Greetings,
one of the many things players miss a lot in E:TW are port battles. There is one idea that has been floating (literally!

) around in my head for some days.
How about binding a certain kind of "ship" with each port that consists of a model of port facilities, especially cannon towers, of course.
Make it have 0 movement points, so it can't be moved out of the port. Make it have 0 movement speed in battle and no bobbing with the wave movement. Make it so big that there is only one single position it can take during deployment phase, still leaving room for the ships in port, of course:

(The shaded part is the "port ship"; the black blobs are ships)
Each cannon tower is only part of that "ship". Make the point a ship would try to steer to to board a ship unreachable. Give that "ship" so many men that the ai would never get the idea to even
try boarding it. If possible, don't give that ship any "sails" (if the presence of something that's technically "sails" is required, it would look far different, of course), so that the ai also doesn't try making the thing "immobile" through chain-shots.
Thoughts?