Something I have noticed in my recent games, when an AI surrenders to me, I get their ships and can see that they are doing.
One problem in particular here is that when you change government, you get a free ship granting you some bonus, usually to your planet.
In this game in particular, I have inherited a Prime Minister Starship, giving 30% bonus to construction, influence and moral.
What is the AI (genius) doing with this ship? It is using it as a scout ship, far from its territory. There are multiple planets where it could be of use.
Save game (former Altarian starship)