A style of flags were designed for naval battles all through the Civil War; those included distinguishing marks for ships

https://gregoryvqbt875.northstarcolumn.com/posts/behind-the-scenes-preparing-for-a-civil-war-flag-reenactment-event-4

A style of flags have been designed for naval battles all over the Civil War; those incorporated distinguishing marks for ships engaged in struggle on rivers and seas alike.