Crews Letter #2003 10   Archimedes and the Traveling Salesman

Good Morning Ladies and Gentlemen:

Knidos on the West end of the Datcha Promontory (Dorian Peninsula) - After we anchored in this harbor, Phyl discovered that the bilge pump was running but not moving water.  She turned it off and reported the problem.  Fred went below to discover that the bilge pump was covered up in water.  In retrospect, it was about 475 litres of water. 

 

What was the last hole in the boat that we had open?  The log transducer.  This little water wheel sticks out through the hull below the forward cabin.  As the boat moves through the water, the log transducer measures how fast water is moving by.  When the boat is not moving, it is a nesting surface for sea life: those nasty little crustaceans that attach themselves to any surface in the sea and grow shells.  Enough sea shells and it doesn’t turn.  Before we left Bodrum, two days earlier, we took it out and cleared it of the new growth.  Maybe it was not closed properly.  He looked there.  It was not leaking, but there was enough water in the bilge that it was there also.

 

Sailors have a qualitative analysis procedure for water inside their boat.  They taste it.  The Turks and the Greeks call fresh water “sweet”.  It is definitely more accurate.  Sweet water is a problem.  Salt water is potential disaster.  This water was sweet.  Knowing that it was sweet water, the urgency level dropped dramatically.  He only had to listen for a moment to determine that the sweet water pressure pump was running. He checked and there was no water coming out of the galley faucet.  He turned the sweet water pressure pump off.

 

It must be a fact that no boat ever sank in the sea from a sweet water leak.  There are stories of people putting the hose from the dock faucet into a disconnected deck fitting, filling a boat with water and sinking her.  That could happen at the dock, but not at sea.  If she carries it away from the dock, moving it around inside the boat can’t make her sink.

 

Fred was blessed with a high school physics instructor, Louis Bolton.  This teacher explained Archimedes Principle with a story.

One day a traveling salesman came to the king of Syracuse, Sicily and offered a crown of pure gold at a ridiculous low price.  The king asked for three days to think about it.  He kept the crown.  He remembered the age old adage: “If it is too good to be true, it probably isn’t.” 

 

He called in his number one scientist, a strange bird named Archimedes, and gave him a challenge.  “In three days you must determine whether this crown is pure gold or a fake.  You can’t deface it in any way.  If you do, I have to buy it.”

 

Even then, good managers knew the best way to deal with a tough problem was to give it to someone else.

 

Arch, short for Archimedes, didn’t have a clue.  On the surface, it was gold.  But what was inside?  How could he know without taking it apart?  One problem with being on the king’s payroll is the king also had soldiers who could do some very cruel things at a bad performance review.  Arch didn’t have a clue.

 

On the morning of the third day, he had given up on the problem and used the last twelve hours to develop the excuse.  A completely sound, scientific explanation of why it couldn’t be done with some very theoretical nonsense tossed in for good measure.  On his way to see the king, he stopped by the town bath to relax, get himself in the right frame of mind and rehearse his presentation one more time.

They filled his tub to the brim with hot water.  He climbed in and some water spilled out.  He had displaced some water.  He leaned back and a little more spilled out, but now he was floating.  He had displaced as much water as he weighed.  He jumped from the tub.  Not stopping for towel or toga, he raced down the street to the royal laboratory.

“Eureka!” he shouted as he ran through town, “Eureka!”

The town’s people always knew he was a strange bird.  Featherless, he was pretty wrinkled as well.

He cut up a gold brick to get a piece of equal weight of the crown.  He filled a bowl with water.  First he submerged the gold brick.  Some water spilled out.  He removed the brick and submerged the crown.  Even more water poured over the edge of the bowl.

Eureka!”

Pausing to dress appropriately for an audience, he gathered up the crown and the brick and toddled off to see the king.

 

The king always enjoyed a discussion when the facts were on his side. 

“If you don’t want to die a dirty death,” he said to the salesman, “you should wash your neck.   We have a way for dealing with thieves around here.  We cut off their feet, right behind their ears.”

The salesman groveled and blamed it on the technicians.  He was sent on an extended cruise of the Mediterranean.  He couldn’t see much from his rowing station in the galley, but the exercise was good.  And he was definitely motivated.

Arch expanded his principle to explain why and how some things float, some sink and others sink faster.

The king enjoyed his new crown.

 

Displacement of water is a powerful idea.  Perception floats because she displaces as much water as she weighs and there is still a lot of her above the surface.  She displaces 17 US tons.

Interesting: “A pint’s a pound, the world around.” is a US expression.  A litre is a kilogram for most of the world and a pound is a quaint measure that only Americans use.  Well, the British use it when talking about money, but that is a different subject.  And so are they, subjects that is.  Little wonder pound and quart is part of the “imperial” measurement system.  For both pounds and kilograms, the measure of weight is a volume, pint or litre, of sweet water.  A US ton is 1,000 quarts, 2,000 pints, of water and a metric ton is 1,000 litres of water.  Archimedes should be proud.  Why Americans are still using the British Imperial system when the rest of the world is metric?  Maybe we think we are the British Empire, revised.

 

Back to the boat that was not sinking.  The valve for the swim deck shower had spit off the water supply hose.  The pressure pump had dutifully pumped 475 litres of water out of the tanks and into the bilge.  The gauge in the water tank decided to keep reading ½ and the bilge pump couldn’t empty the bilge for what reason we still don’t know.  Several tests have been run and the pump and hose to the outside will not fail on demand.

 

The anchor held.

 

Keep a Tight Luff,

Phyl & Fred

 

Errata:  In the Crews Letter #2003 07 I Love a Parade, there was a totally avoidable error.  Fred said, “The American sailing cruiser, Traumerei, didn’t actually join the parade, but her skipper couldn’t pass up the opportunity to blow his own horn.”  Had he performed a reasonable level of research, he would have correctly said, “The American sailing cruiser, Traumerei, didn’t actually join the parade, but her skipper couldn’t pass up the opportunity to blow her own horn.”   This error has been brought to our attention.  It is duly noted.  Please make the correction in the appropriate document. 

 

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