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R/O Duties

In Radio Officer Tales I have tried to describe some of my experiences at sea during my short career as a ship’s Radio Officer (R/O) in the 1960’s British Merchant Navy.

A few years ago I was in conversation with a serving Merchant Navy Captain. He told me that he was the only officer on board his ship that had ever sailed with a Radio Officer. He admitted that even his senior subordinates had no idea about what an R/O did.

It is now over fifty years since I “swallowed the anchor” to follow a different career ashore. Sadly my recall ability is not what it was, however I have tried for this story to remember as much as I can about what I did as an R/O when joining a ship for the first time and what I did when on radio watch and the other duties that I carried out on board ship. I have tried to avoid making lists of activities because to be honest, as a reader I would find that incredibly boring. It is also necessary for me to say from the outset that what I describe only applies to dry cargo liners and specifically to the ships belonging to Thos and Jno Brocklebank Ltd; it being the only shipping company that I ever worked for. I know that the range of duties of an R/O on a passenger ship of the time differed markedly from mine.

The Radio Department of Thos and Jno Brocklebank were highly professional and encouraged a “can do” attitude amongst their R/O’s. No job was ever considered too difficult for the R/O to undertake on their ship’s wireless installations. In practice that meant that Brocklebank’s provisioning of radio spares, tools and test equipment exceeded the levels required by the International Radio Regulations. The downside to the Brocklebank approach was that an R/O could experience a complete sense of failure if they ever had to call in a shore side repair depot to rectify any problem with the ship’s wireless installation.

Many books have been written about the evolution of wireless or radio communications at sea. Perhaps the two best ones (in my opinion) are “One Hundred Years of Maritime Radio” written by W.D Goodwin and “The History of the Radio Officer in the British Merchant Navy and on Deep Sea Trawlers” written by Joanna Greenlaw. By the time I went to sea in 1963 the use of wireless communications at sea had evolved and been defined by International Regulations to such an extent that it was compulsory for ships over 500 tons to carry a radio officer. Cargos ships such as those I sailed on maintained a pattern of four radio watches per day, each of two hours duration separated by an interval of two hours. When the R/O was off watch, the International Distress frequency of 500 kHz was monitored by the Automatic Alarm equipment.

This story is written from the perspective of an experienced R/O taking sole charge of a cargo ship's wireless station.

Joining a Ship

When joining a ship for the first time it was essential for an R/O to quickly familiarise themselves with the equipments installed within the radio room and to determine whether they were working correctly. Ideally these checks should be done before any luggage was unpacked. It was highly likely on Brocklebank ships that all or most of the equipment installed in the Radio Room of an unfamiliar ship, would be completely new to you as the Radio Department of the company were driven by value for money objectives rather than aesthetics. It was not unusual to find Radio Rooms equipped with equipments from a number of different manufacturers. The exception to that rule on the Brocklebank ships that I sailed on was the Radio Room of the SS Manaar that was almost entirely equipped with Redifon equipment.

To me that radio room which can be seen in part below was a joy to behold and eventually a pleasure to operate when I came to understand how all of the individual units were integrated together.


I am most grateful to David Meare who is the photographer and Copyright owner of the images immediately above and below this acknowledgement for permission to display them on this Web site. David captured these images in 1964 when he was Manaar's Second Radio Officer.

The top image shows to the left, the battery management panel and to the right the aerial change-over panel and below that the very large Medium Wave and High Frequency transmitter. The second image below shows the two Redifon R50M receivers that were located directly in front of the operators chair. Those receivers had a tendency to drift in frequency with temperature changes in the Radio Room. When copying any traffic it was necessary therefore to have one hand on the receiver's frequency control and the second holding the pen to write down the message!



In addition to the Radio room, an R/O’s domain would include the emergency battery locker and the motor generator locker where the motor generators or alternators would be installed. These could be located at a distance from the Radio Room. These generators were required in the event that the ship did not have domestic power supplies of 240 volts AC. All the ships I sailed on had domestic supplies of 110 Volts DC so the motor generators were essential.

The Brocklebank ships I knew all possessed an R/O’s workshop where any major repairs or metal fabrication could be carried out. Brocklebank R/O's were also responsible for the ship's Radar installation so a visit to that equipment and a check on its spares was also essential.

Although rare on Brocklebank ships it would be true to say that on joining a ship for the first time some deficiencies might be encountered. These might include missing tools, emergency batteries in need of attention, battery records not up to date, radio component spares missing or in a used state. On one ship I joined, I found that virtually all of the thermionic valve spares for the radio room’s transmitters and receivers had been used before and although still working after a fashion they needed to be replaced. Some R/O's did not like to reorder spares because they thought it an admission of failure on their part as they wished to maintain a reputation for frugality.

According to the regulations, a ship would have to carry spare aerials and aerial insulators as well as lengths of new phosphor bronze wire to fabricate replacement aerials as required. Sometimes the state of these spare aerials left something to be desired.

