I have put ships in enemy trading paths set to auto attack and guard. I can't tell if it's attacking the freighters or not. I usually end up seeing the freighters pass them right by so I do it manually. I can't do that every round, it gets too tedious.
I think it would be good to have an option separate from guard, sentry, and auto attack. This option would be blockade and destroy enemy freighter routes. Your ship would stay put in one spot waiting for freighters to pass by like an ant lion waiting for ants. If they move around too much they will go into enemy defended territory where they will get destroyed. I would like to set it and forget it but have it be effective at intercepting enemy freighters.
This option would be just for freighters. So for example; if an enemy combat ship passes by without attacking your ship then your ship will let it just pass on by and stay waiting for freighters only.
1. One way to implement this is to have your ships attack any freighters that are in range at the end of every turn. If the freighter is out of range then it gets through your blockade. If the freighter stops within range and at the end of your turn it is in range your ships attack it.
2. Another way to do it. You set your ships to patrol between two points and the ship will only move and attack freighters within this area.
3. You could have one patrol for all ships and one patrol focusing solely on enemy freighters.