How many methods are used for swinging a compass?

• A. 2
• B. 3
• C. 4
• D. 5

Answer: (B)

Swinging a compass involves gathering and verifying deviation data from multiple independent observations so the compass can be corrected accurately. In standard practice, three distinct methods are used to obtain a reliable set of readings: the direct method (taking bearings to fixed references while the ship is on known headings), the reciprocal or opposite-heading method (taking the same observations on the opposite course to check for consistency and reveal any changing interference), and a cross-check method (using additional references such as shore landmarks or parallel indexing to confirm results). Using these three approaches covers different points on the compass and different environmental influences, giving a solid, verifiable deviation correction. That’s why three methods are considered the typical number for swinging a compass.