Quick Answer
Use a whistle instead of verbal signals in situations where sound can carry far, such as in wilderness or at sea, to ensure your signals are heard by rescuers over long distances. A whistle is also more reliable in environments with loud background noise. Three short blasts on a whistle, known as the international distress signal, are universally recognized.
Choosing the Right Whistle
Select a whistle that can produce a clear, loud, and high-pitched sound. The most effective whistles are pea-less, as they are less susceptible to freezing in cold weather and can produce a consistent tone. Look for a whistle that can produce a sound above 80 decibels. A whistle with a built-in lanyard or clip makes it easy to attach to a backpack or clothing.
Signal Patterns and Techniques
To signal for help, use a whistle to produce a series of three short blasts, separated by a 2-3 second pause. Repeat this sequence for a total of five times. This pattern, known as the “SOS,” is universally recognized as an international distress signal. To signal over longer distances, such as in open ocean, use a whistle to produce a continuous sequence of short blasts, such as three blasts followed by a 30-second pause, and repeat.
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