Maritime Safety Information
The Maritime Safety Information (MSI) service is an internationally co-ordinated network of broadcasts of Maritime Safety Information. This information contains:
MSI is part of the Global Maritme Distress and Safety System (GMDSS). Every ship, while at sea, has to be capable of transmitting and receiving maritime safety information. Reception of MSI is free of charge to all ships.
MSI is transmitted by a variety of means, using terrestrial and satellite radiocommunications. The GMDSS supports two independent systems to broadcast Maritime Safety Information (MSI):
To ensure that the ships know when to receive MSI for a given area and subject, many of the MSI broadcasts are scheduled, under IMO co-ordination, to a particular time, Land Earth Station and Ocean Region.
All navigational warnings and meteorological forecasts are scheduled broadcasts with a safety priority, which does not produce an alarm at the receiver. Meteorological warnings and shore-to-ship distress alerts are unscheduled broadcasts with urgency or distress priority (broadcast on receipt), which does produce an alarm at the receiver.
Transmission of Maritime Safety Information from ship-to-shore is also possible. This may be accomplished using any transmission means available to the ship. Normally, Digital Selective Calling on MF/HF or VHF will be used or one of the Inmarsat services. Inmarsat has special 2-digit codes defined for this purpose.