Prior to the advent of GMDSS, aside from the short period immediately prior when some ships were equipped with Inmarsat A systems, all ship communications with ships were done using telegrams and radio telephony.

These were expensive means of communicating so it was common practice for shipping companies to eliminate all but essential commercial communications. Most traffic was done by way of morse code in which every letter has to be transmitted and received individually further adding to the expense. To overcome this, the use of codes such as the Boe Code was adopted. These groups of five letters were used to stand for whole sentences. Some of the five letter groupings were standard chartering and shipping terms and others were encrypted and only decipherable by the shipowner concerned.


As the cost of communicating has fallen, many ship operators and managers have embraced the opportunity to communicate more freely and the volume of traffic has definitely increased dramatically and is still accelerating (read about cyber security on ships here).

The practice of coding and communicating in this way is now obsolete although it has parallels with compression and encryption of electronic messaging today but without the need for the sender or receiver of the message to go to the trouble of coding and decoding the message.

Having said that, the volume and method of communication will be determined by the type and age of the vessel and the service it is operating on, and the ship management strategies and procedures of the ship operator and cargo owners.

Commercial communications can be split into two main categories: those concerned with the employment of the vessel (voyage related communications) and those related to management of the vessel (operational communications).

In the first category will come matters such as voyage instructions, notices of arrival contact with ports, agents and cargo interests. Ship operational communications will revolve around ISM and safety management, stores and supplies, crew changes, and increasingly performance monitoring, monitoring of equipment and perhaps an Internet of Things as ships become more connected.

Voyage related ship communications

Ships operating on spot markets generally have very little need for anything other than basic communications in regard to the employment aspect. Voyage instructions will be given by the owner or the time charterer and are usually confined to a brief resume of the final fixture terms along with agents’ contact details. Those familiar with broking practices will know that here the use of standardised abbreviations is the norm and all necessary details can be contained in just a few lines of text.

Armed with details of the next voyage, the master only needs to send arrival notices to the load port agent at prescribed intervals. He may also ask for a ship chandler to attend or for the agent to arrange medical facilities or some other need of the vessel. Large vessels that undertake long voyages may only complete a handful of voyages annually and may even be on a consecutive voyage contract so will not even need the fixture details for each voyage.

Ships that operate in the short sea markets will make far more voyages and so have a higher communications requirement. That said, many will be operating for much of the time in range of mobile phone coverage and some companies prefer to make use of this medium for communications whenever convenient.

Passenger vessels other than ferries operating on day services, will also need to keep port agents advised of arrival times and to request stores and other services. Depending upon the ports being visited there may also be a requirement to send passenger lists to the port agent or immigration authorities although frequently this will be taken care of by the shore offices of the shipowner.

Other non-cargo ships such as cable layers, offshore vessels, seismic survey and research ships will need to keep owners and charterers advised of positions and port agents advised of needs. 

Communication between ships and service providers such as pilots and tugs is mostly done over VHF radio. 

Container monitoring at sea

Liner vessels, which carry many thousands of containers have surprisingly few voyage related communications with ports and service providers outside of the company as much of the work is done by port agents. That said, there is a pent-up demand from shippers and receivers of cargo to have more regular information about conditions on board especially where reefer containers are concerned.

With reefer containers, crew must take regular readings of temperatures and monitor the boxes for malfunctions. Reporting as necessary any untoward events. There are some IoT systems in operation which automate this process using sensors in each container that transmit to a hub onboard which in turn transfers data by satellite. The information is then accessible by the crew as well as by the ship operator and potentially also the cargo owner. Depending upon the ship’s route and number of transhipments to shore and other vessels, there may be times when the information is not available but over time these gaps will likely be eliminated as more ports and vessels are connected.

Container vessels also have rather complicated stowing requirements necessitated by different kinds of hazardous cargo being carried and the port rotations. Because ships rarely discharge only or load only at each port, containers will be both discharged and loaded which sometimes means that boxes have to be moved onboard to permit safe carriage of newly loaded cargo.

Planning the stowage of container ships was difficult enough when ships were small but with modern vessels carrying several thousands of boxes the permutations are of another magnitude. Most stowage plans are now made by computers and that information needs to be shared and monitored by the shore offices, ships and ports. This can generate a lot of data and so places a high load on ships’ communication needs.

There is a move from the major liner operators including A.P. Moller – Maersk, CMA CGM, Hapag-Lloyd, MSC and Ocean Network Express to develop standardised information requirements in the container and logistics sectors. These common information technology standards will be made openly available, free of charge, to all stakeholders of the wider container shipping industry via a neutral non-profit body.

The increasing volume of cargo-related communication requirements has been a major driver in leading container operators making use of VSAT communications.

Operational communications

This is an area where probably much more information flows between ship and shore office than does with voyage related communications. But there is a marked divide between small and large operating companies. It may be a surprise, but the average shipping company has only around 10 ships in its fleet. Considering the major companies have fleets running into hundreds of vessels, it suggests that many companies have just one or two ships in operation.

In addition, many of the tens of thousands of ships in the world fleet are engaged on domestic trade routes, often returning to their home port each day. For such ships, the communications requirement is frequently limited to emergency needs only and is covered by GMDSS regulations.

In the larger fleets and especially those with newer equipment, there will be a great deal of monitoring systems employed – notably on the main engines. The company Safety Management System required under  ISM rules will be complex and may involve a requirement for regular safety reports and bulletins as problems arising on one ship are advised to others to allow appropriate action.

The communications needs for these companies are very large and once again will require more bandwidth to transfer the data generated. The larger fleets are also those most likely to have a crew communications policy that allows crew to make private communications. As the data flow increases so does the need to manage and prioritise communications. There are many systems that can do this either provided by the communications service provider or a third party.

These systems are able to schedule routine communications to quiet periods and to be able to recognise different communication methods at times of high traffic and so prioritise according to user or application in use. Such systems are especially useful on ships which have large numbers of crew and supernumeraries on board such as offshore vessels, passenger ships, research vessels and the like.