Are modern merchant ships worth scarce torpedoes?

Are scarce modern merchant ships valuable enough to justify torpedo attacks?

Yes, but Soviet submarines may exhaust much of their limited load defeating the convoy escorts first.

Modern cargo ships carrying concentrated military loads justify torpedo expenditure. The constraint is tactical rather than economic: the submarine must first survive the escorts protecting them. A commander may fire several weapons at one escort because a single miss reveals the boat and invites an immediate counterattack. Four such salvos can consume most of an eighteen-weapon magazine, leaving little ammunition for the merchants behind the screen even when those merchants are valuable targets.