While on tow, late in 2012, the Larvik Rock barge capsized off the English coast. This barge is used for transporting rock for civil engineering applications and is unusually large, with a length overall of 122 meters and a beam of 36.6 meters. While still upside down the Larvik Rock was towed to the Port of Rotterdam, the Netherlands and moored at the Mammoet Heavy Lift Terminal in Schiedam. To upright the barge Mammoet Salvage developed a plan to “parbuckle” it with sheerlegs while keeping most of the barge underwater. This reduces the required capacity of the sheerlegs and therefore the cost to the client. When preparing the project Mammoet Salvage was supported by the marine engineers of Mammoet Solutions.
On Thursday 28 March the Larvik Rock was towed to a part of the Calandkanaal where the water depth was sufficient for the operation. The barge was then moored and ballasted. Mammoet provided the Jumbo dive support vessel and the Wieringer pontoon carrying the required pumps and compressors. The salvage crew started by flooding starboard ballast tanks of the Larvik Rock, which continued through the night.
On Friday 29 March the Matador sheerlegs (floating crane) arrived on site and connected to the Larvik Rock’s pre-assembled rigging. Saturday morning the sheerlegs started lifting while some of the barge’s ballast tanks were emptied with compressed air. Once it was turned 90 degrees divers closed the bottom valves of the barge. The manholes were then opened and pumps were lowered into the tanks. The tanks were pumped out during the night and on Sunday the sheerlegs released the Larvik Rock once it was free-floating. Finally, the pumps were used to adjust the barge’s trim and heel after which it was towed back to the Mammoet Heavy Lift Terminal.