Naval battle near Hel

The Battle of Hel was a naval raid took place on July 29, 1571, when a squadron of the Royal Dano-Norwegian Navy raided the Baltic Sea ports of Puck and Hel, destroying or capturing fifteen ships of the privateer fleet (Polish: "Flota kaperska") of the Polish–Lithuanian Commonwealth, and taking those that were captured back to the city of Copenhagen.
Background.
After the conclusion of the Northern Seven Years' War, Polish-Lithuanian and Swedish privateers continued to attack merchant vessels which traded with Tsardom of Russia via the port of Narva. Both the Polish-Lithuanians and the Swedes refrained from direct attacks on Dano-Norwegian fleet, while Denmark regarded all such raids as piracy. Under the circumstances, Copenhagen decided to undertake activities directed against the Commonwealth.
Battle.
In July 1571, a squadron of eighteen Danish ships under a Danish admiral, Franke, entered the waters of the Gdańsk Bay. On July 29 near Hel, the Danes attacked and destroyed two Polish-Lithuanian ships, commanded by Krzysztof Minckenbeck, after which a Danish landing party landed on and penetrated into Hel Peninsula without resistance.
On the same day Dano-Norwegian ships entered the Bay of Puck, where eight Polish-Lithuanian warships plus five captured ships were stationed near the port city of Puck. The Dano-Norwegians broke the resistance of Polish-Lithuanian privateers and captured all thirteen ships, taking them to Copenhagen. As a result of the raid, the Polish–Lithuanian Commonwealth Navy was reduced to half of its previous strength.
Aftermath.
In late August 1571, Dano-Norwegian ships once again appeared in the Gdańsk Bay. This time the Polish-Lithuanians had been warned in advance, and all Polish-Lithuanian warships had left Puck, sailing to the city port of Gdańsk, where they found protection. For two weeks the Dano-Norwegian fleet blockaded Gdańsk, demanding that all ships inside Gdańsk be handed over to them. The Gdańsk authorities refused to do so, and to punish the city, a Dano-Norwegian blockade was enacted on the city, and stopped in the Øresund as many as thirty-four merchantmen which were headed for Gdańsk. The Dano-Norwegian victory proved that Polish-Lithuanian privateers, although experienced enough to guard the sea coast, were unable to successfully engage the Royal Dano-Norwegian Navy.