Flat-Bottomed Boat, Keel, Standing Rigging, Chinese Junk, Daggerboard, Balanced Rudder, Compartment and Junk Rig

Posted by PITHOCRATES - May 16th, 2012

Technology 101

Typical River Transport has a Flat Bottom and a Shallow Draft with Little Freeboard

What do most of the oldest and greatest cities in the world have in common?  Madrid.  Lisbon.  Paris.  London.  Amsterdam.  Belgrade.  Vienna.  Rome.  Cairo.  Kiev.  Moscow.  Baghdad.  New Delhi.  Shanghai.  Ho Chi Minh City.  Bangkok.  Hong Kong.  São Paul.  Buenos Aires.  Santiago.  Quebec City.  Montreal.  Detroit.  Boston.  New York.  Philadelphia.  Pittsburgh.  What do these cities have in common?  Rivers.  Coastal water.  Or safe harbors on the oceans.

Why is this?  Is it because their founders liked a good view?  That’s why people today pay a premium to live on the water’s edge.  But back then it was more necessity than view.  These were times before railroads.  Even before roads connected these new cities.  Back then there was only one way to transport things.  On the water.  And rivers were the early highways that connected the cities.  Which is why we built our cities on these rivers.  To transport the food or raw materials a city produced.  And to transport to these cities the things they needed to survive and grow.  And some of the earliest river transports were flat-bottomed boats.  Like the scow.  Punt.  Sampan.  And the barge.

Rivers are calm compared to the oceans.  Which allows a different boat design.  River transport doesn’t have to be sturdy to withstand rolling waves and high winds.  Which allows the design to focus on the main purpose of a boat.  Hauling freight.  Typical river transport has a flat bottom.  A shallow draft with little freeboard (i.e., sitting very low in the water with the top deck very close to the surface of the water).  And a square bow.  This allows these boats to operate in shallow waters.  Allowing them to run up right onto a river landing or beach.  Where they can be easily loaded with their cargoes.  Or unloaded.  And their flat, rectangular shapes maximize the cargo they can carry.  Propulsion is simple.  A man can push a small boat along with a pole.  Animal power can pull larger barges.  Or, later, motors were able to power them.  Or a tugboat could pull or push them.

The Chinese Junk had a Flat Bottom with no Keel allowing them to Carry a Lot of Cargo

These flat-bottomed boats are great for hauling freight.  But they are not very seaworthy.  Because the ocean’s waves will toss around any boat with a shallow draft and little freeboard.  Breaking it up and sending it and its cargo to the bottom of the ocean.  Which has confined these to the calm of rivers, bays and coastal waterways.  Cargoes that have to travel further than these allow are loaded onto an ocean-going vessel with a deeper draft.  And a higher freeboard.  With a keel.  That can withstand the leeward force of the wind.  So instead of being pushed sideways (or simply rolling over) the keel allows those sideway winds to fill a sail and propel a ship forward.  By sticking deeper into the water.  So as the wind tries to push the boat sideways the large amount of water in contact with the keel pushes back against that leeward force.  Allowing it to sail across the wind.

But there is a tradeoff.  The curved sections of the hull that form the keel reduces the amount of cargo a ship can carry in its hull.  Also, these ocean-going vessels have a lot of sail.  And a lot of rigging to hold it in place.  Standing rigging.  While the sails required running rigging.  To raise and lower sails depending on the wind conditions.  Which takes up space that can’t be used for cargo.  And requires a lot of sailors.  In fact, much of the upper deck is full of rigging and sailors instead of cargo.  But this was the tradeoff to sail into the rougher waters of the ocean.  You had to sacrifice revenue-earning cargo.  But there was one ship design that brought together the benefits of the flat-bottomed river scow and the ocean-going fully rigged sailing ship.  The Chinese junk.

The Chinese junk dates as far back as the 3rd century BC.  And began crossing oceans as early as the second century AD.  Long before the Europeans ventured out in their Age of Discovery.  The junk has a flat bottom with no keel.  But a high freeboard.  Which lets it carry a lot of cargo.  And operate in shallower waters than a fully rigged sailing ship.  But it could also sail in the rougher seas of the ocean.  When it did it lowered a daggerboard.  A centerboard that can lower from a watertight trunk within the hull into the water to act like a keel.  To resist those leeward forces.  Often installed forward in the hull so as not to take up valuable cargo space in the center of the ship.  Because they mount this forward the leeward forces could cause the back end of the ship to torque around the daggerboard. To counteract this force they use an oversized rudder on the stern.  To balance the resistance to those leeward forces.  Because the rudder was so large and had to deflect a lot of water it was difficult to turn.  Taking a team of men to operate it.   To help turn such a large rudder they developed ‘powered’ steering.  With a balanced rudder.  The axis the rudder turned on was just behind the leading edge of the rudder.  So when they turned the rudder the water hitting the part in front of the turning axis helped turn the rudder in the direction the crew was trying to turn it.  So the large rudder area past the turning axis could deflect the large volume of water necessary to turn the ship.

