Communications

In the last century, communication instruments depended on radio waves travelling horizontally through the atmosphere (i.e. telegraphy and radio). Such systems were very variable in performance due to atmospheric conditions. However, the introduction of satellite communications systems (satcomms) - which transmit the message up to the satellite and then down to an earth station - has dramatically increased the reliability of maritime communications and at present virtually all medium and long range communication equipment installed on fishing vessels relies on satcomms.

Very High Frequency Radio (VHF) has been retained for short distance communications but the range is limited under normal circumstances to less than 20 nm. Various companies provide satellite links for satcomms (e.g. Inmarsat, ICO, Eutelsat, Argos, Globalstar, etc.) and as systems develop there will possibly be others. One piece of communications equipment that has become mandatory for all vessels above a certain size (including fishing vessels as legislated by national administrations) is the Global Maritime Distress and Safety System (GMDSS). Distress messages are transmitted by Inmarsat C which is a data system that is 100% reliable. This equipment is also used by Vessel Monitoring Systems (VMS) which are being introduced by many fisheries management authorities. It is reliable and relatively inexpensive as the data messages are literally transmitted in one or two seconds. Emergency Position Indicating Radio Beacons (EPIRBs) are designed to float free from a sinking vessel and transmit the position for some time after the vessel has sunk to assist in the rescue of any survivors.

For voice communication, more sophisticated systems are used which require greater bandwidth and time, increasing the cost of the message. However, as mentioned earlier, more and more satellites are coming into service, particularly low- earth orbiting satellites, which will eventually allow maritime communication to be accessed by a cellular phone. Such systems are even now allowing fishing vessels to access the Internet and e-mail services. Furthermore, marketing systems allow fishing vessels to sell their catch while still at sea.

Modern communication has rendered earlier systems such as radio direction finding, Morse code signalling and semaphore largely irrelevant. Nonetheless, one traditional communication method, the International Code of Signals, still plays a role when language becomes a problem between ships of different nationalities. The short three or four letter codes and combination of hoists allow a shorthand information exchange between vessels even if they do not know one another's language.