Tom from Cornwall wrote:The British (and I wonder whether he is including references to the Canadians, Australians, New Zealanders, et al...) may have "employed" 302 fleet destroyers during the war but how is that a scrupulous extraction of only BoA costs? What about the world-wide nature of RN (and Commonwealth) operations
The estimate seems reasonable to me. 150 DD's in the East and Med? I'd bet $20 the British never reached that level until 1945, if at all. Seems an understatement, actually.
If you want to critique his analysis, I'd suggest providing some of your own. How many DD's did the Eastern/Med fleets have?
Tom from Cornwall wrote:The RN's pre-war plans (I am not well-read on USN plans) were never aimed solely at war with Germany. Prior to 1935, British naval rearmament was concentrated on the threat in the Far East.
Yes that's why large fleet units don't enter the calculus at all.
Finally, what about the "Lion" Class battleships? Firstly delayed and then scrapped in the shipyards - a "cost" of the BoA or available finance and shipbuilding resources more appropriately used given the British Empires strategic needs at the time?
What are you getting at? Again, large fleet units (>DD unless CVE) aren't part of the analysis.
Re the use of CVE's at Salerno, sure, they had some other utility but it was a side-effect. Consider this countervailing side-effect not included in the analysis:
The cost of major warships sank by submarines was not used in the estimate.
So Royal Oak, a fleet carrier, and a bunch of cruisers aren't included in the cost ledger.
My impression is you that the trees are blocking your view of the forest. The majority of BoA costs are shipping losses and shipping inefficiencies (due to convoying) - $14.65bn. The DDE's, FF's, corvettes, and other escorts are nearly $5bn - and that's ignoring expenditure on later-cancelled escorts, which would add another couple billion most likely.
For the remaining $7bn of BoA costs, a 20% error in the analysis ($1.4bn) would only change the ratio by 0.5 (i.e. it would be half of Germany's BoA cost).
There are things I would have done differently had I the time and source access. I would have compared personnel resource ratio, for example. A Liberty ship had a crew of 60-100, up to twice a U-boat's. DDE's had ~200 aboard, Flower-class corvettes had 85.
If we assume 5,000 Liberty-ship equivalents (=35mil tons GRT), 500 DDE's, and 500 Flower-class equivalents, that's on the order of 700k crewman - almost certainly an underestimate as I'm ignoring DD's, CVE's, sloops, etc. Bogue-class CVE probably needed close to 1,000 men aboard (646 excluding the air group). As shore-based crew (maintenance, longshoremen, command) typically exceeds seagoing crew for modern navies, there could have been 2mil men committed to the BoA on the W.Allies side (USN was 4mil IIRC). What was the U-boat Waffe? 50-100k? [Before you attack the foregoing analysis, note it's a 5min effort so will of course be off. I'm not interested in being right other than the general outline of the differences. That said, feel free to put more resolution on it.]
On the broader historical question of BoA economic cost ratio, I'm not primarily interested in whether the OTL cost ratio was 10:1, 8:1, or 12:1. Whatever that ratio, there's no decent argument that the ratio wasn't extremely favorable to Germany.
And the OTL ratio includes German costs - most of them - that are irrelevant to the ATL: most of German spending on subs (after mid-'42 or so) was nearly useless. As I said, the cost ratio prior to Allied domination of T7/9 was probably at least 20:1.
That pre-'43 cost ratio is the relevant picture for this ATL, as it involves - at a minimum - the T21's indefinite extension of the extremely unfavorable pre-'43 ratio. As I think T21 would have produced even better cost ratios for Germany, the evaluation is even worse.
Just look at the DDE vs. T21 ratio: A T21 firing 18 torpedoes at escorts could expect 2 hits at the OTL 11% success ratio. A DDE cost ~2x a T21, 2 DDE's sunk has 4x the value one T21. How often does the DDE sink a T21? Say it's one in five encounters (an extremely high success rate given RN's evaluation) - that's a 20:1 resource expenditure. And that assumes the T21 doesn't sink any merchant ships with its remaining 5 torpedoes.
In truth 10:1 DDE-T21 exchange is more likely plus several merchant ships. It's not hard to foresee 50:1 attrition ratios being feasible.