Manpower alone did not make the retained-cruiser proposal impossible. The Royal Navy formed an entire division for land service from personnel who might otherwise have crewed reserve ships. Without enough escort hulls, Britain could not organize comprehensive convoys early, and German submarines found worthwhile targets. Their success then justified greater German investment in submarine warfare, reinforcing the threat. Retained long-range cruisers could have served as convoy command ships, provided radio coordination, and handed ships over to destroyer escorts in the danger zone.
Notable Point · 2:15:56-2:18:48
How escort scarcity encouraged German submarine investment
Britain had reservists but too few retained hulls for early convoys, allowing German submarine success to attract further investment.