A few candid comments from Decca Navigator users:

"In naval use, only the Mk 3 and Mk 5 were fitted in Royal Navy/Royal Canadian Navy ships and it is believed that only the Mk 5 was used in Canadian ships. The Mk 3 had no lane identification feature which must have made it very difficult to use".

"DECCA was very accurate out to about 300 NM, but it had a bad habit of losing its signal and it was a difficult to recalibrate. Loran 'C' was much more user friendly and many welcomed its arrival".

"Much of the problem with Decca in North America was geography as opposed to the "not invented here (NIH) syndrome. The US Coast Guard set up an experimental chain covering the entrance and approaches to New York harbour. It worked well there (out to about 200 miles) because the master and slave stations could be properly displaced. The Nova Scotia chain was not as fortunate."

"We always used to joke that DECCA was an acronym for Dedicated Englishmen Causing Chaos Abroad "


Cdr. Bob Willson (Ret'd) was a navigation officer aboard HMCS HAIDA in 1957. This is how he remembers the Decca Navigator. "When we went to Europe in the fall of 1957, we were "temporarily" fitted with a rented Decca Navigator of a very early Mark, so that we could use it in waters around the British Isles and in the Baltic. It was removed when we got back to Halifax as there were no Canadian chains at that time.

The Decca set that was fitted was similar to the one in the above picture which was rented and installed in the Charthouse for our trip to Europe. There was no Nova Scotia chain at that time, although I believe it was started up soon after. The recorder/indicator was located on the chart table close to the inboard bulkhead and right against the after bulkhead. I am not sure where the receiver was but it was either on the inboard bulkhead or else on the other side of the bulkhead, by the ladder in the Ops Room lobby. That was great for the Navigator but not much use to the Officer of the Watch, even though the Decca system was intended for pilotage. It would have been much more useful on the bridge, but I guess it was not sufficiently weatherproof. Certainly in the Prestonian Class frigates, and the Cadillacs, it was on the bridge, but they had enclosed bridges.

As I remember the antenna was just a single wire and it ran from somewhere on the starboard bulwark near the after part of the bridge up to the starboard yardarm. Why the antenna was placed on the starboard side when the unit was to port of the centreline I do not know. The set was removed when we got back to Halifax and was not reinstalled during the rest of my time in the ship (until July 1958). I know, from other ships, that Decca was fitted in all of them when the Canadian East Coast chains were up and running, but I am not sure of the dates.

I know there were Decca chains on the Canadian East Coast, a demo Great Lakes chain, as well as all around the coasts of the UK and into the Baltic.  There were chains in the Bay of Biscay, the Med and the approaches to Gibraltar, too.

Bob also relates some information about time keeping since this is very relevant to navigation. Destroyers were outfitted with two "Chronometer Watches" and two or three "Deck Watches", plus an assortment of stopwatches. The Chronometer Watches (CW) were kept in the soft metal, lined drawer in the Chart Table and were wound and checked against a radio time signal daily, usually at the same time (GMT) each day. There was a log in which the daily error was recorded and a daily rate of error calculated. The daily rate was important if you could not receive a radio time signal, as it was then used to estimate the daily error to be applied to calculations. These time pieces were never reset, unless for some reason they stopped. If the daily rate exceeded an acceptable maximum the CW was taken to the nearest Chart depot and exchanged. The Deck Watches (DW) were calibrated against the Chronometer Watch and could be taken to the bridge to provide an accurate time for celestial observations (e.g. star sights) , or to the radio office to get the time check, then taken to the Chart Room to calculate the CW error. There were dozens of publications held in the bookcases in the Chart Room.


J.David Perkins of Halifax recalls the use of Decca aboard a submarine. "As PO of the Watch and Chief of the Watch in submarines, one of my responsibilities was maintaining the track on the chart and of course in coastal waters and that meant using Decca. We took, and plotted visual (using the periscope) and Decca fixes at least every half hour and when close to land, more often. My first encounter with Decca was in 1957 aboard HMS/M Solent running out of Portland, Dorset. Even as killick of the watch I was being instructed in its use. Of course, in a submarine the OOW was up on the bridge so the Chief did the navigating except for celestial which was left to the Navigation Officer".

Michael Young offers this recollection of Decca useage. "Normally Decca fixes would be obtained hourly unless there was reason to fix more frequently - high speed, current, weather or making a landfall for example. In HMCS Cayuga we once did a full power trial off Halifax and fixing our position every ten minutes. We went over 34 knots! The OOW could come down from the bridge, read the meters and then plot the fix up top. Or he could get the RP or ORO to take a reading and pass the results up for plotting. It was also used for blind pilotage (lane riding) so the Decca indicator would be near one of the radars and the plot table - on the overhead? One former Tribal officer stated that when he served in HMCS Haida circa 57-58 she did not have Decca so it only came into widespread RCN use in the late 50's/early 60's. The minesweepers had it, plus the track plotter feature, in 1957. Decca was shut down in Canada in the mid 80's. Loran C was much better in Canadian waters than Decca and I remember that Loran A was superb off the East Coast - usually better than Decca except when close in.


