Dennis has got most of it right. The current
J30 Class rules read as follows:
"5.12 Sails
.2 Sails shall be of single-ply woven polyester or nylon sail cloth, except that Genoa #1 may, alternatively, be made of polyester substrate/polyester film laminate and Genoa #3 is not restricted.
Woven polyester is often referred to by trade names including Dacron® and Pentex®. Polyester film is often referred to as Mylar. Other materials such as Kevlar® and Spectra® may be used only in the #3 Genoa #3."
In answer to your questions:
Main: Only Dacron or Pentex which is another form of polyester or Dacron.
#1 Dacron or mylar film
#3 Unlimited
Spinnaker: Only Nylon is legal and includes Airex but not polyester. Things get a little tricky with respect to the weight of the cloth. Several years ago we approved Airex 650. It is a 40 gram or 3/4 oz cloth. I went so far as to review the data from several of their production runs to be sure that this cloth was of sufficient weight. It only comes in red, white and blue so if you see a light chute in any other colors it is probably not legal. Airex 650 only is as low as you can go.
Larry Christy
J30 Measurer
