The next major step was setting up the frames on the strongback. I decided to start with frame B: it’s light, simple, and sits roughly in the middle of the structure, which makes it a good reference point for everything that follows. All frames on the strongback Looking back, there’s one thing I should have done earlier when building the frames: marking both the centerline and the waterline on each one. The centerline is relatively easy to establish after the fact, but the waterline can be tricky on some frames. Fortunately, I later found a reliable way to work around this using the laser level, which I’ll describe below. Marking the center line The yard owner kindly lent me a few wooden boards to use as vertical posts for holding the frames. My method for fixing these posts was systematic. First, I clamped the board in place and used a level to get it perfectly vertical. Then I pre-drilled and fastened a first screw. After removing the clamp, I rechecked the vertical alignment; the si...