Page "Seafarers of Catan" Paragraph 23

Furthermore, the pirate mechanics have also changed: the pirate moves through the middle of the map in a fixed path every turn, and attacks the owner of any nearby settlements.

Players win resources if they are able to fend off the pirate attack ( which depends on the number rolled by the dice, as well as the number of warships in the defending player's possession ; warships are created from using Knight cards on existing ships ), but lose resources if they are unsuccessful.

Maritime expansion is only permitted by building a settlement at the waypoint, however, this increases the chances of a pirate attack.