The 'Battle of Danzig Bay' took place at the beginning of 'Weiss' (i) as German warplanes attacked Polish warships in Danzig Bay as the first air/sea battle of World War II (1 September 1939).

In 1939 the Polish navy was readied primarily as a means of supporting naval communications with France, Poland’s main ally, in the event of a war with the USSR. After it became apparent that the aggressor would be Germany rather than the USSR, and that the entrance to and from the Baltic Sea would therefore be blocked, three out of the Polish navy’s four modern destroyers were withdrawn from the Baltic Sea to the UK in 'Peking'. The remaining naval forces, comprising one large minelayer, one destroyer, five submarines and a number of smaller vessels, were to execute two major naval operations, both aimed at disruption of the German naval movement in the area of the Danzig Bay and maritime movements between the main body of Germany and East Prussia. All the submarines were despatched for their operational zones in the southern part of the Baltic Sea for 'Worek', an attempt to defend the Polish coast against possible German landings.

All Poland’s remaining surface vessels were to be despatched from the naval base in Gdynia to the Hel peninsula, from which they were to start 'Rurka', an operation to lay a mine barrier between Hel peninsula and Danzig to prevent any German ships from entering the area.

At dusk on 1 September, 10 Polish warships departed Gdynia for Hel on the other side of the bay, which was to be the base for the minelaying operation. The ships were the large minelayer Gryf, the minelaying minesweepers Jaskółka, Czapla, Żuraw, Czajka, Rybitwa and pe]Mewa, and the gunboats Komendant Piłsudski and Generał Haller. The destroyer Wicher had left for her position earlier that day and did not become involved in the battle.

During the afternoon of the same day a German reconnaissance aeroplane spotted Gryf, and within 30 minutes the Germans had organised and launched an air attack.

While crossing Danzig Bay, the flotilla was surprised by a group of 33 German warplanes, most of them Junkers Ju 87B Stuka single-engined dive-bombers. The German aircraft split into two groups and attacked. The Polish ships zigzagged wildly to make themselves more difficult targets, and concentrated anti-aircraft fire forced the German warplanes to bomb from an altitude higher than was standard. The air attack was mostly unsuccessful and the Polish vessels suffered only minor losses. The backbone of the Polish flotilla, Gryf with more than 300 mines on board, remained unharmed.

Soon after the repulse of their first air attack, however, the German bombers returned at about 18.00. The German aircraft scored were no direct hits, but two Polish minelayers, Gryf and Mewa, suffered damage from near misses and machine gun fire. 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 Gryf, Commander Stefan Kwiatkowski, was killed by machine gun fire, 29 of his men were wounded, and his ship’s rudder was jammed. Gryf's first officer, Lieutenant Commander Wiktor Łomidze, assumed command and, fearing that the 300 mines were now a liability, ordered the munitions be thrown overboard.

After the air attacks, the Polish flotilla reached Hel. However, since Gryf had jettisoned all of her mines and was damaged, 'Rurka' had to be cancelled. Wicher did not receive the cancellation order and steamed straight to the pre-designated zone of operations to cover the minelayers and, under the command of Lieutenant Commander Stefan de Walden, spotted two German destroyers, and later a ship misidentified as a light cruiser. Wishing not to jeopardise 'Rurka', Wicher did not attack.

After their return to the Hel peninsula, Wicher and Gryf were stripped of most of their equipment and served as anti-aircraft platforms in the Hel naval base.