The Oberon class was a British-built diesel-electric submarine based on the successful British Porpoise class submarine. At the time Canada purchased these submarines, the Oberons were considered the quietest, non-nucleur submarines in the world. Twenty seven were built in total. Thirteen were constructed for the Royal Navy, while another fourteen were built and exported to other countries' navies: six to the Royal Australian Navy, three to the Royal Canadian Navy,  three to the Brazilian Navy, and two to the Chilean Navy. Chatham Dockyard in the UK built the Canadian boats and some for the RN but it did not build all the Oberon class submarines. Other yards included Scotts at Greenock, Vickers at Barrow, Scott-Lithgow and Cammell Laird.

Oberons employed QT28 steel instead of the UXW used in the Porpoise class. This was easier to fabricate and gave a significant increase in diving depth. Additionally, they made use of glass-reinforced plastic (GRP) in the casing and other improvements helped the class become even more silent than the Porpoises.

After serving with the Royal Navy for 27 years, HMS Olympus was placed on the Disposals List and subsequently sold to the Canadian Navy in 1989 for use as an alongside training boat for Canadian submariners.  HMS Osiris was dismantled for spare parts by Cammell Laird in 1993 and all parts (even the complete engines) were shipped to Canada to be used as spares for the three 'O' boats that were still in service.

A complete set of RCN Oberon-class training manuals are available at the Historic Ships Naval Association web site. These can offer the reader a greater insight into the capabilities of the submarine.

In the 1960's, all submarines like most ships of the day, were built and relegated to provide at a minimum, twenty years service. Therefore, on initial build and commissioning, each of the three Canadian O-boats were to enter Major Refit (complete rip-out) on a 3 year cyclic basis, but the Navy did not go to that extreme since the boats were new and not worn. Refits were normally scheduled to last 18 months but were always overshot. During their service life only two submarines maximum were operational at any given time but never three.

The normal cycle for each submarine was 3 years at sea and 1.5 years  in refit. With three boats, it meant that there were always two operational boats and one in refit. The two operational boats were often deployed to sea simultaneously, but seldom in the same exercise or the same operational area. Dual deployments were sometimes made in local operational areas. Submariners looked forward to their 1.5 years in refit after 3 years of sea duty. One benefit in refit was that the working day ended at 13:00.

There was however, a very brief one week period in the late seventies when all 3 boats were capable of self-propulsion on the surface, one not capable of diving until certain trials had been completed, another one preparing to enter refit, and only the third was soundly operational. There were also periods when only one submarine was operational. By 1973 or 74, the N.a.M.M.S Manual (Naval Machinery Maintenance Systems) was amended to extend the operational O-Class cyclic period from 3 to 5 years.

There are two batteries and two battery compartments in an Oberon class boat. Compartment #1 is situated under the accommodation space  while the #2 compartment is  under the Control Room. The steel deck, bulkheads and deckheads are lined with rubber to protect them against the corrosive  effects of spilled acid or acid spray. All fixtures in  the battery compartments are made of insulated material or coated with an insulating material. Wooden gratings on the deck are made from teak wood and are impregnated with paraffin wax to reduce the damaging effects of battery acid. To prevent the movement of cells in rough seas or radical underwater manoeuvers, wooden wedges are driven vertically between certain cells so that all cells are solidly wedged against one another and against the compartment bulkheads.

A single battery consists of 224 lead acid, primary cells, type D7420, wired in series. Each cell, weighing in at 1,120 pounds, has an output of 2.2 volts @ 7,420 amp/hours. The cells are mode from either fiberglass or treated plywood with a rubber liner. Together, they provide a nominal operating voltage of 440 VDC within an operating range of 390 to 650 volts. Within each cell there is 18.5 gallons of electrolyte which operates in a specific gravity range between 1.080 to 1.280.  It is estimated that each cell is 4 feet high and approximately 16 inches by 12 inches. The wiring of the cells can be split in half electrically speaking by means of the battery Mid Point Link Switch.  This will provide a battery with twice the current capacity but a lower nominal voltage of 220 VDC. This is an ideal configuration when slow speed but long duration is required.

Each cell is fitted with an electrolyte agitator (to prevent stratification of the water and acid) . In addition, each cell is cooled by pumping cooling water through a pipe which attaches to the terminal interconnecting strip.  There are a total of 8 posts per cell.  – four for positive and four for negative. For each polarity, an interconnecting metallic strip bonds all four posts together and the attached water pipe picks up the heat produced by the cell.

A single battery bank is recharged by a 1280 kw generator which is powered by a Model ASR1 16VMS diesel. Adequate ventilation of the battery compartments is imperative as the cells start to emit hydrogen gas beyond a certain point in the charge cycle. Any mixture of 4% hydrogen gas in air is considered to be explosive.  Each battery compartment has four hydrogen eliminators. The gas is eliminated by mixing it with oxygen on the surface of a catalyst. This forms water which is easy to dispose of.

There are three types of charges:

a) An Operational charge is performed the night before sailing. This type of charge is completed one hour after the battery voltage reaches 560 volts.
b) A Normal charge is performed every two weeks to bring up the battery to its highest state of charge. This type of charge is completed five hours after the battery voltage reaches 560 volts at the finishing rate of charge.
c) An Equalizing charge is performed at two month intervals to ensure each individual cell is brought up to highest state of charge. This type of charge is carried out for a minimum of seven hours and a maximum of ten  hours after the battery voltage has reached 560 volts at the final rate of charge.

Rates of charges:

1) If Specific Gravity (SG) is below 1180 , the charge is 1650 amps for each battery.
2) If SG is above 1180, the charge is 1250 amps per battery.
3) The finishing rate is 280 amps per battery.

The two batteries can be reconfigured for parallel or series operation. When in parallel, they would still nominally output 440V with 14,840 amp/hrs capacity. When in series, the two batteries produce an 880 volt output for full propulsion in 'Group Up' for approximately half hour. This was reckoned to be enough time for the sub to get away from any troublesome enemy.

