from The Ships of Canada's Naval Forces 1910-1981
by Ken Macpherson and John Burgess

This introduction presents the activities of the Royal Canadian Navy against the background of the "Battle of the Atlantic" struggle, which an anonymous Admiralty historian had divided into eight phases. The Battle was the longest in history, beginning on September 3, 1939 and ending on May 8, 1945. The following excerpts from each of these phases revolve around the loss of RCN ships (shown in red) in the battle:

September 3, 1939 - June 9, 1940 - During this period, U-boats found most of their victims in the southwest approaches to the British Isles. Transatlantic convoys were initiated almost immediately on the outbreak of war. They were escorted by battleships, cruisers, or armed merchant cruisers, as the greatest threat at the time was the surface raider.

June 10, 1940 - March 17, 1941 - Italy entered the war on June 10 and soon afterward, France collapsed. The Canadian destroyers found themselves engaged in the melancholy business of evacuating troops from France, and in the process Fraser was rammed and sunk by HMS Calcutta on June 25 ... The newly acquired HMCS Margaree was lost in collision in convoy on October 22 with most of her ship's company, many of them survivors of Fraser. The HMCS Bras d'Or foundered in the Gulf of St. Lawrence in October.

March 18, 1941 - January 11, 1942 - In March, the HMCS Otter was destroyed by fire off Halifax. Faced with a growing number of convoy escorts in what had been so happy a hunting ground, the U-boats moved their patrols farther into the Atlantic. It was now imperative that continuous escort be provided across the ocean. On September 19 HMCS Lévis was torpedoed and sunk and on December 7 Windflower was lost in a collision.

January 12 - July 31, 1942 - Four days after Pearl Harbor, Hitler declared war on the U.S., and in mid-January a large force of U-boats made their appearance off the eastern seaboard and in the Caribbean. In these waters they took a staggering toll of merchant shipping, especially tankers, as no convoy system had been established for coastwise traffic ... Canadian mid-ocean escorts inaugurated the "Newfie-Derry run" at Iceland. An escort of one of the earliest convoys on the that run, HMCS Spikenard was torpedoed and sunk on the way across, on February 10.

August 1, 1942 - May 21 1943 - In August and September U-boats were again active in the Gulf and the St. Lawrence River, and the armed yacht Raccoon and the corvette Charlottetown were torpedoed and sunk on September 7 and 11, respectively. HMCS Ottawa was torpedoed and sunk on September 13, corvettes Louisburg and Weyburn on February 6 and 22, 1943.

May 22, to September 18, 1943 - At the end of May the first of 19 merchant aircraft carrier ships went into service. There were no attacks on North Atlantic convoys in June, but land-based bombers launched a devastating assault on U-boats transiting the Bay of Biscay ... whereas merchant ship losses were negligible during the rest of the period.

September 19, 1943 - June 6, 1944 - The expected renewal of U-boat attacks on North Atlantic convoys began with a wolf pack attack on ON.202, September 19-23. One of the first victims was HMCS St. Croix. HMCS Chedabucto was accidentally lost on October 21 in the St. Lawrence River ... HMCS Valleyfield was lost south of Newfoundland on May 7 ... During the last quarter of 1943 the RCN Tribals were used extensively on convoys to Russia, then early in 1944 took part in a series of attacks on German shipping off the coast of Norway. Prior to D-Day, three of them participated in strikes against German shipping in the Channel; Athabaskan was lost in one of these strikes on April 29.

June 7, 1944 - May 8, 1945 - The HMCS Skeena was dragged ashore in a strong gale off Reykjavik, Iceland in October of 1944. With the Normandy beachhead secure, the British-based RCN ships shared with their RN sisters the task of defending the Channel approaches from Biscay-based U-boats, ... The anticipated U-boat onslaught against post-invasion traffic failed to materialize; instead, attempts began almost immediately to resume operations in British coastal waters. They achieved little success while suffering heavy losses, but HMC ships Regina, and Alberni in 1944, and Trentonian and Guysborough in 1945, were among their victims... toward the end of the year there were five or six U-boats off Halifax and in the Gulf of St. Lawrence. Shawinigan and Clayoquot fell prey to two of these, and Esquimalt to another in April, 1945.