The decline in merchant losses was not attributed to convoys alone. Q-ships were becoming more effective while German submarines were tiring under repeated operations. Maintaining a large share of roughly 120 available boats at sea imposed a demanding tempo on crews and machinery. Campaign output depended on readiness, maintenance, and crew endurance as well as submarine numbers.
Notable Point · 39:30-40:05
Operational tempo wore down the U-boat campaign
Losses began to fall as Q-ships improved and German submarines tired under the high rate of operations needed to keep so many boats at sea.