D.E.M.S.:   Naval Gunners in
Defensively Equipped Merchant Ships (DEMS)

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Box 29030
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August, 2001



The purpose of this handout is to provide a brief description of a wartime phenomenon whereby Naval personnel served alongside Merchant Navy crews in Canada's wartime Defensively Equipped Merchant Ships (DEMS), many ships as heavily armed as a naval frigate.

To meet the requirements of International Law, these naval personnel (subject to the Naval Discipline Act) were signed on merchant ships as Deckhands and were paid about one dollar a week by the shipping company. In effect, they were merchant seamen when 'signed on', including having to wear civilian clothes when in neutral ports. By the end of 1945, like most of Canada's wartime navy, all but a handful who wished to make the navy a career, were released.

In the late 1970s, a group of ex-DEMS in the Toronto area organized these veterans into the DEMS Branch of the Royal Canadian Naval Association; they still meet annually although in ever diminishing numbers. Of the current membership of less than one hundred, about a quarter attend the Annual Reunions. Although DEMS made up about 15% of the crews of Canadian open-ocean merchant ships, post-war publications and events seldom made mention of this group. Along with other wartime specialty groups such as Combined Operations, we are fading into history. However, we should ensure that DEMS is recognized in Canada's Military and Maritime History.


The story about building and arming Canadian merchant ships in WW II is intricately entwined with that of the British maritime system.

Prior to our Declaration of War on 10 September, 1939, Canadian/British merchant shipping was placed under control of the navy. The Royal Canadian Navy inherited several responsibilities, including the protection and control of shipping. This included routing, convoying, ship examination plus the protection of the ship by its own crew. It was in this latter task that DEMS (Defensively Equipped Merchant Ships) came into being.

High value merchant ships had been fitted with naval guns at the outbreak of war, including the fitting of 43 large calibre guns which had been stored in Canada by the Admiralty. Generally, only those Canadian ships which operated in the Eastern Atlantic and English Channel were fitted with some rudimentary armament, such as a WW I 'Stripped' Lewis Gun.

The navy was responsible for providing and manning this armament. It is estimated that between 200 and 400 Canadian naval gunnery personnel were transferred from our naval fleet to assist the British in this task during 1940-42.(This included the Channel Guard) Subsequently, approximately another 1600 naval personnel were trained for this task.

After the very heavy loss of British/Canadian shipping in the 1940/41 period and particularly after the Fall of France, it was decided to provide merchant ships with dedicated armament and specialized gunnery training of both naval and merchant seamen.

Merchant Ship Production:

In the period 1939-1945, we built 438 merchant ships, 217 for our own Merchant Navy with the remainder exported to Britain. The Canadian ships were added to our pre-war fleet of 41 plus another 10 acquired. (1) Over sixty Canadian registered/owned ships were lost.

The 10,000 ton freighters were based on a British 'North Sands' design. Canada decided that she would expand her own merchant fleet by building from the same design. Later, we also went into production of 4700 ton freighters and 3500 ton coasters. Thirteen of the 10,000 tonners were built as tankers. (2)

Canadian built ships were owned by the Park Steamship Company, an arm of the Department of Munitions and Supply, and were operated by Canadian shipping companies. These ships were named after Canadian parks, ie SS ROCKCLIFFE PARK. Ships built for the British account were named after Canadian forts, ie SS FORT QU'APPELLE. Crews for these ships were recruited from the Merchant Navy Manning Pools, in Halifax, Saint John, Montreal and Vancouver. In general, the armament built and placed in these ships was common to both the Forts and the Parks.(1)


During the war, Canadian industry built over 18,000 naval guns, most for the British Admiralty but a good percentage for arming the Canadian and British merchant fleets. (3) Nearly all Canadian open-ocean and coastal ships were armed, including the coastal ferry services.

In 1943, a typical 10,000 ton Park ship with a naval Leading Seaman or Petty Officer Gunlayer and six Seaman Gunners, would be fitted with the following armament: (This was in addition to bridge armour and degaussing) (4)

  • 4 inch gun aft
  • 12 pdr (3") forward
  • 4 x 20mm Oerlikons
  • 2 x Twin .50 cal. Machine Guns
  • 20 Rail Anti-Aircraft Rocket Launcher (Pillar Box)
  • 2 x Parachute & Cable devices (600'of Wire)
  • 2 x Fast Aerial Mine devices (1000' of Wire+Bomb)
  • 8 x Smoke Floats
  • Torpedo Nets
  • 2 x Minesweeping Paravanes and
  • 2 x .303 Ross or Lee-Enfield Rifles


