These strips of Duct Tape go from one side support under the center support around the opposite side support and back across the center support to the original side support so that the adhesive is touching adhesive. These should be spaced out every 6-8 inches in between the intersections.
It is important that the ribs are not taunt. They should have a little bit of slack because when you lay down the side supports will move to the sides. Otherwise they would be help to close to the center support and the Hammock would not be wide enough.