The most common short coming would be the failure of the previous R/O to update and incorporate all of the paper amendments into the numerous Admiralty and International Telecommunication Union (ITU) Service documents that the ship had to carry in the Radio Room. These books were vitally important as they provided the R/O with the information of Coast Station operation, Radio determination and Special Service Stations and Call signs used in the Maritime Service. It really was a case of cut and paste and some R/O’s found the job so onerous (i.e. boring) that they would put it off and put it off for as long as they could, even leaving the ship before it was completed!

Watch keeping



An unusual Radio Room Clock with a 24 Hour dial showing the two silence periods. This was purchased by me from E-Bay a few years ago. I'm told it has a Russian or Eastern European movement.

Unlike the ship whose clocks were regularly moved backwards or forwards to reflect local time. The Radio Watches and the Radio Room clock stayed on Greenwich Mean Time (GMT) now renamed as Universal Time Coordinated (UTC) time.

It could be claimed with some justification that R/O’s were the ultimate clock watchers because they were controlled and driven by the inexorable movements of the hands of the Radio room clock. Whereas a Navigating officer would need to plot the course to be followed by the ship in order to safely reach its destination, so an R/O would need to record which Coast stations to listen to and the times and radio frequencies of transmission of Traffic Lists, weather forecasts, time signals and navigational warnings between their departure and destination ports.

The primary duty of an R/O was to monitor the International Distress Frequency of 500 kHz for Distress, Urgency or Safety messages. To assist with this monitoring all ship stations had to observe and monitor the Silence periods that occurred at fifteen and forty five minutes past each hour of the two hour watch keeping period. The duration of the Silence period was three minutes. During that time all ships were expressly forbidden to transmit unless directly involved in a Distress, Urgency or Safety incident. Outside of these Silence periods, R/O’s were obliged to listen on 500 kHz using headphones unless involved in a different activity. When that occurred a listening watch was maintained on 500 kHz by the use of a Watch receiver that was fitted with a loudspeaker.

At the time I was at sea, The Area Communication System was still in operation. I believe that its origins were the World Wide Admiralty Communications network used during the Second World War. This network divided the World into eight geographic areas with transmitting and receiving stations based in each Area. A British or Commonwealth Merchant ship was permitted to use an Area station for the routing of telegrams. Each Area transmitting station published the times and frequencies of their traffic lists in the ITU list of Coast Stations. The stations of the Area Communication System transmitted and received messages on a wide range of frequencies in the short wave bands.

For me, being required to send and receive message traffic by means of the ship's short wave transmitter and receiver over thousands of miles was a fascinating and extremely interesting part of the job and presented many challenges not least the use of the relatively low powered transmitters fitted on Brocklebank ships. Choice of frequency band, the likelihood of signal fading and the ever present electrical noise and static all added to the problems and challenges.

Messages to and from the ship to the company or its shipping agents were always in the form of a telegram. Traffic lists were essentially a list of ships call signs for which the Coast or Area Station held telegrams.

Some Coast Stations might also broadcast the number of telegrams held immediately after the call sign. In the Case of the SS Manaar for example this might be copied as GFRG 2 (two telegrams to be forwarded to the ship).

The ITU Service documents would also show whether a destination port required any notification of infectious diseases before the day of arrival so that the medical authorities could be alerted in the event of a problem.

An extra watch keeping task on Brocklebank ships was the requirement to maintain company communication schedules (Skeds) that were distributed across the two hour watch keeping periods and the four daily watches. The purpose of the Skeds was to provide alternative message routing paths between ships and the company and to allow company ships to maintain contact with one another in case they required non urgent assistance.

Over the course of a Watch, the R/O was required to record at approximately ten minute intervals any traffic they heard on 500 KHz. This was to enable the Regulatory Authorities to check whether the R/O was monitoring the International Distress Frequency.

The wireless log book had to be signed by the R/O at the commencement and end of each watch keeping period. The ships wireless log had to be countersigned each week by the Captain. This ensured that he was kept acquainted with all of the ship’s radio department activities.

Any Coast station could ask a ship to provide information concerning its voyage and position. Such messages were preceded by the letters TR. It was standard practice for a ship to send a TR to its nearest coast station on its departure from port. UK Coast stations would forward ship's TR's to the Area 1 Coast station located at Portishead near Bristol for traffic routing within the Area Scheme.

Irrespective of watch keeping periods, the R/O was on call 24/7 whilst the ship was at sea. Many times when off watch and asleep in my cabin I would be woken by an Apprentice or ship's quartermaster with the message that the "Old Man" (Captain) wanted you on the Bridge because something or other was "on the Blink" (not working properly) or that he wanted an urgent message sent.

