For what it's worth, in PHRF Narragansett Bay
, there is no change in rating due to sail cloth, only for sail size. I asked this question for both the main and spinnaker. I bought a 1/2 oz spinnaker that is the same size as the class spinnaker. It works great in light air. In PHRF-NB
area there is no reason to make the 1/2 oz spinnaker OD class legal.