A style of flags have been designed for naval battles all over the Civil War; those blanketed distinguishing marks for ships

https://gregoryvqbt875.northstarcolumn.com/posts/reenactment-use-of-civil-war-flags-bringing-history-to-life-2

A style of flags have been designed for naval battles throughout the time of the Civil War; those blanketed distinguishing marks for ships engaged in combat on rivers and seas alike.