Whirling Psychrometer. Wet and dry thermometers mounted in a frame hinged on a handle. Is whirled to increase evaporation at bulb of wet thermometer.
Whirlpool. Current that has a rotatory motion over a comparatively small area. Is troublesome in that it may turn ship's head against maximum rudder at maximum speed. Its suctional effect is largely mythical.
Whirlwind. Small but very intense revolving storm, the wind circulating very rapidly around a low-pressure centre-line.
Whiskers. Spars projecting transversely from just forward of catheads and approximately horizontally. Purpose is to give adequate spread of guys of jib boom. Sometimes called 'sprit-sail gaffs'.
Whistle. Sound-producing instrument that is required to be fitted on any power-propelled vessel unless a siren is fitted.
Whistle Buoy. Navigational aid buoy that emits a whistling sound through mechanism actuated by wave movement.
