Instruments aboard American ships of the Union navy were quite common. Remember that these guys were on blockade duty and generally saw no action at all. Boredom was a BIG problem. The picture I posted earlier was the band aboard the flagship USS Wabash which was a huge ship for its time.

But this kind of musical talent aboard a Union ship was not unheard of. The USS Constitution, which lies anchored in Baltimore, Maryland, had a paid string quartet aboard -- recruited from the crew -- and they played extensively as it sailed the Mediterranean during the American Civil War.