How Do They Build 150-Ton Ship Propellers With Millimeter Precision? Extreme Engineering Documentary

How do engineers build a ship propeller wider than a three-lane highway and weighing up to 150 tons? Follow giant ship propeller manufacturing, from computer-aided design and foam patterns to sand casting, a critical 10-minute molten-metal pour, robotic CNC machining, hand polishing, laser inspection, and precision balancing. See how heavy-lift crews transport and install these bronze giants, how divers replace blades underwater, and how shipyards repair damaged propellers and sha