This diagram illustrates the different battery and motor armature arrangements depending on the speed requirement. (RCN drawing)
Ex-submariner Don Courcy has kindly provided a copy of the O-Boat Electrical Training Manual  for anyone wishing more detailed information on the battery and charging system. Degaussing was not performed in a conventional, diesel submarine. That task was done by dockyard staff, after refit, by wrapping cables around the boat, and passing current through them.
This is how an Oberon looks when it is snorting. (DND photo via Buster Brown) 

All three of the Canadian O-boats carried a variation of torpedoes in their early years. These encompassed the Royal Navy's Mk. 8, the Mk. 20, and the USN's Mk. 37. By the end of the their demise, they embarked the USN's highly acclaimed Mk. 48 that is presently in use aboard today's Canadian Victoria Class submarines.

In some cases, after commissioning,  Mk. 8 torpedoes were used in calibrations and other trials during work-ups. It has been suggested that Ojibwa had been delivered as "not weapons capable" since this boat was used extensively for conversion training when she arrived in Canada. Bob Davidson, who served aboard Ojibwa says "To the best of my recollection, when we commissioned Ojibwa we had a couple of the "big babies" (ie MK 8's) onboard. But when we did our Torpedo trials (Loch Long I think) we took on a few of the smaller torpedoes, like the Mk 37's. I don't believe we fired the Mk8's but we had a good run with the smaller ones. Since there were no torpedoes onboard for a quite a while, we stored all our "spuds" on the racks".

LCDR Geoffrey Meek, former CO of Onondaga, recalls the following. "Aboard Onondaga, we did the work-ups and inspection with Mk8 Mod4 torpedoes as well as the discharge trials in the Loch Long. During the workups, we embarked and did trials with Mk37 torpedoes. These torpedoes we received from,  and had to be prepared by, the USN depot ship which was based in the Holy Loch, Scotland. I believe it was USS Proteus. After the workups, we never carried Mk8s again nor did we ever embark Mk20s that I recall". Michael Young confirms that Onondaga was commissioned with Mk 37's in the summer of 1967.

The original Northrup Mk 37 mod 0 torpedoes [4], carried from 1968 to 1973, were electrically propelled, swim-out weapons. Due to its electric propulsion, the torpedo swam smoothly out of the launch tube, instead of being ejected by a blast of pressurized air therefore significantly reducing its acoustic launch signature. The guidance of a  Mod 0 torpedo was accomplished by a gyroscope control during the initial part of its straight run trajectory. When 700 yards from the target, a passive sonar homing system took over. This was a Doppler-enabled active homing sonar with magnetostrictive transducers operating at 60 KHz. The electronics was based on miniature vacuum tubes but later it was converted to use solid-state devices. Mod 0 could be fired from all tubes but were usually only fired from the countermeasures tubes, No. 7 and 8.

The Mk 37 Mod 1 was a wire guided, electrically powered torpedo with a guidance range of 13,000 yards to target. This was achieved by 10,000 yards of wire inside the torpedo (increasing the length to 4.1 meters) and an add-on external dispenser which held 3,000 yards more of guidance wire . Guidance was achieved using the GARTU (Gyro Angle Retransmission Unit) and  TCCS 9 (Torpedo Control Calculator System). The wire guidance made the torpedoes longer, slower and heavier than Mod 0, but offered better target acquisition capabilities and higher ability to intercept agile submarines because of the wire guidance.

Between 1973 and 1975, Canadian Mk 37 torpedo inventory was modified. All Mod 0 torpedoes were sold back to the USN. Mod 1 torpedoes were upgraded to Mod 2. This upgrade included an Otto Fuel propulsion system  which added another 6 knots of speed and 12 nm of range. The weapon also received upgraded the electronics and transducers. These upgrades were required to keep up with the new classes of  submarines which could out run an electric Mk 37 torpedo.

One disadvantage of the Mk 37 was its susceptibility to flooding at a depth well above that which could be easily be reached by any self-respecting SSN or SSBN. Another drawback of all Marks of this torpedo was was the inability to withstand sustained immersion. Once the tube had been flooded, the weapon either had to fired within a few hours or withdrawn and stored, otherwise its reliability was compromised. On a positive note, the use of the shorter Mk 37 torpedo allowed additional bunks to be fitted in the fore ends thus allowing 10 additional trainees to be carried above the boat's normal complement.

In 1988 the Mk 37 torpedo inventory was replaced with the Mk 48 Mod 4 torpedo.


At sea in the North Atlantic, heat was supplied through the ventilation system by electric heaters of the main ventilation system, up to #77 bulkhead. The 10X6 fans had in-line plenum heating elements that ran at either high or low settings. For obvious reasons, the engine room had no heat supply. The motor room and the after torpedo room had their own axial flow fan that also had a heater with high or low settings. Variances in external cold sea temperatures was an ongoing battle to stay warm.  One source of heat would come from engines which have just been shut down.  In the course of just a couple of hours, the residual engine room heat would equalize with the ambient temperature with the rest of the boat. Beyond that, the Galley, Motor Room cubicle and the (Do Not Enter)  Radio shack with their warmth and coziness were the prime locations  for keeping warm when dived. For those who worked outside these spaces, crew  had to put on additional clothing or jump in a bunk bag and climb under their mattress as noted by Buster Brown.

As far as cooling, the same ventilation system was used with two big air conditioning plants located in the A.M.S. Each of the spaces were also fitted with “spot coolers” that could be used either to “cool” or “heat”. If the submarine was operating in tropical climates and an operational requirement called for "Ultra Quiet", then the air conditioning would be shut down. There was a reason for this. In tropical waters,  noise level values (in db) need to be decreased by shutting down all unnecessary machinery to achieve the Ultra-Quiet state in support of the mission. ie: "So you can listen for........and not to be heard".


The book "Canadian Submarine Service in Review" by J.David Perkins  provides an excellent summary of the differences between the three Canadian submarines.


