Industrial depth decides who can replace a lost fleet

How would the war change if half of every navy disappeared on 1 January 1942 but the crews survived?

The Axis navies would suffer more because smaller surviving fleets and weaker replacement capacity would deepen their existing presence problem.

Surviving crews would give countries with substantial shipbuilding capacity personnel for newly constructed ships. Japan and Italy would have less ability to replace their lost hulls quickly. Even before construction was considered, the proportional loss would have unequal operational effects. Britain and the United States would still possess more ships because their fleets began larger. Smaller Axis fleets would have still fewer ships available to sustain their existing presence and control at sea.