All but about 200 of the DEMS were Gunners, the remainder were Convoy Signalmen, Telegraphists and Coders who would serve on the Convoy Commodore's staff. As noted earlier, probably up to 400 General Service trained personnel served prior to 1943, these seemed to be third class gunnery (Quarters Ratings (QR3) and Anti-Aircraft Lewis Gunners (AALG)). Many of these went on to become the Leading Seamen and Petty Officer Gunlayers. Because of the shortage of these trained gunners, many Royal Navy and Royal Artillery personnel manned the armament in Canadian ships. Conversely, Canadian DEMS served in Allied ships. It was noted that the number of DEMS serving at sea in early 1945, was 570. (1) The number of Canadian DEMS lost in WW II was about fifty with two thirds of them lost in other than Canadian ships.(5)

After 1942, six junior naval officers (Sub Lieutenants) were sent from ship to ship to both assess the DEMS' capability and to oversee training; however, DEMS generally consisted of very junior naval personnel with the chiefs and petty Officers plus commissioned officers manning the shore establishments.

In 1943, specialty Canadian DEMS gunnery training was instituted; these were trained as Seamen Gunners (Third Class), Gunlayers (Second Class) and Chiefs/Petty Officers (First Class). The length of the courses varied from six to eight weeks. Prior to these gunnery courses, a naval recruit would have been required to pass the four to six week Basic Naval Training, thereby getting drafted to his first merchant ship about three to four months after joining the navy. The Leading Seaman Gunlayer would have served in the navy for a minimum of two years and had experienced about three ships. The numbers trained in 1943/44 DEMS gunnery courses were; (1)

  • Seamen Gunners (O/Sea & Abs) . = 1147
  • Gunlayers (L/Sea).     =   212
  • First Class (Chiefs/Petty Officers)..=  110

An assessment of the relatively large armament package carried in a Canadian merchant ship, would make it obvious that the few naval DEMS could not man all the armament without help. The help came from merchant seamen, mainly trained in the DEMS Training Centres. Most of this training was in the form of two day courses however, training was also conducted in their own ship by the naval gunners. The streaming and recovery of the torpedo nets and minesweeping paravanes were normally the responsibility of the Mate and Bos'n. The Second Officer was normally designated as the Defence Officer and responsible for directing the ship's armament in action. As a result, he had a lengthier course in the Training Centres.

The Naval DEMS gunnery training in Canada was conducted in HMCS STADACONA, Halifax, HMCS CORNWALLIS, Deepbrook NS and HMCS GIVENCHY, Esquimalt,BC. In addition, there were five DEMS training centres/gunnery ranges established at Sydney, NS; Halifax/Cow Bay, NS; Saints Rest, NB; Couteau Landing, Que and Sea Island/Lulu Island, BC. Because we were part of the British system, there were some sixty DEMS Bases around the world which provided training, ammunition, pay and assistance to Canadian naval crews in merchant ships. (6)

Most of the post-1942 DEMS belonged to the Royal Canadian Navy Volunteer Reserve (RCNVR), were single and generally under the age of 20. An Ordinary Seaman DEMS would earn about $53.00 a month, including shipping company and naval allowances. An Able Seaman would earn about $63.00. They were paid through a Pay Book, kept by the individual and paid any arrears in any Naval/DEMS Pay Office. Ship's Masters would often pay advances where naval pay facilities were not available. However, the DEMS Gunners did provide a working pool for deck, engineering and catering sections. if employed, they received a merchant seaman's pay but the remaining gunners would have to double up on their watches but share in the monitory rewards.


Canada is a major trading nation and although our Open-Ocean Merchant Navy is small, our NATO naval commitments include the protection of Allied Shipping. There is a proliferation of anti-ship missiles, mines and torpedoes in the world's arsenals. We may not have heard the last of DEMS.

The End


  1. The Naval Service of Canada, The King's Printer,Ottawa1951.
  2. Mitchell & Sawyer, "Wartime Standard Ships-Vol II" Journal of Commerce & Shipping, Liverpool, England. 1966
  3. Kennedy, J.deN. History of the Department of Munitions & Supply, The King's Printer, Ottawa, 1950.
  4. Reid, Max, DEMS at War, Commoners Publishing, Ottawa,1990.
  5. 1939-1945 The War Dead of the Commonwealth,Halifax Memorial
  6. DEMS Pocket Book,(BR 282) The King's Printer, Ottawa, 1942

DEMS Veteran and author Max Reid can be reached either at the regular mail address at the top of this page or at the e-mail address of DEMS veteran Doug Sephton can also be reached through the same regular mail address or by e-mail at . For bibliographic information on Max Reid's book DEMS at War please go to the SOURCES PAGE of the Allied Merchant Navy of WWII website.

Cliff McMullen's page The Defensive Arming of Merchant Ships is uploaded on Tom Purnell's Convoy HX-72 and the Sinking of the Canonesa site. Please Click Here to go directly to Cliff's page.

To view Tim Vickridge's photos of the DEMs plaque at Monument Hill Reserve, Freemantle, Western Australia, please Click Here.

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