They made a quite nice , closed flow in the commercial part of the business, and the small naval ship part of the business nicely closed as well.
They make the warships in the open area, or in the building, after finishing them they transport them to the fitting basin thought the dock with the barge , and when they finished they let them go.
Now, the description given by you showing something that means the moving the half finished ship to the commercial dry dock (to a low security area ) , way away from the new buildings and new area ( presume those make carrier/capital ship parts ) , and after moving back the ship to the fitting area.
See? there is a lot of unnecessary movement, with lot of resources and risk each time.
Yet the current understanding is that they still chose that method.
Assuming they are rational, there must be some reasons and benefits for why they made that choice which we do not know about.