How capable would a united British, Australian, Canadian, and New Zealand fleet be?
Short answerVery capable on paper but operationally overstretched; the viable model is independent fleets that cooperate in procurement and combine for selected wartime task groups.
NotesThe map of carriers, amphibious ships, submarines, escorts, auxiliaries, mine countermeasures vessels, and patrol ships looks impressive only until those hulls are assigned across the Atlantic, Pacific, Arctic, Indian Ocean, and Southern Ocean. None of the navies has enough ships for all its own commitments, and combining their flags would not erase geography. Shared designs can nevertheless distribute research costs and make wartime groups easier to integrate. The practical model is cooperation in industry, standards, logistics, and operations among separate national fleets.