In the movie “13 days” there’s a scene where the SecDef argues with an Admiral over a destroyer firing star shells near a Soviet cargo ship. What was (is) the real purpose for this?
The situation was the Cuban blockade, and the destroyer was preparing to fire a shot across the bow of the cargo ship (which JFK had expressly forbid). But they did fire star shells (flares) which shook a lot of people up. The admiral explained that this was common practice.
So, why the flares? Did it have to do with the functioning of the guns - to get some idea of windage - or was it a warning shot?
I hope I didn’t spoil the movie for anyone, but the Soviets do not nuke the gool 'ol USA in the end.
Star shells, or illumination rounds, exist mainly to provide a better view of the target. Certainly, the target would have appeared on radar at ranges vastly greater than the range of the star shells, which makes star shells a little less important in the modern day than they were in the 1930s, for example.
Radar can’t do everything. Star shells would allow you to identify the target, see what is going on on its decks, etc. It could have detailed what sort of ship this was; the US Navy had some idea of what kind of ships were in the area but they wouldn’t necessarily have been able to tell one ship from another of the same approximate size. So radar will tell you you’re looking at a medium-sized surface object travelling southwest at 15 knots; star shells will tell you you’re looking at a commercial vessel in the 400-foot range with three derricks and 20-30 people on board (shielding their eyes and looking nervous).
The real intention might have been to make a warning shot, however. A star shell could be very intimidating, especially if the vessels was fairly fragile, and if the captain had been ordered to avoid trouble.
Oh, well, uhh, forget I said anything. I really haven’t heard of any starshell use in broad daylight, so I guess it was probably to scare and/or irritate the vessel’s crew. Sorry about the useless info.