Hi Nick

At the weekend I pulled the battens out a foot or so from my Irwin main, stretched the luff out and ran a straight line from the corners. I measured 165 mm at the furthest point from the back of the bolt rope. This wasn't measured under laboratory conditions so allow plus or minus 10-15mm for a sailmaker-quality measurement.

I believe the luff round on this sail is typical of most of the Mosquito sails in use in Aus.

Here's luff round in action on a Goodall radial ----


Any hope of a photo of the square top?