A lot of mishaps can occur out on the water, but thankfully most are more inconvenient and embarrassing than anything else. But when lives are on the line – your boat is on fire or sinking rapidly with people on board, for example, or someone is in imminent danger of dying without immediate medical assistance – you want every available resource dispatched to your position. A Mayday! call will bring that kind of help. Not only will the U.S. Coast Guard respond but the Coast Guard may notify state and local search and rescue units in your vicinity and ask them to respond as well. The Coast Guard will also transmit an Urgent Marine Information Broadcast over marine-band VHF-FM radio Channel 16, notifying all vessels in the area of your emergency. In many cases a nearby Good Samaritan will be first on the scene to render assistance.
A Mayday – the term is derived from the French venez m'aider, meaning “Come. Help me” – should be transmitted if possible via marine-band VHF-FM radio Channel 16 or 2182 kHz MF/SSB. Emergencies can go from bad to worse in seconds so try to get as much information across in as little time as possible. International Maritime Organization protocols call for beginning the transmission with the word "Mayday" repeated three times, followed by the name and number of your vessel and its position. If you have a marine GPS, relate the latitudinal and longitudinal coordinates. If not, state your distance and magnetic or true bearing from the closest navigational landmark. If time allows, you can also relay your departure point, departure time and the speed at which you were traveling. All of these can help rescuers locate you. (See Sidebar for step-by-step instructions.)
Once you’ve made contact and given your information, Coast Guard Search and Rescue planners will keep you advised of their actions and give you an estimate of when rescue units will arrive on the scene. If you have a medical emergency, assign someone to monitor the radio from the time you make the call until the rescuers are on the scene. The Coast Guard will direct you to the nearest safe haven and advise you on what actions you should take in the interim.
The Rescue Coordination Center or local Coast Guard station may deploy a helicopter, rescue vessel or nearby commercial ship, depending on your location, local weather, availability of crew and equipment and nature of the emergency.
When the Coast Guard receives your Mayday, the Mission Coordinator will determine your degree of danger by considering several factors: the nature of your situation and the gear on board your vessel (first aid kit, food, water, life jackets.), the accuracy of your position, the tide, visibility, current and sea conditions, present and forecasted weather, special considerations (age/health of those on board, for example), whether you have reliable communications, the degree of fear in those on board, and the potential for the situation to deteriorate further.