Images Let Navy Keep Tabs On Harbor

February 17, 2009 - via Newport News Daily Press

Home to the largest U.S. shipyard, one of the country's largest container ports and the world's largest Naval base, the Hampton Roads harbor is one of the most economically and strategically important port areas in the world. With its location in the heart of the Atlantic Coast, it's also home to the Navy's Atlantic Fleet.

Those features make for a strong maritime resume, but there are downsides. Hampton Roads is in an area at risk for hurricanes, tropical storms and other natural disasters. And, with a high concentration of military installations and high-value military assets, the harbor is a potential high-profile terrorist target.

That's why over a two-week period last September, a small fleet of boats quietly patrolled the harbor, surveying the silty basin 50 feet below. Fitted with special equipment, the boats were searching the harbor bottom for debris, obstructions, and even mines.

Commissioned by U.S. Fleet Forces Command and conducted by the Naval Oceanic Office, the Navy pieced together a high-resolution, photograph-quality scan of the harbor and ship channels.

What they found was not unexpected: A couple of sunken vessels and an array of typical marine debris, including thousands of old, rotting tires. Most importantly, there were no mines.

Knowing what lies underneath is crucial to keeping the navigation channels safe and clear from obstruction, which in Hampton Roads is a top national security priority. "We need the ability to get the fleet underway when the need arises," said Capt. Joe Atangan, the Navy's fleet oceanographer who helped coordinate the scans. "One of the biggest things that can prevent the fleet to do that is obstructions ... put there by man or by nature."

With thousands of Navy and commercial vessels using the harbor and waterways each year, keeping a close tab on bottom changes is a priority, said Lt. Cmdr. Phil Rosi, a Navy spokesman. "Seeing the daily and weekly ship traffic in and out of here, ensuring we have access at all times is key," Rosi said.

Using a tool called side-scan sonar, Navy crews canvassed miles of the harbor from near the Hampton Roads Bridge-Tunnel to the opening of the Atlantic Ocean, collecting highresolution pictures that the service will use as a baseline for future studies.

The sonar devices emit fan-shaped pulses toward the seafloor across a wide angle perpendicular to the path of the vessel. The data is recorded in a series of slices that are stitched together to create a photograph-like image of the sea bottom.

After the on-the-water work was completed, it took the Navy nearly three months to analyze the data and piece it together into a full report. Images that the Navy captured in September will serve as a frame of reference for future studies. By creating a snapshot in time, the service's researchers will be able to more easily determine what has changed on the harbor bottom after a hurricane or an attack.

"The beauty is, should an event occur, we're going to be able to go in and rapidly assess" what has changed, Atangan said. "For example, if a mine was to be laid, we could more easily ID it from what was there already."

In the case of a natural disaster or an attack, the Navy could conduct a quick assessment of the primary ship channel and clear a path to get the fleet to sea as soon as possible. "If we didn't have the data, it could take months to clear the harbor for navigation. This allows us to reduce it down to weeks or maybe even days," Atangan said. September's scan marked the first time since just after Sept. 11, 2001, that the bottom of the harbor was imaged, Atangan said. The Navy hopes to conduct new scans more frequently in the future, but with budgetary concerns, it's unclear if that will be possible.

Other ports with Navy bases also have been surveyed in recent months, including Pearl Harbor, San Diego and Groton, Conn. A base near Mayport, Fla., is next on the docket.

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Author:Peter Frost