what if Britain kept up naval spending through the 1920s?

There is some interesting information here about a proposed Vickers diesel that was in their alternate design for what became the Queen Elizabeth class the Vickers Fisher (V-F) design.

https://www.tapatalk.com/groups/all...s/diesel-powered-g3-battle-cruiser-t8853.html

10 Mar 2018, 19:39 #1

On the Correctly estimated QE class battleship thread,
correctly-estimated-qe-class-battleship-t8835.html
I made the following statement:
However, if my information is correct, then the large Vickers battleship diesel engines were a viable powerplant for Nelson and Rodney by the time they were designed. And using them instead of boilers and turbines may have allowed a modified G3 to be built on 35,000 tons.

The following replies were made:
Stevep59: “Of course with my pet obsession I noticed the comments "And using them [diesels] instead of boilers and turbines may have allowed a modified G3 to be built on 35,000 tons." That sounds interesting to put it mildly. Presumably quite a lot would still have to go to get ~48-49kt down to the 35kt allowed in the treaty but I'm guessing you end up with something faster than OTL Nelsons.

Hood:A diesel-powered G3 is an interesting idea. One immediate advantage would have been the cleaning up of the stern hull form, the steam plant only just squeezed in and some compromises had to be made with the underwater form to accommodate the gearing. It might have gained an extra 0.25-0.5kt in speed. N3 though might have been a better candidate given speed was not so critical. Given the problem with Adventure's diesel-electric powerplant it is probably optimistic to think a diesel capital ship was a workable proposition.

I felt compelled to investigate the mounting of the diesel engines in question in a battle cruiser with G3 characteristics. It has been a while since I promised to create this ‘own designs’ thread but I had many false starts and I had to start from scratch several times as new data invalidated my earlier efforts and, as a result, this took way, way longer than I had intended.

Below is the Vickers-Fisher (V-F) design (rival to the Admiralty’s Queen Elizabeth design) that the diesel system I am evaluating was designed for:





29,000t V-F plans.

These diesels are large slow turning direct drive engines designed to turn large diameter propellers of high thrust efficiency. Each 12-cylinder engine can deliver 15,000bhp giving an installed HP in both designs of 60,000bhp. If my understanding is correct, this design was expected to reach her design speed of 25 knots at 56,000bhp at a load displacement of 29,000t. The rival Admiralty design had 75,000shp installed: direct drive turbines driving small diameter fast turning propellers. The propulsive inefficiency of this system is amply demonstrated as, despite the extra 15,000 HP installed in the Admiralty design, it also had a speed of only 25 knots at its load displacement of 27,500t.

A very interesting design feature of the Vickers battleship diesels is the fact that they are modular units. Each module consists of four 70-inch, 2,500hp cylinders. To increase HP, additional modules are simply attached in series. The V-F designs use four, three module engines; each producing 15,000bhp. Obviously, there are practical limits on how long an engine inside a ship can be. Four modules appear to be the maximum practical length for a single engine compartment, although it may be possible to insert transverse bulkheads between modules and allow a single engine to run through multiple compartments.

Schematic of Vickers battleship diesel engine (Source: Fisher Papers, FISR 5/42, Churchill Archives Centre, Cambridge).

Another design feature that radically departs from what I would consider a normal diesel engine is that these modules are skeletal constructions. They are literally stripped to the bone leaving the crankshaft and piston rods in full view. The crankshaft bed is connected to the cylinder housings only by twelve tubular supports. Compared to more regular diesel engine design, such as those used on Deutschland class panzerschiffe, this diesel system should be very lightweight. The probable aim being; the less weight absorbed by machinery, the more weight available for other aspects of a warship design such as firepower and armour protection. The V-T design carries more and thicker armour than the Admiralty Queen Elizabeth design and both have the capacity to carry 8x16-inch guns instead of 8x15-inch guns: armour and firepower superiorities that arise from the more compact diesel machinery.

and

https://www.tapatalk.com/groups/all...ctly-estimated-qe-class-battleship-t8835.html
 
This is from British War Production on Hyperwar. The figure in brackets in Column 2 is expenditure on new naval construction, which I think is more useful for the purposes of this thread than the combined Vote 8 and 9 in Post 38.

Expenditure on Armaments 1924-33.png
 
This is also from British War Production on Hyperwar, but because of the way it is calculated it can't be compared with Table 1 in Post 42.

Expenditure on Armaments 1934-39.png
 
One of my spreadsheets...
View attachment 380645
This is a modification of the above spreadsheet with:
  1. Revenue and Expenditure maintained at 1921-22 levels from 1922-23 to 1938-39.
  2. Total defence expenditure increased by £50 million from 1922-23 to 1939-40.
  3. The £50 million has been split £15 million Army, £15 million Navy and £20 million Air Force.
  4. The accumulated budget surplus 1922-23 to 1938-39 IOTL was £107.8 million. ITTL it would have been £776.8 million. I haven't attempted to calculate how that might have reduced the National Debt and the cost of servicing it.
  5. In spite of the increase of £50 million the total annual defence expenditure from 1922-23 to 1934-35 is still at least £20 million less than 1921-22. This money is used to increase civil spending or to pay off some of the National Debt.
Revenue and Expenditure 1918-40 Plus £50 million from 1922.png
 
Threads like these and the mad stats skills you guys are throwing around here fascinate me. I mean, I'm a history nerd and a facts and figures guy (to a degree), but you folks here take it to another level. That's awesome. I don't have anything else to contribute, except this: Churchill zig-zagged quite a lot in his life and for him to change his mind was not inconceivable. Part of the sheer political genius of Churchill was that by the time he would explain his zig-zag, you found yourself nodding along and thinking that really, the only option was to zig-zag and change your mind, old sport.
 
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