In an annex to the weekly Naval Military and Air Reports on the progress of the war, there was was a brief summary of the huge serviceability issues that arose from from warships being at sea for extended periods of time:
Typical Examples of Performance of His Majesty’s Ships.
Between the outbreak of war and 31st December, 1941, H.M.S. Renown was at sea 390 days and during this time she steamed 137,000 miles.
H.M.S. Victorious. Steamed 41,378 miles in the first 8 months of her service. 13,000 miles of this distance were steamed in the first 5 weeks of her service.
H.M.S. Cumberland. Steamed 195,876 miles from the outbreak of war to 31st December, 1941. From 18th November, 1940, to 18th May, 1941, H.M.S. Cumberland was at sea for 206 days out of a total of 213.
H.M.S. Forester. Steamed 172,000 miles during the war up to 31st December, 1941, and was at sea for 601 days during that period. One destroyer flotilla consisting of eight ships passed the million mile mark steaming during the war in June 1941.
One of our submarines covered a distance of 25,800 miles in five months, of which only 40 days were spent in harbour, and these mostly without a depot ship. During that time this submarine went from 660 N. latitude to 260 S. latitude. Another of our submarines spent 251 days at sea in one year of war.
From the Naval Situation Report for the week as reported to the British War Cabinet 19th March 1942, see TNA CAB66/23/9.