The development of the Canada's three Oberons begins with the laying down of the R.N.’s last “Oberon”, HM Submarine Onyx in Chatham.  By 1964, Canada was anxious to commence a construction program where at the time, the Royal Navy was as equally anxious in getting an improved Oberon class submarine together for its own purposes.  As Onyx was laid down and to be built as a  standard Oberon, she was quickly transferred to the RCN and would be re-named Ojibwa.  A second HMS/m  Onyx was then to be laid down at Cammel-Laird’s in Birkenhead as a Super O, or “22 class” (side number  designated SS 22). The Ojibwa was always referred to as "The Go Boat" and Okanagan, a 22 Super O, was called "The Show Boat" as a bit of competition between the crews.

Because of her advanced state of construction and the cost involved in making changes, it was not possible to incorporate a full range of Canadian modifications in the submarine. For all practical purposes, Ojibwa entered Canadian service as an RN fitted Oberon.

In her 1993-94 refit, Ojibwa was successfully re-engined by separating the hull aft of the engine room bulkhead using a high pressure water stream to cut the hull without heat or metal loss. The engines were withdrawn , rebuilt engines from HMS Osiris were inserted and the hull welded back together using conventional pressure hull welding techniques.


Following completion of Ojibwa, Onondaga and Okanagan were to be Chatham ‘yard’s first crack at building 22’s while the Australian Navy paralleled with their six submarines construction program in Scottish Yards.  Hence, the RCN and Canada were to end up with one standard Oberon 09 class and two 22’s, the latter more commonly referred to as the “Super O’s”.

Onondaga was one of the "super O-boats" to be constructed and could be called "Canada's first Oberon" since she was built from the keel up for the RCN. She received many Canadian changes including an open-concept control room, relocation of the radar office to the machinery space under the control room, an an inboard battery-ventilation system, enhanced air conditioning and Canadian communications equipment. As far as accommodations were concerned, she was still an RN Oberon. The Canadian Oberons used United States Navy torpedoes throughout their career. In 1996-97, Onondaga was re-engined in the same way as Ojibwa, by receiving Ojibwa's rebuilt engines.


Being the last procurement, Okanagan received many additional improvements. To improve habitability, the galley was relocated to the accommodation space instead of the after end of the control room.  This eliminated the undesirable stream of traffic though the control room that was a thrice-daily feature in Ojibwa and Onondaga. A spacious cafeteria was provided adjacent to the galley while the traditional broadside messes became bunk spaces. An open concept sound room and Canadian communications were also provided.

For the first decade of their existence, the O-boats were considered to be training submarines and were not expected to be up to full operational standards . Although they were originally provided with a state-of-the-art sensor suite, little effort was made to keep it updated. To make all three O-boats battle-worthy, they were given a wide range of improvements in a program known as the Submarine Operational Update Project or SOUP.  Beginning with Ojibwa in 1980, as each boat entered its cyclical refit , it was fitted with the Singer Librascope computerized Submarine Fire Control System (SFCS) Mk 1 Mod C and Gould Mk 48 Mod 4 heavyweight torpedoes, upgraded navigation aids. and other operational improvements. In 1989, the Triton sonar suite was purchased for the Oberons. It is characterized by the bulbous bow dome. At that time, the stern countermeasures torpedo tubes were removed to make room for a towed array, passive sonar. This gave the O-boats an enhanced operational capability well into the 1990's.

As a last act, Okanagan participated in the search for the cockpit and flight recorders from the wreckage of Swiss Air Flight 111 which crashed off Peggy's Cove, Nova Scotia on September 2, 1998.  Both recorders were recovered. HMCS/m Okanagan was the most glamorous and up-to-date O-boat ever built in her time and was sadly, the last ever submarine (and vessel) to be built in Chatham dockyard’s long history of submarine construction.

Select this link to read about Okanagan's prang with a British re-supply ship.


Larry Hickey adds this regarding the 22 Class. "Following completion of Ojibwa, Onondaga and Okanagan were to be Chatham ‘yard’s first crack at building 22’s while the Australian Navy paralleled with their six submarines construction program in Scottish Yards. Hence, the RCN and Canada were to end up with one standard Oberon 09 class and two 22’s, the latter more commonly referred to as the “Super O’s”.

Onondaga was one of the "super O-boats" to be constructed and could be called "Canada's first Oberon" since she was built from the keel up for the RCN. She received many Canadian changes including an open-concept control room, relocation of the radar office to the machinery space under the control room, an an inboard battery-ventilation system, enhanced air conditioning and Canadian communications equipment. As far as accommodations were concerned, she was still an RN Oberon. The Canadian Oberons used United States Navy torpedoes throughout their career. In 1996-97, Onondaga was re-engined in the same way as Ojibwa, by receiving Ojibwa's rebuilt engines".

D.H. Buster Brown also adds: " All 3 of the boats carried Mk. 8's at time of commissioning until the Mk. 37's became available in late 1968. Here's a little more info to add to Larry's regarding Super O's. The Super “ O”s” HMCS/m Okanagan was the most glamorous and up-to-date O-boat ever built in her time and was sadly, the last ever submarine (and vessel) to be built in Chatham dockyard’s long history of submarine construction. She was to be a “Super O”, or in some corners a “ 22”, the term(s) applied to the improved Oberons that began with the building of Onondaga. A brief account of the development of the Canada’s three Oberons begins with the laying down of the R.N.’s last “Oberon”, HM Submarine Onyx in Chatham. By 1964, Canada was anxious to commence a construction program where at the time, the Royal Navy was as equally anxious in getting an improved Oberon class submarine together for its own purposes. As Onyx was laid down and to be built as a standard Oberon, she was quickly transferred to the RCN and would be re-named Ojibwa. A second HMS/m Onyx was then to be laid down at Cammel-Laird’s in Birkenhead as a Super O, or “22 class” (side number designated S 21). Following completion of Ojibwa, Onondaga and Okanagan were to be Chatham ‘yard’s first crack at building 22’s while the Australian Navy paralleled with their six submarines construction program in Scottish Yards. Hence, the RCN and Canada were to end up with one standard Oberon 09 class and two 22’s, the latter more commonly, the “Super O’s”.

