By ashleykaren
CBBT’s (the Chesapeake Bay Bridge-Tunnel) Thimble Shoal Tunnel project faced a delay this month. The massive Chessie TBM ran into a big antique ship’s anchor at the bottom of the Chesapeake Bay. This incident has put a complete stop to the tunneling.
According to Deputy Executive Director of Infrastructure at the CBBT, Michael Crist, construction crews conduct surveys of an area before they begin boring and excavating tunnels. Yet, they can’t always find everything.
“Any time you dig in the ground, you will find something,” said Crist. The anchor, which Crist calculated at 10 feet long with flukes 3 or 4 feet long each, was not found in the initial survey. “It was buried under large rocks. We missed it,” he said.
The anchor has the signature of “W.L. Byers Company.” According to Jeanne Willoz-Egnor, Curator of Maritime History and Culture at the Mariner’s Museum in Newport News, “It is difficult to provide more information about the anchor without better photographs and more details.
However, based upon the narrow available information, the anchor is probably from the 20th century, conceivably 1920’s.” Willoz-Egnor remarked that the battleship Missouri ran aground in the Thimble Shoal channel in 1950. A notable number of anchors were deployed in the area to re-float the battleship.
The W. L. Byers Company was well-known for its “stockless” anchor. The stock of an anchor is a bar that sticks out from the central anchor shaft at a separate angle from the flukes. It works to roll the anchor on its side on the seabed, which causes one of the flukes to dig into the sea bottom. Of course, the other fluke sticks up, making a hazard in shallow water. They were hard to store. Stockless anchors worked and were much easier to stow.
Nevertheless, the tunnel excavation project is on break until the anchor can be dismissed. “We don’t know if there is any damage to the cutters,” said Crist. “We won’t know until we get crews down to clear the area and assess the situation.” He said it would probably be December before they would have more answers. Crist mentioned that even though the tunneling is halted, there is still plenty of work to do.
The $756 million project intends to construct a second parallel tunnel between the first and second islands of the bridge-tunnel complex. The new tube will be a mile long and will carry two lanes of traffic southbound, while the current one will change from two directions to two northbound lanes.
Chessie, the German-made tunnel boring machine, has a 43-foot diameter head. The tunnel tube is constructed behind the head, as the TBM moves slowly forward. A massive conveyor belt system carries material from the tunnel to trucks for haul-off.
The tunneling is approximately 13 percent complete, and it is now supposed that the project will not be finished until 2027. “We will keep at it,” said Crist.
