Kaj Høyer served as 3rd Officer on-board a Danish ship requisitioned in South Africa in 1940. In late 1942, volunteered for the South African Air Force. He was trained as navigator end served in RAF 205 Grp in Italy was killed in action on 13 July 1944.
Kaj Høyer was born on 4 February 1912 in Lyngby. He was son of Edvard Høyer and Anna Margrethe Høyer (née Larsen). In the late 1920s, he was engaged by the Danish East Asiatic Company (EAC) as a ship-boy. He was sailing on-board several of the company’s ships—MS India for instance—during the 1930s. Høyer was still at sea when the Germans forces crossed the Danish borders on 9 April 1940. Records show, that he was engaged as the 3rd Officer on-board the MS Selandia (II) in Cape Town on 16 August 1940. It is likely, that Høyer was on-board the vessel prior to this date.
MS Selandia (II) had been built in 1938 for the EAC, and had arrived to Saigon on its maiden voyage on 6 April 1940. Following the German occupation of Denmark, the vessel was requisitioned by the French authorities (operated by the Compagnie des messageries maritimes). The Danish crew remained on-board. The vessel left Saigon guarded by French marines in May, and arrived in Capetown on 22 June 1940. At this point—following the French armistice with Germany—the vessel’s Danish captain arranged for MS Selandia (II) to be requisitioned by the South African authorities to prevent it to fall into enemy hands. In August 1940, the Danish flag was lowered once again, and the South African flag raised. MS Selandia (II) sailed on the route Durban-Mombassa for the next year. At least on some occasions, the vessel carried troops to the war zone. In June 1941, the vessel was damaged by in an aerial attack in Alexandria. In November 1941, the vessel sailed for the United states, where it was repaired. The vessel returned to Durban in September 1942 fully loaded with war supplies.
Strategic Air Force
On 10 November 1942, Høyer enlisted in the South African Air Force. He was trained as a navigator. On 18 November 1943, he was posted to Royal Air Force in the Middle East On 12 April 1944, then holding the rank of 2nd Lt, he was posted to 40 Squadron at Foggia Main as part of Sgt Smith’s (617605) crew. Høyer was the first of three Danes to be posted to 205 Group, which was the RAF component of the Mediterranean Allied Strategic Air Force. Høyer’s squadron was part of 236 Wing. Later, Børge Nielsen joined 104 Squadron, which was also part of this wing, and Ole Gert Grønning joined 150 Squadron, which was part of 331 Wing at Regina.
The Mediterranean Allied Strategic Air Force (MASAF) had been formed in late 1943 and incorporated USAAF’s newly created 15th Air Force and the RAF’s 205 Group, operating as day and night bomber formations respectively. At the end of the war, 15th Air Force mustered eighty-five heavy bomber squadrons and twenty-two long-range fighter squadrons, while 205 Group remained a much smaller group of six Wellington squadrons and three heavier squadrons of Liberators and Halifax aircraft.
From early May to mid-July, Høyer carried out fourteen operations at the squadron. Several of these were related to the so-called Oil Campaign. Others were related to the Allied air interdiction operations in Italy in 1944.
The Oil Campaign
Germany was heavily dependent on imports of oil from Romania. The only way to stop the supplies of oil from Romanian oil fields to Germany was to bomb the oil installations as well as preventing the oil to be transported to reach Germany. An early attempt to bomb Ploesti—the city with which the campaign is most often associated with—had been carried with heavy losses out by the USAAF’s Eighth and Ninth Air Forces from bases in Libya (Operation Tidal Wave). As the MASAF moved to Italy, major operations on the Romanian oil fields began. The majority of these operations were carried out by the Fifteenth Air Force, but the squadrons of 205 Group were involved as well.
