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A-Frame Job

January 20, 2018

The research vessel Atlantis is a sophisticated, general-purpose platform in its own right, but it is also specially outfitted to be the support vessel for the submersible Alvin. From 2011 to 2013, Alvin underwent a complete upgrade to significantly enhance its capabilities, which had implications for Atlantis. The new sub is slightly larger and heavier, which meant an upgrade for Atlantis’s A-frame—the structure used to launch and recover the sub. During a shipyard period in 2013, the A-frame was strain tested by gradually increasing weights attached to a yellow spreader bar on the main lift line. For safety reasons, it was tested up to 100,000 pounds—about twice the weight of the sub. (Photo by Dutch Wegman, Woods Hole Oceanographic Institution)