Ship to Shore Communication

Wireless is no longer regarded merely as a means of summoning assistance in an emergency. It is an invaluable aid to navigation, and its use does much to reduce the possibility of accidents. It is still the principal means by which a ship can communicate beyond her visible horizon

ALL CONTINENTS ARE WITHIN CALL of the modern ship’s wireless installation. Ships that are equipped for medium- and shortwave transmission, direction finding and long-distance telephony may need three separate cabins to house all the apparatus, and economy of space is essential. The medium-wave telegraphy equipment of the Orion (23,371 tons gross), illustrated above, is a good example of a modern ship’s lay-out, with the receivers and amplifiers in front of the operator’s chair, and the transmitting instruments to the right. One clock shows Greenwich time and the other local or ship’s time.

THE first practical use to which wireless telegraphy was put was as a means of communication between ships at sea and the mainland. Although wireless has developed beyond all recognition, marine communications are still its most important application.

Broadcasting services and transmissions of all types are of tremendous importance on land, but they could all be replaced by wire circuits. For the ship at sea, wireless is the principal means of establishing communication with points beyond the visible horizon.

Before the use of wireless, inter-ship communication had to depend on such methods — flags, semaphores and the like — as are described in the chapter “Distant Signalling at Sea”. The working range of such methods of signalling was rarely more than a few miles, and in fog they were completely impracticable.

An Italian scientist named Guglielmo Marconi came to England in 1896, took out the first patent for wireless telegraphy, and brought his apparatus to the notice of the Engineer-in-Chief to the Post Office, who was interested in the subject. With the co-operation of the War Office and the Admiralty, several experiments were carried out, sometimes between points on land, and sometimes across water. It soon became apparent that signalling could be carried out more easily across the sea than over land.

As it was clear that ordinary telegraphic signalling presented more difficulties at sea than on land, it became certain that the sea was the natural field for the development of the new invention.

In 1897, ranges of twelve miles were attained during a series of experiments carried out in Italian warships at Spezia, in the Gulf of Genoa.

The first ship to be fitted with a permanent wireless installation was the East Goodwin lightship, which was equipped by Marconi for communication with the South Foreland lighthouse in 1898. The lightship was rammed by the steamer Matthews in the following year, but the crew was rescued — thanks to a wireless report sent at once to the shore station. At the earliest stage of its development, therefore, wireless was able to prove its value as a means of saving life and safeguarding property.

The particular installation that made history in this way was capable only of communicating with one fixed station at a distance of a few miles. To-day, wireless telegraphy and telephony are put to so many uses in connexion with shipping that it is almost impossible to keep track of them all. Primarily, however, they must always be regarded as a means of preventing disaster or of summoning assistance.

Ships are enabled to keep in touch with one another, and with coastal stations, and thereby to determine their positions. They are also kept supplied with regular information relating to bad weather conditions that may be approaching. Time signals are available, enabling ship’s chronometers to be checked to a high degree of accuracy. Medical advice may be sought without loss of time. All these services are of vital importance, and yet they comprise only a small fraction of the vast organization which is included in the title of “ship-and-shore communication”. Before the war of 1914-18, many owners of cargo-carrying ships were too conservative to use wireless. During the war, however, the new means of communication became invaluable, and its use in the Navy led to the development of one of the most important principles now employed.

It had been discovered before the war that it was possible to determine the direction from which a wireless signal was being transmitted. The frequent location of enemy submarines by this means was one of the immediate results. The possibility that a ship would, in the future, be able to determine her own position by another application of the same principle was not fully realized until some years later.

To-day, direction finding is one of the most important branches of marine communication. With a network of shore stations equipped with direction finding receivers, in addition to a large number of radio beacons from which ships can determine their own positions, fog has lost some of its terrors for shipping. Seamen may now take a bearing on an unseen object 100 miles away with an accuracy often comparable to that with which they used to sight a familiar landmark at a distance of five or six miles.

They may also determine the depth of water under the ship, by means of instruments, such as echometers, working on principles closely allied to that of wireless, and, by one of the most recent applications, they may receive visible and audible warning of the presence of an obstruction in darkness or in thick fog.

