Vectored Thrust

above image is of a Sprint F3 boat from HobbyKing (link)

The “Vectored thrust” feature improves steering control for boats and hovercraft that use a steering servo to aim the motor. This feature should not be used on cars or boats with a rudder that is controlled separately from the motors.

The feature is enabled by setting MOT_VEC_ANGLEMAX to the angle of deflection of the motor when the steering servo is at its maximum position.