The Great Lakes form a sprawling ecosystem of nature and industry. In a strong economy, ships can transport up to 200 million tons of cargo across these waters each year. But now the shipping industry has declared a state of emergency. The cause is a region-wide dredging backlog. Shippers worry sediment buildup threatens to choke some navigation channels.
It shows how much cargo a ship can hold for every inch of water it occupies. For the biggest vessels – the “thousand- footers” – one inch of draft corresponds to 267 tons of cargo. That’s why every bit of clearance matters to shippers trying to get the most bang from every trip.