They are building a 70-foot Frank Gehry-designed sloop at the Brookin Boatyard. (Gehry designed the interior. See the windows, below.) Hulls that size are always built upside down, and at a certain point in the process they are flipped. Flipping a big boat is always a social event here in Brooklin, and on Friday it seemed half the town was down at the boatyard to watch. Slow motion fun. Launch date is a year from now.