Ojibwa 72 CZFQ September 23, 1965 1980-2 May 21, 1998
Onondaga 73 CGNQ June 22, 1967 1982-4 July 28, 2000
Okanagan  74 CGLM June 22, 1968 1984-6 Sept 12, 1998
Olympus Not commissioned -
training boat
--- Transferred 1989 -- Stricken April 27, 2000
Osiris Not commissioned. 
Stripped of parts. 
--- Parts transferred to the
Canadian Navy. 
-- --

1998 - Oberons berthed at HMC Dockyard, Halifax. (Photo by Jerry Proc) 

oberon_layout_s.jpg Oberon Class deck layout. Click to enlarge. Note the location of the Comms Office in the middle view. (Graphic courtesy Canadian Submarine Service)

Length: 295 ft. 3"  Beam: 26 ft. 6"
Draught: 18 ft. Displacement: 2007 tons (surface)
                      2406 tons (submerged)
Top Speed: 12 knots (surface)
                   17 knots (dived) 
Crew: 7 officers, 58 ships company; 10 
Range: 9000 nm @ 12 knots Max dive depth: 600 feet
Battery: Two batteries of 224 cells each  and either could produce 440 volts nominal at 7,420 amp hours. 


On the surface, the Oberon class used HF and UHF communications as did a surface ship. Underwater, VLF broadcasts were received at periscope depth and also at greater depths by use of the 'ALK' buoy VLF antenna outfit which increases the reception depth. When at periscope depth, the submarine could communicate on HF and UHF using the ALN mast and UHF facilities on the ECM mast. Communications are possible at almost any depth with surface units and other submarines using the Underwater Telephone. However, this method is a very insecure means of communication.

When transmitting a series of messages to a submarine as a HF broadcast, the Operations Commander screened the messages to ensure that the number was kept to the bare minimum so as to reduce the transmission duration. He would further decide if any of the messages had to be acknowledged and also how many times a message should be run on the broadcast.

There was always the uncertainty as to whether a submarine received a particular message so this had be given consideration when controlling a broadcast. Provisions did exist to place a  message on an essential traffic list and this would force the submarine to ask for a retransmission of the message had she missed it on the broadcast runs.

The broadcasts were sent at 100 words/ minute and received in the submarine on a tape recorder. This greatly reduced the submarine's time at reception depth or with the ALK buoy streamed.

 RADIO EQUIPMENT MANIFEST - 1960's and 1970's era
AN/URC 32 The main HF transmitter for ship to shore (CW, RTTY, voice)  (Photo courtesy RCN)
Collins 618T HF transceiver for sub-to-shore and sub-to-ship. Frequency Range: 2-29.999MHz in 1KHz steps. Modes: AM, CW, USB, LSB, Data. Power requirements:  28VDC or 115 VAC 400 Hz. Power Output AM/CW: 125W. SSB: 400W PEP (Photo courtesy Fair Radio)
AN/ARC 552 VHF/UHF transceiver for ship to ship and ship to aircraft.  (Photo courtesy RCN)
URR502A Racal RA 17C receivers with the CV5046 LF converter (Photo courtesy RCN)
CFA Receiver for VLF,  14 to 22.5 KHz .[Note 1]  (PDF courtesy RN Communications and Radar Museum)
Model 28 ASR teletype, 100 wpm. 
Model ? Phillips, 3 speed tape recorder similar to the one used in the Sound Room
Model?  FSK keyer and converter
KL7 Off line crypto. (Photo by Jerry Proc)
KWR-37 On-line crypto. (Photo by Jerry Proc)
Loran 'A' This was a HF, long range radio fixing aid used in most portions the North Atlantic. It was located at the after end of the chart table in Onondaga and Okanagan. In Ojibawa, it was located in the radar office.  In any of the subs it could be used on the surface or dived. The receiver was patched to the HF section of the Communications Mast as required. The actual model of the Loran 'A' receiver is not known at this time. 
It was located above the chart table and could be used on the surface or dived. It used the UHF section of the communications mast or the UHF section of the ECM mast. The changeover was controlled from the radio room. Decca was a relatively short range aid used in coastal areas only, but was highly accurate. The receiver mark is not confirmed at this time but it was likely the Mark XII, introduced by Decca in 1962.
Consol Consul is a radio fixing aid. It was a system of dots and dashes transmitted by shore stations and received by the sub's normal communications receivers and masts. It could be used while surfaced or dived. It was a long range aid, but was very inaccurate when compared to Loran 'A'. The results obtained were plotted on special Consul Charts. Consol was seldom ever used.
UA4 ECM Set SHF D/F set for S, C, X and J bands. (See writeup elsewhere in this document)
The late 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".
ALK Wire VLF aerial installed inside a recoverable buoy. It was controlled by the EUA. (Image courtesy Godfrey Dykes web page)
ALM Omni directional VLF aerial array comprising of a series of loops and fitted inside the fin. (Image courtesy Godfrey Dykes web page)
ALN Telescopic HF and UHF (225 to 400 MHz) mast consisting of stainless steel tubes. 
ALW Buoyant, disposable VLF wire antenna .
AMK UHF/IFF combined antenna associated with the ECM mast.
AWJ Sited on the fin, it was an emergency whip aerial for two-way use but for surface use only. It was a hand erected, telescopic whip aerial consisting of five sections.  When collapsed, the first four sections (top down) fit inside the bottom section. When extended it was 25 feet 6 inches tall and when retracted, 6 feet 8 inches tall. 

Canadian Oberons used this whip antenna when transmitting on HF while in port.  That meant that the main radio mast did not have to be raised.

