The starboard screw is right-handed and the port screw is ______-handed.

The starboard screw is right-handed and the port screw is ______-handed.

• A. Left
• B. Right
• C. Neutral
• D. Mixed

Answer: (A)

Balancing propeller torque on a twin-screw vessel is the key idea. If the starboard propeller turns to the right-handed direction, it rotates clockwise when viewed from the stern. To counteract that same kind of torque and keep the ship tracking straight, the port propeller must rotate in the opposite direction, i.e., left-handed (counterclockwise when viewed from the stern). This opposite rotation balances the yaw forces and makes steering and handling more predictable, especially under power. So the port screw is left-handed.

Balancing propeller torque on a twin-screw vessel is the key idea. If the starboard propeller turns to the right-handed direction, it rotates clockwise when viewed from the stern. To counteract that same kind of torque and keep the ship tracking straight, the port propeller must rotate in the opposite direction, i.e., left-handed (counterclockwise when viewed from the stern). This opposite rotation balances the yaw forces and makes steering and handling more predictable, especially under power. So the port screw is left-handed.