports are also included on the GCI Radar Convoys that landed on the assault beaches to assume the duties carried out by the FDTs. TRE was also active in many other interrelated areas of radar systems development in support of the “D-Day” invasion. The following come to mind: the OBOE navigational system for improved bombing accuracy, used extensively to soften enemy defences in the landing areas; the continuing development in the field of radio countermeasures (electronic warfare) through the use of counter and counter-counter measures to stay one step ahead of the enemy’s systems; the mobile radar systems which would follow the battle line once established on the Continent; and the mobile, personal and aircraft beacons used primarily for photo-recce over-flights. In their development, it was necessary to ensure that final products were compatible with those used by other Allied forces.
The FDTs in addition to all other applications of radar equipment, had one thing in common – a good percentage of the radar officers and technicians were members of the Royal Canadian Air Force, attached to the Royal Air Force as Radio Direction Finding (RDF) personnel. Their input is included in the following paragraphs.
During April 1944, exercises took place off the Humber coast with No.12 Fighter Group Sector. These included the use of “window”** (known as “chaff” by the US Forces). Exercises were continued in May, 1944, with No.11 Fighter Group Sector and Naval authorities in the Portsmouth and Portland areas. By the end of May the FDTs were ready for action and they sailed from Cowes, on the Isle of Wight, to join the Assault Task Forces at 22.00 hours on 05 June 1944.
* – On 27th February 1942 a British raid at Bruneval on the Cherbourg peninsula captured apparatus from a German Wurzburg radar installation and brought it to Worth Matravers for study by TRE.
** – Window – metallic strips cut to a half wavelength of the enemy’s detecting radar systems. Dispersed from an aircraft, the radar return would simulate a large formation of aircraft.
Fighter Direction Tenders (FDT)
Fitment and Testing of Fighter Direction Tenders
The concept of using ground radar installations on floating vessels was initially tested during the invasion of Sicily in July 1943. An RAF mobile GCI unit was temporarily mounted on Landing Ship Tank (LST) 305 for use in the Mediterranean Theatre. Results were so successful that the AOC-in-C Fighter Command recommended that similar vessels be converted and equipped for landings in Europe. Fighter Command had originally recommended the conversion of four LSTs to be used by Combined Operations. At a meeting with the Admiralty in November 1943, it was decided that only three vessels were to be equipped to perform interception and raid reporting functions, under the code name “Becky”. Specifications were prepared and by the middle of February 1944 conversion of the three LSTs had been completed.
The LSTs selected for FDT conversion were part of the 112 made available to the Royal Navy during World War 2 under the US lend-lease programme. They were built in the USA for use in assault landings on enemy beaches and were originally designed to carry eighteen 30-ton tanks, or 27 three ton trucks and 8 jeeps, or 177 troops. Upon conversion to the FDT role, the LST would have a displacement of 3,700 tons and a length of 328 feet, comparable in size to a Naval cruiser. The vessel would carry a Naval crew of 8 officers and 92 ratings in addition to 19 Air Force officers and 157 airmen.
The conversion of the three LSTs was carried out by John Brown’s Shipyard on the Clyde in Scotland. The work included welding shut the bow unloading doors and covering the hatches with armoured plate. Three hundred tons of pig iron were secured to the main deck to slow roll action of the vessel. A new deck was laid over the vehicle cargo space to contain the operational accommodation for the Filter Room, Communications Office, Cypher Office, Air Control Room and Radar Receiving Room. A Direction Finding Office was provided forward for the installation of Naval D/F equipment. Space was provided at the aft end of the tank deck for the Transmitter Room, Transceiver Rooms, Aircraft D/F, Radio Counter-Measures Office and W/T Storeroom. A bridge Visual Direction position and a bridge Plot House were constructed above the deck.
Two GCI radar systems were installed on each FDT – a Type 15 GCI forward and a Type 11 GCI amidships. The radar aerials were 30 ft above water level which limited the accuracy of aircraft height readings The Type 11 radar on 520 Mc/s were provided as an alternative if the 200 Mc/s band was seriously jammed. Mk111 IFF (Identification, Friend or Foe) was installed to provide identification only when Air Movements Liaison Section information did not provide the answer. The IFF was normally left switched off. Airborne Interception (AI) Beacons were installed on the FDTs to aid the control of night fighters. Each FDT carried 1.5 metre Mark IV and 10 centimetre Mark VIII A1 Beacons. Finally, many channels of VHF/R/T and W/T were installed to provide the essential communications.