AYG Used for SHF D/F equipment such as the UA4.
oberon_antennas_s.jpg This graphic shows how the ALK and ALW antennas are streamed. Click to enlarge. (Graphic courtesy Canadian Navy) 
Donald Courcy was a Sparker who served aboard Canadian submarines between 1965 to 1973. He describes some of the equipment used in the 'Silent Service' during the mid 1960's. "The radio shack was located just aft of the control room, on the starboard side, across from the Heads.
As I sat in my chair, I had access to the 618T and the '552 with my right hand. Control units were located on the ceiling, just above my head. Under the desk was the tape recorder and it and could be pulled out between my legs. The URC32 was in a separate room to my left while the Racal receivers were in a 19 inch rack to my left, just behind me. Most of the ship-to-shore traffic was sent by CW using either the 618T or the URC32, or by teletype using the URC32. I remember that the AN/ARC 552 VHF/UHF transceiver could be operated by remote from the control room while the HF equipment was operated only from the radio shack. We had both on-line crypto equipment for teletype and off-line crypto equipment for CW. Encrypted CW messages were sent in five letter groups and decryption was labour intensive.
The main HF antenna was telescopic and was raised above water when at periscope depth. We also had an HF whip on the bridge which was used on the surface. The VHF/UHF antenna was located on the upper part of the HF telescopic antenna. We also had a long wire antenna used for VLF reception when submerged. Canada did not have VLF broadcast but we could copy the American VLF signals. The traffic sent on VLF was either Canadian traffic or NATO traffic relayed to us via the American VLF system. It was mostly short, coded messages related to ongoing exercises"

For additional explanations about message handling, select this document.

Teletype Model 28 ASR. It had to be completely disassembled in order to get it down the hatch. Donald Courcy comments. "The use of the Model 28 ASR teletype was not restricted to sending and receiving RATT traffic. While the submarine was deep, I often published a newsletter and I used the five level Baudot tapes and the ASR to make  multiple copies for distribution throughout the submarine. I first typed the newsletter to generate the tape. If  ten copies were needed, I just ran the tape 10 times. We didn't have photocopiers aboard submarines". (Photo by Jerry Proc)
Gerald Sigrist who retired from the submarine service in 1969 after 12 years service, offers more insight into VLF reception. "We were able to copy VLF down to periscope depth which is 60 feet in most boats. There was a receiving antenna in the fin so it would probably be about 30 feet and if I remember correctly the British broadcast was sent on 16 kHz.

We copied set routines which were re-broadcast 4 times or until we were able to send a message stating which numbers we had received. We also used a towed antenna which when streamed usually came pretty close to the surface. The broadcast routines were sent high speed CW which we copied with a  recorder then halved the 90 WPM to 45 and again to 22 to be readable. It  worked pretty good in those days. Of course, to transmit we had to get an antenna out of the water. This would be done by raising the radio mast  (similar to a periscope but containing antennae). If that didn't work we had to surface".

Developing the submarine broadcast format  had some problems at the onset. Attempts to use CW were unsuccessful mainly due to the need to record a signal with the BFO adjusted to a high enough in frequency on order to be able to obtain a readable copy when replayed at slower speed. Subsequently, the signal from CFH was changed to a standard AM transmission, full carrier, double sideband, tone modulated (believed to be 300-400 Hz). Now, a tone could be provided which would not be lost when replayed at slower speed.

Phil Rody served as an Oberon communicator from 1969 to 1983.  "We used RACAL receivers to copy VLF signals when we were deployed to UK waters. When we were in Canadian or American operational areas, we used our own home broadcast and copied the RATT broadcast  from CFH on 73.6 or 133.5 KHz. Both were sent at 100 wpm.

The messages on the RATT broadcast were sent four times a day on four separate schedules. These skeds commenced at 0030Z and then at 0300, 0600, 0900, 1200, 1500, 1800 and 2100Z daily. Once the schedule was completed, the message was removed from the system and unless the submarine sent a ZDK [2], the message was considered to have been received. If a submarine came up for a sked and got all the messages and had traffic to send they would ZID [3] the last number received, and those messages could be removed from the broadcast prior to receiving four transmissions.

There were occassions when a submarine would miss four skeds in a row, but that was unusual. As sked times approached, reports were made to the Control Room for the Captain. Example....."Control, Radio.....30 mins to the next routine." If you received a roger for that you would report again at fifteen minutes and again at five minutes. If it was a "Must" Routine....i.e. the fourth routine in a row that you would miss you would report...."Control, Radio 30 mins to the next routine. This is a Must Routine". The Control room would either acknowledge and reports would continue, or they would say...."We will not be up for that routine", at which time you would stop reporting.

If there was no further new traffic after a submarine had ZID'd their traffic, then no traffic would be sent. A call tape was still sent which carried a short Service Message which would state there was no new traffic and the submarine would know there was nothing for them. When two submarines were at sea at the same time, the TFC (Traffic) List  indicated  the numbers for the Sked and which boat the messages were for.

C11LS 029 - Routine - Ojibwa
C11LS 030 - Routine - Onondaga
C11LS 031 - Routine - Onondaga/Ojibwa

The boats then knew which messages they needed to copy. Once Onondaga for example had ZID'd, the messages for her would be removed, but the TFC List would tell the other submarine what messages she needed to get.

No such device as a Burst Encoder was used to send CW messages back to shore. All shore-bound CW traffic was sent by hand at normal speeds. High speed Morse was used only to send broadcast messages to the boat.

By 1969, broadcasts using CW were still being sent but not for too much longer. Morse Code was still used for transmission purposes. Starting in the 1990's, the Oberons used the LES-9 satellite system to receive the broadcast in the UHF band.  A great deal of work was invested in the Mill Cove shore station in order to use the LES-9 system which was never under control of the US Navy".

