I can tell you that the raider in passive mode in naval trading boxes generate money and resources every turn.
Naval fleets in active mode in naval boxes sometimes attack commercial or war fleets that are in that commercial box
Passive transport vessels in commercial quarries only serve to supply the remaining fleets that are there if they are stacked with them.
Do not confuse merchant ships with transport vessels, which are the latter that generate resources in maritime trade boxes.
In this game I have not seen the possibility of building new commercial fleets as far as I could play.