Using a Hand-Bearing Compass

Choose conspicuous charted objects with useful crossing angles, identify each before reading, and stand clear of speakers, phones, steel rigging, wiring and the steering compass. Hold the instrument as designed, let the card settle, read without parallax and repeat doubtful observations.

Record target, magnetic bearing and time. Convert to true if plotting on the chart, then draw the reciprocal from the object towards the vessel. Bearings taken while the vessel moves should be obtained quickly or advanced to a common time when the required accuracy justifies it.

Three lines that do not meet form a cocked hat, but the vessel is not guaranteed to be inside it. Random observation errors may surround the position; shared errors—wrong variation, compass interference, misidentified object or plotting bias—can displace every line in the same direction. Use depth, position, additional lines and safe-side judgement rather than treating the triangle centre as truth.