Sea trials were carried out in the Ailsa Craig area which included radar calibration and communications tests. It was necessary to raise the Type 11 antenna to eliminate a 20 degree “blind” area either side of the bow. Otherwise the tests were generally acceptable.
Fighter Direction Tenders in the Assault
During the assault and until GCI facilities became established ashore, the control of fighters operating in the assault area and the main shipping area would be exercised from the three FDTs.
FDT 216
Off the American beaches (Omaha and Utah) in the western half of the assault area for the control of those British and American fighters detailed to operate therein.
FDT 217
Off the British beaches (Sword, Juno and Gold) in the eastern half of the assault area for the control of those British and American fighters detailed to operate therein.
FDT 13
In the main shipping route for the control of those fighters detailed to operate in that area.
FDT 217 acted as the co-ordinating vessel to order reinforcements, if necessary, depending upon which part of the assault area was being attached. As dawn broke, the beaches were being bombed by RAF aircraft and the Allied cruisers and destroyers commenced shelling. All three FDTs commenced radar watch at H-hour (07.25 hours) on 06 June and were immediately in contact with the fighter aircraft providing air defence to the armada.
Ref: Canadians on Radar 1940 – 1945 (George Grande, Sheila Linden, Horace Macaulay)
On the first evening the Luftwaffe carried out a bombing raid on the British beaches, resulting in casualties but no serious damage to shipping and stores. FDT217 observed the raid but it was quickly lost in the numerous echoes from the concentration of shipping and permanent echoes from the coastline. The beachhead area was subjected to sporadic attacks by ME109 and FW190 fighter-bombers, normally during poor weather or low cloud cover. There were also a number of JU88 raids at dusk. It was estimated that enemy air activity resulted in 30 to 40 sorties per night. FDT13 had very little call for fighter control as the shipping lanes were not subjected to enemy attack.
D+4
Two Spitfire Squadrons moved onto a landing strip in the “GOLD” area and established contact with FDT217 and No 15083 mobile GCI now operating ashore.
D+5
A Wing operating from a landing strip in the “GOLD” area was now under the control of FDT217 for use when weather conditions in the United Kingdom made it impossible to supply low level cover from there.
D+7
During the period from D-Day to D+7, FDT217 controlled 225 aircraft, obtained 66 contacts, intercepted 37 friendly aircraft, destroyed three enemy aircraft and damaged a further two. The figures for FDT216 were 62, 49, 33 and 3 respectively.
13 June 1944
FDT13 returned to Port for re-fuelling and re-victualling.
15 June 1944
FDT216 returned to Port for repairs of damage she had suffered in collision and FDT217 relieved her off the US Beaches as No 15082 mobile GCI radar station which landed on Omaha Beach was still not fully operational. At the same time FDT13 was positioned 20 miles east-north-east of Barfleur to intercept enemy mine layers and torpedo aircraft attacking shipping at night, approaching round the Cherbourg peninsula.
23 June 1944
FDT217 was withdrawn from off the US Beaches after continuous operation for 17 days.
27 June 1944
FDT216 relieved FDT13 off Barfleur and on 01 July when the shore based GCIs were working inland from Barfleur. FDT216 was moved to a position 23 miles west of Le Havre to assist in the interception of enemy aircraft laying mines at night off the British beaches.
The results achieved by the Fighter Direction Tenders during the period from 06 June to 26 June 1944 are as follows:
- 52 enemy aircraft destroyed during day by fighters under FDT control
- 24 enemy aircraft destroyed during night by night-fighters under FDT control
07 July 1944
FDT 216 was torpedoed by a JU88 and turned turtle about forty minutes later. The entire crew, Naval and RAF, was rescued by her escorting corvette HMS Burdock with the exception of five airmen reported missing.
Final Days of FDT217 and FDT13
The following information on FDT13 and FDT217 was provided by Karl Work, an RCAF radar technician on FDT217 during the assault. FDT217 remained anchored off Cowes, Isle of Wight, until the middle of November 1944, before sailing up the Irish Sea to Loch Fyne, arriving off Inverary 30 November 1944. She wintered there with a skeleton maintenance crew of two Naval officers and 20 seamen, along with the complete radar personnel of one officer and eight technicians, plus approximately 15 other RAF trades personnel. FDT217 sailed to the London Engraving docks in June at the end of February 1945 for refit to go to Japan. She sailed in July and reached Malta before being recalled in August 1945. The crew were paid off in England and the ship was returned to the USA.
