Definitions

from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A fixed compass card on which bearings relative to a ship's heading are taken.

from The Century Dictionary.

  • noun Nautical, an instrument for detecting errors of the compass by the bearings of celestial objects.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Navig.) An instrument similar to a mariner's compass, but without magnetic needles, and having two sight vanes by which bearings are taken, esp. such as cannot be taken by the compass.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun A device used to take a bearing on a distant object.

Etymologies

from The American Heritage® Dictionary of the English Language, 4th Edition

[Origin unknown.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

Named from Pelorus, reportedly the name of Hannibal's pilot.

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Examples

  • Second, it must be remembered that the bearing of any object obtained from the pelorus is the bearing _by compass_.

    Lectures in Navigation Ernest Gallaudet Draper 1919

  • Two pelorus repeaters swung to point a few degrees right of course.

    Rescue Ferrets at Sea Richard Bach 2002

  • Light clusters, clear, deep, on the face of the radio gear ... fans up softly off the dial of the pelorus ... spills out portholes onto the white river.

    Gravity's Rainbow Pynchon, Thomas 1978

  • The easiest and most accurate way to find the error of your compass is, first, to find the bearing of the sun by your pelorus.

    Lectures in Navigation Ernest Gallaudet Draper 1919

  • If you set your pelorus, so that it will exactly coincide with the course you are steaming as shown by the compass in your chart house and then get a bearing of the sun by noting where the shadow from the pelorus vane cuts the circumference, this bearing will be the bearing of the sun by compass.

    Lectures in Navigation Ernest Gallaudet Draper 1919

  • Steady the ship on this heading until the shadow from the pelorus vane at the proper L.A.T. cuts the circumference of the pelorus dial at the proper magnetic bearing.

    Lectures in Navigation Ernest Gallaudet Draper 1919

  • All being ready, secure the lubber's point of the pelorus at North and clamp the sight vane to the sun's magnetic bearing at the time you have figured to take the first heading.

    Lectures in Navigation Ernest Gallaudet Draper 1919

  • If, now, the compass were correct it would agree with the pelorus in showing the ship's head to be North.

    Lectures in Navigation Ernest Gallaudet Draper 1919

  • Starboard or port your helm until at the time calculated the reflection of the sight vane on the pelorus dial cuts on the proper magnetic bearing.

    Lectures in Navigation Ernest Gallaudet Draper 1919

  • If there is any Deviation on this heading, adjust the cast iron cylinders (called Quadrantal Correctors), which are on each side of the compass bowl, by moving them toward or away from the compass until the ship's head by compass is North-east at the proper time and bearing by pelorus.

    Lectures in Navigation Ernest Gallaudet Draper 1919

Comments

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  • "No: I hold you a pelorus, a flexing mirror, strange quarters for the wind of God."

    The Bone People by Keri Hulme, p 535

    February 12, 2017