The Largest Security-Cleared Career Network for Defense and Intelligence Jobs - JOIN NOW


River / St. Laurent / Restigouche / Mackenzie
DDE destroyer escorts / DDH helicopter destroyers

With the formation of the North Atlantic Treaty Organization, the Canadian government decided that the country's naval contribution should take the form of anti-submarine forces, a role that was to dominate the navy's activities for 50 years. In November 1948, the St. Laurent-class program for construction of seven anti-submarine escort vessels was announced. These ships, bearing the names of Canadian rivers, also perpetuated the names of Royal Canadian Navy (RCN) destroyers that had served during the Second World War.

The requirements for the class called for small ships capable of 25 knots, having larger armament and more sophisticated action-information systems than the existing frigates. The vessels were to be Canadian-designed, suited to rapid production in Canada in wartime and were to use equipment and material from North American, preferably Canadian, suppliers. The design for the new ships incorporated several innovative concepts, including a flush upper deck and well-rounded deck edges to facilitate de-icing at sea and decontamination of nuclear fallout.

The successful St. Laurent-class destroyer escorts (DDE), in addition to being the first postwar destroyer design in the world, was also the first major class of warship designed and built entirely in Canada (seven were built between 1955 and 1957). Ordered in 1948, the St. Laurent design was similar to the British Type 12 Whitby-class frigate but used more American equipment. Designed to operate in harsh Canadian conditions, these ships looked remarkably different from other warships of the time. They were built with nuclear and chemical warfare in mind, which led to their rounded hull and the addition of a prewetting system to wash away fallout and other contaminants. In addition, the living spaces of the ship were part of a 'citadel' which could be sealed against contamination for the safety of the crew. Of note were such innovations as the incorporation of an operations room from which the captain fought the ship. With the advances in fighting capabilities and the crew comfort that were integrated into the class, these ships were commonly referred to as the "cadillac of destroyers" by the sailors who sailed in them.

The 20 steam-driven DDE-205 St. Laurent-class anti-submarine (ASW) destroyer escorts built in the 1950s and 1960s were never intended to be the sole destroyer-type warships in the Canadian fleet inventory, but circumstances dictated otherwise. In fact, the 205-class and its variants comprised the bulk of Canada's naval surface combatants for nearly 30 years - a remarkable achievement.

During their three decades of service the St. Laurents, or "cadillacs" as they were known, evolved into several variants

  1. the seven-ship Improved St. Laurent (ISL) class of DDH helicopter-carrying destroyers,
  2. the three-ship un-modified Restigouche class,
  3. the four-ship Improved Restigouche (IRE-257) class,
  4. the four-ship Mackenzie (DDE-261) class, and
  5. the two-ship Annapolis (DDH-265) class
Being a successful design, a further seven anti-submarine ships were ordered in 1951 by the Canadian Government. Referred to as the Restigouche class, they were built between 1953 and 1959. Wishing to capitalize on the investments made in building these two classes of ships, the Government decided in 1958 to order an additional six ships, similar in design to the Restigouche class. This final flight of destroyers gave the navy a combined fleet of 20 modern anti-submarine destroyers. The first four of these ships became the MacKenzie class and the final two the Annapolis class.

In the early 1960s many were converted to carry helicopters. This involved the removal of one of the Limbo ASW mortars and the aft 3"/50 gun to make room for the hangar and landing deck, and various other improvements all over the ship. Activated fin stabilizers were added to reduce the ship's roll in heavy seas, as well as the Beartrap device which allows helicopter recovery in almost any sea state. One CH 124 Sea King helicopter was carried. The transom was altered drastically in order to allow for the placement of the new Canadian designed SQS 500 series VDS. The VDS was instrumental in extending the range of the ship's sonar, then limited to about 2000 yards, and is in essence a complete sonar set that can be lowered by cable to great depths behind the ship.

