The Annapolis-class destroyer escort was a two-ship class of destroyer escorts that saw service with the Royal Canadian Navy and Canadian Forces from the 1960s to the 1990s. The final version of the design, the class was used extensively for anti-submarine warfare purposes. Both ships were sunk as artificial reefs after being retired, one on each coast of Canada. Design and description The Royal Canadian Navy had intended to place a six ship order under the of destroyer escorts; however, during the design phase, the last two vessels ordered were altered to the St. Laurent DDH design and were classed under the new Annapolis designation. The ships measured in length, with a beam of and a draught of . Initially, the ships displaced and had a complement of 228. The ships were powered by two Babcock & Wilcox boilers connected to the two-shaft English-Electric geared steam turbines providing . This gave the ships a maximum speed of . The ships were initially armed with two /50 calibre dual-purpose guns mounted in a single turret forward. The extra topweight of the helicopter required the return of the American Mk 33 3-inch gun over the heavier 3-inch/70 calibre guns used on the preceding class. The 3-inch/50s weighed and fired a projectile that weighed . The guns had a muzzle velocity of and a range of at a 45° angle. The guns could fire 45 – 50 rounds per minute with a lifespan of 2,050 rounds. The guns were placed in a Mk 33 mount. The mounting allowed the guns to elevate from −15° to 85°. The elevation rate was 30° per second and train rate was 24° per second. The mounts could train 360°. For anti-submarine warfare, the ships were armed with a Mk 10 Limbo mortar. The Limbo was a British-designed three-barrel mortar capable of launching a projectile shell between . Placed on stabilized mountings, the projectiles always entered the water at the same angle. The total weight of the shell was . They also had a Mk.4 thrower with homing torpedoes. Initially the ships were outfitted with one SPS-12 air search radar, one SPS-10B surface search radar, and one Sperry Mk.2 navigation radar. For sensing below the surface, the class was given one SQS-501 high frequency bottom profiler sonar, one SQS-502 high frequency mortar control sonar, one SQS-503 hull mounted active search sonar and one SQS-504 VDS medium frequency active