dogvane

plural dogvanes

1. nauticalA small vane of bunting, feathers, or other light material, fastened to the end of a short staff and placed on the weather gunwale of a sailing ship to assist the helmsman to judge the direction of the wind.

   she had an ugly knack of stopping, and swinging one leg all manner of ways, like a dogvane in a calm.

   1826, Old Sailor, Greenwich Hospital

   1 more example

   Nor was any mariner surprised when, after inspecting the compass, and then the dog-vane, and then ascertaining the precise bearing of the odor as nearly as possible, Ahab rapidly ordered the ship’s course to be slightly altered, and the sail to be shortened.

   1851, Herman Melville, Moby Dick or the Whale

2. obsoletenauticalA cockade worn on a hat (worn in the British Navy in the 18th and 19th centuries)