The mast drag depends on the local inflow angle of attack. At very shy angles, the stagnation point sets on the front side of the mast, and the mast reduces the total drive. As the angle of attack increases, the stagnation point moves onto windward, flow is accelerated around the front side of the mast and the mast starts to develop positive drive.

For a fractional rig, the airflow is deflected towards the top more than in a masthead rig, inceasing the efficiency of the mast. Most of the positive drive from the mast comes from the part above the hounds.