The Washington Treaty regulated replacements and rebuilds

The treaty allowed normal replacement after a capital ship reached the prescribed age and required powers to disclose the dimensions and timing of new construction. A ship lost accidentally could be replaced immediately, provided the replacement stayed within national tonnage and other treaty rules. Reconstruction was constrained, but improvements for defence against aircraft and submarines created room for armour, bulges, and anti-aircraft work. Renown's already-started alterations received explicit treatment in the agreement. This watch point shows that treaty fleets evolved through detailed legal permissions and exceptions, not through a simple building holiday.