Why treaties chose a naval holiday

Why did the naval treaties impose a construction holiday instead of allowing each power a fixed annual tonnage?

Because negotiators believed sweeping disarmament would preserve peace, although it could also create fear and opportunity for aggressors.

Treaty negotiators believed a strong halt to construction would reduce insecurity and make peace more likely. That assumption is challenged by the risk that deep disarmament frightens status-quo powers while convincing aggressive states that opponents are becoming weaker.