Found your site last week and was interested in the Decca section. I worked for the Decca Navigator Co. in England from 1974-1983 and was pleased to see so much detail included. My department installed and upgraded the main-chain equipment on a global basis. I have spent months at many of their sites, the last being The South Persian Gulf chain in 1983. My travels took me to many countries and the team spirit that pervaded the company was always evident. In addition, I spent some time working in Bill O'Brien's lab in the late '70's and remember him as an inquisitive but kindly founding father.

There are many ex-Decca group employees out there, many still working for the subsequent Racal /Thales empire. Your inclusion of a note from Doug Sim was also interesting since I had worked with him during that time and had  not heard from him since. Now resident in Atlanta, GA, I would be happy to fill in any gaps in future research.

Now for a anecdote. My first boss at Decca Navigator used to tell a story of  his time in Newfoundland, installing the chains there. One of the watch keepers developed a habit in the winter of coming through the door and after knocking the snow of his heavy winter boots, toss them up onto the top of the Dectra transmitters. There, they would rest on the wire mesh top and be kept warm until he went home. One day he came on duty and tossed his boots up as normal, only to have them sail on down into the transmitter tubes and take the station off the air! Seems there was some maintenance  work going on and nobody told him.

Best wishes,
David S. Jones
Litra Manufacturing Inc.
Norcross  GA,  USA
"D.Jones" <>


I served with Decca from early 1957 until the end of 1960, working in Dutch New Guinea (now Irian Jaya) seconded to the Royal Netherlands Navy and in Italy, on NATO trials of the system The former  carried out sea depth charting around the coast of New Guinea and the latter, tested the system on fighter aircraft.

The little grey cells are not as numerous or sharp nowadays, but I well remember my short training period at Little Wymondley in Hertfordshire and at the end, losing the toss of a half-crown which sent me to New Guinea and my colleague Jim, to Jersey Island. C.L (?) Hamilton was the Manager at the time, I think

During my time in New Guinea our chain commander was injured in a light aircraft crash while carrying out base-line checks. ‘Clocks’ were crudely rigged  up in the cockpit for this purpose and while flying low, it was thought that the aircraft wing clipped a palm tree. The naval pilot didn't survive by the way. At our master station was located in Merauke on the south coast. During my time there a path  (100 yards or so long by about
a yard wide) running from our accommodation to the diesel generator hut, was constructed from upturned, half litre Heineken beer bottles driven into the sand. A civil engineering feat taken very seriously and necessary because of the incessant mud caused by torrential rain. Consuming the beer prior insertion into the ground by the way, allowed the sand to penetrate the bottles, thereby increasing the stability of the path.

I served on ‘Green’ slave station  located on Frederik Hendrik Island just off the west coast. At the end of  transmission each day, we supplied electrical power to the adjoining native village. This provided lighting and radio power for the local mission and the police station. ‘Red’ station was located inland at a place called Tanahmerah (“red earth” in Malay language coincidentally!). I also spent several weeks on the naval survey ship maintaining the receivers and aerials and fitting the replacement vessel. Those weeks involved some very rough weather and unfortunately, curry was a very popular and  regular meal on board, which was far easier coming up than keeping down.

When I first arrived at the small airport in Merauke, I was picked up by a rather dour looking Dutchman in an old open top ancient military jeep, with what was obviously a newly-shot deer slung in the back. As the passenger seat was full of gear including the rifle, it was clear I was meant to sit along side the deer in the back. This turned out to be the only taxi service in Merauke

Italy was in many ways a welcome change from new Guinea but nowhere as interesting. There I worked in a  coastal town called  Sabaudia, located  between Rome and Naples and then on the island of Sardinia. In Sabaudia, Green station was set up on the beach almost as in New Guinea, but without the parrots and the mosquitoes.

Apologies for not expanding on the technical details. I do remember however, that in New Guinea we had a Redifon transceiver and one of the gang was a ‘Ham’. The call sign was I believe,  JZ0 PB.

I have just retired  after some 22 years  in sales engineering followed by 24 years in higher education. I count my time with Decca amongst the happiest of  those years.

Brian Kenny
United Kingdom
December 2002


My name is Paul Troiani. I was in the U.S. Army from 1965 to 1968 and served in Vietnam in '66 to '67. Was
one of the Army's first 7 men to be trained in Decca Navigator. I was stationed in Vung Tau in a Decca van and was the first G.I. to work with the reps from Decca - Ron Angle, Dave both from the U.K. and Fred Wisenburg and John Wisley from the U.S. I also met a guy by the name of Fred Staley from L.F.E., an American company wanting to make Decca equipment. I loved the system but time goes on.

