The lubbers line serves what purpose on a compass?

• A. It Measures the Depth of Water
• B. It Shows Wind Direction
• C. It Indicates the Ship's Heading on the Compass Card
• D. It Shows Current Speed

Answer: (C)

The lubber’s line is the fixed reference on the compass card that shows the direction the vessel is pointing—the ship’s heading. When you read the compass, you align the ship’s bow with this line, and the corresponding mark on the compass rose gives you the heading relative to magnetic or true north, depending on the instrument. It’s a reading aid for heading, not a measure of depth, wind direction, or current speed.