Current triangle set and drift Practice Questions

1. In a current triangle, what does 'set' refer to?

• A.The direction toward which the current flows, expressed in degrees true✓
• B.The speed of the current in knots
• C.The difference between course made good and course through the water
• D.The distance traveled by the vessel over the ground

Why: Set is the direction toward which a current flows, expressed in degrees true. It is distinct from drift, which is the speed of the current in knots.

2. In a current triangle, what does 'drift' refer to?

• A.The direction the current flows relative to true north
• B.The angular difference between heading and course made good
• C.The speed of the current expressed in knots✓
• D.The lateral displacement caused by wind and current combined

Why: Drift is the speed of the current expressed in knots. Together with set (direction), drift fully describes a current vector used in current triangle construction.

3. The drift of a current is 2 knots and acts for 3 hours. What is the displacement vector used in the current triangle?

• A.2 nautical miles in the direction of set
• B.3 nautical miles in the direction of set
• C.6 nautical miles in the direction of set✓
• D.5 nautical miles in the direction of set

Why: Distance equals speed multiplied by time: 2 knots × 3 hours = 6 nautical miles. The current vector plotted in the triangle has a length of 6 miles in the direction of the set.

4. The current triangle is also known by which other term in celestial and coastal navigation?

• A.The velocity parallelogram
• B.The current sailing diagram or vector triangle✓
• C.The course correction rhumb triangle
• D.The deviation correction diagram

Why: The current triangle is also called the current sailing diagram or vector triangle. It graphically represents the three velocity vectors: vessel through water, current, and vessel over ground.

5. Tidal current tables list the set of a current as 315°T and drift as 1.8 knots. A vessel heading 045°T at 6 knots STW will experience what general effect on its track?

• A.The current will push the vessel to the right (south) of its intended track
• B.The current will push the vessel to the left (northwest) of its intended track✓
• C.The current will accelerate the vessel directly along its 045°T heading
• D.The current has no lateral effect because it is not at 90° to the heading

Why: A current setting 315°T (northwest) will push a vessel heading 045°T (northeast) to its left — toward the northwest — deflecting the track counterclockwise from the intended CMG. Any current not directly ahead or astern produces lateral drift.