Paul Troiani

By Brian Flett
(from The Orcadian dated 6 April 2000)

Tuesday, April 4, marked the end of an era for post-war technology in Orkney, with the complete shutdown of the Racal-Decca navigator station in Dounby.

For over 40 years, the Decca station has transmitted a series of signals which helped fishing vessels, other shipping and aircraft to pinpoint their exact location. The entire network was switched off this week, because the Northern Lighthouse Board and its sister organizations, Trinity House and Irish Lights, who have been footing the bill for maintaining the radio based signalling system since the early 1990s, believed it was no longer necessary because of the advent of Global Positioning System (GPS). It is now extensively, if not universally, fitted on board fishing vessels and is even available on handheld equipment, to establish accurate locations anywhere in the world from a series of signals received from earth-orbitting satellites.

The Decca station in Dounby started transmitting from a group of wooden  huts, in the same field now occupied by the three large masts, on  September 1, 1955. The base was set up by Ken King, who had been  running a station in the south of England. The first person to take charge of  running operations in Dounby was Harry Cordock along with Gordon Pirie who lived in Stenness, and Davy Johnstone from Dounby. Current station manager, Jim Anderson, recalls those early days.  “I joined Decca in May 1956. It wasn’t supposed to be officially open until  later, but the fishermen were in such a hurry that we opened it when it was still manually controlled. We had to take readings and check other things to make sure everything was all right. After that, you were just waiting there in case anything went wrong. It was a case of diving at the switches and doing something about it if anything happened.”

He explained the importance of the Decca station in Dounby to the UK signalling network.
“This was the North Scottish Master station, with ‘slave’ stations in Lewis, Peterhead and Shetland. Their signals were phase compared with the master station, to produce a pattern on Decca navigation charts which vessels had to have.”

Jim added: “I think there were four engineers to begin with, but it grew to five plus a handyman when we moved into the new building in January 1958. The first and second engineers lived on the premises. Harry Cordock
was first engineer, and Duncan Bell was second engineer. When Duncan returned to Edinburgh he was replaced by Ken MacInnes from Stromness. That was when the transmission system became reasonably automatic. You still had to be there, but you could turn your back on it for a few seconds. It was a 12-hour shift system we worked, and every 15 minutes we had to take readings off the receivers. The figures were recorded in logs in triplicate, even though there was a machine recording them as well.”

Jim Anderson remembers one particular occasion when the Decca transmitting station at Dounby was put out of action by the weather. “It was in wet snow, which pulled two wires down off the top of the aerial. We got a telegram about it, thanking us for getting it back on the air again. Luckily, Ken King was in Stromness at the time. He was the aerial man and took charge of the repair. We got the loan of Jim Hourston from Dounby Farm’s tractor and cattle float to give us some shelter while we were working in the field, because it was horizontal sleet that day. The wires were repaired on the ground and hoisted up again. The system was off for a few hours. It was dark when the wires came down. We didn’t realise why we weren’t transmitting a signal until daylight came and I saw one of the wires lying on the ground. All coastal stations sent out warning signals to all shipping telling them about the problem.”

Tommy Mainland joined Decca in December 1966 in Dounby. He remembers what it was like working a shift system, when living on the station. “When I joined, we used to do 12 hours on a day shift, from 9 in the morning till 9 at night. The next day, you went on at 9 at night and worked till 9 in the morning, and then you “allegedly” had two days off. I worked that shift pattern for a while, and then eventually we changed that to one week at 9 to 5, a week of 5 till midnight, and a week of midnight till 9 in the morning. It ended up that when we got “sleeping” night watches, we did 24 hours on, and 48 hours off.”

Jim Anderson remarked: “Eventually the station became more automated, we were able to sleep at nights. A number of local folk joined Decca in Dounby as well as Tommy. John Gray from Stromness had two stints here after he came out of the RAF, and Jack Twatt came around 1969 or 1970.” George Grieve joined Decca at Peterhead in January 1967, one month later than Tommy Mainland.

George recalled the shift system he had to cope with. “Peterhead was the ‘purple slave’ station. We just did 24 hours on, 48 hours off. But during the time off at Peterhead we were always very busy doing the marine servicing side of it - with the navigators on the fishing boats, which we also did up here, but not in such large numbers. If they broke down when they were trawling, they would pull up their nets, come ashore and get it fixed, rather than chance going without it. We installed the equipment on board the boats and serviced it. It was 24 hours a day. They were paying for it, and they expected to get it. If the system broke down at 3 o’clock in the morning, you were expected to be there.”