Comments
The following comments were reflected in a report on the role and operation of British Headquarters Ships and Fighter Direction Tenders used in the assault on the Continent of Europe in June 1944 – Operation Neptune (file DEFE 2/421, Public Records Office, Kew, UK).
The Fighter Direction Tenders performed remarkably well and their operation was a great success. Possibly more time during the fitment period would have resulted in a better layout of work space and equipment. However, it was essential to press on with the training of personnel and testing of equipment to ensure readiness on D-Day.
Continuous employment on a “watch and watch” basis of four hours on and four hours off, in poor working conditions, imposed a very serious strain on the personnel. The radar personnel had been on these vessels for five months, living in cramped accommodation intended only for tank crews on short transit trips.
There was no air conditioning and the work areas were overcrowded. With a lack of exits, someone defined FDT as “floating death trap”.
No criticism could be found with the radar equipment. It worked efficiently and was never taken off the air for maintenance during the operation.
The rigid procedures used in the selection of officers and men to staff the FDT’s proved to be justified by the way they all stood up in working together under very adverse conditions. They indeed were worthy of high praise.
The Death of FDT216
This part captures some of the experiences and comments of personnel who were with the Fighter Direction Tenders during the landings on the Continent of Europe and the days following as stronghold were established on the beachheads.
Of grave concern to all was the loss of FDT216 along with five RAF airmen. The escorting corvette HMS Burdock was on site at the time and its Commanding Officer, Lieutenant (RN) H. M. Collier gave the following account:
“At 01:00 hours on the morning of 7 July 1944, FDT216 was approached by a low flying JU88 aircraft and at 01:02 a loud explosion was heard and a pall of black smoke rose from the FDT. At 01:05 a signal was received that she had been torpedoed on the Port bow. At 01:45 the noise of her pig iron deck ballast moving was heard and she turned over on her Port side and remained there for about 90 seconds before turning turtle and floating bottom up. The rescue of survivors continued until 02:45. The red lights on the life jackets and the small whistles that the RAF personnel carry, proved invaluable in picking up the scattered groups and enabled 250 men to be picked out of the water in just over two and a half hours. All survivors were kept below decks in case of further action and were given a quick rub down and a tot of rum which was much appreciated. A muster was then organized and found that all Naval officers and ratings, as well as the ship’s dog, were present but five RAF other ranks could not be accounted for. The organization for dealing with survivors at Portsmouth worked smoothly and effectively and grateful thanks are also due to the WVS (Women’s Volunteer Service) Mobile Canteen which arrived on the jetty almost as soon as the buses and ambulances”.
Note: The following is not part of the above account, but this prediction was credited to a Scot’s rigger in the John Brown’s Shipyard on the Clyde: “Nay laddie! You dinna put ballast on the top deck – She’ll turn turtle”).
CONCLUSION
The Allied invasion of Normandy on 06 June 1944, included the 3rd Division of the Canadian Army that landed with the British Forces on “D-Day”. The Royal Canadian Navy provided 10,000 sailors and 109 vessels as part of the massive armada that battled the choppy waters of the Channel while escorting the flotilla on the way to the beaches. RCAF Lancasters and Halifaxes dropped thousands of tons of explosive on German coastal defences. Canadian paratroopers accompanied the Allies as they jumped from aircraft or landed in gliders. Even though they had caught the German Army Command by surprise, the coast of France was well defended and at the end of the first day 2,500 Allied personnel had been killed, including 350 Canadians. In addition 574 Canadians were wounded and 47 taken prisoner. But the success of this day would turn out to be a major turning point in the Second World War.
In planning for Operation Neptune / Overlord it was thought that the FDTs would only be needed in the assault area for a few days, after which control and co-ordination would be taken over by the GCIs ashore and the day fighters by 483 Group Control Centre (see footnote). As it turned out all three FDTs were required off-shore for about three weeks after “D-Day”, imposing added strain on the staff. Many of the officers and men had been aboard the vessels for over five months and as previously mentioned, working in surroundings originally designed for assault forces on short sea journeys. The final results of their efforts far exceeded expectations and received high praise from the Royal Navy.
