sentences:  They were pitched over the side by a modified depth charge thrower.As part of the 1964 naval program, the Royal Canadian Navy planned to improve the attack capabilities of the "Restigouche" class.Unable to convert the vessels to helicopter-carrying versions like the "St. Laurent"s due to budget constraints, instead the "Restigouche"s were to receive variable depth sonar (VDS) to improve their sonar range, placed on the stern, and the RUR-5 anti-submarine rocket (ASROC).