The Weekend Navigator Part II Copyright 2008 Coast Guard Auxiliary Association, Inc.

Chapter 25: Other Instrumentation Wind sensors Weather instruments Other instruments

Wind Sensors Speed is measured with an anemometer Direction is measured using a vane Used to measure true wind speed and direction

Wind Sensors Sea surface responds directly to wind intensity and fetch Waves generally build perpendicular to wind direction

Wind Sensors Wind direction and speed are key forecasters of weather –Lower atmospheric pressure is usually 90 o to 120 o off to your right in the Northern Hemisphere –SE winds usually proceed a warm front –After a warm front, winds veer to the SW –Warm fronts usually proceed cold fronts –After a cold front, winds veer to the NW

Weather Instruments Barometer measures pressure for indicating approaching fronts and storms Sling psychrometer measures local temperature and dew point for anticipating fog

Weather Instruments GPS for monitoring speed over ground –Composite of boat speed and effects of wind and currents Water temperature can be important in identifying current patterns (i.e. Gulf Stream)