Hearts in Bondage (1936)

Best friends Kenneth Reynolds and Raymond Jordan are US Navy officers and Kenneth is engaged to Raymonds sister But the eruption of the Civil War divides them as Raymond stands by his native Virginia while Kenneth remains on duty as a Northern officer Kenneths uncle John Ericsson designs a new kind of ship an ironclad he calls the Monitor Eventually the war pits Kenneth on board the Monitor against his friend Raymond serving aboard the Souths own ironclad the Merrimac as it is called here A naval battle ensues one that will go down in history