British practice put testing before commissioning and acceptance of a new ship. Defects found during those trials therefore remained the builder's responsibility. German practice put testing after commissioning, allowing an earlier claim that a ship was in service while placing subsequent repair costs on the navy. Derfflinger's September 1914 commissioning illustrates the difference: practical readiness came later, around November or December in this comparison. The date on a fleet list alone could therefore overstate the force available for operations.
Notable Point · 28:28-29:47
Why commissioning dates can exaggerate fleet readiness
British and German commissioning practices affected both operational readiness and who paid to correct defects.