Which circle is defined by a radius equal to the distance from the anchor to the pelorus or antennas plus the length of the anchor chain released?

Which circle is defined by a radius equal to the distance from the anchor to the pelorus or antennas plus the length of the anchor chain released?

• A. Letting-go circle
• B. Swing circle
• C. Drag circle
• D. Kink

Answer: (C)

When a vessel is anchored, the ship’s position relative to the anchor can sweep out a circle as the rode pays out and the vessel shifts with wind or current. The center of that circle is the anchor on the seabed, and the radius is the sum of two distances: the length of chain released plus the fixed distance from the anchor to a reference point on the vessel, such as the pelorus or an antenna. That offset matters because the reference point you’re watching isn’t located exactly at the anchor, so you must add its distance to the anchor to get the true radius of the circle the vessel traces. This circle is called the drag circle because it represents the boundary of motion when the anchor is dragging along the bottom, with the rode paid out to its maximum extent. It’s a practical way to visualize how far the ship could drift while the anchor’s holding power is being tested or is insufficient. The other terms describe different situations. A swing circle refers to movement around a held anchor when the vessel swings within the rode length; a letting-go circle would apply to a scenario where the anchor is released and the vessel drifts away; and a kink isn’t a term that fits this nautical geometry.

When a vessel is anchored, the ship’s position relative to the anchor can sweep out a circle as the rode pays out and the vessel shifts with wind or current. The center of that circle is the anchor on the seabed, and the radius is the sum of two distances: the length of chain released plus the fixed distance from the anchor to a reference point on the vessel, such as the pelorus or an antenna. That offset matters because the reference point you’re watching isn’t located exactly at the anchor, so you must add its distance to the anchor to get the true radius of the circle the vessel traces.

This circle is called the drag circle because it represents the boundary of motion when the anchor is dragging along the bottom, with the rode paid out to its maximum extent. It’s a practical way to visualize how far the ship could drift while the anchor’s holding power is being tested or is insufficient.

The other terms describe different situations. A swing circle refers to movement around a held anchor when the vessel swings within the rode length; a letting-go circle would apply to a scenario where the anchor is released and the vessel drifts away; and a kink isn’t a term that fits this nautical geometry.