When a large destroyer becomes cruiser-like

When does a large destroyer become a small light cruiser?

When it is large enough and its guns, rather than torpedoes, become the primary fighting system.

The answer avoids treating displacement alone as a clean dividing line. A large destroyer remains a destroyer when torpedoes are at least as important as its guns, as on the Tribal class. The hull also needs to reach roughly 2,500 to 3,000 tons before cruiser comparisons become persuasive. A ship becomes cruiser-like when guns clearly dominate its fighting role, while torpedoes become secondary rather than merely absent from an escort design.