Mounting the stern crossbeam
Friday, May 19th, 2017 at 6:57 am
I’ve been waylaid by the cleaning and repair of the Baker hydrofoil rigid wing sail but I think it’s time to relate how we mounted the stern crossbeam. You might remember that when the Oracle team assembled the AC72 platform they connected the three central structures and then lowered them as a unit onto the hull and that we couldn’t do this because of a ceiling height and possible weight restriction. Because of the shape of the crossbeam and where it needed to go—seated on the hulls and tucked inside the end of the central pod—we knew we needed more clearance over the hulls than we had available.
Maneuvering the stern crossbeam. Notice the forward crossbeam is lifted and the aft of the central pod is raised to provide enough space to tuck the crossbeam into position.
Since we had to pick up the stern crossbeam and move it about ten feet to get it into position we used our gantries. This meant having to disassemble them afterwards but using chain falls severely hampered our maneuverability. We lifted the crossbeam and moved it as close as possible to its final seated position. At that point I crawled into the hulls and loosened the bolts at each end of the forward crossbeam. This allowed us to lift the aft end of the central pod about a foot or two and the forward crossbeam about six inches (we didn’t want to raise it too far because we didn’t want the hulls shift position and misalign the connection points). Then, with five people working together (two operating chain falls on the forward crossbeam, one on the chain fall at the aft end of the central pod and two on the gantry chain falls) we slowly tucked the crossbeam into the back of the central pod and gently lowered all three pieces onto the hulls.
We had to put a little pressure on the central pod to pull it towards the port hull so the connection points would align.
Sitting inside the port hull under the connection point of the stern crossbeam installing hardware.
The process went flawlessly and except for having to rig up a way to put a little pressure on the central pod (to pull it towards the port hull) we had to do very little maneuvering to get all of the connection points to line up. I then reinstalled the hardware in the forward crossbeam and installed the new hardware at the point where the stern crossbeam connected to the hulls. I also installed the bolts that connected the forward crossbeam to the hulls at the daggerboard wells. Next up, installing the hardware at the connection point between the central pod and stern crossbeam—which was an interesting experience as long as the person doing it isn’t claustrophobic (thankfully I’m not)!
Done! Notice Lyles in the background giving a celebratory cheer!
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