Why a June 1944 Allied fleet total is hard to define

How many ships did all Allied navies have in service in June 1944?

Thousands, but no single total is meaningful until the count defines auxiliaries, chartered merchantmen, naval-crewed vessels, and small craft.

The combined total ran into the thousands, but any precise figure depends on what the historian counts. Chartered merchant ships, vessels with naval personnel, small combatants, and torpedo boats can move the result substantially. A published figure that excludes torpedo boats may be internally consistent yet answer a different question from one that includes every naval combatant. The passage is useful for learning why fleet-strength comparisons require definitions before arithmetic.