All these aspects of wireless affect chiefly the master of the ship and the crew. The passengers’ safety, it is true, is concerned with every one of them, but it is doubtful whether the passengers realize all that wireless is doing for them. They appreciate it as a means of communicating with friends on shore and as the medium by which their daily news-sheet is kept up to date. With a vague feeling of security they know that somewhere in the background there is a reliable means of keeping in touch with the world from which they are otherwise isolated.

Shipowners are no longer reactionaries where wireless is concerned. They realize that it is better, and cheaper, by means of scientific aids to render disaster improbable than to develop costly and cumbrous means of saving life when trouble does occur. There must always be lifeboats and rafts, but every oceangoing vessel fitted with wireless is a potential lifeboat, equipped with every device calculated to assure not only her own safety, but also that of other vessels which may be in difficulties.

It is now compulsory for all passenger-carrying vessels with a gross tonnage in excess of 5,000 to be equipped with direction-finding apparatus. Smaller ships which are not so fitted, however, are served by the coastal stations specially maintained for that purpose. Such a ship, may call the nearest coast station ask for a bearing, which can be given almost instantaneously, with an accuracy of within two degrees.

Obtaining Bearings in Fog

The larger ships can make use of the automatic radio beacons, of which there are over 200 in the world, twenty-five of them being situated round the coasts of Great Britain. These beacons are installed in lighthouses or lightships and are entirely self-operating, requiring no additional staff to maintain or use them. At regular intervals they radiate characteristic signals, and ships with direction-finding receivers obtain their own bearings by locating two or more of these beacon transmissions. Certain of these stations use a rotating beacon, so that small ships fitted only with normal receivers may obtain their direction with the aid of a stop-watch.

Normally the signals are sent out every half-hour, but in foggy weather they operate at intervals of six minutes. These beacons are in many ways equivalent to the lights which are placed all round the coast to assist navigation. Each has its characteristic code, and may be readily identified. They differ from lighthouses and lightships, however, in that they are equally reliable and useful in clear or foggy weather.

AUTOMATIC WIRELESS BEACONS are located at twenty-five points round the coasts of the British Isles. Most of the beacons are installed in lighthouses, and by means of their characteristic signals a ship may find her own position without the necessity of obtaining wireless bearings from a coastal station. The call-signs of the various beacon stations are shown in brackets. The beacon stations work on a wavelength of approximately 1,000 metres.

The beacon stations round the British Isles are operated by Trinity House, by the Northern Lighthouse Board and by the Irish Lights Commissioners. A map showing their locations and call-signs appears on this page. The stations work on a wavelength of approximately 1,000 metres, and many of them may be heard on any good broadcast receiver capable of receiving on that wavelength. Five, of them transmit a sound signal simultaneously with the wireless signal, and by noting the time elapsing between the reception of the two, the distance of the ship from the beacon may be estimated.

A further contribution to safety at sea is the auto-alarm device. Ships which do not maintain a continuous wireless watch are enabled, by this ingenious apparatus, to detect a distress call from another ship within range. The auto-alarm is coupled to a receiver which will respond only to one particular type of signal. This alarm signal consists of a series of twelve dashes, each of four seconds’ duration, separated by intervals of one second. Should such a signal be received during the operator’s absence, the auto-alarm will ring a bell in the wireless room, in the operator’s cabin and on the bridge.

It is also a reversible device which may be set to transmit a distress call, should the need arise. In its most modern form it will respond to the distinctive alarm signal, even through the heaviest interference and atmospherics, but not to any other type of signal. Its use was legalized at the International Convention for Safety of Life at Sea, held in 1929, and it has greatly eased the burden of watching in ships which carry only one wireless operator. About 1,200 ships in the British Mercantile Marine are fitted with the auto-alarm.

The procedure followed when a distress call is intercepted is one which involves the least possible loss of time. The signal SOS is transmitted, followed by particulars of the ship, her position and the difficulties in which she is. The nearest coast station intercepting such a signal immediately ceases all other work and attempts to communicate with the ship. It often has also to “close down” several other ships and coastal stations which may be interfering with its reception.

So efficiently is this carried out, however, that silence soon prevails upon the particular wave-band in which the distress call has been transmitted. Casual listeners who have happened to hear a distress call on 600 metres will appreciate the celerity with which a coastal station will silence everyone in the vicinity, leaving the ether clear for a solitary, weak signal which is more dramatic than the most sensational of “outside broadcasts”. Another ship is generally in a better position than the coastal stations to render assistance, but the shore transmitter often assumes the role of master of ceremonies until it is definitely known that help has arrived.

