Ways to communicate on the water.
Emergency Whistle
Using a whistle, you can send out all kinds of messages using morse code a combination of long and short sound blasts that create letters. The most important to remember being the universal signal for SOS or emergency.
0 - 0 - 0 - ( ) - ( ) - ( ) - 0 - 0 - 0
three short blasts, followed by three long blasts, finished with three short blasts repeating
Beyond emergency signaling, it is an easy way to simply get the attention of group member further away.
Visual Distress Signals
Similarly to Sound, Lights are also an effective method for communication on the water. They can be used in many of the same ways to send messages or call for help via morse code. Other ‘VDS’ (Visual Distress Signals) include Flares, Dye Packs, Smoke Flares, and Strobe Lights and are required for most nautical crafts, including all motorized ones and are only legally usable in emergency situations.
VHF. Channels. Emergency calls. Voice procedure.
VHF radios are used for a variety of reasons on the water, Cost Guard communication, Boat to Boat Messaging, Public Correspondence and others. They are critical on the ocean for their excellent range over uninterrupted space.
For emergency calls on the water, you cannot get much better that the international distress channel and the key phrase ‘Mayday, Mayday, Mayday’ repeated three times. Then add information about the boat / vessel and your location and the nature of the issue. Repeat until a response.
For handhelds, make sure that the power is turned all the way up for emergency broadcasts. In addition, most modern radios will have a ‘DISTRESS’ button that will automatically assign the radio to the emergency broadcast frequency.