We were down this past December during a BIG north swell (wind was also out of the North, like STRAIGHT North, the entire week). Anyway, we spent a night at Cooper during the peak of that Swell on a Catamaran. I would say that the south end of the mooring field would have been less than pleasant- rolly and wind-piled. However, the balls that are tucked in under the point on the north side of the field were not bad at all. The mooring field was pretty empty that night, but those northern moorings were ok. NOT GREAT. But ok. Again, on a Cat.