Nowadays, a navy will order a number of ships of a specific class from the shipyard, and they’ll all be made the same. Like the type 23 destroyer, or the Arleigh Burke Class. All the ships of the class are made almost exactly the same. This was probably not how it always was. When did naval ships begin having models or classes, where several of almost the exact same would be built by a nation? And what did naval shipbuilding look like before that?