Just recently got the ability to build the different ships for my city. I started and produced one large battleship however, when I went to my naval yard to build it the yard only said I was missing armament. Next I went and produced armament for each other the other 3 three ships. Waited until armament production was done and went to try to create those ships. Non of them were possible in the naval yard saying I was missing armament. I haven't been able to produce any ships at all because of this.