Sometimes when you meet a Governor at a town, settlement (most often), or monastery, the Governor or Monk may require you to escort ship for various purposes (sending immigrants, ultimatums, seeds, transporting a new Governor, etc.). The ships will almost always be intercepted by three opposing enemies (other nations or pirates), prompting a "sea battle" on the main political sea map. To avoid this, attack the ship you are escorting. When you enter the combat screen, sail away from the ship to flee. Most likely the other ship will sail in the opposite direction. After you exit the combat screen, the escort ship will have sailed quite a long distance. If you are close to the target destination, the ship you are escorting should arrive automatically and complete its mission. Note: This may not very well if the target destination is still far away.