Tommy made a comparison between the volume of fishing boat work which had to be done in Orkney by Decca staff at Dounby, to that of the staff at Peterhead. “It was the same principle, but the number of boats concerned was minute compared to what it was at Peterhead. For a while, after I joined, I used to go down to Peterhead in the summer for holiday relief. The reason they wanted me was they wanted someone who could do the marine servicing work, as well as mind the station.”

George Grieve added: “The buildings at Peterhead, Dounby and Lerwick were exactly the same size. The Lerwick station also did the marine servicing, and I used to go up there to relieve, for the same reason as Tommy went down to Peterhead, to do the station shifts and marine repairs. I came up here to Dounby on April Fool’s Day 1972, a Saturday.” The three Decca engineers managed to bring up their families while working shifts, but it wasn’t easy.

George Grieve reacted nostalgically. “It was especially difficult in the summer time, when you were trying to sleep and the bairns were screaming around in the garden. The winter time was not really a problem at all. But when we went on to “sleeping” night shifts, you had two clear days with the bairns, and you seldom had any sleep to catch up on.” Tommy Mainland also felt that a shift pattern worked to his advantage. “I think I saw far more of my kids because I was home during the day, which folk who worked a normal day, weren’t. On the other hand, weekends didn’t exist. Folk would say, ‘What are you doing this Saturday?’ I’d reply, ‘Working’.”

Jim Anderson agreed: “It was great when you got whole days off through the shift system.” The whole system became totally automated in January, 1994, and the individual stations were left unattended except for maintenance work carried out by a locally-based engineer. In Dounby’s case, that person was Jim Anderson.
“I’ve been on call 24 hours a day. I’ve had to go to the control centre which is based at the lighthouse headquarters in Edinburgh, to do shifts there from time to time. I always come out here once a week, although the requirement was only once a quarter to do the maintenance, but I liked to keep it in good order.”

The non-essential staff were kept on until the end of September, 1994 stripping out the entire supply of technical equipment from the main building, and vacating the living quarters, to be replaced by a self-contained air-conditioned aluminum clad cabin alongside, housing miniaturized equipment. Neither Tommy Mainland nor George Grieve felt it hard to leave the Decca station for the last time when they were made redundant at the end of September, 1994.

Tommy commented: “It wasn’t difficult, because we’d had so little to do for the rest of that year. It seemed strange the building being there, but doing nothing.” George remarked: “I was quite lucky. I never got time to think about it. I stopped here on the Friday, and I started with the council on the Monday, and I’ve been with Orkney Ferries for nearly five years since.” But the two have had mixed reactions since they stopped working for Decca. Did they still think about the place, when they passed by? George said: “I certainly do, because I don’t go by that often. I tend to make a detour specially. But I did feel when I was made redundant, that I wanted to get away from the area after 20-odd years here. I didn’t belong to Dounby anyway, and after Decca went, I thought it was a good time for me to go as well.” Tommy said: “Certainly for a month or two, I thought to myself, ‘I used to work here.’ But now I hardly look at the place even, although I can see the masts from the house.”
But they still retain memories of the constant need for vigilance at the Decca station in case of an emergency.

Tommy Mainland said: “To this day, the charger for my cordless drill beeps when it’s up to charge, and it’s exactly the same note as the alarm tone used to be. I still automatically think, ‘What’s gone wrong?’” George Grieve added: “I sometimes do the same now when my mobile phone goes off. I think there’s something wrong somewhere and have to fix it.”  In its heyday, Decca could promise a career for life, providing regular training in electrical work and other aspects of the company’s many interests. Jim Anderson remembered those halcyon days.

“We had a Decca school which was at Brixham in Devon, and they sent us on courses from time to time. The Admiralty weapons and communications company Racal took over Decca in 1981 or so. It was said that they wanted to acquire Decca’s radar company, rather than the avionics side of the business. It was all going fine until a Danish company started making receivers for fishing boats which operated with Decca’s navigation charts, but they didn’t pay any rental for using the system. “A court battle followed, Decca lost the exclusivity, and that started the beginning of the end. Income started to dwindle. Eventually, the Ministry of Transport stepped in, and got the lighthouse authorities to take us over. That would have been the early 1990s.”

Jim went on to talk about the final switch-off for the station. “The equipment here is of no use to anybody else. That’s the end of it. A skip is coming and we’ll throw everything out. We have to get rid of the condensers in the coil house, and there’s oil in them which has to be checked before moving anything there. Alton Tait is taking over the cabin and the engine, so we’ll leave the control gear connected up, and just   disconnect our gear from it.”
Would he shed a tear when closing the whole system down for the last time? Jim Anderson replied: “It will take a nerve to switch it off after keeping it on for 44 years. It’s against your nature, I suppose.”

[Via The Orcadian Limited, Hell's Half Acre, Hatston, Kirkwall, Orkney, Scotland. Technical errors which appeared in the original article have been corrected.]

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Jan 3/03