Usage:
SOS 3 short blasts, followed by 3 long blasts, followed by 3 short blasts. (• • •  — — —  • • •)

INTERNATIONAL DISTRESS SIGNAL6 short blasts followed by a pause of 1 minute then another 6 short blasts. Repeat as necessary. If your signal is heard, there should be an answering whistle of 3 blasts followed by a pause of 1 minute. Repeat this several times and continue until you are located.