On 5/6 May, Høyer became the first of the three Danes to operate against Ploesti—which remained the main target of the oil campaign. Wellington X LN467/G took of at 21.44 hrs from Foggia Main at set course for the marshalling yards at Campina, which were situated in the centre of the Steaua-Romana oil refinery, north-west of Ploesti. The crew—captained by Sgt B. Smith—bombed from north and saw the bomb burst in storage tanks north of the sidings. According to the assessment in the squadron’s operational record book, the raid was highly successful.
A highly successful raid was made in CAMPINA Marshalling yards and oil Refinery, North of PLOESTI. Bursts were seen across the target and two or three fires were reported. Photo-recce at 10.30 hours next day showed extensive damage, particularly in the oil storage depot and huge fires were still burning. Two enemy aircraft were fired at by our crews over the target area but did not press home their attacks. A.A. opposition was slight.
Høyer flew another two operations oil refineries and storage facilities in June 1944. On 2/3 June, he participated in an operation against oil storage tanks on the north side of the River Danube at Giurgiu, and, on 22/23 June, in the operation against the Vado Ligure-Zinola refinery west of Genoa.
An important part of the oil campaign was to prevent the supply of oil product into Germany itself. One barge on the River Danube could carry a load equivalent to a hundred railway wagons, and the river could carry 10,000 tons oil daily. From April to October 1944, 205 Group sowed about 1,400 electromagnetic mines in the Danube. These ‘gardening’ operations were carried out in moon periods at heights of no more than 200 feet, often even lower. Høyer and his crew participated in one of these operations. On 31 May–1 June, forty-two Wellingtons and ten Liberators dropped 129 mines in the river between Slankamen and Stari Banovis. Høyer’s crew successfully dropped their 1,000 lb magnetic mine in the river near Futog in Yugoslavia.
Railway installations, roads and harbours
Another important objective for the MASAF and 205 Group was the enemy’s lines of communication. By early 1944, the Italian front had reached a stalemate. The Allied armies had been unable to break the German defensive Gustav Line through a frontal assault. Similarly, the Anzio beachhead had been secured, but the Allied forces had been unable to break out. Both sides were exhausted from six months of bitter fighting.
On 19 March 1944, the Mediterranean Allied Air Force (MAAF)—of which MASAF was the strategic component—had launched Operation Strangle. The main idea was to deny the enemy essential supplies by bombing the main railway lines and marchalling yards. The objective of Operation Strangle was to achieve a German withdrawal from the Gustav Line. Originally, it was envisioned that the objective could be achieved by air action alone. However, it was realised that this was too optimistic, and that the objective could only be achieved by a combined Allied offensive.
Operation Strangle had been inspired by the research of the British Professor Zuckerman. He had been a professor of anatomy before the war, but, by December 1943, he was head of the Bombing Survey Unit in Palermo. His research on operations in North Africa, Sicily and Italy showed that a disproportionate amount of damage had been caused by raids on railway communication links. Zuckerman later conceived the ’Transport Plan’ in preparation of the landings in Normandy.
Strictly speaking, Operation Strangle ended on 11 May, when the Allies launched a massive attack on the Gustav Line, but the operation was continued under the ground defensive (Operation Diadem).
While the main target of Operation Strangle was railway lines and marshalling yards, as the Germans were forced to move increasing quantities of supplies by sea, a number of harbours were attacked as well. In his first operation, on 1/2 May 1944, Høyer had participated in an attack on the commercial harbour at La Spezia. The harassing attack was made by sixteen Wellingtons attacking in four waves. The first three waves, including Høyer’s crew, scored bursts across the harbour, moles and adjacent installations. The objective of many of these harassing attacks was to disturb the enemy’s attempt to load and unload supplies for the front. Later in May, Høyer’s crew participated in similar attacks on Portoferraio on the island of Elba (11/12 and 12/13 May) and Porto San Stefano (28/29 May).
