Hydraulic Grab Aids Key Bridge Cleanup Efforts

The last week of April marked a month since the collapse of Baltimore’s Francis Scott Key Bridge into the Patapsco River when container ship Dali took down one of its key support columns. The week also marked the delivery of a HSWC500-1000 hydraulic salvage grab to aid in the ongoing cleanup effort.

The grabber is comprised of two hydraulic claws and is nicknamed “Gus.” It weighs 165 tons, and when hooked onto the Chesapeake 1000 crane being used in the cleanup, the unit has a combined lift capacity of 1,000 tons. Manufactured by The Grab Specialist, the grab was delivered to Sparrows Point from its previous home in Galveston, Texas.

The hydraulic grab was built in 2015 and used by the global salvage firm Ardent to clear wreckage from the Troll Solution, a jack-up offshore oil rig that collapsed in 2015. In 2019, it was used after the capsizing of the MV Golden Ray—a 660-foot roll-on/roll-off cargo ship that carried motor vehicles—in St. Simons Sound in Georgia.

According to the manufacturer’s website, the grab is specially designed for handling shipwreck material and can be deployed with two or four tines depending on the size of the materials being handled. In its configuration of four tines (two claws) at Sparrow’s Point, it stands at 24 feet tall when open, 28 feet when closed, and has an opening width of 22 to 29 feet.

The Key Bridge Response Unified Command—consisting of the U.S. Coast Guard, U.S. Army Corps of Engineers, Maryland Department of Transportation, Maryland Transportation Authority, Witt O’Brien’s representing Synergy Marine, and the Maryland State Police—says it chose the grab based on its size and grab capacity.

“The grab was chosen because it is the largest in the U.S.,” says Erin Cox, U.S. Coast Guard Marine Science Technician 3rd Class (MST3) Petty Officer, stationed on the Key Bridge site. “It matches perfectly with the Chesapeake 1000 [crane].”

The grab has lifted sections of the bridge weighing as much as 500 tons as salvage operations start to pivot toward clearing debris from the harbor’s 50-foot main channel.

Army Corps of Engineers officials estimate another 50,000 tons of debris need to be moved.

“The grab is a precision grab,” says Cox. “Based on survey data that we have, the boom goes to the exact point that we want it to, then the grab is deployed.

“Gus has a 5-minute cycle between its open position and closed position. Salvage is a methodical operation, sometimes tedious,” she says. “It's sort of a ‘measure 10 times, cut once’ type of operation. This ties directly back to safety. The Unified Command’s top priorities include the safety of responders and the public as we continue working to reopen the channel.”

In addition to the work the grabber is doing to clear the ship wreckage, it also has other applications, according to Cox.

“The grab has helped to remove bridge pieces and road debris from the river,” she says. “But it has also been used to crush material, so that it is easier for other cranes and ‘clamshells’ to come along and grab those pieces when they’re smaller. The contractors [on site] that I spoke with likened this process to the crushing of cans.”

Once the ship wreckage is completely removed, the grab will be used to move parts of the bridge to widen the channel and increase the flow of commerce. The crane will be outfitted with a GPS transponder to calculate where to “fix and grab” pieces of the debris that remain on the seabed.

In the meantime, a third temporary channel has opened for additional vessel traffic. The Fort Carroll Temporary Alternate Channel has a controlling depth of 20 feet, a 300-foot horizontal clearance, and a vertical clearance of 135 feet, and will facilitate additional commercially essential vessel traffic through the port of Baltimore.

With more equipment on site, officials say they are on track in the process.

“We do not expect the grab to accelerate the current timeline for cleanup,” says Cox. “The use of the grab has been part of the plan, and we are pleased to say that we are on track.”

The Unified Command hopes to fully reopen the Port of Baltimore by the end of May.