Nick,

A set of raked spreaders would definitely help avoid an inverted mast. <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />

Raked spreaders induce prebend since the force is applied towards the rear vertical edge of the mast. If your mainsail is a little fuller than desired it would also help flatten the sail and open the leech.

An inverted mast creates a fuller sail but tightens the leech making the yacht very powerful but also choking the airflow and dramatically reducing forward speed. <img src="http://www.catsailor.com/forums/images/graemlins/crazy.gif" alt="" />

Regards,

Peter