When he was growing up, my dad lived in Mile End.
One day, he asked a young nurse if she’d like to come for a trip to Southend on his motorbike.
When they got there, he hired a rowing boat.
They rowed out as far as they could, way past the end of the pier (and Southend pier is a mile long).
The tide was going out but that didn’t bother him, the estuary is huge.
Then suddenly the oars hit something below the surface.
Then the boat scraped on something and ground to a halt.
It was the seabed, just six inches below.
What Dad didn’t know was that Southend estuary is virtually flat.
So when the tide went out, the rowboat was stranded.
They had to get out and walk back to the shore, about a mile away, through the mud.
He said the nurse never went out with him again after that.
A lot of people make that mistake about Southend estuary.
It looks deeper than it is.
At the start of World War Two, Germany invented a new type of mine.
Previously, all mines had metal horns sticking out.
If a ship hit one, the mine exploded.
But the Germans had developed a mine that ships didn’t have to hit.
It just lay on the seabed.
If a ship went anywhere near it, it exploded.
No one knew how it worked.
In just two months these new mines sank thirty-three ships.
The Germans began dropping them from aircraft, especially at harbour entrances.
A ship could get all the way across the Atlantic, dodging U boats, then get sunk at the mouth of its own harbour.
Churchill made recovering one of these mines top priority.
Scientists were desperate to work on one as soon as they got hold of it, but how?
There was no way of sweeping for them because no ships could get anywhere near them.
It was Germany’s first, and one of their deadliest, secret weapons.
Then one night, Luftwaffe bombers were briefed to mine the route that many British merchant ships used daily.
To drop these mines right across the mouth of the Thames.
In the moonlight the estuary looked like any other vast body of water.
They didn’t know it was only inches deep.
So they dropped their mines and one of them stuck in the mud.
Because it didn’t sink, it didn’t have time to arm itself.
So some very brave men recovered it from the mud, and disarmed it.
Then the scientists had their secret weapon to work on.
They found it was a magnetic mine, triggered by the metal in ships.
No one had ever seen anything like it.
The scientists found a way to de-magnetise all British ships so they wouldn’t trigger the mines.
The sinkings stopped, and Germany’s secret weapon was nullified.
All that massive brainpower that went into developing it, undone by something as obvious as mud.
But that’s experts.
All they can see is their impressive, complicated intellectual reasoning.
They can’t see something so mundane as reality.
When Dad heard about this, he didn’t feel so bad about what happened to him at Southend.
If the cream of Germany’s scientists and the entire Luftwaffe didn’t know about the mud, it was fair enough.
Would that be an unknown unknown?
Exactly,
If they had been smart they would have approached it as a known unknown.
As Lao Tzu said “The wise man knows he doesn’t know. The fool doesn’t know he doesn’t know”
Zen master Yuan-tong said, “When the task is done beforehand, then it is easy.” Perhaps she was part of a dummy run?