When backing, the discharge current strikes the hull high on the starboard side and low on the port side. This interaction tends to move the stern toward which direction?

When backing, the discharge current strikes the hull high on the starboard side and low on the port side. This interaction tends to move the stern toward which direction?

• A. Starboard
• B. Port
• C. Bow
• D. Stern

Answer: (B)

This question hinges on the sideways force produced when electrical current in the hull interacts with Earth's magnetic field. When backing, the discharge current path goes from a high point on the starboard side to a low point on the port side. A current in a magnetic field experiences a force perpendicular to both the current direction and the magnetic field (the Lorentz force). The geometry of this path causes that sideways force to push the stern toward the port side. So the stern tends to yaw left, toward port.

This question hinges on the sideways force produced when electrical current in the hull interacts with Earth's magnetic field. When backing, the discharge current path goes from a high point on the starboard side to a low point on the port side. A current in a magnetic field experiences a force perpendicular to both the current direction and the magnetic field (the Lorentz force). The geometry of this path causes that sideways force to push the stern toward the port side. So the stern tends to yaw left, toward port.