Most sportfish boats are built using a method called cold molding. It starts with a multi-station, male jig that workers fasten seemingly endless sheets of overlapping marine plywood to before glassing the whole structure over.
Once the hull is roughly done, the builder must flip the huge structure so that work can begin on the rest of the boat. Watch this video, which shows the Paul Mann Custom Boats Crew in Manns Harbor, North Carolina, flipping a 63-footer, the 140th hull the builder has completed.
Once the boat is back in the shop, workers will start fitting out the hull in preparation for attaching the deck, which often is built in much the same way as the hull.