It is a describtion that Greg Goodall used when I asked him about spreader rake. Apparently the angle of the spreaders determine how much the prebend chance during a gust. More rake and the prebend changes more and less rake then the prebend changes less. This seems to be linked to accelleration of the boat. If she doesn;t accellerate to much or not at all during gusts, but seems happy to lift then it is adviced to increase spreader rake. Or at least that is the advice for boat using the Superwing mast section.

Wouter