Here is a real world example:
In 1911, after the Australian Government outlayed £3.5m on the Fleet Unit (1BC, 2CL, 6DD, 2SS), Admiral Sir Reginald Henderson was tasked with proving a Naval blueprint for Australia. Henderson's plan was based on assumptions that allowed for an equivalent contribution by 4.5m Australians to 45m British and that Australia shared no land borders and therefore had a minimal requirement for an army. He also pointed out that Britain's sea borne trade was worth £1B per year, Australia's was £162m per year and represents a 16% proportion of Britain's trade. This suggests Australia could pay a higher defence burden than the 10% population proportion. Most of the document concerned crew levels and how to grow these with a close eye on where these recruits would geographically come from.
Over a 20 year timetable the RAN was to expand to 15 000 men, 5 000 reserves and centered on two Divisions based on population. East (NSW, Queensland) with 3BC, 3CL, 8DD, 3SS (1BC, 2CL, 4DD in Reserve) and West (Vic, TAS, SA, WA) with 3BC, 3CL, 4DD, 9SS (1BC, 2CL, 2DD Reserve). The East Division principal bases were Sydney, Brisbane, Westernport (VIC) and Port Stevens (NSW) with minor bases as Tamar River (TAS), Hobart, Townsville, and Thursday Island. The West Division principal bases were Fremantle, Port Lincoln and Westernport. Minor bases were Darwin, Albany, Cone Bay, Hobart and River Tamar.
The outlay was about £40m in infrastructure across the 6 main bases and 7 smaller bases, £20m in ship construction and £28m in operating costs. Paying for this would be about 2% of GDP per year and amount to £90m over 20 years. By 1910, Australia's defence spending was at £3m or 0.9% of GDP and only 14.7% of Government expenditure. By 1911-12 it was at £4.7m while 2% GDP, a usual defence burden, would push this number to £6.7m so the Henderson Plan is affordable. Infrastructure costs will be significant, A Fleet Base like Rosyth took 10 years to build and cost £4.25m. A drydock costs £1.25m and takes 4 years to build. One was needed in Sydney and one in Fremantle.
Never officially adopted, the government followed the blueprint during the war years, some ships were ordered inline with the schedule and several million pounds was spent on base construction. Note that this money was outside war funding. Jellicoe's postwar 1919 review also proposed an annual £4m contribution for Australia's naval defence but to the contribution of a Eastern Fleet, based on Singapore of 8 BB, 8 BC and 4 CV. During the war, Australian prices had doubled and debt soared. The mood on the navy had changed, apart from officer and ship exchange the Jellicoe report was completely rejected.
The schedule was from 1918: (by 1917 1 BC, 3CL, 12DD 6 Subs 1 Tender would already been built)
1918 6 DD, 1 Tender
1919 1 BC
1920 1 CL, 1 Tender
1921 1 BC
1922 2 CL, 6SS
1923 1 Repair Ship
1924 1 BC
1925 1 BC
1926 1 BC (original 6 DD replaced)
1927 2 CL (original 3 SS replaced)
1928 Nothing (3 SS replaced)
1929 1 BC (original 3 CL replaced)
1930 Nothing (original BC replaced)
1931 1 BC
1932 2 CL
The BC were about £2m each, CL £450 000, DD and SS £90 000, Auxiliaries £200 000 each. These are Tiger/Renown size ships at about £70 per ton. CL will be Town/ C Class size. If a carrier was substituted for a later ship it would probably be about 14 000 tons with 18 aircraft as equal and equivalent lifecycle cost for a 27 000 ton BC.
The original 1913 Fleet Unit of 1BC, 2CL, 6 DD and 2 SS had cost £3.5m. The future costs were outlined as £989 500 per year (£70 000 more per year than the yearly cost of establishing the fleet unit)
Out of all the unfulfilled naval expansion plans prior to WW1, this represents an interesting 'green fields' process and the most detailed of pre-war plans as a 68 page report that goes down to including how many bandsmen the navy would need in 20 years time.
https://www.navy.gov.au/media-room/publ ... -henderson
