December 18, 2018 – Associated Underwater Services, Inc. (AUS) recently was hired to remove a 16-foot diameter, domed, bulkhead in support of the construction for the Lake Mead Intake Number 3, Low Level Pumping Station. The bulkhead had 120 – 3-7/8 nuts that needed to be removed in over 500 feet of water. Options to remove the bulkhead were saturation diving and or utilizing a ROV with a tooling package. Saturation diving was estimated to be too expensive when compared to the available budget so AUS designed and engineered, in collaboration with another underwater firm, a tooling package to spin the nuts off with a simple off the shelf Stanley IW16 hydraulic impact powered from an 8 gpm mini Stanly hydraulic power unit. The tooling package was connected to a Mohican ROV submersible skid. During trial testing the tooling package and ROV worked better than expected. In the event the nuts would not come off, were seized and or rusted on AUS planned to utilize a dual action, 10,000 psi, Enerpac nut splitter to break the 3-7/8 inch nuts in halves. A separate tooling package was designed and engineered for the nut splitter. Once in the field the hydraulic impact successfully removed all the nuts without having to split a single nut. The bulkhead, rigged to a 150 ton crane was slid off the bolts and successfully lifted out of the shaft. The bolts were pushed out of the flange and were allowed to fall to the floor where they were captured in a specially designed net. With the bulkhead removed the net was lifted to the surface with all the nuts and bolts. Operations were scheduled for a total of 15 – 12 hour shifts and the bulkhead with all nuts were successfully removed in less than 4 -12 hour shifts, well under budget. For more information about this and other success stories please call Associated Underwater Services. Experience – Technology and Innovation.