A number of flags had been designed for naval battles in the time of the Civil War; those blanketed distinguishing marks for ships

https://zionzikt868.silverstonebrief.com/posts/documenting-the-legacy-collecting-historical-civil-war-flags

A variety of flags have been designed for naval battles for the period of the Civil War; these blanketed distinguishing marks for ships engaged in wrestle on rivers and seas alike.