On 14/15 May, forty-one Wellingtons from 205 Group attacked railway bridges at Latisana, Tagliamento-Casarsa and Avisio. Eight aircraft from 40 Squadron, including Høyer’s crew in Wellington X LP118/F, attacked the Tagliamento bridge at Casarsa. Two Wellingtons dropped flares to illuminate the target, while the remaining six bombed from 7,000 feet. The aircraft observed several hits on the bridge and many near misses. The following day photo reconnaissance confirmed at the bridge was cut, the spans being severely damaged in two places.
In the early hours of 23 May 1944, the Allies launched the attacks to breakout from the beachhead at Anzio (Operation Buffalo). The following days, 205 Group was involved in the tactical support for the operation. On 22/23, 23/24 and 24/25 May, roads at Valmontone and Ferentino were attacked by 205 Group to prevent the German Tenth Army to retreat from Cassino. The general idea of the attacks was for the Strategic Air Force to bomb the towns and villages so that debris of shattered buildings could block the narrow streets. The Tactical Air Force would then attack the traffic jams in daylight. Høyer’s crew took off to attack Valmontone, but they had to return early because of severe electrical storms, rain and icing. The bombs were jettisoned at sea.
Two nights later, on 26/27 May, Høyer’s crew participated in an attack on Viterbo some forty miles north of Rome. The town was attacked over three nights in a row, this being the second night. As in Valmontone the objective was to prevent German reinforcements moving to the Rome area.
In July 1944, Høyer participated in two operations against the marshalling yards at Milan-Lambrate. Three weeks ha passed since his last operation on 22-23 June (the Vado Ligure-Zinola refinery). Since his arrival at 40 Squadron, Høyer had been part of Plt Off. Smith’s crew, but in these three sorties—for some unknown reason—he was the navigator of three different crews.
On 10/11 July 1944, eighty-nine aircraft were detailed for an attack on rolling stock concentrated at the marshalling yards at Milan-Lambrate. Ten Wellingtons from 40 Squadron participated in the operation. The results of the operation were good and left the target area covered in small fires. The tracks were also cut at both ends, which led to rolling stuck being trapped in the yards. Three nights later,
The target was again the rolling stock at the LAMBRATE Marshalling Yards at MILAN, now pinned in the yards as a result of the destruction of the exits in the previous raid.
Nine Wellingtons from 40 Squadron was detailed for the operation. Wellington X LN270/O piloted by Plt Off. Charalambous (162971) took off from Foggia Main at 20.20 hours. Høyer was the navigator of this aircraft. The attack was successful, but six aircraft were lost in the operation. LN270/O was one of them. Apart from Plt Off. Charalambous and Høyer, the crew of the aircraft were Fg Off. Martin, FS Shephard, and Sgt Knight. It was Høyer’s fourteenth operational mission.
 DNA: Parish register, Kongens Lyngby Sogn.
 Ancestry.cu.uk: Massachusetts, Passenger and Crew Lists, 1820-1963.
 Tortzen, Søfolk og skibe 1939-1945 (1981), Vol. 1, p. 485.
 Tortzen, Søfolk og skibe 1939-1945 (1981), Vol. 3, p. 291.
 NA: BT 389/26/183.
 Ancestry.co.uk: Massachusetts, Passenger and Crew Lists, 1820-1963.
 Tortzen, op.cit., p. 378.
 SANDF: Second World War Service Record of Kaj Høyer.
 NA: AIR 27/413.
 Granfield, Bombers Over Sand and Snow (2011).
 Cooke and Nesbit, Target: Hitler’s Oil (1985), pp. 15–18.
 Granfield. Bombers over sand and snow : 205 Group RAF in World War II (2011), p. 265-266.
 NA: AIR 27/413.
 NA: AIR 27/413.
 Granfield, op.cit., p. 254.
 Granfield, op.cit., p. 268.
 NA: AIR 27/413.
 Sallagar, Operation "Strangle" (Italy, spring 1944): a case study of tactical air interdiction (1972), p. 12-23.
 NA: AIR 27/413.
 NA: AIR 27/413.
 NA: AIR 27/413.
 Granfield, op.cit., p. 277.
 NA: AIR 27/413.