Access to the radio room was restricted. TOP SECRET security clearance was required to enter and only on a "need to know" basis. In addition to Radiomen, the only other people who were allowed to enter were the Captain, the Communications Officer and the P.O. Tel (also known as POTS). The P.O. Tel (Petty Officer Telecommunication as it was known later) was the radioman's immediate boss.  CGNQ on the door was ONONDAGA's international call sign  with "Voyage Pride" as the RCN voice call sign. Shipmates who had business with the radiomen knocked on the door and waited. Messages (and hot coffee) were passed  through the little door.
Starboard side looking forward. The access door is at the left and the operating desk is at the right. In the 1960s and 1970s, Model 28 teletype equipment and the shredder was located to the right as well as an intercom system for the submarine. On board music (SRE) was also controlled from the radio room. Equipment racks to the left contained the Collins URC-32 HF transceiver used mainly for teletype radio communications, but also used for CW and SSB transmissions. There was also an equipment rack on the left, closer to the operating desk, which had two Racal RA-17 VLF/LF/MF/HF receivers as well as radioteletype and facsimile equipment, additional crypto gear, and direction finding equipment.
Starboard side looking aft. Some residual equipment was left behind after the submarines paid off. Sitting in the rack are two Collins R-5099/U (2050) receivers. In the late 1960s and early 1970s, Morse code and teletype were the two main modes of ship-to-shore radio communications The world of satellite communications had not yet arrived. Ship-to-shore radio messages were sent and received on the surface or at periscope depth by raising the communications mast.
Starboard side. Looking down at the operating desk. Many an operator sat here with a tape recorder to record Morse code transmissions at 100 words per minute. That would allow the operator to quickly copy the subs schedule and return to the deep where the tape was slowed down and was copied at 25 words per minute In terms of space, two people can sit at the desk and two more could be standing between the Model 28 Teletype and the URC-32 transmitter, plus one more with their back to the compartment door. Operationally, this would be impossible so the compartment was normally staffed by one person. 
All copy and photos in this table by Donald Courcy VE2CW


In mid-ocean, the only means of communication with a submerged submarine is to use radio in the VLF or ELF bands. The ability of radio signals to penetrate water depends on the following factors:

* the strength of the signal.
* the frequency being received.
* the efficiency of the receiving antenna.
* the salinity of the water surrounding the submarine.

In the middle of the Atlantic Ocean, with a salinity of 3.2 %, a VLF signal will penetrate down to a depth of 10 to 20 meters, barely periscope-depth for a modern day submarine. In areas with less salinity, like the Mediterranean Sea or in the brackish waters of the Baltic Sea, it will be possible to receive the same signal  to a depth in excess of 40 meters. Near the Atlantic coast where the salinity is less due to the run off from fresh water rivers, the receive depth could be even greater.

Oberon class submarines received American VLF signals occasionally since the RCN had no VLF transmitting capability. Oberons could receive VLF signals using one of three antenna types:

1) Trailing wire -  Outfit ALW. This trailing wire antenna had positive buoyancy and had the advantage of floating almost on the surface. It  was a way of receiving a stronger signal without breaking the surface. The trailing wire could also receive LF but only when floating on the surface

2) Trailing wire supported by a buoy - Outfit ALK. There was depth gauge in the buoy  which was monitored from inside the submarine.  The depth of the buoy was controlled through a combination of speed and length of extended antenna. If the radio operator wanted the buoy to ascend, more wire would be let out or the submarine would slow down. If the operator wanted the buoy to descend,  then more wire was taken in. ALK2 was for the 10-40 kHz frequency range while ALK-3 covered the 10-200 kHz range

3) VLF loop antenna in the fin - Outfit ALM. This was the preferred method of receiving by operator Don Courcy. When talking about the depth of a submarine, it is always in reference  to the depth of the keel. When a submarine is at  periscope depth, the  top of the fin is just below the surface and the keel is at 60 feet. The depth of the submarine would therefore be 60 feet when receiving VLF at periscope depth. The VLF loops which are located in the fin, would be at a depth of 30 feet. Don remembers receiving VLF signals using the VLF loop at a depth of nearly 100 feet (130 feet keel depth). The maximum VLF reception depth of 130 feet is the accepted limit when conditions are ideal  but under unusual circumstances it is believed that VLF can be received at depths of slightly greater than 130 feet.

OUTFIT ALN-  Consisted of a HF (2 to 25 MHz) and UHF (225 to 400 MHz) mast built with telescopic, stainless steel tubes. The upper portion of the top tube forms the HF radiating element and the UHF antenna is placed on top of that. It is raised and lowered by a hydraulic ram. At periscope depth, and with the mast fully raised, the UHF aerial is 20 feet above the surface of the sea. HF transmission and reception are only possible when the mast is fully raised and the RF interlock switch is engaged. UHF transmissions were permissible with the mast in any position. An RF isolator is fitted within the tube assembly. The mast weighs in excess of 2 tons.
Research of old radio call sign books has revealed some evidence of amateur radio activities on at least two of the Oberons. VE0ND operated in Ojibwa from 1976 to some indeterminate year. Aboard Okanagan, VE0NS was in use from 1971 to 1974. Nothing could be found on Onondaga. These were not club call signs but rather call signs held by individual operators and were used for the duration of the operator's posting.

Phil Rody provides more details " The amateur radio operator was responsible for the use of the boat's radio equipment when it was being operated as a ham station but the P.O.Tel was still responsible for the radio office. Amateur radio was used a lot in foreign ports to make calls home, and was on occasion used at sea, when for example, we were doing a surface transit back to home base. The CO would then allow phone patches to be made back home.  On the air, we could tell other amateur radio operators that we were a warship but were not allowed to state what type nor the coordinates. The boat's radio equipment could only be used on the amateur bands if the operator held a valid amateur radio licence.  When Bob Forbes was operating amateur radio VE0NS, he used  the phonetics "Victor Easy Zero Naked Sailor"

Don Courcy, VE2CW, explains the limited time that was available for amateur radio operation. "A submarine is always tied up in exercises, even in transit. As soon as the submarine leaves Halifax, it is used immediately as a target for sonar detection exercises by NATO ships and aircraft. Even when fleet exercises are over and surface ships disperse back to home ports, submarines are not free and are kept rather busy. Whether going in to St. Georges, Bermuda, to Roosevelt Roads or San Juan, Puerto Rico, to St. Thomas, St. Croix or to any other Caribbean ports or back home to Halifax, submarines in transit are used as targets by US, British and Canadian aircraft, mainly to train their sonar operators.

