Heeling error is defined as the change of deviation for a heel of __________.

Correct Answer: Option A — 1°While the vessel is on a compass heading of 000°

Heeling error is the deviation caused by the vessel's tilt, which changes the magnetic influence of the vertical soft iron and permanent magnets. By definition, it is measured as the change in deviation for a 1-degree heel when the vessel is on a heading of 000° or 180°.