Corvette HMCS Chambly in Halifax, April 1941. Commissioned at Quebec City 18 December 1940, Chambly participated in escort missions and trained other corvettes for the duration of the war. Department of National Defence / National Archives of Canada, PA-105255.

To meet its urgent need for patrol and escort vessels, the British Admiralty decided to build a smaller ship, developed by naval engineer William Reed and based on a whaling boat design. The "Patrol Vessel - Whaler Type" could be constructed rapidly and in large numbers. Satisfied with the design but unhappy with the name, Sir Winston Churchill chose a shorter and more warlike name, the corvette, after a sailboat of old.

A corvette's shape and equipment being quite similar to that of a merchant ship, Canada was able to commission existing shipyards on the Atlantic or Pacific coasts, and along the St. Lawrence down to the Great Lakes, to build corvettes. Contracts were signed for the production of 64 corvettes in 1939-1940. The following years, 43 more were built by Canadian shipyards. They were called Flower class corvettes, as the first ones, supplied to the Royal Navy received flower names (Eyebright, Fennel, Hepatica). Later on, the Royal Canadian Navy (RCN) chose to give them names of Canadian cities (Chilliwack, Napanee, Saskatoon, Levis), although the term Flower class remained in use.

A sheet of sea water splashes over a crew member on HMCS Trillium, September 1943. Photo by Jacques Trépanier. Department of National Defence / National Archives of Canada, PA-037474.

With a length of 62.5 metres and a displacement of 950 tonnes, the first corvettes carried five officers and a crew of some 70 men. They were admirably seaworthy and able to withstand the worst North Atlantic storms. That did not make the corvette a comfortable ship: as soon as the sea gets choppy, corvettes tend to roll and pitch wildly. The fo'c'sle is too short to prevent sheets of water from crashing down on the deck, and the men cannot leave their mess without getting drenched. When the weather is bad, water is everywhere.

"The corvettes spent monotonous months plodding back and forth across the trackless waste of grey seas that were never at rest. To the men who sailed in these ships came a great weariness from the relentless watches, the untempting food, and the constant, chafing motion."
- Lieutenant William Pugsley, excerpts from Saints, Devils and Ordinary Seamen

On 23 October 1944, four days after being commissioned in Kingston, revised Flower class corvette HMCS Belleville pays a visit to her namesake city. The RCN encourages such courtesy calls to foster patriotic feelings in the population. Photo by Richard G. Arless. Department of National Defence / National Archives of Canada, PA-136925.

Corvettes were not ideal to detect and attack U-boats. Equipped with reciprocating piston steam engines because Canadian shipyards did not have the technical expertise to produce high-performance engines, their speed was limited to 16 knots, i.e. they were slower than U-boats. In addition, they navigated with unreliable magnetic compasses and their detection systems were limited to the ASDIC.

Throughout the war, corvettes will have to be modified to extend the fo'c'sle, improve detection systems and armament. The later Canadian-built Flower class corvettes benefited from those upgrades.

"During the summer of 1943, Rimouski had her focsle extended at the Mersey Pulp and Paper Co. at Liverpool, Nova Scotia. At the same time she received many other improvements, including the fitting of Type 271 radar, moving the foremast abaft the bridge, removing the mainmast and completely re-arranging the compass platform, asdic hut and chart-room. She came out a vastly better ship than when she went in. When I assumed command, the ship's company consisted of six officers and about seventy men. Now we had two additional officers, an engineer officer and, of all things, a medical officer, to go with our fine new sick bay. We had somewhere between eighty and eighty five men."
- R.J. Pickford, RCNVR, captain of HMCS Rimouski (from Salty Dips, vol. 2, p. 103)

To serve aboard a corvette required unflinching courage and tenacity, as demonstrated by the glorious deeds of Canadian sailors escorting merchant convoys. The corvette remains the symbol of the Royal Canadian Navy's relentless fight against enemy submarines during WWII.

Nowadays there is only one Canadian corvette still maintained in her original state, HMCS Sackville.