The E.W. Ellefsen cutterhead dredge currently pumping sand from Masonboro Inlet onto the south end of Wrightsville Beach operates 24 hours per day.
The Weeks Marine 277.5-foot dredge can dig 70 feet deep, but usually operates about 30-35 feet underground. Capable of operating at 13,360 total horsepower, the dredge was only using one of four locomotive engines to operate at about 3,500 horsepower during a Friday, April 25 media tour of the dredge that showed the work in action.
About 35 employees work on the dredge in two shifts. Captains work three weeks on and three weeks off.
Captain Jack Dunbar, who took several breaks from interviews to take phone calls during the duration of the tour, has been a captain for six years and has been working on dredges for 34 years.
In the control room on top of the dredge, also referred to as the libre room, operator John Soileau was surrounded by five monitors to run gauges and control the swinging of the cables and angle of the ladder.
“The dredge is kind of like a vacuum,” Soileau said, adding that it normally operates at about 18 feet per second.
With all of the advances in technology, Rolando Serrano, project engineer with the U.S. Army Corps of Engineers, said everything is in real time. The technological changes have been gradual, he added.
The E.W. Ellefsen is the upper limit of size for dredges, but Serrano said they all work on the same principle.
Underneath the water, the cutterhead shaped like an egg beater chops through the sand, sucking up the mixture that travels through rubber and steel pipes before being placed further north on the shore.
Serrano pointed to a survey map, showing how the sand will be moved from the southern tip of Wrightsville Beach. He said surveys of this size take about one to two days to complete.
As for the equipment, the dredge is costly to maintain, with cables changed an average of every 23 weeks and the ladder changed every three months.
“This dredge is not new, but they keep it in very good condition,” Serrano said.
The total length of sand spread will be 8,500 feet once the project is complete, said Bob Keistler, corps project manager. The Wrightsville Beach portion of the renourishment project totals about $9 million of a $17 million contract with Ocean Isle.
“The mobilization, just to get the dredge to show up, is about $3.5 to $4 million,” Keistler said.
The corps has been trying to coordinate the staging areas keeping working pipes away from bird nests. The environmental window has been extended through May 31.
“We take all environmental issues seriously,” Keistler said. “It’s a balance between impacting turtles, impacting bird habitat versus protecting the dunes.”