ILCA roll sail bag, roll your sail instead of folding to keep it in the best condition possible.
Having a smooth sail shape is one of the keys to going fast in the ILCA. Folding your sail creates creases which will often remain even once the sail is on the mast and rigged up. If you have a racing sail which you would like to keep crease-less, your best bet is to roll the sail on a tube of PVC pipe, and then store it in the sail roll bag. Rolling your sail up on a tube helps ensure that it does not get compressed when travelling or being stored.
Don't let poor storage of your sail get in the way of your boat speed.