Training ships as an interwar treaty gray area

How did treaties distinguish a training ship from a combat ship?

Not cleanly; many training ships remained mobilizable, so declared role and agreed adjustments mattered more than an obvious physical distinction.

Signals and declared status might identify a training ship in peacetime, but physical capability could overlap with combat ships. Many such vessels could return to wartime service after adjustment. The category existed because every navy needed training capacity and therefore accepted a measure of treaty ambiguity. This is a useful example of arms-control language accommodating an institutional need that could not be verified from silhouette alone.