HMCS Assiniboine (DDH 234)

HMCS Assiniboine was a St. Laurent-class destroyer that served in the Royal Canadian Navy and later the Canadian Forces from 1956 to 1988. She was the second ship to bear the name. Entering service in 1956, the ship underwent conversion to a destroyer helicopter escort (DDH) in 1962, the conversion performed primarily by Victoria Machinery Depot. She was officially reclassed with pennant DDH 234 on 28 June 1963. After being paid off in 1988, the vessel was used as a harbour training ship until being discarded in 1995. The vessel sank under tow to the breakers that year.

Design and description
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. 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.

As built, the ships were 366 ft long overall with a beam of 42 ft and a draught of 13 ft. The destroyer escorts displaced 2263 t standard and 2800 t at deep load. The destroyer escorts had a crew of 12 officers and 237 enlisted.

Armament
The St. Laurent class was fitted with twin 3 in/L50 caliber guns in two mounts for engaging both surface and air targets. The ships were also fitted with two single-mounted 40 mm guns. The class's anti-submarine armament consisted of a pair of triple-barreled Mk. NC 10 Limbo ASW mortars in a stern well. The stern well had a roller top to close it off from following seas. As with the British Type 12 design, the provision for long-range homing torpedoes (in this case BIDDER [Mk 20E] or the US Mark 35) were included. However, they were never fitted.

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 30,000 shp to drive the ship at a maximum speed of 28.5 knot. The ships had an endurance of 4570 nmi at 12 kn.

DDH conversion
Following successful trials aboard the frigate HMCS Buckingham (K685) and sister ship HMCS Ottawa (DDH 229), plans to convert the St. Laurent class took shape. Th development of the beartrap, installed in Assiniboine during her 1962–63 conversion, finalized the concept. By keeping the aircraft secure, the beartrap eliminated the need for deck handling from landing to the hangar, or from hangar to takeoff.

In the conversion to a helicopter-carrying vessel, Assiniboine was gutted except for machinery and some forward spaces. The hull was strengthened, fueling facilities for the helicopter and activated fin stabilizers installed. The fin 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). 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 3051 t.

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.

Operational history
Assiniboine was laid down on 19 May 1952 by Marine Industries at Sorel, Quebec and launched on 12 February 1954. The ship was commissioned at Sorel into the Royal Canadian Navy on 16 August 1956 and initially carried the hull number DDE 234 as a destroyer escort.

After commissioning, Assiniboine was assigned to the east coast as part of the Third Canadian Escort Squadron. From October to November 1956, Assiniboine sailed with the First Canadian Escort Squadron to northern Europe, making a series of port visits. In January 1959, she transferred to the west coast and in July, carried Queen Elizabeth II and Prince Philip from Vancouver to Nanaimo. Assiniboine was a member of the Second Canadian Escort Squadron based out of Esquimalt, British Columbia. After returning from her conversion to a helicopter carrying destroyer, she was assigned once again to the east coast. The ship was used for trials of the beartrap hauldown system and spent the following two years finding inclement weather conditions to test the system.

In 1974, Assiniboine was anchored in Lisbon, Portugal as part of the NATO Standing Naval Force Atlantic, with crew ashore, when the Carnation Revolution occurred. The tension and confusion of the situation saw the vessel recall her crew and leave the area. On 21 January 1975, Assiniboine recovered the crew from the freighter Barma, the rescue effort hampered by high winds.

Assiniboine was selected by the Canadian Forces for the Destroyer Life Extension (DELEX) program beginning on 23 April 1979 and completed this refit on 16 November. The refit was performed by Vickers Ltd. at Montreal, Quebec. On 2 July 1981, Assiniboine ran aground in Halifax Harbour in heavy fog, requiring the aid from several tugboats to get free. She had been scheduled to take part in a NATO exercise, but was removed after the ship was required to undergo damage inspection. In 1984, while acting as an escort for the Tall Ships race, she was part of the search for the crew of the lost sailing vessel Marques. In July 1984 the ship returned to Halifax with fractures in the plating of her upper deck. Assiniboine was sent to MIL Davie Shipbuilding at Sorel for a 10-month refit. The refit was extended to 17 months following a series of labour strikes at the shipyard.

She was decommissioned from active service in the Canadian Forces on 14 December 1988 and was used as a harbour training ship at CFB Halifax beginning on 3 January 1989. The ship was sold for scrap in January 1995 and sank in the Caribbean Sea while under tow.