On June 20, the M/V Zhen Hua 13 delivered new cranes from China to the Port of Baltimore by navigating the waters of Chesapeake Bay. To reach this destination, the cranes had to clear a major obstacle—passing under the Chesapeake Bay Bridge outside of Annapolis.
As the cranes slid under the bridge, the National Ocean Service provided air gap information as part of the Northern Chesapeake Bay Physical Oceanographic Real-Time System (PORTS®). These measurements, along with real-time tides and current data, helped to ensure a safe and early passage of the ship in to the Port of Baltimore.
In addition to helping ships move safely and efficiently under bridges, NOS also develops hydrodynamic models that provide forecasts of water levels, currents, winds, and other parameters that are used to plan the best time for ships to pass under bridges.
For this passage, forecasts earlier in the week showed water levels were at about one foot above the predicted levels. Since minimum clearance for the M/V Zhen Hua 13 was four feet, the operation was a go. Actual clearance from the bottom of the bridge to the top of the cranes was nearly 10 feet.