[Spectarofdeath]

Privateers. You build a ship, and sell it to civilians and they go and raid enemy shipping for you. Also, merchant ships, maybe have a few merchant shipping lines, and they place orders for ships, and depending on how many ships they have is how much trade you make. Or contracts from other empires to build ships, they give you the schematics and you build the ships and give it to them in exchange for resources. This could help the neutral races who get into wars with the major powers.