The Chinese gave us Papermaking, Printing, the Compass and Gunpowder but the Europeans Conquered the World

So the junk could travel in the shallow waters of harbors and rivers.  And the deep water of the ocean.  It was the first ship to compartmentalize the hull.  Making it very seaworthy.  Especially if it struck bottom and punched a hole in the hull.  Because of the compartments the flooding was contained to the one compartment.  Allowing the ship to remain afloat.  A design all ships use today.  The junk also used a different sailing rig.  The junk rig.  It’s low tech.  Was inexpensive.  And required smaller crews.

A three-mast junk has three masts.  And three sails.  One sail per mast.  And the masts are free standing.  They don’t need any standing rigging to hold them in place.  Because they don’t carry heavy loads of running rigging and sailors.  The sail is stretched between a yard and a boom.  The yard is at the top.  The boom is along the bottom.  Between the yard and the boom battens give the sail strength and attach it to the mast.  Think of a batten as that stick in the bottom of a window shade.  Grabbing this batten allows you to apply an even force on that window shade when pulling it down.  If this stick wasn’t there and you pulled down on the window shade the uneven forces across the shade would tear it.  Same principle on a junk rig.  Which allows them to use less expensive sail material.  To raise this sail up the mast you pulled up the yard via a block and tackle at the top of the mast.  From the deck.  With fewer crew members.  The sail is attached to the mast near one edge.  It’s pivoted to catch and redirect wind to the stern.  Propelling the ship forward.  And the battens will bend in strong enough winds to curve the sail.  Creating lift on the other side of the sail to pull the ship forward.

The Chinese gave us papermaking, printing, the compass and gunpowder.  But it was the Europeans that used these inventions to conquer the world.  For the Chinese had no interest in civilizations outside of China.  For when you had the best, they thought, what was the point?  So the Europeans came to them.  Even took Hong Kong from them.  When it was the Chinese that could have had the technologically advanced civilization.  An army fielding muskets and cannon.  And a navy of junk warships that could have gone anywhere the Europeans could have gone.  And farther.  Into the shallow waters and up the rivers where the European warships could not go.  They could have sailed up the Thames to London.  Up the Seine to Paris.  Even into Amsterdam.  Home of the Dutch East India Company.  That took such a great interest in all those Asian goods in the first place.   That brought the British to China to compete against the Dutch.  Leading to the Opium Wars.  And the loss of Hong Kong.  Imagine how different the world would be had China embraced their technology.  Like they are today.  Perhaps we will soon see the answer to that great ‘what if’ question.

www.PITHOCRATES.com

Share

Tags: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Flint Tools, Levers, Wheels, Animal Power, Water Power, Wind Power, Steam Power, Electrical Power, Nuclear Power and Solar Power

Posted by PITHOCRATES - February 22nd, 2012

Technology 101

Man harnessed the Energy in Moving Water with a Water Wheel

When prehistoric man first chipped a piece of flint to make a sharp edge he learned something.  It made work easier.  And his life better.  This tool concentrated his energy into that sharp edge.  Increasing the amount of energy he could put to work.  Allowing him to skin an animal quickly and efficiently like never before.  Making better hides to protect him from the elements.  Yes, he said, this tool is good.  But in a somewhat less sophisticated manner of speech.

From that moment forward it has been man’s singular desire to improve on this first tool.  To find ways to concentrate energy and put it to work.  Levers allowed him to move heavier things.  Wheels allowed him to move heavier loads.  The block and tackle allowed him to lift or pull heavier weights.  Harnessing animals allowed him to do all of these things even better.  And we would use animal power for millennia.  Even today they still provide the primary source of power for some less developed countries.

But animals have their limitations.  They’re big, they eat, drink, pee and poop.  Which doesn’t make them an ideal source of power to turn a mill wheel.  A big wheel that grinds grain into flour.  It’s heavy.  But it doesn’t have to spin fast.  Just for long periods of time.  Then man had another moment like he did when he chipped a piece of flint.  He noticed in his environment that things moved.  The wind.  And the water in a river.  The wind could blow fast or slow.  Or not at all.  But the water flow was steady.  And reliable.  So man harnessed the energy in the moving water with a water wheel.  And connected it to his mill wheel via some belts and pulleys.  And where there was no water available he harnessed the less reliable wind.

