 The introduction of sailing ships with a square rig, of a type later called the ship of the line, which were heavily armed with cannon, brought about a gradual change in naval tactics.Before and during the First Dutch War, fleet encounters were chaotic and consisted of individual ships or squadrons of one side attacking the other, firing from either side as opportunities arose but often relying on capturing enemy ships by boarding.Ships in each squadron were supposed to support those in the same squadron, particularly their flag officer, as their first priority.