Safe Navigation Using Real-time Oceanographic Data

NOAA's Air Gap Technology Sends USS New York Down the Mississippi River

The new U.S. Navy LPD ship, the USS New York, sailed down the Mississippi River on June 27, 2009, clearing the underside of the Huey P. Long Bridge just north of downtown New Orleans. The naval vessel, built in part from steel salvaged from the World Trade Center towers, sailed downriver, heading out for a month of sea trials. To clear the bridge, the ship used "air gap" technology developed as a part of the installation of NOAA's Physical Oceanographic Real Time System (PORTS) for the port of New Orleans.

The challenge facing the Northrop Grumman ship builders and the Navy was making sure that, despite high water levels in the Mississippi River due to spring runoff, the vessel could clear the bridge by at least two feet. The calculations forecasted a possible clearance under the bridge of about 2.1 feet. Given roughly 140 feet of clearance under the bridge, this would mean the ship would occupy about 98.5 percent of the available clearance as it passed under the bridge.

With a 3 a.m. Saturday final check from the bridge deck, NOAA signaled the ship would clear, and, at 6 a.m., the USS New York set sail under tug boat guidance for the middle of the channel. With the Center for Operational Oceanographic Products and Services Director and PORTS Program Manager on the bridge of the ship, at 6:51 a.m., and just as predicted by NOAA experts, the ship's two mast towers slipped under the bridge signaling by a margin of approximately 2.1 feet... a safe transit!

By a margin of 64 centimeters, the USS New York clears the Huey P. Long Bridge.
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USS New York

Built in part from steel from the World Trade Center towers, the U.S. Navy LPD ship the USS New York travels down the Mississippi River, heading out for a month of sea trials.

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Closer Look

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Waterborne Commerce Statistics Center, Navigation Data Center, U.S. Army Corps of Engineers