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Weeks Marine suction dredge vital to restoring Louisiana’s coastline

Jul 25, 2013 10:44 AM
Cutter suction dredge C.R. McCaskill adjusts an intake pipe during a wetlands restoration project on the Mississippi River near Head of Passes.

Cutter suction dredge C.R. McCaskill adjusts an intake pipe during a wetlands restoration project on the Mississippi River near Head of Passes.

On a drizzly Gulf Coast morning in March, the Weeks Marine cutter suction dredge C.R. McCaskill was pumping a thick mud sludge of dredge spoil through a 30-inch diameter pipe at 400 psi on a six-mile journey into Louisiana’s marshland. It took the mud 25 minutes to reach its destination.

“The project is called a Beneficial Use Project,” said the project manager, Brett Dupuis. Working just north of Head of Passes at the mouth of the Mississippi River, the dredge was re-working a dredge disposal area and sending the material into the marsh to make peninsulas for marsh creation. “The fingers grow vegetation to hold the material in and the marsh fills in between the fingers,” said Dupuis.

In the past quarter-century, Louisiana wetlands have drowned at the rate of one football field an hour according to a recent survey by the U.S. Geological Survey. That adds up to 16.57 square miles per year of prime hurricane protection and wildlife habitat. Perhaps if we played football in the marsh, there would be more public uproar. However, the new Weeks Marine 293-foot dredge was designed and constructed to move massive amounts of material quickly in order to build barrier berms and to restore lost marshland.

A mud ball forms as a result of disgorging six miles of 30-inch pipe at the project’s disposal site.


Charlie McCaskill, the dredge’s namesake and the company’s dredging division technical and equipment manager, began his dredging career in 1976. McCaskill migrated to Weeks Marine when the New Jersey-based company acquired the Louisiana-based dredging company T.L. James. “This is the most modern cutter suction dredge in the country with Tier 2 engines and fully automated controls,” said McCaskill. “I’ve never seen a new vessel start up with such ease. Especially one with such complexity.”

C.R. McCaskill was constructed in Louisiana at the Weeks Marine Houma Repair Facility from modules fabricated and purchased from companies throughout the U.S.

The hull and forward superstructure were manufactured by Corn Island Shipyard in Lamar, Ind. The custom-built switchgear and power distribution equipment were supplied by Avid Controls of Cypress, Texas. At the working end, the A-frame, cutter ladder, ladder hoist, cutter, underwater pump, pump motor and swing winches were fabricated by SPI/Mobile Pulley Works of Mobile, Ala. GIW and Mobile Pulley Works supplied the dredge pumps.

“Each pump has a custom-built two-speed gear, built to our specs by Horsburgh & Scott,” said McCaskill. “The two pumps are in line and allow flexibility to pump at maximum pressure and still be able to push with the same horsepower.”

The MP1 and MP2 pumps are powered by two 5,680-hp GE Tier 2 diesels. Three 2,000-hp Tier 2 diesels provide power to operate the cutter, winches, spuds, underwater pump and hotel load.

“The dredge was engineered and built with all of the best available technology in order to impact the environment in the least invasive way,” said McCaskill. One new dredge, high-powered and environmentally friendly as it is, isn’t going to bring back all of those lost football fields, but C.R. McCaskill is a big part of a huge effort to stabilize the wetlands.

“The peninsulas already out there have stood up against Katrina and Rita and other storms,” said Dupuis. “They’re still here, so they’re doing their job.”

Dredge pump No. 1 on the job, moving material to pump No. 2.

The 30-inch pipe wraps around the dredge’s starboard side to connect with the No. 2 pump.

 

 

Chief Engineer Dustin LaGrange with two 5,680-hp GE 16V 250 Tier 2 engines.

C.R. McCaskill oiler John Brown, in training to be a watch engineer, monitors the pumping system.

 

 

Dredge operator Javier Pena enjoys both a panoramic and electronic view of the operation and the river.

 

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