Sounding the Depth, Sea Marks and Bridge Lights

Posted by PITHOCRATES - December 11th, 2013

Technology 101

It’s Important to know both the Depth of the Water beneath you and the Hidden Dangers below the Surface

On November 10, 1975, the Great Lakes bulk ore carrier S.S. Edmund Fitzgerald sank in a powerful Lake Superior storm.  Waves of 35 feet crashed green water across her deck.  But time and again she bobbed back up from under the waves.  Until she began to lose her buoyancy.  No one knows for sure what happened but the Fitzgerald was taking on water prior to her sinking.  One theory said that she bottomed out on Six Fathom Shoal off of Caribou Island.  As she fell into the trough between two huge waves.

A fathom is 6 feet.  So six fathoms would be 36 feet.  Though the water over Six Fathom Shoal could be as shallow as 26 feet.  Which is pretty deep.  But is dangerously shallow for a ship like the Fitzgerald.  For she had a draft of 25 feet.  At best she had 11 feet (36-25) of clearance between the shoal and her hull.  Or in the worst case, 1 foot (26-25).  With the gale force winds pushing the waves as high as 35 feet that would put the trough approximately 17.5 feet (35/2) below the ‘calm’ surface level of the lake.  Which would bring the top of the shoal above the hull of the Fitzgerald.  Thus making a strong case that she bottomed out and fractured her hull and began to take on water.

The theory continues that as she took on water she settled deeper and deeper into the water.  Growing heavier.  And less buoyant.  Until a wall of water swept across her that was too great for her to shake off.  Sending her to the bottom of Lake Superior so quickly that the propeller was still spinning when the bow hit bottom.  Causing the hull to break.  With the torque of the spinning shaft rotating the stern over until she rested hull-up on the bottom.  This is only one theory of many.  People still debate the ultimate cause of her sinking.  But this theory shows the importance of knowing the depth of the water beneath you.  And the great danger of unseen objects below the surface of the water.

Ships use Sea Marks to guide them Safely through Navigable Channels

Those mariners who first crossed the oceans were some of the bravest ever to live.  For if a ship sank in the middle of the ocean chances are people never saw those sailors again.  For there’s nothing to sustain life in the middle of the ocean.  Everything you ate or drank you brought with you.  And crossed at the greatest speed possible to get to your destination before your supplies ran out.  Which was easy to do in the deep waters of the middle of the ocean.  But very dangerous when the water grew shallower.  As you approached land.  Especially for the first time.

If a ship struck a submerged object it could break up the hull and sink the ship.  Especially if you hit it at speed.  This is why they had lookouts high up in the crow’s nest looking for land.  Or indications that the water was growing more shallow.  And they would ‘heave the lead’.  Big burly men (leadsmen) would throw a lead weight on a rope as far out in front of the ship as possible.  Once the lead hit bottom they’d pull it up.  Counting the knots in the rope spaced at 6-foot intervals.  Or fathoms.  Sounding the depth of the water beneath them.  As the sea bottom raced up to the water’s surface they furled their sails to catch less wind.  And slow down.  As they approached land they would approach only so far.  And safely anchor in a safe depth of water near a promising location for a harbor.  Some sailors would then board a dinghy and row into the shallow waters.  Sounding the depth.  And making a chart.  Looking for a safe channel to navigate.  And a place suitable to build a deep-water dock.  Deep enough to sail in to and moor the large sailing vessels that would sail to and from these new lands.

Of course, we could do none of this during the night.  It may be safe to sail in the middle of the ocean at night but it is very dangerous in the shallow waters around land.  At least, for the first time.  After they built a harbor they may build a lighthouse.  A tall building with a beacon.  To guide ships to the new harbor in the dark.  And even add a fog horn to guide ships in when fog obscures the light.  This would bring ships towards the harbor.  But they needed other navigational aids to guide them through a safe channel to the dock.  As time passed we made our navigational aids more advanced.  As well as our ships.  Today a ship can enter a harbor or river in the black of night safely.  Thanks to sea marks.

If Ships wander just Inches off their Course the Results can be Catastrophic

Landmarks are navigational aids on land.  Such as a lighthouse.  While a sea mark is a navigational aid in the water.  Typically a buoy.  A buoyant vessel that floats in the water.  But held in place.  Typically with a chain running from the bottom of the buoy to an anchorage driven into the bottom of the water channel.  Holding it in place to mark the edge of the navigable channel.  In North America we use the colors green and red to mark the channel.  With the “3R” rule “Red Right Returning.”  Meaning a ship returning from a larger body of water to a smaller body of water (and ultimately to a dock) would see red on their right (starboard).  And green on their left (port).  If you’re leaving dock and heading to open water the colors would be the reverse.

As ships move up river the safe channel narrows.  And there are bridges to contend with.  Which compounds the problem of shallow waters.  Fixed bridges will have red lights on piers rising out of the water.  And a green light over the center of the safe channel.  A vertical lift span bridge or a double leaf (lift) bascule bridge will have red lights at either end.  And red lights over the center of the channel when these bridges are closed.  When the center span on a lift bridge is open there will be a green light marking the center of the channel on the lifted center span.  Showing the center of the channel and the safe height of passage.  When the bascule bridge is open there will be a green light on the tip of each open leaf.  Showing the outer edges of the safe channel.

