Definition
A position line remains valid only at the instant of observation. To combine it with a later observation, every point on it is advanced parallel to itself through the course and distance made good, including tidal set and leeway, over the intervening time. Plotted with a double arrowhead and labelled with the original and transferred times, it underlies the running fix and the celestial sun-run-sun. The transfer inherits all the uncertainty of the estimated run.
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