stabilizers were to reduce roll in rough weather during helicopter operations. All seven St Laurents were fitted with helicopter platforms and SQS 504 Variable Depth Sonar (VDS). St Laurent was equipped with VDS late in 1961, the helicopter platform to be added later. When ships were fitted with the helicopter platform, the single funnel was altered to twin stepped funnels to permit the forward extension of the helicopter hangar. To make room for the helicopter deck, the aft 3-inch mount and one of the Limbos were removed. The two 40 mm guns were also removed. Following the conversion, the displacement remained the same at standard load but at full load, it increased to . Initial studies identified two helicopters that met the upcoming requirements- the Sikorsky S-61 (HSS-2) Sea King and the Kaman K-20 (HU2K). The Sea King was ultimately chosen in December 1961. Assiniboine was the first in the class to receive the full upgrade, re-commissioning as a DDH on 28 June 1963. On 27 November 1963, her new platform was used for the first operational landing of a production CHSS-2 Sea King, and her beartrap landing system was used operationally for the first time a week later. 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 Note that the pennant numbers were originally prefixed with the classification symbol DDE but were changed to DDH in the early 1960s. Service history Pre-conversion All seven ships were laid down between November 1950 and May 1952. All seven ships were completed by October 1957. Assiniboine joined the RCN at Halifax, Nova Scotia following her commissioning and spent the next two years on the east coast. In 1959, the ship transferred to the west coast and served there until being taken out of service in 1962 for conversion to a helicopter-carrying destroyer, the first of the class to go through the process. Fraser after commissioning in 1957 spent the first six years of her career on the west coast. During this period she aided the yacht Redwitch in 1960 and Yaqui Queen in 1964. In 1965, Fraser was subjected to shock tests