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Canada's Cold War Cadillacs - Destroyer Escorts of the RCN

Posted: April 15th, 2022, 8:30 am
by Rainmaker
Hi everyone, and welcome to my series which I’m entitling “Canada’s Cold War Cadillacs”. This series aims to create a definitive series of drawings that depict Canada’s Cold War destroyer escorts through various stages of their service histories, beginning with the St. Laurent – class destroyer escorts, and eventually continuing with the Restigouche, Mackenzie, and Annapolis – classes. This is a work in progress, so stay tuned for updates in the future!

Part One: St. Laurent - class Destroyer Escorts

The impetus 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 was the first class of warships designed for the post-war Royal Canadian Navy.

Design work for a new class of destroyer escorts began in June 1949, with the original completion date planned for 1955. They were designed by Montreal naval architects German and Milne, under the direction of a senior constructor, Sir Rowland Baker, who was seconded from the British Director of Naval Construction. Baker produced a design basically similar to the Whitby - class (Type 12) frigates while incorporating several ideas of his own. The St. Laurent - class destroyer escorts ended up being significantly different in appearance than the Type 12 frigates, but internally, they were much the same, sharing the same powerplant, among other features.

Unlike the Whitby - class, the St. Laurents featured a rounded deck edge that was designed to prevent ice from forming. The vessels were designed to operate in harsh Canadian conditions. They were built to counter nuclear, biological, and chemical (NBC) 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" that could be sealed off from contamination for the crew's safety. The ships gained the affectionate nickname of "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.

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The lead ship of the class, HMCS St. Laurent (DDE-205), was laid down on 24 November 1950 by Canadian Vickers at Montreal. She was launched on 30 November the following year and was commissioned into the Royal Canadian Navy on 29 October 1955. Initially, HMCS St. Laurent and her sister ship, HMCS Saguenay (DDE-206) were painted in the two-tone post-war paint scheme of the Royal Canadian Navy.

Armament included two 3-inch Mk. 33 twin guns in open mounts, two 40mm "Boffin" single mounts, two A/S Mk 10 "Limbo" anti-submarine mortars, and two Mk IV torpedo throwers - an intriguing and little-known Canadian invention that used a converted Mk IV depth charge launcher to fire a single lightweight torpedo. Unlike the Mk. IV depth charge launcher, the cradle was permanently attached to the launcher, and only the torpedo was thrown clear of the ship. The cradle was angled to ensure that the torpedo entered the water nose-first.

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By the late 1950s, the St. Laurent - class frigates lost their two-tone scheme, instead being painted in the RCN's new single-colour haze grey scheme which was heavily inspired by the Royal Navy's Light Admiralty Grey.

By this time period, advances in Soviet submarine technology, specifically the development of nuclear-powered submarines, had caused the RCN to begin earnestly studying the employment of the helicopter in an anti-submarine warfare role. In 1957, HMCS Ottawa (DDE-229) was used as a test ship for helicopter landing trials, with a newly constructed flight deck installed over the rear of the ship and her "Limbo" mortar well temporarily covered over. A Sikorsky S-58 (S/N 9633) of No. 108 (Comm.) Flight Detachment RCAF was loaned to the Royal Canadian Navy for this purpose. With her embarked helicopter, HMCS Ottawa took part in NATO exercises in the eastern Atlantic in the fall of 1957, which validated the use of the helicopter in the anti-submarine warfare role.

The helicopter landing trials on HMCS Ottawa showed landing was not the major concern: deck handling was. Manpower alone was insufficiently quick or certain in all conditions. During the 1957 trials aboard Ottawa, in one particular instance, it took 30 tense minutes to secure the S-58 to the deck during nighttime operations in rough seas. The deck handling issue would eventually be addressed by the invention of the "beartrap", otherwise known as a Helicopter Haul-down and Rapid Securing Device (HHSRD), one of the most significant Canadian innovations of the Cold War period.

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In the early 1960s, the RCN began retrofitting its 3-inch Mk. 33 twin guns with fibreglass shields. Because the St. Laurent - class was not designed with a separate gun director for fire control, the RCN fitted its Mk. 33s with the SPG-48 tracking radar, which was coupled with the Mk 64 Gun Fire Control System (GFCS). The antenna for the SPG-48 was located between the gun barrels on the mounting. Early variants of the SPG-48 used a parabolic antenna, while later versions used a Cassegrain-type antenna.

