In navigation, how is drift defined?

• A. The speed of drift expressed in knots
• B. The direction of drift expressed in true bearing
• C. The change in position of a search object over time
• D. The distance traveled by the search object

Answer: (A)

Drift is the motion of a search object as it is carried by environmental forces like currents and wind. The quantity you use to describe how fast that motion is happening is the drift speed, and in navigation it’s expressed in knots. The direction of that drift is described separately as a bearing. So the defining quantity is the rate at which the object moves due to drift, not just the direction or the total distance traveled. For example, a raft might drift at 3 knots along a bearing of 045 degrees; the speed (3 knots) tells you how quickly its position changes, while 045 degrees tells you the direction.