While at sea, submarines cannot transmit underwater and are restricted from transmitting when at periscope depth or possibly while on the surface thus leaving very little time for amateur radio operation except in foreign or home ports"

2 Harris RF-505  Receiver. 10KHz to 30 MHz HF Receiver. Made from 1974-1981. Modes: ISB, USB, LSB, AM and CW. Tunes in exact 100Hz steps. (Photo courtesy Oldradios.co.nz)
1 SRC-512 
(AN/ URC-505)
(With BRA34 antenna). MF/HF  HF transceiver for submarines. Frequency Range 1.6 to 30 MHz. Power Output - (Low) 40 watts; (High) 125 watts. Modes: USB, LSB, Compatible AM, CW, AFSK, FAX.   (Canadian Navy photo) 
1 SRC-509 Sealand 66 VHF transceiver. Frequency range 156 to 163 MHz
1 WRC-501 225 to 400 MHz general purpose transceiver. Up to 100 watts. 
Fitted in Ojibawa only in 1985.
1 180R-6  Collins Antenna Coupler Group; 2-30 MHz;. 400 watts.
1 AN/BRA-34  Multipurpose, muiltiband communications antenna for submarine use.
1   Antenna Fairing for AN/BRA-34 antenna. This is an external item to the BRA-34 antenna group.
1 OE-5018/BRA34 Coupler for BRA-34 antenna
1 AMK 0A VHF/UHF Stub antenna
7 HT-440  Sealand Handheld VHF radios. Frequency range: 150.8 to 174 MHz. 
4 preset channels. Power: Up to 5 watts  (Canadian Navy photo) 
1 PP5203 60 ma Teletype loop supply  (Canadian Navy photo) 
1 CV504 Patch Panel
2 KY5021/1215 Frequency Shift Keyer. One for HF. Another for UHF.
1 CV5087/1200A HF Demodulator
1 CV483/URA17 A transistorized frequency shift converter which was designed for frequency diversity radioteletype broadcast reception and single/dual channel reception. (Canadian Navy photo) 
Model 28  Teletype (as depicted in this document). In the mid 80's, Ojibwa was not fitted with a Model 28 for some unknown reason. 
2 AN/UCG-504 Printer. Speed - 50 to 2400 baud (selectable 50 to 2400 baud) (Canadian Navy photo) 
1 ALM, ALW and AWJ Antenna Outfits ( see descriptions elsewhere in this document)
LES-9 Satellite  UHF Satellite Broadcast
1 Nestor  Crypto for UHF
2 KW-7 Teletype Encryptor/decryptor
2 KWR-37  On-line crypto
2 KWX-7 Remote control box for KW-7
1 KL-51 RACE Crypto
1 Model ? Loran 'C' Receiver
1 AN/SRN12 OMEGA Receiver (Canadian Navy photo)
1 System ? Satellite Navigation System
1 Sony Sony Entertainment System  (Canadian Navy photo) 
1 AN/WIC-501 Intercom System (no photo available)
1 AN/PIC-2 Loud Hail System  (Canadian Navy graphic) 
1 AN/BYG-501  Submarine Fire-control System/Command and Control System Mk 1 (SFCS/CCS Mk 1) 
SATCOMM - In the 1980's it is confirmed that the Oberons used UHF satellite communications though the LES-9 (Lincoln Experimental Satellite). This satellite, designed by MIT Lincoln Laboratory was launched in 1976 into a geostationary orbit.  Its 21 transponder channels used uplinks between 303.150 and 303.650 MHz and downlinks between 249.350 and 249.850 MHz. Any UHF capable radio equipment could be used with the satellite. Each transponder had an 8 watt output (low power) or 32 watt output (high power). The satellite also had K-band (36–38 GHz) capability but this was not used by the Oberons. LES-9 is still active in 2004 but no longer doing its initial role as a military communications satellite.

AN/BYG-501 Submarine Fire-control System

In September 1974, the company, which had become part of the Singer Company as the Librascope Division, won a USD14 million Australian design competition for what has now been renamed the Submarine Fire-control System/Command and Control System Mk 1 (SFCS/CCS Mk 1). In October 1975, Librascope was awarded a production contract to produce systems for retrofitting into Oberon-class submarines.The SUBICS 900 (SUBmarine Integrated Combat System) is an evolution of the Mk 1 Mod 0 delivered to the RAN in 1978 for the Oberon-class submarines; the Mk 1 Mod 151 for the Indian Navy delivered in 1983; and the Mk 1 Mod C delivered to Canada in 1987 for the Oberon class. Architecture from the Virginia class has also been taken and migrated into SUBICS 900 for the SSK market. The system is designed to integrate sonars/sensors designed and developed by L-3 Communications ELAC Nautik, which are currently operational on diesel-electric submarines.The system entered service at FOC in February 1980 with the recommissioning of HMAS Oxley and was claimed to be the first digital submarine fire-control system in service. Subsequently it was selected by Canada for the Submarine Operational Update Project (SOUP) and by India.The first Canadian vessel with the system known as AN/BYG-501 was HMCS Ojibwa in 1980, and the first Indian vessel with the system was INS Shishumar in 1986. In the mid-1980s SFCS Mk 1 was again renamed, this time becoming Command Control System Mk 1 (CCS Mk 1)

FINAL RADIO?ELECTRONICS FIT (Incomplete. Looking for info. Contact: jerry.proc@sympatico.ca)
[This table is incomplete - looking for input]
2 Collins R-5099/U (2050)  Receiver: CW, AM, USB or LSB, (ISB optional), and FSK (with external modem). Frequency range: 14 KHz to 30 MHz in 10 Hz increments. 

Radar, IFF and Miscellaneous


Initial Fit - The Royal Navy E.C.M.set type UA4 was fitted to the Oberons. It was a transistorized SHF DF set used with aerial outfit AYG , all designed for submarines. Its purpose was to determine the bearing and characteristics of any intercepted radar signal. In principle, it worked exactly like the AN/UPD-501 system fitted in RCN's surface ships.

Type UA4 equipment was capable of monitoring 'X, 'C' , 'S' and 'J' bands simultaneously and displaying the results on three CRT's located in the Radar Office. The C and J bands shared a display which could either display both bands simultaneously or individually. There were four antennas for each band - port, starboard , fore and aft. On any given band, the signals arriving from each antenna were amplified and applied to the four deflection plates in a CRT. The resultant sloped trace and its length  provided a bearing information and some rough idea of distance.

