PRACTICAL SAILING FORMULAS FOR RHUMB-LINE TRACKS ON AN OBLATE EARTH

George H. Kaplan

Peer Reviewed

Abstract:	Although the mathematical basis for rhumb lines on the ellipsoidal earth is well known, the earth’s oblateness is usually neglected in dead-reckoning sailing calculations. This leads to significant errors in the estimated position of a vessel over 1 day’s sailing. This paper provides simple formulas that include the earth’s oblateness, which can be readily applied to sailing calculations. The accuracy of these formulas is assessed, and they are shown to be good to about 10 m over ranges up to 1000 km.
Published in:	NAVIGATION: Journal of the Institute of Navigation, Volume 42, Number 2
Pages:	313 - 326
Cite this article:	Kaplan, George H., "PRACTICAL SAILING FORMULAS FOR RHUMB-LINE TRACKS ON AN OBLATE EARTH", NAVIGATION: Journal of The Institute of Navigation, Vol. 42, No. 2, Summer 1995, pp. 313-326.
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