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By the early 1960s, the Royal Canadian Navy was fully convinced of the future of the helicopter as the ultimate anti-submarine warfare weapon - nothing else in their inventory could effectively counter the fast and deep-diving November - class nuclear submarines of the Soviet Navy. The St. Laurents were being seen as increasingly obsolete against this new threat, thus the RCN embarked on a radical program of converting their destroyer escorts to helicopter-carrying destroyers (DDHs).

In 1962, HMCS Assiniboine (DDE-234, renumbered to DDH-234) began the conversion process - she was to serve as the prototype for the conversion of her six sister ships. Emerging from drydock in 1963, Assiniboine was radically different from before the conversion process. In the conversion to a helicopter-carrying vessel, Assiniboine was gutted except for machinery and some forward spaces. Her 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. She was also fitted with the AN/SQS-504 "Diver" Variable Depth Sonar (VDS), another radical new invention that would also be adopted by the Royal Navy and Royal Australian Navy.

The single funnel of the St. Laurent - class 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 40mm guns were also removed. Because Assiniboine was the prototype for the DDH conversion process, she featured some notable differences from her sisters - her twin funnels were raked at an angle, and her hangar was of a somewhat different configuration.

The most important feature of HMCS Assiniboine's conversion was the installation of the new "beartrap" haul-down device. Conceived by the RCN, the haul-down system was designed and engineered by Fairey Aviation in Dartmouth, Nova Scotia. A prototype was designed and built by Fairey, under RCN supervision, and was installed in HMCS Assiniboine during her 1962-63 conversion. After re-entering service, Assiniboine quickly went to work validating the "beartrap", along with CH-124 Sea Kings from Experimental Air Squadron Ten (VX-10). By mid-1964 the daytime trials were completed and pronounced successful, and VX-10 moved on to validating the "beartrap" during night operations. Using the new system, no manhandling was needed to get the helicopter on the deck and in or out of the hangar. The helicopter was solidly secured on landing and remained so until the next take-off.

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In the late 1970s, the Destroyer Life Extension (DELEX) program was commissioned to upgrade the St. Laurent - class ships with new electronics, machinery, and hull upgrades and repairs. Unlike on later classes, such as the Restigouche - class, upgrades were fairly limited and focused primarily on basic capability enhancements, along with hull and machinery repairs. The St. Laurents received the AN/WLR-1C electronic countermeasures system (ECM), along with TACAN systems to enhance the navigation capability of their CH-124 Sea King helicopters. Their rudimentary Mk IV torpedo throwers were replaced by the new Mk 32 Surface Vessel Torpedo Tubes (SVTT), along with new Mk 46 Mod 5 lightweight torpedoes.

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By the 1980s, the St. Laurent - class helicopter destroyers were beginning to get quite long in the tooth. The namesake vessel of the class, HMCS St. Laurent, had been decommissioned in 1974, following an incident in which she was run aground and her keel substantially damaged, leaving her six sisters to soldier on. In the mid-1980s, HMCS Fraser (DDH-233) was designated the fleet test ship. In 1986, Fraser landed her AN/SQS-504 Variable Depth Sonar, becoming the testbed for the Experimental Towed Array Sonar System, which would later evolve into the Canadian Towed Array Sonar (CANTASS) that equipped the Halifax - class frigates. In 1987, Fraser was the first Canadian ship to carry and was the first to test the NIXIE torpedo decoy system. HMCS Fraser followed that with testing the TACAN antenna, installed on a unique lattice mast which was unlike the pole masts on her sisters.

The St. Laurent - class helicopter destroyers began decommissioning in the early 1990s as the new Halifax - class frigates began to enter service, with HMCS Fraser being the last to be paid off on 5 October 1994. The St. Laurent - class holds the distinction of being one of the most influential Canadian military achievements, being closely tied to several advances in anti-submarine warfare over their service lives, such as the development of the variable depth sonar and the ship-borne anti-submarine helicopter.



