Built with the latest in radar and sonar systems, they were well- equiped to detect the presence of air, surface, and submarine targets. These sensors directed modern guns and ASW weaponry. The FMC 3"/50 Mk.33 was primarily an anti-aircraft weapon, with minimal use with surface targets. It was guided by fire control radars mounted right on the gun. It remained in service with the Canadian Navy until 1998. Her ASW weapons included homing torpedoes and two Limbo mortars, which launched projectiles forward and to the side of the ship.  

When ST. LAURENT was launched, she also carried several other new accoutrements of warship design. Included were an operations room (from which the captain could control the ship in combat), and 12 separate telephone systems for internal communications. 

The ST. LAURENT class served as the basis for another 11 ships, in two different classes, whose design differed only slightly. 

With the advent of the nuclear submarine, however, it became apparent that even more efficient detection of submarines was needed to find submarines at greater distances than possible at the time. It was decided then to modernize the ships of the ST. LAURENT class to carry helicopters and Variable Depth Sonar (VDS). 

In the late 1970's and early 1980's, 6 members of the class underwent a refit intended to extend the service lives of the ships, called the DEstroyer Life EXtension program (DELEX). 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. 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.  

The last member of this class left service in October of 1994.