The Polish Navy of the Second Polish Republic (1919–39) was prepared mostly as means of supporting naval communications with France in case of a war with the Soviet Union. However, after it became apparent that the aggressive side would be Germany, and the entrance to the Baltic Sea would be blocked, three out of four Polish modern destroyers were withdrawn from the Baltic Sea to Great Britain in what was called Operation Peking. The Peking Plan was an operation in which three destroyers of the Polish Navy, the Burza (“Storm”), Blyskawica (“Lightning”), and Grom (“Thunder”), were evacuated to the United Kingdom in late August and early September 1939 prior to the outbreak of war. The remaining forces, consisting of one large mine layer, one destroyer, five submarines and smaller vessels were to execute two major naval operations, both aimed at disrupting the German naval movement in the area of the Danzig Bay and transit movement between Germany and East Prussia. All submarines were dispatched for their operational zones in the southern Baltic to take part in Operation Worek, an attempt to sink as many German ships as possible.
All the remaining surface vessels were to be dispatched from the naval base in Gdynia to Hei Penincula, from where they were to start the so-called Operation Rurka. The plan was to lay a naval mine barrier between Hel Peninsula and Danzig to prevent any enemy ship from entering the area.
At dusk ten Polish warships left Gdynia for Hel, located on the other side of the bay. There, the ships were to start the minelaying operation. They were as follows: large minelayer Gryf minelaying minesweepers Jaskola, Czapla, Zuraw, Czalka, and Mewa and the gunboats Komendant Pilsudski and General Haller. The destroyer ORP Wicher had left for its position earlier that day and did not partake in the battle.
That afternoon a German reconnaissance aircraft spotted Gryf. Within half an hour a German airstrike was organized and launched.
While traversing Danzig Bay, the flotilla was surprised by a group of 33 German warplanes, mostly Junkers Ju 87B, Stuka dive bombers. The German aircraft divided themselves into two groups and attacked. The Polish ships zig-zagged wildly to avoid being hit. Concentrated AA fire forced the planes to bomb from a higher altitude. The air raid was mostly unsuccessful and the Polish vessels suffered only minor losses. The backbone of the Polish flotilla, ORP Gryf with over 300 naval mines on board, remained unharmed.
However, soon after the first air raid was repelled, the German bombers returned, around 18:00. There were no direct hits, but two Polish mine layers suffered damage from near misses and machine gun fire, ORP Gryf and ORP Mewa . A near miss disabled Mewa, killing or wounding her 22 crewmen, so that she had to be taken in tow by Rybitwa. The commanding officer of ORP Gryf, Cmdr. Stefan Kwiatkowski , was killed by German machine gun fire, 29 of his men were wounded, and his ship’s rudder was jammed. Gryf‘s executive officer, Lieutenant Commander. Wiktor Lomidze assumed command. Fearing that her cargo of 300 mines was a liability, he ordered the munitions be thrown overboard.
After the air raids, the Polish flotilla arrived at Hel. However, since ORP Gryf had abandoned all of its mines and was damaged, Operation Rurka had to be called off. ORP Wicher, did not receive the orders calling off the operation and went straight to the pre-designed zone of operations to cover the mine layers. At night, Wicher, commanded by Lieutenant Commander Stefan de Walden , spotted two German destroyers, and later a ship misidentified as a light cruiser, but did not attack, not wanting to compromise the operation.
After return to Hel Peninsula, Wicher and Gryf were stripped of most of equipment and served as anti-aircraft platforms in the Hel naval base.
The exact figures of German losses remain unknown, but are now often estimated to be in range of 200 to 300 killed and wounded or sometimes more. Some of them might actually have been hit by friendly fire, in particular from the battleship, which was initially anchored too close to its target. Polish casualties were much lower, including 15 to 20 killed and 53 wounded. There is a controversy regarding the burial site discovered in 1940, containing the bodies of five unidentified Polish soldiers who were possibly executed by their comrades for attempted desertion. Eight of the prisoners of war are also said to have been tortured, and did not survive German captivity.
Major Henrijk Sucharski (with a sabre) surrendering Westerplatte to General Friedrich Eberhardt (saluting)