Hi ya,
are not the nameplates on modern ships,in much the same place as WW2 warships? As others have said, certainly they were named on the hull at the stern, and also had a nameboard on each side of the superstructure.The smaller ships had the names mounted on a wooden board,teak I think,one board on each side on the superstructure,location varied according to the class of ship. With Battleships however, the names were usually individual letters, permanently mounted toward the stern on the superstructure near the quarterdeck. Again, these letters I think were in burnished,bronze,rather than brass, but I am not sure about this. I did not know that the ships crest was removed at sea,I thought it was a permanent fixture? Obviously the ornate Tompions with the ships crest on, were removed, and only used in port.At sea they were replaced with much simpler ones at sea. A ceremonial Tompion for a 15 inch gun barrel weighed in excess of 100 pounds!
Good luck with your build,
Cheers,
Mick