The need for the
St. Laurent class came about in 1949 when Canada joined
NATO and the
Cold War was in its infancy. The Royal Canadian Navy (RCN) was assigned responsibility for
anti-submarine warfare (ASW) and controlling sea space in the western
North Atlantic. Design work for a new class of destroyer escorts began in June 1949 with the original completion date slated for 1955. They were designed by Montreal naval architects
German and Milne, under the direction of a senior constructor, Sir
Rowland Baker, seconded from the British
Director of Naval Construction. Baker produced a design basically similar to the
Whitby-class (Type 12)
frigate, while incorporating several ideas of his own. Different in appearance to the Type 12 design, the ship that resulted was similar in many respects. The
St Laurent class were built to an operational requirement much like that which produced the British Type 12, and were powered by the same machinery plant. The rounded deck-edge forward was adopted to prevent ice forming. The vessels were designed to operate in harsh Canadian conditions. They were built to counter
nuclear,
biological and
chemical attack conditions, which led to a design with a rounded hull, a continuous main deck, and the addition of a pre-wetting system to wash away contaminants. The living spaces on the ship were part of a "citadel" which could be sealed off from contamination for the crew safety. The ships were sometimes referred to as "
Cadillacs" for their relatively luxurious crew compartments; these were also the first Canadian warships to have a bunk for every crew member since previous warship designs had used
hammocks. Other innovative features not found on other ships of its time included an operations room separate from the bridge, from which the captain could command the ship while in combat, 12 separate internal
telephone systems,
air conditioning, and the latest advances in
radar and
sonar technology. There were also two essentially similar follow-on classes, the (4 ships completed 1962–63) and the (2 ships, completed 1964), the latter completed as helicopter carrying destroyer escorts from the onset, and not converted later as were the seven
St. Laurent-class ships. As built, the ships were
long overall with a
beam of and a
draught of . The destroyer escorts
displaced standard and at deep load. The destroyer escorts had a crew of 12 officers and 237 enlisted.
Machinery The vessels of the
St. Laurent class had two
Babcock & Wilcox water tube boilers installed The steam produced by these boilers was directed at two geared
steam turbines which powered two shafts, providing to drive the ship at a maximum speed of . The RCN had examined the feasibility of operating ASW helicopters from small escorts when it modified the in mid-1956 with a temporary helicopter landing platform fitted the
quarterdeck. Trials held in October 1956 and a larger temporary helicopter landing platform was installed in the new destroyer escort in August 1957. Operational trials were conducted using an
RCAF Sikorsky S-58, a substantially larger and heavier aircraft than the HO4S, and the success of these tests led to approval of the concept. To achieve the goal, the RCN needed a helicopter capable of all-weather day-and-night operations with a heavy weapons load—capabilities the HO4S lacked—and a means to handle and secure the aircraft on the landing platform in rough seas. Trials showed landing was not the major concern: deck handling was. Manpower alone was insufficiently quick or certain in all conditions.
Assiniboine was the first in the class to receive the full upgrade, re-commissioning as a DDH on 28 June 1963.
DELEX program In the late 1970s, under the Destroyer Life Extension (DELEX) program was commissioned to upgrade ten of the
St. Laurent-class ships with new electronics, machinery, and hull upgrades and repairs. However, only enough was done to keep the ships in service into the late 1980s. For the
St. Laurents, this meant hull and machinery repairs only. ==Ships==