It is an international rule that the distress call shall be transmitted only on the authority of the master, or person responsible for the ship.

Broadcast Warnings

Second in importance to the distress service ranks the urgency or priority service, whereby communications from vessels disabled or in difficulty, but not in immediate danger, are given precedence over all others except SOS. A special urgency signal (XXX) precedes the transmission of such messages, and occurrences necessitating the use of this signal, as well as those requiring the distress signal, are classed as “ casualty cases.” Coastal stations round the British Isles handle approximately 150 of these “casualty cases” in a year.

Another branch of what may be termed the “safety service” is also handled by the coast stations. This consists of broadcast warnings to all shipping. Broadcast on behalf of the Admiralty, navigation warnings advise vessels of changes or faults in navigating lights and buoys. Such warnings are broadcast also by the B.B.C. Gale warnings, issued by the Meteorological Office, are broadcast both by the coastal stations and by the B.B.C.

In 1919 the Marconi Company designed apparatus for use in ship’s lifeboats. This development was an important contribution to the safety service, since it meant that the sinking of a ship would not imply the breaking of all means of communication between the survivors and the mainland or another ship. For certain classes of ships the installation of wireless in lifeboats was made compulsory in 1924, and nearly 400 lifeboats are now equipped with wireless apparatus. Using a wavelength of 600 metres, their sets have a working range of about 300 miles.

INVALUABLE DURING FOGGY WEATHER, the many wireless beacons throughout the world are an important contribution to safety at sea. The installation shown is at North Saddle, China, but in appearance it is typical of the beacons round the coast of the British Isles, most of which are combined with coastguard stations or lighthouses.

Illnesses and ailments in a ship that does not carry a doctor can generally be treated by a resourceful captain; serious illnesses, however, may necessitate the sending of an urgent message to another ship or to a shore station. Such telegrams are sometimes sent in plain language, but a special code has been devised for the purpose. By means of this, a telegram coded in one language may be decoded into an accurate translation in a large number of other languages — an important matter where medical advice is concerned. It is also possible for the ship’s doctor, if one is carried, to hold consultations by wireless with specialists ashore.

Ship-and-shore communication is divided up between several bands of wavelengths. In the original classification it was laid down that the coastal services and general short-distance services should use wavelengths between 600 and 800 metres and between 150 and 200 metres. For longer distance and world-wide services the wavelengths used were 2,000 to 2,500 metres, and short-wave bands in the regions of 16. 24, 36 and 60 metres.

Before 1919 nearly all ships were equipped with spark apparatus, the only merits of which were cheapness and simplicity. The average spark signal was broadly tuned and caused serious interference, at close quarters, over a wide band of wavelengths. Since 1927, when the International Radiotelegraph Conference was held in Washington, all transmitters with a rating in excess of 300 watts have been of the valve type. Receiving apparatus of the valve type, however, was used for some time before 1927, on account of the obvious limitations of the crystal and earlier types of receiver.

The standard valve receiver supplied to shipping by the Marconi Company was built in three units—a receiver tuning from 180 to 3,000 metres, a long-wave panel tuning from 3,000 to 20,000 metres, and an amplifier. The same company’s more modern equipment covers all wavelengths from 15 to 20,000 metres.

Most of the safety services are handled, nowadays, on the 600 to 800-metre wave-band. Efforts have been made to clear this band of ordinary traffic so as to free it from interference and to render it more reliable for the vitally important safety service. Since the development of short-wave working, a great amount of the long-distance communication between ships and shore is carried out on wavelengths below 60 metres.

Traffic services, fortunately, make far greater use of the ether than do the safety services, which, though unquestionably the most important users of wireless, do not occupy the ether as often as the others.

The most frequent type of message passing between ships and shore is the ordinary radio-telegram. This may be coded or sent in plain language, and is transmitted and delivered in the same way as an ordinary telegram. About 60 per cent of the messages transmitted relate to the ship’s business, such as arrangements to be made before entering ports, alteration in routes and the ordering of food or equipment.