Ships are massive.  And massive things moving have great momentum (mass multiplied by velocity).  The bigger they are and the faster they go the harder it is to stop them.  Or to turn them.  Which means if they wander out of that safe channel they will probably hit something.  And cause great damage.  Either to the ship.  Or to the fixed structures along the waterway.  Like on an Alabaman night.  When a river barge made a wrong turn in poor visibility and entered an un-navigable channel.  Striking a rail bridge.  Pushing the bridge out of alignment.  But not enough to break the welded rail.  Which left the railroad block signal green.  Indicating the track was clear ahead.  The river pilot thought that one of the barges had only run aground.  And was oblivious to what he did.  And when Amtrak’s Sunset Limited sped through and hit that kink in the track it derailed.  Killing 47 people.  About twice the loss of life when the Fitzgerald sank.  Showing the importance of navigation charts, sea marks and bridge lights.  For if ships wander just inches off their course the results can be catastrophic.


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Visible Light, Additive Coloring, Subtractive Coloring, Printing and Pointilism

Posted by PITHOCRATES - August 28th, 2013

Technology 101

Our Eyes see Shades of Gray with Rods and Color with Cones

If you have colorful flower gardens all around your home and go out at night you won’t see much.  Only shades of gray.  You’ll see none of the vibrant colors of your flowers.  The moonlight, streetlights, the neighbor’s security lights, your landscaping lights, etc., will provide enough lighting so you can see your flowers.  But you won’t be able to see their colors well.  If at all.

If you go out with the bright afternoon sun shining down it’s a different story.  You can see the color.  Rich, vibrant color.  Because of the cones in your eyes.  Which can see color.  As long as it is bright enough.  Unlike the rods in your eyes.  Which work well in low light levels.  Letting you see shades of gray in low light levels.  But saturate at high light levels.  Which is where the cones take over.

Light is electromagnetic radiation.  And the key to color is the wavelength.  What is a wavelength?  Think of a guitar.  If you pluck a thick string it vibrates at one frequency.  If you pluck a thin string it vibrates at a higher frequency.  The thick string will move back and forth at a greater distance (and a slower speed) as it vibrates than the thin string.  So the thick string has a longer wavelength than the thin string.  This is a crude explanation.  But the takeaway from this is this.  As frequency decreases wavelength increases.  As frequency increases wavelength decreases.

Different Wavelengths of Light have Unique Colors and are a Small Portion of the Electromagnetic Spectrum

Light is electromagnetic radiation.  Different wavelengths of light have unique colors and are a small portion of the electromagnetic spectrum.  If you ever conducted an experiment in grade school where you passed a white light through a prism (or if you saw the cover of Pink Floyd’s Dark Side of the Moon) you saw this.  White light enters the prism and a ‘rainbow’ of colors exits the prism.  Violet on the bottom.  And red at the top.  This is the visible light spectrum.  From violet (the smallest wavelength) to blue to green to yellow to orange to red (the largest wavelength).  Wavelengths smaller than violet are ultraviolet, X-rays and gamma rays.  Wavelengths larger than red are infrared, microwave, FM, AM and long radio waves.

In low light levels rods can make out things in shades of gray.  But cannot distinguish color.  As the light intensity increases the rods saturate and lose their ability to see.  While at the same time the cones begin to see.  There are three types of rods in the eye.  Those that see long wavelengths (around the color red).  Those that see medium wavelengths (around the color green).  And those that see short wavelengths (around the color blue).  These are the primary colors of light.  Red, green and blue.  If you add any combinations of these light wavelengths together you can get any color in the visible spectrum.  The cones will ‘see’ a color based on the combination of wavelengths they sense.  If the cones sense only red and green the eye will see yellow.  If the cones sense all wavelengths equally the eye will see white.

If you’ve ever bought a color inkjet cartridge, though, you may be saying this isn’t right.  Inkjet cartridge packaging has three dots of color on them.  None of them green.  There’re red, blue and yellow.  Not red, blue and green.  Green isn’t a primary color.  Yellow is.  And that is true.  When it comes to painting.  Or printing.  Or dyeing.  That uses subtractive coloring.  Where we use dyes, inks and pigments to absorb light wavelengths.  A blue paint, for example, will absorb wavelengths of all colors but blue.  So when you look at something dyed, printed or painted blue only the blue wavelength of the source light (such as the sun) reflects onto the cones in your eye.  The other wavelengths from the source light get absorbed in the dyes, inks and pigments.  And don’t reflect onto the cones in your eyes.

Our Brain blends Wavelengths of Color together into a Continuous Color Image

Artists mix paints together on a palette.  Each individual paint absorbs a set of wavelengths.  When mixed together they absorb different wavelengths.  Allowing the artist to create a large palette of colors.  The artist applies these colors to a canvas to produce a beautiful work of art.  But not all artists.  Georges Seurat didn’t mix colors together for his masterpiece.  A Sunday on La Grande Jatte.  The subject of Stephen Sondheim’s musical Sunday in the Park with George.  Where George explains the technique he used.  Pointilism.

