Semmes knew Galveston had been taken by the Federals in October and believed, based on gossip in northern newspapers taken from captured merchantmen, that in January he would find a large (and unarmed) fleet of invasion transports anchored off the bar here. His idea was to run in among them in the dark, guns blazing, and slip away again before dawn. It was an audacious plan, but still not spoiling for a straight-up fight against Federal warships.
What he didn't know was that Galveston had been recaptured on January 1, and when he arrived late on the afternoon of January 11 he discovered that the blockading squadron was still offshore, and (in fact) lobbing shells into the town. That's when he led away Hatteras, that had been sent to investigate the strange sail, away from the rest of the squadron where he could take her on in a single-ship action.