Refits explain why fleet size is not fleet availability

After paying off at Chatham in August 1908, Formidable spent about eight months in refit before recommissioning in April 1909. Corrosion, machinery wear, weapons strain, and the need to open the hull for heavy lifting make periodic dockyard time unavoidable for a complex warship. A representative peacetime force can be divided into quarters: ships on station, in major refit, training or preparing to deploy, and transiting or receiving shorter upkeep. A nominal force of 24 vessels might therefore provide only about six continuously on station. If a navy needs ten escorts deployed at once, the same arithmetic points toward roughly 40 in the overall force. Maintenance cycles are a force-structure requirement rather than evidence that idle ships are being wasted.