During the summer of 1864, "Teaser" was called upon to leave the Potomac once more. On this occasion, the Union forces needed her guns to help defend strategic bridges across the rivers at the head of Chesapeake Bay near Baltimore, Maryland, against Lieutenant General Jubal A. Early's raiders. On July 10, she departed the lower Potomac, rounded Point Lookout, and headed up the Chesapeake Bay. That night, she had to put into the Patuxent River because of heavy winds and leaks in her hull. Before dawn the following morning, she continued up the bay. During the forenoon, the leaks became progressively worse and, by the time she arrived off Annapolis, Maryland, she had to remove her exhaust pipe for temporary repairs. Early that evening, "Teaser" reached Baltimore where she put in for additional repairs.