I noticed that my mainsail curves too much. The leach curves in a lot and it is hard to get the tell tails to fly properly. It is a Doyle stack pack, which is fully battened. I think the problem is... There are no battens in there. There are spaces for 4 battens. Anyone know what kind of battens go in there? Can I buy some kind that I can cut to size? I'm assuming that this will help straighten out the mainsail.
Second question, the bottom of the mainsail opens up when wind goes through at the proper angle. The best example I can think of to explain this is cells in a skydivers parachute.
It can be helped closed somewhat with some Velcro. What is the purpose of this? Is it just to help stiffen up the sail while pointing close into the wind?