Plenty strong for a spinnaker. A 20 did the Worrell with mast head chute years ago in the roughest year. They used some running backstays I think.

The issue with the 20 hulls failing along the glue seam in the mid 90's was corrected and has not been a problem since. That was a post/hand finishing problem. The finising guys were sanding through the layup trying to fair out the seam because the glue jigs were mis-aligned.