Resolve Marine Group has released some details on how it successfully raised and refloated the "Machinist" dry dock at Guam Shipyard in Apra Harbor, Guam.
The 825 ft floating dry dock sank on January 2, 2011 during a rough weather event. Resolve - whose prior experience includes raising dry docks-- was the successful bidder for the salvage job. Resolve began the salvage on January 31 and successfully refloated the dry dock on March 3.
Resolve's salvage master, salvage engineer, and salvage divers first conducted a comprehensive casualty assessment to determine the structural and watertight conditions of the dry dock and to assess the status of dry dock systems.
A detailed engineering analysis was undertaken and a salvage plan was developed and implemented, involving extensive preparatory work both topside and underwater.
The dry dock was submerged at a depth beyond normal operating limits, so great care was taken to minimize hydrostatic pressures on tank boundaries during the refloating, and to keep global hull stresses and stability within allowable limits. The U.S. Coast Guard and U.S. Navy reviewed and approved the complex salvage plan.
Due to the extensive maintenance being performed on the dry dock prior to sinking, a large portion of its pumping system was inoperable. To overcome this challenge, Resolve mobilized 12 high-capacity electric salvage pumps. Additionally, numerous gauging systems were established to monitor tank pressures and condition throughout the refloating operation.
"Large sunken dry docks are notorious for testing your skill and tenacity, and this was no exception," said Resolve Salvage Master Todd Schauer. "We were fortunate to have the support of an outstanding team including our client Guam Shipyard, as well as Heger Drydock and Mako Diving.
March 24, 2011