The personnel on the “floating radars” and mobile units that landed on the “beaches” to carry out the shipboard and ground controlled interception of aircraft were worthy of all the recognition they received. The GCVI mobile units would continue on in the following weeks providing the important control and interception of aircraft as the Allied battle-line marched eastwards across Europe.
[Footnote – In the original text by Grande, Linden and Macauley, they make reference to 483 Group Control Centre. Subsequent research has cast some doubt on this point. It seems more likely that a simple typing error may have been made in the original text, and in all probability, it should have read 83 Group Control Centre. However, we encourage any new researchers to examine this possibility – Editor]
My father was on FDT 216 , he did say they went into Omaha, which day I don’t know. They took some German prisoners down to the beach and all well behaved except the highest ranked gentleman who Dad said didn’t last the day.
A month later when 216 was hit by a torpedo Dad took a live shell as a souvenir before he jumped into the water, I still have the shell today, Dad had it made into a cigarette lighter and mounted in a wooden base.
Tim – my father was also on FDT 216 when it was torpedoed. So happy to communicate if you wish
Martin
Hi Martin,
I only managed to get details from Dad when he was about 85. He was reluctant to speak at length so it took some time to piece things together. What do you know from your Dad. Different sites give interesting information and the Combined Operations site is excellent.
Your Dad would have been off Omaha & Utah too I assume.
my dad was on FDT 216. Oliver C Miles, Flight Lieutenant. I believe he was in charge of the radar operations. I remember looking over some war memorabilia with him. Among the things was an armband with a waterproof red light. He laughed and said I never turned it on. I asked why not. He said because he didn’t want the Germans to pick him up. I only learned after his death that he (and I’m sure others) had been issued with a cyanide capsule and been told not to be taken alive.. He initially enrolled with the RCAF and was among the first of those to be sent for radar training by the RAF. I am delighted to find this website and would love to hear from other children, grandchildren, who served on RDF 216
Hi Gary,
Many thanks for your post. As I mentioned to Tim, I will soon be adding more material to the FDT section. Do I take it you are from Canada? Great to hear from you and hopefully we can be in closer contact going forward.
Thanks,
Peter Best
Hi Gary,
I just read your comments, the cyanide capsule bit is something I’ve never heard in anything I’ve read over the years. It goes to say that my Dad also on 216 never mentioned this so god knows how many of them had these just in case of capture. When 216 was hit he did say it threw him out of his bunk so must have been on the four hour rest period
Hi Tim,
Apologies for my slow reply to your interesting. I will shortly be adding some further material to the FDT section and as we have had several sons and daughters of veterans contact this web site, it may be a good time to add there names to a seperate list. There is no doubt that the FDT’s played an important part in the RAF at D-Day.
Thanks again and please keep in contact.
Peter Best
Hi Peter,
My father’s name was Alan Hamilton. He was born in Bristol 8/6/21. He was in the RAF, but also Combined Ops. His position on FDT 216 I don’t know, maybe a radar operator as I found information on meetings of ex radar personnel in papers after he passed in 2013. After the war he was in the TA until the mid 1950’s.
He took some persuading to talk about the period at all but I asked him about D Day and it was just amazing to hear his description, I knew I’d be lucky to get anything out of him so I was hanging on every word. He never showed emotion so everything was bottled up. Through the Combined Ops. site I managed to get Geoff Slee to contact the navigator from 216 and he had a conversation with my Dad which was a release for him as I don’t know if he’d mentioned any of this to anyone. Anymore info I get I will pass on.
My grandfather James Gaughan was one of the 5 RAF personnel killed when the FDT216 was hit. The RAF Historical Branch confirmed the details to me today as well as supplying me with copies of the correspondence to and from my grandmother.
Hi Jacqueline,
I’m guessing my Father knew your Grandfather, when I mentioned the story of the torpedo hit on 7/7/44 and the five lives lost Dad immediately reeled off the five names complete with nicknames too. What do you know if anything,have you managed to get any details to build a story together
Hi there – Jacqui is my cousin and we are slowly putting together this information. As kids we knew our Grandfather had died at sea but my Grandma never seemed to know the details. Based on information received from the RAF it would appear that the torpedo hit the ship close to where my Grandfathers last know location was:
On the night of 6/7 July 1944 LAC Gaughan was serving as a Wireless Operator on board His Majesty’s Fighter Direction Tender 216 (HM FDT 216) when it was struck by an enemy torpedo off the Normandy Beaches. Tragically, LAC Gaughan and four other RAF Personnel of the 184 RAF Personnel on board were lost when the ship sank.
