I am quite sure that the hundreds of people who camp each year at the Treen Farm campsite in the fields above the stunning scenery of Pedn Vounder just a mile or so east of Porthcurno are unaware that they are holidaying on what was a crucial site from World War Two in the run up to and immediately after D-Day in June 1944. In fact, several of the buildings that form the campsite’s facilities today are survivals from those wartime days, although having been spruced up a little. The site was chosen in late 1943 to house OBOE.
OBOE was the first electronically-controlled precision bombing system of both the RAF and USAF and it played an important part in the Allied Air Forces’ bombing campaign against Germany. The system used two stations. One station was called the Cat and gave the pilot a narrow beam to fly over the target based upon the radar range and the second station called the Mouse gave a signal to the navigator/bomb aimer to release the bombs based upon its radar range to the target. To overcome the problem of detecting and controlling the aircraft at ranges up to 300 miles, a transponder was used in the aircraft. This received the pulses and re-transmitted them back to the two stations. The system increased accuracy down to 52 feet independent of range. That means it was just as accurate as the NATO Cruise missiles used in Serbia in 1999 56 years later!
Air Marshall Harris described the significance of the OBOE system in these words: “At long last we were ready and equipped and Bomber Command’s Main Offensive began at a precise moment, the moment of the first major attack on an objective in Germany by means of OBOE. This was the night of March 5/6 1943 when I was at last able to undertake, with any real hope of success, the task which had been given me when I first took over Bomber Command at the beginning of 1942 – the task of destroying the industrial capability of Germany.” The city was Essen and the target was Krupps. The raid which saw bombs concentrated in the main industrial area in 10/10ths cloud was a great success compared to previous raids which scattered bombs over the Ruhr.
With D-Day approaching the need for an OBOE system in Cornwall was apparent to help the RAF hit targets that would be crucial to the success of the landings in Normandy. Thus Treen was chosen. It was used to help target sites along the Normandy coast and in the hinterland behind the landings, and also employed against the submarine pens at St Nazaire, Lorient and Brest. Mosquito fighter-bombers from squadrons based at Cornwall’s airfields and RAF Predannack on the Lizard in particular were equipped to use it to full advantage allowing for pin-point accuracy in high-speed bombing raids by the wooden wonders.
Flight Lieutenant A.R. Craig of the Royal Canadian Air Force recalled his time at Treen: “I served as a Technical Officer at RAF Sennen’s Chain Home radar station until April 1943 when I was sent to Great Malvern to learn the mysteries of OBOE. (Malvern was the Telecommunications Research Establishment known as TRE.)I was taught by Dr F.E. Jones who along with George Reeves had invented OBOE. I was then sent back to Sennen where construction was begun from scratch of RAF Treen which was a new OBOE station. Two new controllers arrived, Bill Green DFC and Jimmy Newman DFC. The other Tech Officer was Ted Palmer from New Zealand. When the station was ready we marked the submarine pens at St Nazaire and Lorient with some success.”
Flying Officer R.H. Carlyle of the RAF remembered: “I was transferred to Sennen to a station at Treen which was under construction jointly with TRE. Sennen was about 10 miles by road from Treen (5 would be more accurate!) so I arranged a private billet and was able to be at the station all hours of the day. We designed operations room equipment and had it made locally. We had to set up the two sequenced transmitters. In doing so, we were in the process of setting up one of the transmitters and grounded the high voltage capacitor according to proper technique with George Reeves. Unfortunately, the proper ground had been removed and when I touched the proper ground I was thrown against the wall of the Nissen hut and suffered a middle finger paralysis for several months.
“The station became fully operational and was extremely busy prior to and after D-Day, such that I lived there, leaving only for meals, for about 3 weeks. We had a tremendous crew of mechanics. In the workshop one morning was a sign that read, ‘The impossible we do at once. Miracles take a little longer.’ Our longest range and latest assignment was 300 miles approximately; bombing of the U-boat pens at Brest. In 1982 I met the navigator of this operation, F/L Andrew Denholm, who had pictures of this successful operation.”
Due to the success of the Normandy campaign Treen by the late summer of 1944 was out of range of useful targets. The station closed and the airmen were transferred to a mobile station at Bawdsey in Suffolk. Full credit to the Halls family who have farmed Treen Farm for generations for maintaining the buildings and giving them a new lease of life on their campsite. If you fancied staying there you’ll find their website by searching for Treen Farm Campsite.
If you are able to supply any more details on RAF Treen or those who served there please use the Contact Us page of the website. I am grateful to A Cassidy’s ‘Top Secret Radar, World War II’ account published in May 2000 for many of the details above.