You have a decent backwind, but they turned to catch it as well. It works well for them if they try to intercept you. You could have the ship turned to make it harder for them to reach you, though then you'd have to take time later to realign and get back on course, probably taking a while.<br/><br/>(green is your ship with heading, orange is the npc ship, blue is the wind)<br/><br/>(http://s23.postimg.org/orkuc1cuj/shps.jpg)