Emergency Equipment

When the ship's R/O was off watch, the International Distress Frequency of 500 kHz was monitored by the Automatic Alarm receiver. This was designed to respond to the Auto Alarm signal that consisted of a sequence of 4 second transmissions, separated by one second intervals. These Auto Alarm signals were generated by a device known as the Auto Keyer. In the event that the ship in distress was without electrical power, then all of the emergency equipment including the Auto keyer was powered by the ship's emergency batteries. When I was at sea all of the emergency equipments were standalone units. The image below shows all of a ship's emergency equipment accommodated in a single Ancillaries equipment cabinet. This Ancillaries rack was designed, built and introduced into service around the early 1970's after I had left the sea.


A Marconi Marine Ancillaries Rack, Circa 1970, showing from top to bottom, The Emergency Transmitter, the Auto Alarm Receiver, the Auto keyer, emergency (Reserve) receiver, battery charging and power distribution panel and aerial switching unit. This rack was purchased from E-Bay a few years ago.

Lifeboat Equipment

Every vessel was required to carry a lifeboat transmitter/receiver. These were painted a bright orange and were normally kept in the Radio Room. They were designed to float but there were anecdotal stories around at the time that when some of them were thrown into the sea they sank like a stone!

It was usual to test them once a week and to transmit into the lifeboat aerial system once a voyage. For me that was usually when the ship was tied up in Colombo harbour. The equipment was powered by a hand cranked electrical generator so to test it was a two man job. The second man was usually the junior R/O and if he was not available (because the ship only carried one R/O) then the power generation was usually delegated to a navigating cadet. The unit was capable of transmitting and receiving on the International Distress frequency of 500 kHz and transmitting on the International aeronautical emergency frequency of 8364 kHz. The testing of this equipment was recorded in the Ship's wireless log book.



Testing Manaar's Lifeboat equipment in early 1966 somewhere in the Indian Ocean.

Navigational Support

A number of R/O duties were focused on supporting the Navigation Department on board ship. It could be argued that the most important of these was the taking of radio Direction Finding(DF) bearings when the ship was sailing in dangerous waters, possibly in bad weather and when the ship was beyond the range of its radar. Other duties would include taking weather forecasts, receiving navigational warnings (Naveams) and the receipt of time signals to allow the navigators to determine the rate of change of the ship's chronometers. Maintenance and repair of the ship's radar equipment fell within the navigational support category.

Some of the ships I sailed on regularly produced meteorological reports that I would send as "Obs" messages to the UK Met office via the Area Coast Stations.


Messages to and from the ship were exchanged as chargeable telegrams that required costs to be accounted for. The words in a message would be counted and a cost applied for each word. On ships that exchanged large numbers of telegrams the accounting responsibilities during the voyage could be significant. Coast Station and Land Line charges were listed in the ITU'S List of Coast Stations in terms of Gold Francs per word. For Company accounts, these Gold Franc charges were converted into Sterling with the use of a ready reckoner at a rate of exchange advised by the Radio Department.


A radio officer in addition to operating a ships station was also expected to repair any faults and to carry out routine maintenance on all of the ship's radio equipment. The metering capabilities built into each item of equipment was excellent. It was my practice to record the readings for every item of equipment every week in an exercise book. The availability of such information was invaluable in monitoring any slow decline in performance and for rapid fault finding when an equipment failed.

Every ship that carried an R/O had to be capable of transmitting and receiving distress messages even in the event of a total loss of the ship’s electrical supply. This meant having two banks of large capacity 24 volt, lead acid batteries to power the emergency equipment and the emergency lighting in the radio room. These batteries had to be regularly charged and discharged to ensure that they were capable of satisfactory operation in an emergency. It was required practice to check their performance under load and to record the results daily. The specific gravity of the dilute sulphuric acid electrolyte in the cells of each battery had to be measured and recorded monthly.

Each year the complete ships radio station would be surveyed by a Post Office surveyor and any fault or deficiency would have to be rectified and confirmed by re-survey before the ship was allowed to sail. Of particular interest to a radio surveyor were the dates and results of the Direction Finding receiver's calibration and check bearings.

Within Brocklebanks, the pressure was therefore on the ship’s radio officer to ensure that the radio installation was maintained to the highest standard.

Because of the radio officer’s technical ability in electronics and skill in fault diagnosis and repair it was not unusual to provide support and help to the engineering, electrical and navigating departments whenever problems were encountered with ship borne equipments that did not fall under the remit of the Radio Officer. These could include engine control systems, echo sounders, automatic pilots, gyro compasses and radio broadcast equipments. Privately owned radios, record players and reel to reel tape recorders could also find their way on to the R/O's repair bench.

I hope the foregoing throws some light on what an R/O did in the 1960's British Merchant Navy. If I have omitted any duty because of failing memory then I hope that you dear reader will forgive me. All of these duties and responsibilities combined with the ability to travel World wide made for an extremely interesting and rewarding career. With the benefit of hindsight it is sad to realise now that in the mid 1960's when I left the Sea, the days of the R/O as I knew them were already numbered. I never ever thought then, that the demise of the Radio Officer would occur within my working lifetime.

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