The God Engines - John Scalzi

Captain Ean Tephe is a man of faith, whose allegiance to his lord and to his ship is uncontested. The Bishopry Militant knows this — and so, when it needs a ship and crew to undertake a secret, sacred mission to a hidden land, Tephe is the captain to whom the task is given. Tephe knows from the start that his mission will be a test of his skill as a leader of men and as a devout follower of his god.