The Steam Engine eliminated the Major Drawbacks of Water Power and Wind Power 

The water flowed day and night.  You didn’t have to feed it or clean up after it.  And a strong current had a lot of concentrated energy.  Which could do a lot of work.  Far more than a sharpened piece of flint.  Which was ideal for our first factories.  The water wheel shaft became a main drive shaft that drove other machines via belts and pulleys.  The main drive shaft ran the length of the factory.  Workers could operate machinery underneath it by engaging it to the main drive shaft through a belt and pulley.  Take a trip to the past and visit a working apple mill powered by a water wheel.  It’s fascinating.  And you’ll be able to enjoy some fresh donuts and hot cider.  During the harvest, of course.

While we built factories along rivers we used that other less reliable source of energy to cross oceans.  Wind power.  It wasn’t very reliable.  And it wasn’t very concentrated.  But it was the only way you could cross an ocean.  Which made it the best way to cross an ocean.  Sailors used everything on a sailing ship from the deck up to catch the wind and put it to work.  Masts, rigging and sails.  Which were costly.  Required a large crew.  And took up a lot of space and added a lot of weight.  Space and weight that displaced revenue-earning cargo.

The steam engine eliminated the major drawbacks of water power and wind power.  By replacing the water wheel with a steam engine we could build factories anywhere.  Not just on rivers.  And the steam engine let ships cross the oceans whenever they wanted to.  Even when the wind didn’t blow.  And more space was available for revenue-earning cargo.  When these ships reached land we transferred their cargoes to trains.  Pulled by steam locomotives.  That could carry this revenue-earning cargo across continents.   This was a huge step forward.  Boiling water by burning coal to make steam.  A highly concentrated energy source.  A little of it went a long way.  And did more work for us than ever.  Far more than a water wheel.  It increased the amount of work we could do so much that it kicked off the Industrial Revolution.

With Nuclear Power our Quest to find more Concentrated Forms of Energy came to an End 

We replaced coal with oil in our ships and locomotives.  Because it was easier to transport.  Store.  And didn’t need people to shovel it into a boiler.  Oil burners were more efficient.  We even used it to generate a new source of power.  Electrical power.  We used it to boil water at electrical generating plants to spin turbines that turned electrical generators.  We could run pipelines to feed these plants.  Making the electricity they generated even more efficient.  And reliable.  Soon diesel engines replaced the oil burners in ships and trains.  Allowed trucks and buses to run where the trains didn’t.  And gasoline allowed people to go anywhere the trains and buses didn’t go.

The modern economy ran on petroleum.  And electricity.  We even returned to the water wheel to generate electricity.  By building dams to build huge reservoirs of water at elevations.  Creating huge headwater forces.  Concentrating more energy in water.  Which we funneled down to the lower elevation.  Making it flow through high-speed water turbines connected to electrical generators.  That spun far faster than their water wheel ancestors.  Producing huge amounts of reliable electrical power.  We even came up with a more reliable means to create electrical power.  With an even more concentrated fuel.  Fissile material gave us nuclear power.  During the oil shocks of the Seventies the Japanese made a policy change to expand their use of nuclear power.  To insulate them from future oil supply shocks.  Which it did.  While in America the movie The China Syndrome came out around the time of the incident at Three Mile Island.  And killed nuclear power in America.  (But as a consolation prize we disproved the idea of Keynesian stimulus.  When the government created massive inflation with Keynesian policy.  Printing money.  Which raised prices without providing any new economic activity.  Causing instead high inflation and high unemployment.  What we call stagflation.  The Japanese got a big Keynesian lesson about a decade later.  When their massive asset bubble began to deflate giving them their Lost Decade.)

And with nuclear power that quest to find more ways to make better and more efficient use of concentrated energy from that first day we used a flint tool came to an end.  Global warming alarmists are killing sensible sources of energy that have given us the modern world.  Even animal rights activists are fighting against one of the cleanest sources of power we’ve ever used.  Water power.  Because damming rivers harms ecosystems in the rivers we dam.  Instead political pressures have turned the hands of time backwards by using less concentrated and less efficient sources of energy.  Wind power.  And solar power.  Requiring far greater infrastructure installations to capture far less amounts of energy from these sources.  Power plants using wind power and solar power will require acres of land for windmills and solar panels.  And it will take many of these power plants to produce what a single power plant using coal, oil, natural gas or fissile material can generate.  Making power more costly than it ever has been.  Despite wind and sunshine being free.  And when the great civilizations become bankrupt chasing bankrupt energy policies we will return to a simpler world.  A world where we don’t make and use power.  Or machinery.  Much like our flint-tool using ancestors.  Albeit with a more sophisticated way of expressing ourselves.

www.PITHOCRATES.com

Share

Tags: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,