BDOC Navigation and Seamanship (NSS) Practice Exam 2025 - Free NSS Practice Questions and Study Guide

When an anchor is said to be 'dragging', it means that it has lost its hold on the seabed and is moving with the vessel. This situation is detected when the vessel's position is reported outside of the defined drag circle, which is a radius around the anchor point that accounts for the length of the anchor line and the potential swing of the vessel.

The drag circle is crucial for determining if the anchor is effectively holding the vessel in place. If a fix—meaning a precise position of the vessel—indicates that the vessel is outside of this drag circle, it suggests that the anchor is no longer providing a secure hold, thus confirming that it is dragging.

In contrast, an anchor confined to its designated area indicates that it is holding within expected limits. A fix cannot be established may suggest issues with navigation or positioning equipment, which doesn’t necessarily indicate that the anchor is dragging. An anchor being completely submerged doesn’t provide direct evidence of its effectiveness as it can be submerged and still be holding well. Therefore, observing the vessel outside of the drag circle is a clear indicator of dragging.