Passengers’ business affairs are also largely concerned, and the remainder of the traffic consists of trivial social messages. In the course of handling routine traffic, shore stations receive a large amount of information concerning the position and movements of ships. Such information is forwarded to Lloyd’s by the coastal stations.

Long-Distance Telephone

Such stations are so arranged that their reliable ranges overlap considerably. A small ship proceeding coastwise may thus remain continuously in touch with her owners or with a point on shore. A larger ship, with more powerful equipment, may establish communication with her destination before her voyage has begun. Ships on the North Atlantic route can communicate with Canada and with the United States while they are still in Southampton Water, and their transmissions are frequently heard in Great Britain while the ships are within sight of the American coast.

Ship-to-shore telephony is a service provided almost entirely for the convenience of passengers, and only a few of the largest liners are equipped for this work. Their traffic is handled by the G.P.O. station at Rugby, and this class of work is carried out entirely on the short waves. Owners of ordinary short-wave receivers may intercept conversations between British telephone subscribers and their friends on board the Queen Mary, Empress of Britain, Bremen, Europa, Normandie and a few other large liners which have telephony installations.

DIRECTION-FINDING APPARATUS is compulsory in all passenger vessels with a gross tonnage of more than 5,000. The use of such apparatus enables a ship to plot her own position with great accuracy, and is also a means of ascertaining the exact direction from which a distress call is received. Some of the most notable rescues of recent years have been made possible only by the use of direction finders.

Telephony is used, however, also by many small trawlers, for the trawler skipper generally operates the wireless set himself, and he is not a trained operator, nor does he always know the Morse code. The telephony equipment in such vessels is designed especially for use by unskilled operators, and is provided with the minimum number of adjustments and complications.

Many lightships also are fitted with small telephony installations, and interesting (and sometimes amusing) conversations between lightships and trawlers may often be intercepted in the 150-200-metres band. Many of the trawler skippers, under the stress of extreme emotion, have a habit of shouting into the microphone. This merely has the unfortunate effect of rendering their transmission unintelligible.

There is a great demand for the smaller and cheaper type of telephone apparatus, which, with ratings of 300 and 60 watts, will cover reliable ranges of from 200 to 500 miles. The sets are compactly built, easily handled, and may be used also for telegraphic working, which increases their range still more.

Wavelengths between 109 and 230 metres are used for telephony, and telegraphy is transmitted on 220 metres or on the 600-800 metres band.

This means that a trawler in difficulties is not confined to communication with similar ships using the same band of wavelengths, but can speedily summon assistance from a coastal station or from one of the enormous number of ships keeping watch on the 600-800 metres band, on which the auto-alarm is always set. It is natural that there should be more services from shore to ship than from ship to shore. Ships’ equipment is severely restricted in size and in power and, to come just within compulsory requirements, a transmitting set with a range of only 100 miles is installed in many ships with a gross tonnage of less than 5,000.

At the other extreme in the scale of power, however, comes the great station at Rugby, one of the functions of which is to transmit special telegraph services of a broadcast nature. Long press messages (British Official Press and “Shipress”) are transmitted every day, chiefly to furnish news in the daily papers and news sheets published in the larger ships. Time signals, directly controlled by Greenwich Observatory, are also transmitted from Rugby, with meteorological messages. This station’s long-wave transmitter has a worldwide range in all conditions, but some ships are not equipped for receiving it.

Coastal Stations

By an agreement between the Marconi Company and the General Post Office, the Rugby station is used to bring all ships under Marconi control into action when it is necessary to get an urgent message through to a ship which is difficult to reach by the ordinary methods.

Rugby is essentially a high-powered transmitting station, and is not equipped for reception. Telephone messages from ships are received at the General Post Office station at Baldock, Herts, and thence transmitted to the Central Telegraph Office or Faraday House in London. Most of the incoming traffic from ships, as distinct from telephone calls from their passengers, is handled by Burnham Radio in Somerset. Coastal stations generally have their transmitting and receiving equipment in the same building, and this prevents reception of messages while the transmitter is operating.

At Burnham Radio, however, the receivers are separated from the transmitters (which are at Portishead, Somerset) by a distance of twenty-five miles. Thus the station may maintain communication with several ships at the same time, since its own transmitter does not interfere with the operation of receivers.

The transmitters at Portishead are remotely operated from the control point at Burnham, which also handles the telephone and telegraph lines for distributing the traffic over the land system of communications.

