how many tons is a big crane
Big Blue is a gantry style crane that stands 233 feet tall, and has a span of 540 feet from leg to leg. It weighs 4,600 metric tons (10.1 million pounds). It was built in 1976 by the German company Krupp. The two legs straddle the huge dry-dock at Newport News Shipbuilding, where the first Ford-class aircraft carrier is currently being assembled.