[quote=caliban22]
So we could build like cruisers,frigates, and bigger ships,but we Would need to find the plans to build one. and to build battleships/battlebarges/whatever we would need to hold a forge world?
[/quote]

Since this is all purely fluff based if you can get the plans and the equipment together anywhere you can build any ship. This is a forge world though so it not only has the resources to build one but has the ability to build them at a reasonable speed. I reference the story about how the Imperium used a feral world to construct a cruiser one time taking many generations to do so.

Think of it kind of like this, on any world you can build a leman russ or baneblade if you get the resources and the plans together for it. A forge world though can build it better and faster turning out tanks swiftly while your work by hand to make a single tank. THink of that like trying to build a battleship or even escort in orbit over a world compared to using the shipyards of Mechanicus forgeworld to construct battleships.