The Portishead transmitting station houses one telephony transmitter for the small coasting vessels, one telegraph transmitter for coastal and medium-distance services, two for medium-distance service alone, and three shortwave transmitters for long-distance working.

THE DIRECTION-FINDING LOOPS in the Orion, one of the wireless cabins of which is illustrated at the top of this page. The old form of rotating loop-aerial has almost been superseded by the modern screened fixed loops, which are robustly built and completely weatherproof. More than 4,093 ships, of which about 1,309 are British, are fitted with direction-finding equipment.

At Burnham there are nine shortwave receivers, which enable all the main shipping routes to be covered. There are also three receivers for the medium-distance service and two for coastal work. The station is connected directly with London and Bristol by teleprinter circuits, which enable traffic to be handled with the minimum loss of time. During the year 1934 this station handled more than two million words, and the volume of traffic at this Somerset station is steadily increasing.

More than 150 ships communicate with Burnham every day, and reliable contact is maintained with ships in the most distant parts of the world. Indeed, the range of the station is world-wide, with the possible exception of certain parts of the Pacific Ocean.

A development which has been necessitated by the increasing complication of wireless apparatus is the provision of skilled technical men at most of the important ports. Many difficult problems arise in connexion with modern equipment, and careful inspections of the ship’s gear must be carried out at regular intervals.

The increasing use of electrical machinery on board the larger ships has led to special difficulties with the wireless apparatus. Electric lifts, generators, fans and motors all have a marked effect upon a sensitive wireless receiver, especially when it cannot be placed in a particularly favourable position in the ship.

Electrical noises have been traced to revolution counters, gyro compasses, screen-wipers, electric whistles and a host of other small units, all of which are a potential source of trouble if they should go out of adjustment.

Stays and funnel guys often cause interference with a short-wave transmitting aerial, and much highly skilled technical work is necessary before many of these difficulties can be overcome. The ship’s operator is no longer in supreme command of his apparatus. He must be qualified to maintain it in the best possible order, but many faults are likely to develop which are beyond his control, and a surprisingly large staff of “shore technicians” is necessary to deal with them.

Special problems have to be faced in the designing of apparatus which has to withstand not only the influence of a salt atmosphere, but also the effects of great variations in temperature. In the Red Sea in summer, for example, the atmosphere is extremely humid, and special measures must be taken to keep the gear dry.

Robustness and Reliability

Materials have to be evolved which will remain unaltered in size under extreme changes of temperature, and, in effect, another vast “shore staff” is constantly at work in the laboratories, safeguarding the lives of those who rely on the provision of reliable apparatus.

In large liners the passengers’ telephone service must be capable of operating simultaneously with the ship’s telegraphic service. This has necessitated the building of transmitters which have a high degree of accuracy and stability in all conditions. Two. or even three cabins are necessary for the separation of the various transmitting and receiving units in these large ships.

A modern direction-finding receiver is a scientific instrument of great accuracy. Continual checking and resetting is necessary, however, if such a receiver is really badly treated. The loop aerials used with such receivers are placed in exposed positions, and must be rendered absolutely rigid and waterproof.

The ability to convey ordinary intelligence and information and to obtain prompt assistance in time of need is also contributory to safe navigation, and in these ways — apart from the aspect of direction-finding — wireless is of the utmost importance. Shipowners no longer carry wireless because they are compelled by law to do so; they are convinced of its enormous potentialities for increasing safety and for assisting them in the transaction of their business.

Development continues apace, and the possibilities of television as an aid to shipping have yet to be explored. The last word in wireless communication can never be uttered; but wireless will always be regarded as one of the greatest blessings that have ever been conferred upon those who go down to the sea in ships.

A TYPICAL MODERN INSTALLATION in the Athlone Castle (25,564 tons gross). On the left is the direction-finding receiver, with the coupling to the external loop aerial. In the centre is the ordinary receiver, with the aerial lead-in and switching, and on the right are the transmitters. The call-signs of the Athlone Castle, GWZB and GTZM, are well-known to radio enthusiasts who make a hobby of listening-in on the shipping wavelengths.

You can read more on “Distant Signalling at Sea”, “The Modern Ships Wireless” and

“The Work of Trinity House” on this website.