While the original St. Laurent design was for a 2,800-ton ASW destroyer escort, the final two ships of the design, HMCS Annapolis and HMCS Nipigon, were 3,000-ton vessels built specifically as DDH anti-submarine escorts. That the variant classes differed in their combat systems and air capability was a testament to the excellence of the original design in facilitating the addition of new weapons and sensors, including most significantly a flight-deck and hangar. Across the classes the hull form, propulsion system, auxiliary equipment, electrical system, navigation system and accommodation arrangements remained the same, offering significant economies in terms of training and support.

The St. Laurent design was also the basis for a general-purpose frigate that was designed in the late 1950s. The GP frigate program was ultimately scrapped, but the design for the star-crossed ship was to be 20 metres longer and 1,000 tons more in displacement than the 205-class. The GP frigate's planned hull form was similar to the St. Laurent design and would have been propelled by the same Y-100 steam main machinery system. The design also incorporated improvements to accommodations, combat systems and hull strength. The ship was intended to become the fleet's air warfare frigate and, as such, influenced the design of the DDH-280 Iroquois class commissioned into service in the 1970s.

In effect, the GP frigate and the St. Laurent ships were the equivalent of today's "spiral development" concept of dividing a common ship class into variants by capability. Although the detailed operational requirements for a single-class surface combatant were being studied bythe navy, the program could certainly result in a build of common design, with some ships differing in size and capability outfit to meet a broad spectrum of operational requirements. The benefits of building to a common hull and general arrangement would be felt immediately through reduced construction costs, and over the long term through more economical single-class crew training and life-cycle material support.

The ships were initially intended for only 25 years of operation, and it had become apparent that they would not be replaced until they were nearing 40 years of service. In the mid-1970s, delays in constructing replacements for the older vessels led to the need to upgrade the St. Laurent-class destroyer escorts. The Destroyer Life Extension (DELEX) Project was designed to extend the operational life of Canada's 16 active steam-driven destroyers pending their replacement by new ships. For the ST. LAURENT class, DELEX meant that the electronics for both radars were upgraded with solid state replacements, Mk.32 torpedo tubes and the new Mk.46 Mod 5 torpedo were added, and hull and machinery repairs were undertaken so as to allow safe operation for up to another 15 years.

In 1978, the Department approved the use of $79.9 million from operations and maintenance funds for the "safe-to-go-to-sea" package. In 1980 Treasury Board approved the capital program for $133.9 million. The project was to be completed by 1986, but the completion date was set back to 1989-90 because of lack of operations and maintenance funding for refits in 1980-81 and delays in delivery of some equipment.

In 1984 the Auditor General of Canada was concerned with an issue involving a non-military objective when an unproven radar was bought contrary to the recommendations of the Department's technical experts and against a departmental directive to buy "off-the-shelf" equipment. The radar was ordered from a Canadian company largely to support industrial development and Canadian sourcing objectives. In 1984 the Auditor General of Canada reported that the Department was then estimating that the delivery of proven, militarized radars would be three years late. In response to Public Accounts Committee questions in March 1985, the Department responded that the problem was well in hand and that the radars would be less than three years late. But reliability problems persisted, and the estimate by the Department is that fully approved radars could be five years late.

All the ships were repaired in critical areas and have had unsupportable equipment replaced or modified to provide continuing "safe-to-go-to-sea" capability. Ten ships have been furnished with updated equipment necessary to maintain approved combat and communication capabilities. The six oldest ships, which were to be replaced by the new Canadian Patrol Frigates, received no additional work beyond the "safe-to-go-to-sea" package. No deliberate attempt was made to increase the capability of the fleet through DELEX. The DELEX program provided work for the Canadian shipbuilding and electronics industries, enabling them to keep up with new developments to be prepared to bid on systems for the Patrol Frigate program, implemented in 1983.

As the new frigates came into service in the 1990s, the veteran helicopter-carrying destroyers of the various classes were decommissioned and disposed of.

Join the mailing list

Page last modified: 11-07-2011 15:32:52 ZULU