The action of 18 February 1639 was a naval battle of the Eighty Years' War fought off Dunkirk between a Dutch fleet under the command of Admiral Maarten Tromp and the Spanish Dunkirk Squadron under Miguel de Horna. Horna, who had orders to join with his ships Admiral Antonio de Oquendo's fleet at A Coruña, escorted at the same time a transport convoy carrying 2,000 Walloon soldiers to Spain, where they were needed. The attempt to exit Dunkirk was done in sight of the Dutch blockading squadron of Maarten Tromp. A 4-hour battle ensued and Horna was forced to retreat into Dunkirk leaving behind two of his galleons, whilst another ran aground. Despite his success in stopping the sortie, many of Tromp's ships suffered heavy damage, and the Dutch Admiral was forced to abandon the blockade. Therefore, De Horna, after repairing his squadron, was able to accomplish his mission.