If you're still reading by now, thank you so much for taking the time to do so! As always, comments, constructive criticism, and feedback of all kinds are warmly welcomed. A big thanks to BCRenown for his Annapolis - class drawing, which was instrumental in me being able to create this series of drawings. Stay tuned for Part Two - the Restigouche - class destroyer escorts!

Re: Canada's Cold War Cadillacs - Destroyer Escorts of the RCN

Posted: April 15th, 2022, 8:38 am
by eswube
Great work! :)
And great initiative - I always appreciate when someone starts (and completes) a series of drawings of a larger group of (classes of) ships, that thanks to it are then made in consistent style, color palette etc.

Re: Canada's Cold War Cadillacs - Destroyer Escorts of the RCN

Posted: April 15th, 2022, 1:08 pm
by graham
Great Work, Ship bucket at its best good drawing, good history/information
On the 68 day of my diet just what I need :D
Graham

Re: Canada's Cold War Cadillacs - Destroyer Escorts of the RCN

Posted: April 15th, 2022, 4:14 pm
by st_lawrence
Beautiful ships and beautiful drawings!
It's always fun to see more RCN stuff

Re: Canada's Cold War Cadillacs - Destroyer Escorts of the RCN

Posted: April 16th, 2022, 11:13 am
by Rhade
Hats off...

Re: Canada's Cold War Cadillacs - Destroyer Escorts of the RCN

Posted: April 16th, 2022, 2:11 pm
by Gollevainen
really good work!

Re: Canada's Cold War Cadillacs - Destroyer Escorts of the RCN

Posted: April 23rd, 2022, 9:30 am
by Hood
Excellent work and very comprehensive coverage of the changes made to these ships.
This promises to be an excellent series.

Re: Canada's Cold War Cadillacs - Destroyer Escorts of the RCN

Posted: October 19th, 2022, 9:11 pm
by Rainmaker
And we're back, nearly six months later, with installment number two! After starting a new job back in June, I found my spare time severely diminished, but I've finally gotten around to finishing this series of drawings. Thanks for all your patience in the meantime!

Part Two: Restigouche - class Destroyer Escorts

Based on the preceding St. Laurent - class design, the Restigouche - class Destroyer Escorts had the same hull and propulsion, but differed in their weaponry. Initially, the St. Laurent - class had been planned to be 14 ships, however, the order was halved and the following seven were redesigned to incorporate improvements made on the St. Laurents as they had been introduced into service. As time passed, their design diverged further from that of the St. Laurents.

Unlike the St. Laurent - class, the Restigouches received a British-made Vickers 3-inch (76 mm)/70 calibre Mk 6 dual-purpose gun in the forward position, which necessitated raising the bridge an extra deck level to allow forward visibility over the gun mount. The gun armament was controlled by a Mk 69 fire control director, which incorporated an AN/SPG-48 fire control radar, mounted on top of a small deckhouse abaft of the bridge. The Bofors 40 mm guns of the St. Laurent - class, as well as the Mk IV torpedo throwers, were omitted from the final design. [I have seen several sources which claim that the Restigouche - class was in fact fitted with the Mk IV torpedo thrower, but after poring over hundreds of photos from the time period, I have never seen any evidence that they were fitted, therefore unless corrected I am willing to definitively conclude that they were never fitted with said equipment.]

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The lead ship of the class, HMCS Restigouche (named for a river that flows through Quebec and New Brunswick), was laid down on 15 July 1953 by Canadian Vickers Ltd., in Montreal, Quebec. The ship was launched on 22 November 1954. While still on sea trials by the builder, Restigouche collided with the freighter Manchester Port on 21 November 1957 in the Saint Lawrence River. The ship suffered damage to her port side superstructure and hull. HMCS Restigouche was commissioned at Montreal on 7 June 1958 with the number DDE-257.

