Norfolk-Wilmington districts work together on dredging project

Posted November 2, 2009
By Pamela Spaugy
Norfolk District Public Affairs

11/02/2009 - NORFOLK, Va — The Corps' only split-hull dredge, the Currituck, is in great demand.

From Oct. 19-23, the Wilmington, N.C.-based ship and crew of four, called Virginia Beach, Va., home. The 150-foot long, 484-ton dredge moored at Rudee Inlet during that time and is the only vessel capable of navigating shallow channels and removing sand from the shoals and deepening navigational channels.

The Currituck, which spends most its time working the coastline from Florida to Maine, operates seven days a week and has little downtime, according to First Mate Weldon "Tumpy" Davis.

Davis, who grew up near the water, comes from a family of fishermen. He has been dredging for 16 years and has served with the Corps for 14 years.

The Currituck, which holds up to 15 dump trucks of sand per load, deepened the channel two feet and replenished the north side jetty of Croatan Beach, said ship's Captain Martin "Marty" Willis.

Willis, who lives 30 miles from Moorehead City, N.C., says, "This the best job to have if you like being on the water. I see dolphins, whales, sharks -- all kinds of fish -- it just doesn't get any better than this."

"Rudee Inlet must be constantly surveyed and monitored to ensure the channel is safe for navigation," said Kristin Mazur, project manager and engineer with the Norfolk District, U.S. Army Corps of Engineers.

"Weather events can cause significant shoaling therefore it is critical to maintain the channel with the Currituck on a regular basis, (about three to four times per year). Commercial fishing boats, charter sport fishing vessels, research vessels from Virginia Marine Science Museum, U.S. Navy craft, several party/tour boats, and various transient vessels benefit from the dredging of the Currituck, a valuable Corps resource," she added.

It was a clear, calm day on the water Oct. 22. Dolphins were jumping in the wake of boats crossing the channel. As the Currituck positioned itself at the mouth of the inlet, 10 large vacuum pumps were turned on and began sucking water and sand from the ocean floor. Within minutes, the clear water coming through the pumps and emptying into the holding bin -- also known as a hopper -- began to darken as sand filtered through the pump and filled the void. As sand comes in, water is pumped out.

It's difficult to imagine the amount of sand this small vessel can hold. The hopper, shaped like an upside down pyramid, is full within two hours. "When mounds of sand start to pierce the top of the water, swirling around in the hopper, it's time to empty," Willis explained. The pumps stop and the ship heads toward the disposal site. In this case, it was only 800 feet away.

Pointing to the beach, Willis says, "We have discovered that by disposing the sand 20 to 30-feet from shore, the current and tide washes most of the sand toward the shoreline, which replenishes the beach."

It's the way the sand is released that makes this vessel so unique. Once the ship and its cargo of sand are in position, the hull begins to slowly open -- like a giant clam. Once the water mixes with the sand it begins to slowly sift away in small and large pieces only to find its way back to the bottom of the ocean floor.

Its cargo dumped, the hulls which are like two metal claws, come together once again and the ship heads back to the channel for another load. "The outboard unit, which swivel 360 degrees and can be raised and lowered, gives the Currituck an incredible maneuvering ability," Willis said.

When you look off the coast of Croatan near Rudee Inlet, the Currituck, which can dredge up to 3,500 cubic yards of sand a day, is no longer in site. It is on its way back to North Carolina for another dredging job. This vessel, after all, is in great demand.