Lifting the AC72

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Sorry it’s taken so long to get the final stage of the installation of the AC72 written, but the final days of the Speed and Innovation installation and the opening events took up a lot of time!

The morning of the lift. The cradles and platforms are ready for placement.
Worshipping the foils?

The goal was to lift the platform about 8′ and place it on columns so the exhibition could be installed underneath. Obviously we didn’t have the luxury of hanging the platform from an overhead crane like Oracle did; we had to lift the platform from underneath. One of the problems we had to work through was identifying the best lifting points. We were pretty sure we could lift at the forward crossbeam using the same lifting points Oracle used. We knew it was the prime lifting point because of photographs showing Oracle’s lifts and because there were removable plates mounted on the underside of the crossbeam that had lifting straps attached to them. We had a quick discussion with Hampton Roads Crane and Rigging and they decided we could position two forklifts under those lifting points.

Placing the cradle under the starboard hull.
I love this picture. Jim looks like he’s conducting and orchestra.

Picking up the stern was a little more problematic.  We knew we didn’t want to lift from two points because maintaining a stable four-point lift would be impossible. We were also concerned that any significant twist of the platform might cause unwanted stress or damage.  We needed to identify a single location to perform the lift–the one spot that was the strongest that also wouldn’t put too much stress on the platform.

The platforms had to be perfectly placed to support the cradles and boat.

We picked out a couple of spots and I called Chris Sitzenstock, the former Oracle shore team member who gave us periodic advice through the assembly process, to discuss our options.  After talking to Chris, we decided to lift from the center of the stern crossbeam where it attached to the central pod.  This was a particularly strong position for several reasons: there were at least thirty titanium bolts holding the two pieces together; there were thicker layers of carbon fiber where the hardware was seated; and a couple of “ribs” to either side of the connection point on the inside of the stern crossbeam would provide additional strength where the lifting strap would be located.  We just had to cross our fingers that the two main connection points between the stern crossbeam and hulls could support the platform for the short duration of the lift.  We were confident this wouldn’t be a problem since Oracle’s chosen lifting point on the forward crossbeam would create a similar situation—if they weren’t concerned about undo stress at the main connection points forward, then the same situation aft shouldn’t cause a problem.  HRCR decided to use a small carrydeck crane to lift platform from overhead.

Success!

Overall, the lift went very smoothly with the only complaining noises coming from the daggerboards.  In the video below the three fade outs are the times we had to stop and deal with the stabilization of one or both of the daggerboards. You’ll notice by the end of the video that the daggerboards are hanging from the ceiling by ratchet straps. This allowed them to freely move through the hulls as the lift proceeded.