[T]he major benefit of using cardboard is that my little guy can lift up such a massive ship and play with it. Also, I used material that was all destined to be recycled or thrown out, and with the exception of white spray paint and styro-foam craft balls, I had everything on hand to make it. So, the basic structure is heavy corrugated cardboard, lighter cardboard for the detailing on the conning tower and ‘sandwich filler’ greeblies, a packing tube for the engine nozzles (sawed into three pieces), cereal box cardboard for lighter details, duct duct tape, masking tape, and a lot of carpenter glue. All told, it took about three days (including one very late night to do the detailing), and I now have templates worked out for the overall structure. It has an internal support structure (one center piece running down the middle with ‘ribs’ about every 5″), and the overall length is shy of three feet. As far as making ships of this scale, it was a relatively quick build-up and a great weekend project.
Templates not included in the link, unfortunately.