Not true Jim
Some sails are designed so that the battens force the sail into shape. Most dramatically on a windsurfer or Hobie cat but can also be seen on some full batten sails. I used to use the batten tensions on my Hobie 16 to power or depower the sail. Same thing with my windsurfers. Some battens are designed to extend the roach of a sail which puts tension on the material that causes a bow. Some battens are even designed with varying thicknesses to make them bow more near the mast.If your sails were flat, they would create no lift. Roger, your battens should be left as loose as possible(or out) when the sail is down. You decide how much bow to put into the sail based on the wind conditions. You want the sail to be flatter in stronger winds thus depowering the sail. Too much bow in these conditions will cause drag and make the boat difficult to balance. In lighter conditions, more bow will provide more lift making you go faster.This sounds like a fairly high performance boat. What is it?Tim R.