On a magnetic compass, the fixed line used for directional reference is called what?

On a magnetic compass, the fixed line used for directional reference is called what?

• A. Lubber line
• B. North line
• C. Bearing line
• D. Card line

Answer: (A)

The line that stays fixed on a magnetic compass for reading direction is the lubber line. It’s attached to the compass housing and is aligned with the vessel’s fore-and-aft axis, so it provides a consistent reference point as the compass card rotates to show magnetic north. When you read a bearing, you look at the number on the rotating card that lines up with the lubber line—the bearing is the direction relative to that fixed reference. This setup lets you relate the ship’s direction to the compass reading accurately. Other terms aren’t standard for this fixed reference on a marine compass, which is why they aren’t used in practice.

The line that stays fixed on a magnetic compass for reading direction is the lubber line. It’s attached to the compass housing and is aligned with the vessel’s fore-and-aft axis, so it provides a consistent reference point as the compass card rotates to show magnetic north. When you read a bearing, you look at the number on the rotating card that lines up with the lubber line—the bearing is the direction relative to that fixed reference. This setup lets you relate the ship’s direction to the compass reading accurately.

Other terms aren’t standard for this fixed reference on a marine compass, which is why they aren’t used in practice.