In this section, we shall examine the numerous maritime operations conducted around Flushing and throughout Zeeland. The port of Flushing and its surrounding waters formed an important Allied operational zone. On the one hand, the area was of great significance to the French efforts to secure the approaches to the harbour of Antwerp; on the other, the strategic importance of defending Antwerp itself generated a constant flow of naval traffic in that direction.
In the early morning, at 06:00 hours, the HrMs Flores returned to Flushing after having been ordered to Rotterdam the previous day. The sinking of the HrMs Van Galen in the Nieuwe Waterweg on 10 May had alerted the Dutch naval command to the dangers of deploying larger warships in narrow waterways. As a result, the Flores was recalled to Flushing, where she could be employed in naval artillery support operations.
The small French destroyers (chasseurs(1)) no. 6 and 9 arrived in the morning, at approximately 07:00 hours, carrying 2,000 litres of fuel each intended for the army vehicles and armoured cars of the Allied ground forces. During their approach, the vessels were attacked by waves of three German Heinkel He 111 bombers. The small French ships were equipped with only twin-barrelled machine guns for anti-aircraft defence, but they received support from other units in the harbour area. The French anti-aircraft vessel FS Mardyck, a Dutch 75 mm anti-aircraft battery, and two machine-gun platoons stationed at the harbour all opened fire on the German aircraft. As a result, the He 111s remained at medium altitude, which significantly reduced their bombing accuracy. All German bombs missed their targets, but the aircraft withdrew virtually unharmed. Once the French vessels had moored, it became apparent that the Dutch authorities were unable to provide a fuel tanker truck to unload the petrol supplies.
(1) The French chasseurs - literally “hunters” - identified only by numbers, were in reality very small wooden warships. The designation “destroyer” was somewhat misleading, considering that contemporary destroyers generally displaced between 1,000 and 1,500 tons. The numbered French chasseurs, by contrast, displaced only 300 to 400 tons and were armed with a single 75 mm gun and a few machine guns for anti-aircraft defence. They were primarily intended for coastal escort and patrol duties in shallow waters. The larger French destroyers, classified as torpilleurs ("torpedo boats"), such as FS Cyclone and FS Siroco of the Bourrasque class, were considerably more substantial vessels, with a displacement of approximately 1,300 tons. These were capable warships, armed with a main battery of four 5-inch (130 mm) guns, anti-aircraft weaponry, and torpedo tubes.
In the early afternoon of 11 May, two French transport vessels — FS Rouen and FS Côte d’Argent — arrived at Flushing under the escort of the French destroyers FS Cyclone and FS Siroco, together with the British destroyers HMS Valentine and HMS Winchester. The transports disembarked the 1st and 3rd Battalions of the French 224th Infantry Regiment of the 68th Division. During their arrival, the convoy came under attack from several German bombers, but the combined naval and land anti-aircraft defences in and around Flushing forced the attackers to withdraw to safer airspace.
(2) The Royal Navy’s Old Admiralty-class destroyers were partially converted between 1937 and 1939 into fast escort vessels. Many of these modernised destroyers took part in the maritime operations off the Dutch, Belgian, and French coasts during May and June 1940. Originally commissioned during or shortly after the First World War, only the converted ships of the class remained in active service by 1940. They displaced approximately 1,188 tons unloaded, carried a complement of 135 officers and men, and, following conversion, were typically armed with four 4-inch anti-aircraft guns and eight .50 calibre anti-aircraft machine guns. Some vessels of the class, however, carried slightly different armament configurations.
Later that afternoon, another convoy arrived, consisting of the transport ships FS Newhaven and FS Pavon, escorted by the French destroyers FS Fougueux, FS Frondeur, and FS Adroit, as well as the British destroyer HMS Westminster. This convoy too was spotted by the Luftwaffe and soon came under attack from several Heinkel He 111 bombers. The convoy was protected by aircraft of the French naval air squadron AC-2, equipped with twin-engined Potez- 63 fighters.
Once again, the German bombers failed to inflict damage on the ships. However, Messerschmitt Bf 110 fighters of 4./ZG 26 succeeded in shooting down a French naval aircraft, which crashed directly into a house in Flushing. Moments earlier, the French aircraft had attacked a He 111P, most likely inflicting fatal damage upon it, before the German heavy fighters dived upon them. The French aircraft was credited to Oberfeldwebel Stahl, who also claimed a second Potez that later crashed near Biervliet, piloted by Lieutenant de Vaisseau Folliot. The crew of the first French aircraft - Maître Pilote Samedy and Quartier-Maître Le Maresquier - were killed in the crash. The German He 111 they had attacked earlier crashed shortly afterwards near the village of Kapelle. Of its four-man crew, all but one survived and were taken prisoner of war.
In the evening, at approximately 21:00 hours, the small French destroyer FS Diligente, accompanied by FS Incomprise, arrived in the harbour carrying 15,000 litres of fuel intended for army vehicles. Unfortunately, the Dutch authorities had not been able to requisition a fuel tanker truck, with the result that three French naval vessels were unable to unload their hazardous cargo.
The French Navy was highly active around the Westerschelde throughout this second day of the campaign. Many of its vessels were engaged in a shuttle service between the Westerschelde ports - particularly Flushing and Antwerp - and Dunkirk. To protect these vital logistical routes, the French and British navies also undertook extensive minesweeping operations.
In the course of the day four British minesweepers arrived at Flushing equipped for clearing magnetic mines. Their method involved towing an electrically charged cable through the water between two vessels. The powerful electromagnetic pulse continuously transmitted through the cable was intended to trigger the detonators of magnetic mines. Despite these precautions, the main shipping channel and the harbour approaches proved to be free of mines.