Step 8: Sewing the fortification for the spine and stand-offs
1. Turn the sail with the front side up and sew the seam of the two sail halves with a three steps zigzag seam.
2. Turn the sail with the back side up and sew the Mylar/Rip stop at 1 to 1,5mm from the border with a straight seam. Repeat this for the other side of the fortification.

3. Sew the fortification for the stand-offs at 1 to 1,5mm from the border with a straight seam.

EXTRA: Tune the seam distance between two holes to be 3 mm, to get a nice result.