What if the fully crewed and armed Civil War US Navy went back to the War of 1812 or the Revolutionary War?
Short answerIt would initially be very successful, especially with explosive shells, but ammunition and fuse maintenance would become problems without the supporting infrastructure.
NotesA fully crewed and armed Civil War fleet would initially have a strong advantage against War of 1812 or Revolutionary War opponents. Explosive shells would be particularly dangerous to the earlier ships of the line. The counterfactual supplies the ships without their supporting infrastructure, however, so ammunition would eventually run out and fuses would still need maintenance. The answer also leaves open what opposition might assemble once the displaced fleet became a sufficiently serious threat.