Did someone catch the explanation for why the rattleback reversed ? Interesting & articulate presentation by the proffessor.

Looks to me like there should not be any diffence in torque [if considered in isolation] when the turtles were opposed at right angles to the lever/boat ?

Unless the direction the turtles face, in relation to the spin direction, causes asymmetric drag [like a helicopter advancing & retreating blade] when combined with the down-lift generated by the boats hull. This could cause the rocking motion, if there were any sort of relative air flow ?

That is, changing kinetic energy of induced torque [horizontal rotational KE] put into the system into a vertical component of KE i.e. rocking instability, by the aerodynamic forces ? The toy then takes the path of least resistance as it tries to stabilize its angular velocity [wobble] & reverses direction ? Just thoughts 

Edit : Nahh - not likely there was any breeze around it so it must be a theory related to the detabilization & reversing of the magnetic poles ?

vortex energy.