Wheel effect

The sideways push of a rotating propeller, especially noticeable when it first begins to turn or when its speed increases. If the propeller is ‘right-handed’ (turning clockwise when viewed from astern) it will tend to take the stern to the right (starboard). The same propeller when running in reverse will tend to take the stern to port. The effect is as if the propeller were a wheel, though with a very poor grip, and it is easy to picture the direction in which the wheel would run.