A new beta is available called "aitraffic" please check out the pinned forum post of how to optin.
This beta adds 10 A.I. controlled Flounder vessels to the map who will drive round on random, but logical routes. I haven't fully finalised the routing system so it is possible they might get too close to land on some islands.
A.I. vessels will continue to exist as long as they remain inside a 20km bubble around you. Your visual range is 15km so there's a good 5km buffer where even though you can't see them, they are still being tracked within the game and will prevent any ships blipping out of existence as soon as you lose sight of them.
Currently A.I. vessels are pretty dumb and have no knowledge of your position or any other A.I. vessels. This will be improved later so that they will try to avoid a collision. Ideally they will follow maritime rules for collision avoidance.
They also cannot dock and will not attempt to go inside ports or other enclosed water ways, but I'm hopeful that this will be possible. I also want to get AI vessels to spawn docked in the ports to add a bit of life there too :)
A.I. positions are also not currently saved into save games but they will be shortly.
Feedback on A.I. doing silly things and/or performance issues always gratefully received on the forums :)
The next stage will be to increase the number of active vessels to see how far the system can be pushed. Ultimately there will be a config area to setup the maximum number of AI vessels.
Changed depots in aitraffic branch