Yep, that wingmast can generate quite alot of power on its own. Remember that their is 1.5 sq. mtr. of area in the mast and it is a (symmetrical) WING shape. Almost like a helicopter rotor blade.

I always secure my mast rotation in addition to tying the boat down. If I don't then the mast will go look for angle with the optimal power ratio and shake my boat about. With a secured mast rotation the chance are that the angle it wrong and a stalled flow goes across the mast reducing the force generated.

Lets face it guys these boats just want to FLY !

Wouter