Project Detail

Amethyst Semi-submersible Drilling Rigs

Portland, ME

“These two rigs are every bit as good as those built in Korea, by one of the premier shipyards in the world.”

Derek Leach Project Director Petrodrill

Scope of Work

Cianbro constructed two, 12,000-ton, offshore, semi-submersible, oil drilling vessels.

Project Details

  • Transported drilling rig components via barge and tow from the Gulf of Mexico to Casco Bay, Maine
  • Aligned and welded the 5,500-ton deck box of each rig onto four columns that were sitting on a pair of pontoons
  • Installed mechanical equipment and associated piping
  • Installed electrical cabling, instrumentation, and associated equipment
  • Performed structural work
  • Installed all control and propulsion systems
  • Completed mechanical installation and pre-commissioning of the drilling equipment
  • Tested and commissioned all on-board systems and drilling equipment
  • Applied corrosion prevention coating
  • Outfitted living quarters for a 115-person crew
  • Conducted sea trials during the commissioning phase

Lean, Innovative, and Unique Project Solutions

As the first U.S. company to employ the “floatover” mating process, the Cianbro team submerged the pontoons while moving and aligning the 5,500-ton deck box onto the columns to successfully complete the mating phase of construction. Cianbro self-performed all core competencies to complete the final phase of this fast-track project.


ACM Build Maine Award
Project Management Institute - Maine Chapter Project of Distinction