The Vickers 3-inch Mk 6 main gun proved to be an early source of teething problems for the Restigouche - class. Designed as an air-defence weapon for the Royal Navy's Tiger - class cruisers, they were designed with a high rate of fire of 120 rounds per minute; however, the ammunition feed system was notoriously complex and prone to mechanical breakdown. This mounting used about 40 shear pins throughout the mount and the ammunition feed system. Two types were provided, pre-scored aluminum pins for peacetime use and un-scored steel pins for wartime use. The aluminum pins were a source of many problems during routine firing missions as the failure of a single pin would cause the mounting to cease fire and shut down. The Royal Canadian Navy would attempt to address the issue by opening a repair and overhaul facility for the weapons at the Naval Armament Depot in Dartmouth, Nova Scotia which was capable of fully rebuilding the guns - this, combined with reducing the maximum rate of fire to 90 rounds per minute, would eventually result in improved reliability for the weapons.

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By the early 1960s, the Restigouches received fibreglass shields for their 3-inch/50 calibre Mk 22 guns. HMCS Gatineau received an early electronic countermeasures system (ECM), likely a variant of AN/WLR-1. She was also the only vessel of her class fitted with a unique discone antenna mounted on the aft superstructure. In March 1968, Gatineau joined the NATO Standing Naval Force Atlantic (STANAVFORLANT), the first Canadian warship to do so. She served for nine months in the role before returning to Canada.

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As part of the 1964 naval program, the Royal Canadian Navy planned to improve the attack capabilities of the Restigouche - class. It was originally intended to convert the vessels to helicopter-carrying versions like their predecessors, however, the RCN was unable to achieve this due to budgetary constraints. Instead, the Restigouches underwent a conversion program called the Improved Restigouche Escourt (IRE) conversion. The stern was lengthened and redesigned to accommodate the SQS-505 variable depth sonar (VDS), and the aft deckhouse was rebuilt as a magazine for the RUR-5 ASROC anti-submarine rocket launcher. The addition of the ASROC launcher necessitated the deletion of one of the Limbo anti-submarine mortars. The destroyers also received a stepped lattice mast which held the radars along with the AN/WLR-1C countermeasures system. Corvus decoy launchers were added on the fantail, and a new structure was erected on either side of the lattice mast to accommodate the AN/SLQ-501 Canadian Electronic Warfare System (CANEWS).

HMCS Terra Nova was the first to undergo conversion, beginning in May 1965. The conversion took ten months to complete, followed by sea trials. The sea trials delayed the conversion of the next ship for four years. By 1969, the budget for naval programs had been cut further, and only four out of the seven (Terra Nova, Restigouche, Gatineau, and Kootenay) would get upgraded to IRE standards and the remaining three (Chaudière, Columbia, and St. Croix) were placed in reserve.

On 23 Oct 1969, while in European waters, HMCS Kootenay suffered a gearbox explosion that killed 9 crewmen and injured 53 others, the RCN's worst-ever peacetime accident. She was towed to Plymouth, part of the way by HMCS Saguenay , and then to Halifax by a salvage tug. While she was under repairs, she underwent the IRE conversion process. She was re-commissioned on 7 Jan 1972.

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The Destroyer Life Extension (DELEX) refit for the four surviving Restigouches was announced in 1978. An effort by Maritime Command to update their existing stock of naval escorts, the DELEX program affected 16 ships in total and came in several different formats depending on the class of ship it was being applied to. For the Restigouches this meant updating their sensor, weapon, and communications systems. The class received the new ADLIPS tactical data system, Marconi SPS-502 air search radar, as well as upgraded fire control systems and satellite navigation. The AN/SQS-505 C3 sonar dome replaced the previous SQS-10, and the 103 mm Bofors illumination rockets and Corvus chaff systems were removed, replaced by a Super RBOC chaff system mounted on top of the ASROC magazine.

The class was also fitted with two triple 533-millimetre (21 in) Mk 32 torpedo tube mountings in order to utilize the new Mk 46 torpedo. They were situated between the ASROC launcher and the Limbo mortar well. The ships began undergoing their DELEX refits in the early 1980s, however, by the time the ships emerged from their refits, they were already obsolete, as the Falklands War and the introduction of sea-skimming anti-ship missiles had drastically changed the way surface battles were fought. HMCS Gatineau was the first vessel of her class to receive the DELEX refit, re-entering service on 12 November 1982.

