Back in April a 112-foot barge mounted with a crane and christened with the disquieting name Vengeance capsized and sank in the bay, coming to rest on top of the Transbay Tube.
Now, roughly four weeks later, the U.S. Coast Guard says it’s turned the capsized vessel back upright. But it will take “anywhere from a week or two” to get it to the surface and towed away, according to spokesperson Cory Mendenhall.
“The final procedure is still in the works,” Mendenhall told Curbed SF. “They flipped it over [rightside up] but it’s still resting on the bottom.”
Those crossing the bay may see a similar looking vessel with a large green crane in the general area of the sunken barge. The Coast Guard says this is the Mare Island, there to assist with the salvage of the Vengeance.
Mendenhall says that turning the ship over has moved it from its original position but that it’s still “sitting very near” the BART tube.
BART spokesperson Alicia Trost told Curbed SF that there’s still no evident danger to the tube, which is buried under 30 feet of soil and “designed for such things.”
The Vengeance apparently sank as a result of the same April storm that collapsed part of a hillside in Oakland and evacuated several homes. Nobody was onboard. Divers plugged its leaky fuel tanks shortly after it came to rest.
Salvagers flipped the submerged ship via a maneuver called a parbuckle. Business Insider reported on the parbuckling of a shipwrecked cruiseliner off of Italy in 2013:
It involves building a ramp between the two heights, looping a rope under the object and rolling it up the ramp, which is far easier than lifting a heavy object vertically.
Parbuckling been used to salvage large ships since as far back as 1943, when the 35,000-tonne USS Oklahoma was righted in Pearl Harbor. [...] A ship isn’t exactly a cylinder so parbuckle salvage is more about rotating it into the right position than rolling a wreck up a ramp. [...]
Parbuckling is risky because it involves exerting a diagonal force on the ship. If wreck slides sideways instead of rotating, it may not be possible to return the ship into a position where it can be levered upright.
The Vengeance parbuckle seemingly came off without a hitch, but was only the first part of the two-step process of getting it out of there.
- Sunken Barge Settles Atop BART Tube [CBS SF]
- How Parbuckling Works [Business Insider]
- Vengeance Now Upright [Reddit]
- Storm Collapses Hillside [Curbed SF]
- Barge Righting Operation [Coast Guard]