Flyer, they were not charging a USN ship, they were entering port and overtaking the vessel. Ever been to north Island when a Carrier is on the way in or out? No one sits back and waits, there nor here.
There is no published notice to mariners stating that USN or any military vessels are to be avoided by any set distance. There is nothing published about horns and whistles being the precursor to being fired upon. Just because some Contractor thinks blowing a horn is a warning doesn't mean anyone else understands what it means.
The Don