Instead of mixing paints together to make colors Seurat applied these paints unmixed onto the canvas.  And let the eye mix them together.  The individual pigments absorbed all wavelengths but the desired color.  As these different wavelengths of different intensities fell onto the cones the brain blended these dots of color together.  In the musical George (Mandy Patinkin in the original Broadway cast available on DVD) shows someone what the painting looks like up close.  A bunch of dots of different colors.  And then moves backward with him.  As they do the dots blend together into a rich palette of colors.  Producing a beautiful painting.

In 4-color printing we use a combination of these techniques.  Where they reproduce a color photograph by blending the three primary colors (red, blue and yellow) and black.  The original photograph is broken down into its primary colors.  Before digital printing this was done with photography and color filters.  One for each primary color.  They then made screens for each color.  To vary the intensity of each color they broke solid colors into dots.  The amount of white paper showing between the dots of ink lightened the shade of the color.  The paper runs through a press that adds each of the primary colors onto the image.  Overlapping colors to produce different colors.  Subtracting wavelengths to produce a color image.  With the brain blending these colors together to reproduce the original color photograph.  (They added black to make a cleaner image than they could by mixing the inks together to make black.)

Video displays are more like pointilism.  Televisions in the days of picture tubes had three electron guns repeatedly scanning the phosphorus coating on the inside of the picture tube.  Each gun hit one of three different colors of phosphorus.  Red, blue and green.  These dots of phosphorus glowed at different intensities.  Each pixel on the screen has one dot of each phosphorus color.  The three colors blend together into one color pixel.  We use different technology today to produce the same wavelengths of red, blue and green.  That produce a color image.  That falls on the cones in our eyes.  With our brain blending these pixels of color together into a continuous image.


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Gas Prices Stay High along the Environmentalist West Coast due to a Lack of Refinery Capacity

Posted by PITHOCRATES - May 20th, 2012

Week in Review

Take a look at an electoral map.  Say from the 2008 national election.  What do you see?  Blue (i.e., Democrat) on the coasts.  Red (i.e., Republican) in the middle.  And blue in the union Midwest.  Okay, now what else do you associate with the blue on the coasts?  That’s where there are high concentrations of liberals.  (The blue in the Midwest is more organized labor than liberal).  And what is one of the biggest issues with liberals?  That’s right.  The environment.  (I’ll just assume you said the environment).  Especially in California.  Where they have tougher emission standards than the federal government has. 

They take their environmentalism serious on the coasts. So much so that they punish the use of fossil fuels through high taxes and excessive regulations.  It is for these reasons you don’t see them building many new refineries in these regions.  For there are few things they hate more than petroleum oil.  From drilling it out of the ground.  To transporting it.  To refining it.  Their basic attitude towards the oil industry is, “Sure, you’re welcomed to do business here.  But you will pay.  And pay.  And pay.”  So with that in mind here’s a little story about high gas prices on the West Coast (see Unlike the East, gas prices stay stubbornly high out West by William M. Welch posted 5/18/2012 on USA Today).

“We are seeing a tale of two coasts,” says Michael Green, spokesman for AAA, which monitors pump prices. “On the West Coast, gas prices are rising steadily, while on the East Coast they are steadily decreasing.”

Oil analysts blame a refinery slowdown in western states for sending retail prices in the opposite direction of wholesale costs.

In California and Oregon, the average price of regular gas has increased 20 cents a gallon so far in May, AAA reports. Average pump prices were down 19 cents in Florida and 18 cents in Virginia…

Tupper Hull, spokesman for Western States Petroleum Association, blamed unexpected maintenance and other problems at refineries…

“Our concern is a lack of competition at the refinery level in California,” says Charles Langley, gasoline analyst at Utility Consumers’ Action Network in San Diego. “We’re not saying there’s a conspiracy. It’s just that with this few competitors, it’s very easy to game prices by turning off capacity.”

Bob van der Valk, petroleum analyst in Terry, Mont., said gasoline inventories are at a 20-year low in California for May. Supplies will return to normal, he said, but perhaps not in time for upcoming holiday travel.

The high prices on the West Coast are of their own making.  Prices have fallen on the southern half of the East Coast.  Because they aren’t as blue as they used to be.  They love their environment there.  Which is why they live there.  But they know they need petroleum oil and gasoline to live.  And they know that there is a direct correlation between anti-oil policies and the price at the pump.  Something they apparently don’t know on the West Coast.  For they hate oil.  Don’t want anything to do with oil in their state.  And yet almost everyone drives a car in California. 

If they want lower gas prices they have to make it easier to do petroleum business there.  That means they need to make it easier to refine gasoline in California.  Which means backing off on the taxes.  And the excessive environmental regulations.  They can do that.  Bring the price at the pump down.  And still have a beautiful environment.  Like they do on the southern half of the East Coast.


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