Annapolis-class destroyer

HMCS Nipigon underway during NATO Exercise Ocean Safari '85.
Class overview
Name:	Annapolis class
Builders:	Halifax Shipyards Ltd., Halifax Marine Industries Ltd., Sorel
Operators:	Royal Canadian Navy  Canadian Forces
Preceded by:	Mackenzie class
Succeeded by:	Iroquois class
Built:	1960–1964
In commission:	1964–1998
Planned:	2
Completed:	2
Retired:	2
General characteristics
Type:	Destroyer escort
Displacement:	3,420 long tons (3,474.9 t) full load
Length:	366 ft (112 m)
Beam:	42 ft (13 m)
Draught:	23.5 ft (7.2 m)
Propulsion:	2-shaft English-Electric geared steam turbines 2 Babcock & Wilcox boilers 30,000 shp (22,000 kW)
Speed:	28 kn (51.9 km/h; 32.2 mph)
Complement:	228
Sensors and processing systems:	Original: 1 × SPS-12 air search radar 1 × SPS-10B surface search radar 1 × Sperry Mk.2 navigation radar 1 × URN 20 TACAN radar 1 × SQS-501 high frequency bottom profiler sonar 1 × SQS-502 high frequency mortar control sonar 1 × SQS-503 hull mounted active search sonar 1 × SQS-504 VDS medium frequency active search sonar 1 × UQC-1B "Gertrude" underwater telephone 1 × Mk 64 GFCS fire control with SPG-48 tracker (GUNAR) DELEX: 1 × Marconi SPS-503 air search radar 1 × Raytheon/Sylvania SPS-502 surface search radar 1 × Sperry Mk.127E navigation radar 1 × URN 25 TACAN radar 1 × SQS-505(V) or SQS-510 hull mounted active search sonar 1 × SQS-504 VDS medium frequency active search sonar 1 × SQR-19(V) CANTASS towed array sonar 1 × UQC-1B "Gertrude" underwater telephone 1 × Mk 64 GFCS fire control with SPG-515 tracker
Electronic warfare & decoys:	Original: 1 × ULQ-6 jammer 1 × WLR-1C radar analyzer 1 × UPD-501 radar detector 1 × SRD-501 HF/DF DELEX: 1 × SLQ-501 intercept (CANEWS) 1 × ULQ-6 jammer 1 × SRD-501 HF/DF
Armament:	Original: 1 × FMC 3-inch/50 Mk.33 twin gun 1 × Mk. NC 10 Limbo ASW mortar 1 × Mk.4 thrower with homing torpedoes DELEX: 1 × FMC 3-inch/50 Mk.33 twin gun 2 × triple Mk.32 12.75-inch torpedo tubes firing Mk.44 or Mk.46 Mod 5 torpedoes
Aircraft carried:	1 CH-124 Sea King ASW helicopter
Aviation facilities:	Midships helicopter deck and hangar with Beartrap.

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 St. Laurent-class 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.

The Royal Canadian Navy had intended to place a six ship order under the Mackenzie class 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 366 feet (112 m) in length, with a beam of 42 feet (13 m) and a draught of 13 feet 2 inches (4.01 m). Initially, the ships displaced 2,400 tonnes (2,400 long tons) 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 30,000 shaft horsepower (22,000 kW). This gave the ships a maximum speed of 28 knots (52 km/h; 32 mph).

The ships were initially armed with two 3-inch (76 mm)/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 1,760 pounds (800 kg) and fired a projectile that weighed 24 pounds (11 kg). The guns had a muzzle velocity of 2,700 feet per second (820 m/s) and a range of 14,600 yards (13,400 m) 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°.