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With the advent of the Gulf War in August 1990, Maritime Command was asked to have a fleet of ships available to send to the Persian Gulf, preferably three ships. The Iroquois-class destroyer Athabaskan and the replenishment ship Protecteur would be made part of the task force, however, all the other Iroquois-class vessels were in refit. Maritime Command chose from among the remaining fleet the vessel with the best electronic countermeasures suite, HMCS Terra Nova, to deploy with the task force. Terra Nova was quickly altered to make her ready for an active war zone. The ship's ASROC system was landed and instead, two Mk 141 quad launchers for Harpoon surface-to-surface missile system were installed. A Mk 15 Phalanx close-in weapon system was placed on the quarterdeck in place of the landed Limbo ASW mortar, and two 40 mm/60 calibre Boffin guns were installed in single mounts where the ship's boats were. A small platform was erected above the aft deckhouse from which sailors could deploy Blowpipe man-portable surface-to-air missiles, giving Terra Nova a very limited anti-air capability. The ship was also fitted with new chaff, electronic, and communications systems. HMCS Restigouche also received a similar refit before deploying as Terra Nova's intended replacement in the Persian Gulf in 1991.

The Restigouche - class destroyer escorts were some of the longest-lived vessels to have served in the Royal Canadian Navy. HMCS Restigouche was paid off on 31 August 1994. She was sunk off Acapulco, Mexico as an artificial reef in June 2001. Kootenay was paid off on 18 December 1996 and was also sold for use as an artificial reef off Mexico. Gatineau and Terra Nova were paid off on 1 July 1998 after 45 and 46 years of service respectively, and were finally sold for scrapping in October 2009.


As a final note, I've made a few small corrections on the St. Laurents in the first post in this thread, missing railings, rigging, and those sorts of things. If the archivist could kindly re-upload those for me, it would be much appreciated! Once again, thank you for taking the time to view my work, and stay tuned for the next update, which should include both the Mackenzie and Annapolis - class vessels.

Re: Canada's Cold War Cadillacs - Destroyer Escorts of the RCN

Posted: October 19th, 2022, 9:31 pm
by acelanceloet
One small comment on all these: are you sure the shading on the hull is accurate? there seems to be such an abrubt end of the shading forwards and the shading on the bow suggests an very extreme flare, of which I can find little evidence on pictures (but I only took like 2 minutes for that)

Btw, do these ships have an anchor hatch that is fully flush with the hull and sealed shut when not in use? Because I don't believe I have seen an anchor opening outlined in just a bit of highlighting and grey lines.

Other then that, amazing work! and I cannot wait to see more.
If you redrew or updated components for these ships, let me know if you need help getting them on the shipbucket wiki ;)

Re: Canada's Cold War Cadillacs - Destroyer Escorts of the RCN

Posted: October 20th, 2022, 3:05 pm
by Rainmaker
acelanceloet wrote: October 19th, 2022, 9:31 pm One small comment on all these: are you sure the shading on the hull is accurate? there seems to be such an abrubt end of the shading forwards and the shading on the bow suggests an very extreme flare, of which I can find little evidence on pictures (but I only took like 2 minutes for that)

Btw, do these ships have an anchor hatch that is fully flush with the hull and sealed shut when not in use? Because I don't believe I have seen an anchor opening outlined in just a bit of highlighting and grey lines.

Other then that, amazing work! and I cannot wait to see more.
If you redrew or updated components for these ships, let me know if you need help getting them on the shipbucket wiki ;)
Hi Ace,

Thank you for your reply. I've attached a couple of images to help illustrate the bow shape. Image 1, Image 2, Image 3. I'll admit, the hull and bow shading was one of the things I struggled with the most on this drawing and if you think you have a better idea of how it could be done, please let me know!

As you can see from those photos, they do in fact have an anchor hatch that is fully flush with the hull and sealed when not in use. My understanding is that this was done to prevent ice buildup when operating in the North Atlantic - the edges of the hull were rounded for the same reason.

I haven't redrawn anything in a major way, just recoloured for the most part, but maybe it would be worthwhile to put together a small Canadian parts list of items that were unique to Canadian vessels, like the SPS-502 air search radar and the Mk 69 GFCS, etc.