In this section we shall look into the numerous maritime operations around Flushing and Zeeland. The Flushing port and surrounding waters were a true Allied zone of operation. On one hand the importance of the Flushing area for the French attempts to guard the entrance of Antwerp harbour and on the other hand also the paramount importance to defend Antwerp itself that caused plenty of sea traffic into that direction.
In the early morning - at 0600 hours - the HrMs Flores returned to Vlissingen, after she had been ordered to Rotterdam on the previous day. The sinking of the HrMs Van Galen at the Nieuwe Waterweg [10 May] had warned the navy staff for the risks of deploying larger war ships on narrow water-ways, and as such the HrMs Flores was ordered to return to Vlissingen in order to be made available for artillery support operations.
The small destroyers [chasseurs (1) ] 6 and 9 arrived in the morning [around 0700], bringing a load of 2,000 litre fuel each, intended for the army vehicles and armoured cars of the land forces. During their arrival German He-111's attacked the French ships in waves of three planes. The small French ships had only twin-barrelled machineguns as AA, but they were supported by other units. The French AA-vessel FS Mardyck , the Dutch 7,5 cm AA battery and the two machinegun platoons at the harbour jointly opened up against the German planes. As a consequence the He-111's kept flying on medium altitudes, not improving their aim. All German bombes missed their targets. The planes returned virtually unharmed. When the ships had moored it appeared that the Dutch forces were unable to provide a tanker-lorry for offloading the petrol supply.
(1) The French Chasseurs [literally 'Destroyers'] which were only identified by a number, were in fact only very small wooden destroyers. In fact the title destroyer was not fitting the size of the ships, bearing in mind that a regular destroyer had a size equal to about 1,000 - 1,500 tons. The French numbered Chasseurs were only 300-400 tonnes ships, with one gun of 7,5 cm and some machineguns for AA. They were designated for coastal escorting duties and patrolling duties in shallow waters. The available French class of larger destroyers ("Torpilleurs "), like the FS Cyclone and Siroco, both of the Bourrasque class, were considerably larger ships with their 1,300 BRT. Capable ships with a main battery of four 5 inch (13 cm) guns and AA, as well as torpedo tubes.
In the early afternoon of the 11th two French mail-boats [FS Rouen and Cote d'Argent ] - escorted by larger French [FS Cyclone , FS Siroco ] and British destroyers [HMS Valentine , HMS Winchester ] - arrived at Flushing. The transports disembarked the 1st and 3rd Battalion of the French 224 Regiment Infantry [68th Division]. During their arrival they were attacked by several German bombers, but the combined efforts of all AAA means available in and around Flushing had the Germans fly off to safer air-space.
Later in the afternoon the next arriving convoy [transporters FS Newhaven and Pavon , destroyers FS Fougueux , FS Frondeur , FS Adroit and the British HMS Westminster (2) ] was also spotted by the Luftwaffe and soon after attacked by He-111's bombers. This convoy was also escorted by a representation of the French navy airforce, squadron AC-2, that was equipped with twin engine Potez -63 planes. Again the Germans failed to damage any of the ships, but Bf-110's of 4/ZG26 did succeed in downing a French navy fighter-cruiser that crashed straight into a house in Flushing. The subject French plane had first attacked a He-111P, which they most likely fatally damaged - when suddenly the Bf-110's of the ZG26 dove down on them. The French plane was claimed by Oberfeldwebel Stahl, who also claimed a second Potez , which crashed at Biervliet [piloted by Lieutenant de Vaisseau Folliot]. The unfortunate crew of the first French plane - [Maitre Pilote ] Samedy and [Quartier-Maitre ] Le Maresquier - perished. The German He-111 they had attacked before crashed shortly after near the village Kapelle. Its four men crew - except for one fatality - survived and became POW.
(2) The Old Admiralty Class destroyers of the Royal Navy were partially converted in 1937-1939 into fast escorts. Many converted destroyers of this class took part in the maritime events along the Dutch, Belgian and French coasts in May and June 1940. The destroyers were commissioned at the end of, or shortly after WWI and only the converted ones were in use in 1940. The displacement was 1,188 tons [unloaded], the complement 135 men and the armament (after conversion) comprised four 4" AA guns and eight .50 AA machineguns. Some different armament configurations were carried too.
In the evening  the small French destroyer FS Diligente [accompanied by the FS Incomprise ] arrived in the harbour, carrying a load of 15,000 litre fuel for the army vehicles. Unfortunately the Dutch had still not managed to requisition any tank-lorry. As such three French navy units could not unload their dangerous cargo.
The French navy was very active around the Westerschelde this second day. Many of their units were involved in the shuttle service from the Westerschelde [Flushing, Antwerp] to [mainly] Dunkirk. In order to safeguard the huge logistics on the Westerschelde the French and British navy also unleashed extensive mine-sweeping activities.
Four British minesweepers arrived in Vlissingen. These were equipped to sweep magnetic mines by pulling a power cable through the water in between two ships. The strong electromagnetic pulse which was continuously sent through the cable was supposed to trigger the magnetic mine fuses. The main waterway and approach of the harbour appeared to be free of mines however.