Star Trek: 10 Things You Never Knew About Chakotay
4. His First Posting Was A Clue With A Sting In The Tail
The character bible for Chakotay notes that, early in his career, he served aboard the USS Merrimac. This ship saw plenty of service during The Next Generation. It carried Ambassador Sarek back to Vulcan after negotiations with the Lagarans, before remaining with the Vulcan Science Academy for some time. It took part in Captain Picard's blockade during the Klingon Civil War as well.
The USS Merrimac(k), from which Chakotay's first ship took its name, was a frigate that was active during the American Civil War. It was a Union vessel that was sunk, before being raised by the Confederacy, refitted, and transformed into the ironclad ram CSS Virginia. The hope was that the ship would then work against the Union, smashing the blockades that were impeding the Confederacy.
The significance of the Merrimac switching sides (spiritually) was not to be lost on the character of Chakotay, as he resigned his Starfleet commission to go and fight for the Maquis against the Cardassians, who were, at that time, allies of the Federation. By extension, this Starfleet officer was turning against his own people - politically at least.