Re: Shipbuilding Efficiency

In article <EMOdnXife-a7Q-HaRVnyhwA@xxxxxxxxxxxx>,
Andrew Clark <aclark@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
"David Thornley" <thornley@xxxxxxxx> wrote

What it seems to me is that the US and Britain were doing two
somewhat different things, and that both were making rational

Except in this one instance, Britain and the US were doing the *same*
thing - producing a pretty much identical (British) design of merchant ship
as quickly and cheaply as possible.

Wrong.

The British were going for cheaply, the US for quickly. These are
two conflicting goals, and emphasizing one rather than the other
will inevitably lead to different decisions.

The idea in the US was to produce large quantities of high-quality
equipment of all sorts very fast. Britain didn't have the resources
to burn for that, and built more moderate quantities of high-quality
equipment more slowly.

That logic is flawed. The US certainly built more stuff, but it had vastly
more workers and more factories and more resources. Even at a lower rate of
efficiency, that sort of gross scale will always tell.

Right.

However, the US was able to build more, even when sacrificing efficiency
for other purposes. I am arguing that this is what the US did.

What needs to be done is to compare *efficiency rates* of British and US
industry - tonnage per worker, for example - not simply gross output.

Okay, what was the tonnage per slip? I would strongly suspect that
the US was much more efficient in that, since the US spent a lot
of money and labor on building ships as fast as possible.

There is no one holy criterion for efficiency. Normally, output per
worker is the most informative. In peacetime, it is the one that
most determines the standard of living, and the purpose of an
economy is to provide a good standard of living. In wartime,
the goals are more varied.

The phrase "actually necessary" suggests that the study authors
had a set of criteria in mind, and assumed that their US counterparts
were working on the same criteria.

Note the phrase "actually necessary". This is important. This
implies that the writer thought that efficiency per worker, or per
pound/dollar, was the important thing, and that was to be varied
from only if necessary. There may well be reasons to sacrifice
one measure of efficiency in wartime.

It's kind of like somebody blaming Patton for taking unnecessary
risks. The question is whether his risks were justified, not
if they were necessary.

In fact, the US made stuff faster than the British did, and less
efficiently. There is a tradeoff here, and the optimal point
depends on conditions and assumptions.

I think we can take for granted that any professional academic study of
industry efficiency will understand that the optimum rate of efficiency
varies with circumstances.

Not what I'm saying.

The optimum *definition* of efficiency varies with circumstances.
That is a different point, and one that in my experience is often
missed.

You are basically trying to imply that the
authors of the studies to which I alluded were idiots and/or amateurs.

Um, let's get this straight on the references.

You alluded to studies, which presumably had competent authors.

We are then supposed to accept that these competent authors would
not make specific mistakes, mistakes that I've seen made a lot
by lots of different people.

If you have something to cite that refutes what I am saying, that
indicates that the authors were aware of different sorts of
efficiencies, please post.

The British were not pouring ships into the water at the same speed
as the US, and they were not under the same constraints. They had
different economic constraints.

Your original point was "The US had resources that it could spare to
accelerate the building of these ships, and spent them to gain speed at the
cost of efficiency".

Right.

My point is that the British also wanted speed and had
resources which it spent to get speed. The issue is how the relative
shipbuilders used their resources to maximise speed.

No, the issue is how the relative shipbuilders traded off. The Brits
did not come anywhere near maximizing speed, as can be seen from what
the US accomplished. The Brits favored efficiency, while the US
favored speed. Is this too hard to understand?

It's like the old line about the US preferring to throw artillery
shells than infantrymen at a problem. If you've got the shells,
why not? In this case, the US had resources to spend lavishly
on producing ships fast.

Wrong. Brown's figures show that the US could have produced ships
cheaper, both in man-hours and in money. That is not the same as saying
they could have been produced faster. Man-hours do not directly

The question is not whether or not the US can afford the inefficiency, but
whether the cost of the inefficiency is worth the benefit it has bought.

Yup.

Crunching the figures from Brown posted by the OP, which I'm assuming are
accurate, the US production was so basically inefficient that doubling the
workforce only bought a 7% reduction in completion time over the British
time.

However, we don't have to assume. We can research completion times.
I never did in any detail, but the US produced ships in awfully low
times sometimes.

It would be interesting to compare different sorts of efficiencies.
It sounds like the authors of your studies concentrated on one
particular sort.

Saving a matter of two months (using realistic labour force values) on
the delivery of merchant ships was never critical to the outcome of WW2 or
any of its operations.

In terms of when such-and-such a merchant ship is available, it isn't
that important, true. However, this has a considerable influence
on the total rate of production, given that slips were in limited
supply.

I'm going to pull some numbers out of somewhere I'm not going to
mention. Suppose that it takes one week from launching a ship to
starting on the next one. Suppose that one outfit builds in two
weeks on the slip, while the other takes five. That means that
the first outfit can produce twice as many ships per slip, and
the increased rate of production is critical to the outcome of WWII
operations. The Allies were short on shipping for most of the
late war, and producing more ships was much better than producing
fewer.

Given that yard workforces cannot be arbitrarily doubled - there are
practical considerations involved

Why not? It's going to cause some inefficiencies, of course.

- it seems obvious that the inherent US
production inefficiencies were only be partially and very expensively
overcome by throwing men at the problem.

Wrong end of the stick.

The practice of throwing men and resources at the problem in large
numbers was at least one major cause of any inefficiency.

Real cost-benefit for the US and
the Allied cause lay in improving US production efficiency to British
standards, not by mere scaling-up of inputs. In other words, building
smarter, not bigger.

Making decisions on ordinary cost-benefit analyses is for peacetime.
The need was to produce lots of ships, fast, and if that was expensive
then expense was acceptable.

If the US had had unlimited shipyards, it would have been better
to build Liberty ships more efficiently. As it was, US shipbuilding

Not at all. If the US yards had matched British production efficiency
standards, they would have been able to turn out ships 46% *faster*.

Ever been in any sort of production? Software? Manufacturing?

You can usually produce things faster, but it's going to cost.

The only way the US was going to be able to match British efficiency
would by by using skilled manpower efficiently. The requirement for
skill holds down production numbers, and so does efficiency.

If the US could have thrown resources at shipbuilding and kept
efficiency up, that would have been even better. However, that
was impossible.

--
David H. Thornley | If you want my opinion, ask.
david@xxxxxxxxxxxx | If you don't, flee.
http://www.thornley.net/~thornley/david/ | O-

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