Sadly, the bodies of LAC Gaughan and his comrades were never recovered and as you are aware, they are remembered on The Runnymede Memorial to The Missing at Egham, Surrey.
There were three Fighter Direction Tenders operating off the Normandy D-Day Beaches namely FDT 13, FDT 216 and FDT 217. The FDTs were Landing Ship Tanks (LST) that had been converted to carry a multitude of radar and signals equipment, which was used to intercept German communications, plot enemy aircraft activity way beyond the range of the Home-based radar stations and direct allied aircraft involved in operations over the D-Day beachheads. The day-to-day operation of the actual ship was carried out by Royal Navy personnel, but the radar and signals systems were operated 24 hours a day by a mix of RAF and RCAF personnel.
Any photo’s or further details would be appreciated.
I hope you have seen Peter Best’s feature on Fighter Direction Tenders. Regards, David (Editor)
no – i have not! but i would love to! How would I go about getting a copy – is it online, or available in some other way?
Thanks, Catherine
We always welcome additional information. Even in 2024 when we remember the 80th Anniversary of the D-Day invasion, attics are still being cleared. And the dog-eared, slightly mildewed note-book that you find in some forgotten corner may reveal hitherto unknown facts about the preparations, enactment and aftermath. Please stay in touch!
Hi all,
My Great-Grandfather was Joseph William Stanley Morse, he was a telegraphist (pretty apt considering his last name!) and joined the RNVR in 1939.
He was part of the original crew drafted to pick up the LST from the US to bring it back to the UK for conversion to FDT 216 – I have a transcript of a voice recording he put together for my 2nd cousin for a school project in the 70’s/80’s I think.
Unfortunately he was rather circumspect with detail but I’ve added the relevant part of the transcript below if anyone is interested:
“After the Dunkirk evacuation and the Battle of Britain, I eventually left Golden Eagle on 19 April 1943, returning to HMS Pembroke until 29 June 1943. I was then drafted to the United States to pick up a Tank Landing Craft (LST) in New Orleans. I spent around four to five months in the United States, being moved from one location to another due to several changes with the original LST. Eventually, I ended up at the U.S. Naval Base in Norfolk, Virginia, and was later drafted to another LST, which returned to England in December 1943.
Again, there were changes. The vessel was taken over for conversion into a radar-equipped ship to support the RAF during D-Day. The purpose was for RAF personnel to work with Fighter Command aboard our ship — FDT 216 (Fighter Direction Tender) — to provide radar coverage over the beaches until land-based radar could be established.
On D-Day minus 1 (5 June 1944), we sailed from Weymouth with many other ships to support the landings at Omaha Beach. Many Americans lost their lives there.
FDT 216 patrolled the beachhead, relaying fighter direction to intercept enemy aircraft in the vicinity of Omaha. Around ten days later, after the landings had been consolidated, we were ordered to relieve our sister ship, FDT 217, which had been covering Sword Beach and needed to return to Portsmouth.
On 6 July 1944, while on patrol, we were torpedoed by a German fast attack boat (E-boat). Our radar detected the torpedo. Orders were given to prepare to abandon ship. I was assigned to lifeboat station “Charlie”, where we waited for the final order. Eventually, the affirmative was given, and we abandoned ship. I’m not sure how long it was before we were picked up by an escorting destroyer, but it seemed like a very long time. We were taken back to Forces, where we were re-kitted as we had lost all of our personal belongings. This was 7 July 1944.”
I know he was in the Navy and not the RAF but I thought I might help add some more context to the whole thing.
Really fascinating reading about your relatives and their experiences!
Thank you, Charlie, for this most interesting account. I think it is remarkable how the different forces (Navy and RAF, UK and US) managed to work together (mostly!) for a positive outcome. I hope you have been in contact with the British War Museum to give them a copy of your Great-Grandfather’s memories – every tiny memory helps to build the jigsaw into a huge, coherent picture.
Best wishes, David (Admin, son of Eric Heathcote)
I found these three video clips on the Imperial War Museum Website that people who had family on the FDT217 might be interested in. They are three videos showing the radar, the boat sailing and what appears to be inside the boat.
https://www.iwm.org.uk/collections/item/object/1060020971