SOS calls are not used very often, but they are an essential part of maritime safety procedures. Typically, they are issued by the commander or leader of a boat when there is a threat to the safety of people on board, a threat to the vessel, or during times of catastrophic weather conditions. The language for communicating SOS calls is English.
When a person or vessel is in danger and needs emergency assistance or rescue, an SOS call is made by VHF DSC station (distress alert). This call takes priority over other calls. The last known position of the vessel and the time in UTC is given when the SOS call is made. Whenever the radio station is connected by GPS, this information is sent automatically. It can also be manually sent and should be updated every four hours.
If you have to send an SOS message, you should first use DSC on Channel 70. Wait for an acknowledgement from the coast station. If this doesn't come within 15 seconds, move to VHF on Channel 16 and send the SOS message again.
Make sure the message you send is clear and easy to understand. Here are some examples:
You should switch to Channel 16 while waiting for the answer to your SOS call. If there is no answer, the call will automatically be redialed at intervals of three and five minutes.