From "Traitors: The Secession Period" by Edward S. Cooper.
Whereas William F. Rogers turned his Revenue Cutter Henry Dodge over to Confederate authorities in Galveston, John Newland Maffitt did not turn his command over.
Captain Maffitt, commanding the USS Crusader was in Mobile, Alabama, at the time of secession. He considered himself a North Carolinian but refused to turn his ship over to Confederate authorities and even went so far as to say he'd shoot anyone who tried to board the Crusader.
Another account had him saying, "I may be overpowered but in that event what will be left of the Crusader will not be worth taking."
He sailed his ship back to New York Navy Yard, turned it over, resigned his commission and journeyed South where he joined the Confederate Navy.
Of course, Maffitt went on to provide great service to the Confederate Navy in a variety of roles.