When snorkelling, the E.C.M. would be manned at all times - either in wartime or in major peacetime exercises. In addition to a visual indication of an enemy transmission, there is also an audio signal. The intensity of the audio signal is an indication of the nearness of the transmitting radar set to the submarine and is reported almost continuously to the OOW (Officer of the Watch) by the Radar Plotter on the set.

The final fit ECM device, if there was one, is not known at this time.

UA4 E.C.M. (Image courtesy RN Museum of Radar and Communications) 

The Oberon's masts are listed in this display plaque near the Onondaga Submarine Museum. (Photo by Don Courcy) 
Onondaga as seen in June, 2009. Five of the seven masts are raised. From L-R: Attack Periscope,
Search Periscope, Radar Mast, ECM Mast and Schnorkel Induction Mast. The two masts not raised are the Communications and Schnorkel Exhaust Masts. On the ECM mast, the sensor has  been removed.  (Photo by Don Courcy) 


1998 - The forward torpedo room of Okanagan while she was still in commission.. Those are Mk 48 torpedoes in the racks. (Photo by Jerry Proc) 

The Torpedo Room contains a series of metal bars called the swing-out/static gear. Some of the bars are chrome plated while others are finished with enamel paint.  These come into play when "traversing" or "ramming" each of the torpedo warheads. The chromed plated bars are strictly cosmetic as they are prominently exposed when the racks are full of torpedoes. Bars painted with enamel are generally hidden from view with when there is a full crew, curtains, torpedoes and stores aboard  an operational submarine. Swing-out gear also acts as structural support when rigging the false deck for Rush Escape purposes through the One Man Escape tower. 

Four Oberon-class submarines awaiting disposal at HMC Dockyard in Halifax. (Photo by Cpl. Rod Doucet, Crowsnest  Vol. 2, No. 1 Spring 2008)
After serving with the Royal Navy for 27 years, Olympus was placed on the Disposals List and subsequently sold to the Canadian Navy in 1989 for use as an alongside training boat for Canadian submariners. This is Olympus as she appeared in 1998. The boat did not dive. (Photo by Jerry Proc)

When the Oberon boats reached end of life,  the Canadian government announced its intention to purchase four used submarines of the British  Upholder class. The deal was announced on April 6, 1998 and ratified in July 1998. When the submarines were delivered they were redesignated as the Victoria class. The old Oberon class submarines were disposed of in the following manner:

Onandaga  became a submarine museum in Rimouski Quebec in June 2009.Currently, amateur station VA2GNQ is active from the sub.
Okanagan and Olympus were scrapped and dry-towed to Port Maitland Ontario for processing.
The fate of Ojibwa is still undetermined as of Aug 29, 2011.

Please refer to the "Last Voyages of the Oberons" document for more details.


[1] The CFA receiver is listed as part of the radio manifest in the O-Boat Training Manual (page 14-10) but no one seems to have remembered using one or seeing one installed. It may have only been installed in Ojibwa and when that sub arrived in Canada, she likely had the CFA replaced by the Racal URR-502. The CFA may have been kept aboard as a spare. Can anyone confirm this? Contact: jerry.proc@sympatico.ca

[2] ZDK -  As a question: "Will you repeat message ...or portion ... ?
                  As an answer "Following repetition (of ...) is made in accordance with your request"

[3] ZID  - As a question: What is (are) station serial number(s) or channel number(s) of last message(s) you
                 received from me (or from ...) ?
                As an answer: Station serial number(s) or channel  number(s) of last message(s) received from
                you (or from ...) is (are) ..

[4] Speed 24 knots, Range 21.5 nm; warhead 330 lbs (150 kg) ; Weight  1,430 lbs. (649 kg)

Contributors and Credits:

1) Don Courcy, VE2CW,   <ve2cw(at)rac.ca>      Web http://www.radioman.ca
2) Gerald Sigrist <adpna.sigrist(at)ns.sympatico.ca>
3) The Canadian Submarine Service in Review by J. David Perkins
4) VLF and ELF Communications
5) RCN  C.F. 'O' Class Submarine Training Notebook - Chapter 14, Operations Equipment Circa, late 1960's and 70's.
6) RF505 photo  http://www.oldradios.co.nz/forsale/radios/rf505a/harrisrf505a_5_hires.JPG
7) http://en.wikipedia.org/wiki/Oberon_class_submarine
8) http://www.godfreydykes.info/OTHER%20SUBMARINE%20AERIALS.htm
9) Scandia Manufacturing  http://www.scandia.net/
10) http://www.absoluteastronomy.com/topics/Oberon_class_submarine
11) http://rnmuseumradarandcommunications2006.org.uk/UA4.pdf
12) http://www.rnmuseumradarandcommunications2006.org.uk/ALN.pdf
13) http://www.rnmuseumradarandcommunications2006.org.uk/CFA.pdf
14) LES-9 http://www.tbs-satellite.com/tse/online/sat_les_9.html
15) LES-9 http://www.aero.org/publications/martin/martin-8a.html
16) Phil  Rody <phillip_rody(at)rogers.com>
17) Zcodes    http://www.cyberbeach.net/lberta/zcode1.html
18) D.H. "Buster" Brown <retsubmarine(at)eastlink.ca>
19) http://en.wikipedia.org/wiki/Mark_37_torpedo
20) Michael Young <ejmy(at)rogers.com>
21) Brian Cooper   CASAP.NDHQ Ottawa 88-90    <brian158(at)ns.sympatico.ca>
22) Geoffrey Meek <2meeks(at)sympatico.ca>
23) Bob Davidson  <bobnwinnie(at)rogers.com>
24) MK 37 Torpedo: HNSA http://hnsa.org/doc/torpedomk37/index.htm
25) Gilles Poirier <poirier(at)ns.sympatico.ca>
26) CPO Jim Feener,  Brookfield, N.S.
27) Paul Renner <rennersp(at)nbnet.nb.ca>
28) Keith Allen <KEACLA1(at)aol.com
29) AN/BYG-501   http://articles.janes.com/articles/Janes-Underwater-Warfare-Systems/SUBICS-900-United-States.html

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May 25/18