舰艇: warship, naval vessel...
讹诈: to extort under false pretenses, to blackmail, to bluff, to defraud...
沿海: coastal...
顺路: by the way, while out doing sth else, conveniently...
悬挂: to suspend, to hang, (vehicle) suspension...
商讨: to discuss, to deliberate...
除非: only if (..., or otherwise,...), only when, only in the case that, unless...