The first warship “Harriet Lane” arrived and fired on the Nashville.
Nashville was sailing without a national flag and without the customary navigation lighting. Any warship in anyone’s navy would have fire a shot across her bow to determine nationality and intent. Once she identified herself and lit her navigation lights, she was allowed to proceed into Charleston harbor.
I like your response. You not only admitted that the Harriet Lane was a warship, but you also admitted that it was at the harbor entrance, and that it fired on the Nashville.
I'm sure they could hear the cannon shots at Beauregard's HQ.