THE NUMBERS AREN’T ALWAYS RIGHT

In 1917, Britain was just six weeks away from starving to death.
We have the same population as France, but only half the landmass.
So we can’t grow enough to feed ourselves.
Which means most of what we eat must be imported.
And Germany had worked out that the best way to win World War One was to cut Britain’s jugular.
The constant supply of food from the USA and Canada.
And the most efficient way to do that was with U boats.

 


During that war, U boats sank a massive twelve million tons of British shipping.
That’s five thousand merchant ships.
In February 1917 alone, they sank 465,000 tons.
In March it was up to 510,000 tons.
And in April it was up to 875,000 tons.
Britain was starving to death with only six weeks of food left.
Merchant ships were easy to sink because they were slow, unarmed, peacetime ships.
The U boats could pick them off one at a time.
One possible solution was suggested.
Convoys.
Form the merchant ships into large groups of around fifty, and protect each group with armed warships.
But the Admiralty experts turned the idea down.
Looking at the numbers, they said it couldn’t be done.
There were 2,400 ships sailing to and from Britain every week.
That’s 300 a day.
There simply weren’t enough warships to protect that many ships.
So they refused.
Until someone pointed out that the experts had been reading the numbers wrongly.
There were indeed 2,400 ships a week, 300 a day.
But most of those were sailing across the English Channel to supply  the army in France.
The ships that were actually feeding Britain, sailing across the North Atlantic, were actually less than 7% of that number.
140 ships a week, 20 a day.
And that number could be protected by the Royal Navy.
The Admiralty experts then objected that grouping all the ships together would make them an easy target for U boats.
Until it was pointed out that currently the ships were spread across the whole North Atlantic, which made them a much bigger target than a convoy would be.
The Admiralty experts then objected that protecting convoys was a defensive role, rather than warships aggressively seeking out U boats.
Until it was pointed out that the convoy would act as bait to attract U boats to where the warships could destroy them.
Rather than having the warships search the entire Atlantic Ocean looking for U boats.
The Admiralty experts didn’t like it.
Protecting lots of slow, dirty old merchant ships wasn’t the romantic role they saw for the navy.
But they had no choice.
With Britain starving, they had to give the convoy system a try.
And the convoy system won the war.
In the next fifteen months, U boats managed to sink just 400,000 tons of merchant shipping in total.
That’s less than a tenth of what they were sinking before convoys.
Just 154 ships sunk, out of 16,539 that sailed.
Meanwhile the Royal Navy sank 150 U boats.
That’s nearly one U boat sunk for every merchant ship sunk.
Thanks to the convoy system.
The system that wouldn’t work according to the experts.
It’s worth remembering that when people quote numbers at you as proof that something won’t work.
The numbers may be right, but maybe they’re reading them wrong.

As Bill Bernbach said “We’re so busy listening to statistics, we forget we can create them.”

  • iain Maclean

    Ah statisticians; those wunnerful people who can, “draw a straight line from an unwarranted assumption to a forgone conclusion.” 
     
    Another fascinating blog Dave. I had no idea that U-boats operated in such numbers in the First World War.

    According  to statisticians in the late 1890s, London would be knee-deep in horse manure by 1920. They simply didn’t foresee the rapid development of motorised transport.

    Like accountants, they’re good at looking backwards.  What’s worrying, is that unlike marketing people, all company boards have an accountant/FD. This may account for the sluggish behaviour of many companies out there.

    Damn, I’ve digressed again. Sorry.

  • Dave Trott

    Ian,
    Love that that line ” They can draw a straight line from an unwarranted assumption to a forgone conclusion.”
    I may have to nick that

    • iain Maclean

      Feel free. I nicked it from someone, but can’t remember who.

      Oldguyitis strikes again.

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