Dual-purpose 4.7-inch guns and escort survival

Would fewer destroyers lost or damaged by air attack have major effects on the Battle of the Atlantic?

The effect would be real but uneven, with the largest gains among particular destroyer classes, coastal convoys, experienced crews, and fast minelaying cruisers.

Battle of the Atlantic escort work often fell to older First World War-era V and W destroyers, while many air-attack losses involved newer destroyers in the Mediterranean. Wider dual-purpose 4.7-inch fitting could still improve the survival and anti-surface power of Hunt-class destroyers and coastal-convoy escorts. Preserving experienced prewar crews would also improve the transmission of anti-submarine and ship-handling skills. The greatest offensive gain might fall to very fast minelaying cruisers able to overtake and destroy enemy torpedo craft before trailing destroyers rescued their crews.