An installed anemometer (fig. 10-9) is an instrument fixed somewhere
aloft, usually at the masthead. The wind blows on a propeller attached
to one end of a wind vane that pivots. The whirling propeller revolves a
spindle, communicating with a synchro repeater on a pilothouse or chart
house bulkhead. Figure 10-10 shows one type of synchro repeater.
The upper dial of the repeater is graduated in lo-degree intervals and
shows the relative direction from which the wind is blowing. In this
illustration the direction is about 287°. The lower dial indicates the
relative wind speed (true wind speed when the ship is stationary). The
wind speed dial in the illustration shows about 87 knots. This reading
means that the force exerted by 87 knots of wind is whirling the
When using an installed anemometer, always compare the readings
observed with the wind conditions as they appear outside. If two
anemometers are installed, make sure that the windward anemometer is
Figure 10-9. Installed anometer.
Figure 10-10. Synchro