Buys Ballot's Law - Landsman (and Meteorologist) vs Mariner

That’s a classic one but please keep it to yourself. My wife and landlubber friends think I have special powers because after a life at sea, I can predict wind shifts and incoming rain.

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Burgess (I’m using the 4th edition 1978) has bit on the accuracy of wind direction observations. It involves the karate chop over the compass repeater which I mentioned in an old thread.

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The advantage of using the appearance of the sea to estimate true wind direction is there’s no need to convert relative wind to true.

For better accuracy Burgess recommends using both methods, a true wind by the appearance of the sea and by determining relative wind (by funnel smoke, or flag etc.) and converting to true.

Burgess claims error is within 10 degrees or 5 degrees with practice.

MfS_wind_observation.PNG

The sea state photos in Marine Observers Handbook is mentioned. Most of the sea state photos I’ve see IIRC are taken pointed upwind.

This is a question of orientation. For directions on the earth using south would have been equally as useful as using north but using south has no particular advantage. North became the standard for historical reasons.

Using “facing the wind” as an orientation however does have advantages. When making observations the direction is into the wind. Weather vanes, picking the direction off a compass and so forth all point into the wind.

So why did Buy Ballot pick “back to”?

My guess is it’s because Buys Ballot wasn’t making observations, he was in an office plotting observations on paper using the wind barb symbols

Ballot might have just replaced the wind bards as shown on his weather map in his mind’s eye with an imaginary person “with one’s back towards the place from which it arrives’.

On a weather map the wind barbs fly with the wind.

He was left-handed…?

Buys Ballot stood upon the deck
Straighter than a mast pole,
He said “Low pressure is on my left,
When the wind goes up my Asshole”.

Attributed to Steve Colgate
Master Sailor and my Brother-in-law.

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So of course I understand that facing either way, front/back and switching sides left/right is logically the same. But one seems more seamanlike then the other.

This is the passage that sent me to Bowditch to check:

Bowditch describes Buys Ballot’s law, a handy rule of thumb invented by a Dutch meteorologist in 1857 that’s based on the unassailable fact that in the Northern Hemisphere, hurricane winds blow in a counterclockwise direction. The rule says this: When your back is to the wind, stick out your arms, making a T. Your left hand will point to the low, your right to the high.

Slade, Rachel. Into the Raging Sea: Thirty-Three Mariners, One Megastorm, and the Sinking of El Faro (p. 72). HarperCollins. Kindle Edition.

However:

About George Michelsen Foy

George Michelsen Foy was born on Cape Cod, in Massachusetts. He has worked as a commercial fisherman, a magazine editor, a first mate on British tramp ships

From the book:

you would know that if you stood facing the wind in the northern hemisphere, given that the system’s wind rotates counterclockwise, the zone of low pressure would lie to your right.IX

Foy, George Michelsen. Run the Storm: A Savage Hurricane, a Brave Crew, and the Wreck of the SS El Faro (p. 71). Scribner. Kindle Edition.

This is from David Burch:

If the Buys Ballot direction does not match your plot, and you checked both, then chances are you are not quite into the closed isobars. This could also be indicated by a pressure that is not dropping or dropping very slowly.

Regarding Buys Ballot’s law there is something special going on with that wind! The air flows with a small deviation. In the Northern Hemisphere the wind has a deviation to the right, in the Southern Hemisphere a deviation to the left. The cause of this is the Coriolis effect.

Another formulation is:

In the Northern Hemisphere, the wind blows from a high-pressure area to a low-pressure area with a deviation to the right, due to the rotation of the Earth on its axis.

This meteorological law is based on the Coriolis effect. If the Earth did not rotate on its axis, flowing air masses would move in a straight line if no other force was acting on them. For the atmosphere, the rotation of the Earth causes moving air masses to accelerate sideways, on which no other force acts. In the Northern Hemisphere an acceleration to the right relative to the direction in which the air is currently flowing, and in the Southern Hemisphere an acceleration to the left relative to the direction in which the air is currently flowing.

If there is a low pressure area somewhere, there is a tendency to flow towards that low pressure area. But the Coriolis effect makes the air flow around it more. Air that loses some speed due to friction will be slightly accelerated towards the center of the low-pressure area by the force of the air pressure difference, but then the Coriolis effect keeps the speed high.

In the Northern Hemisphere, due to the Coriolis effect, the air flows clockwise around a high pressure area and counterclockwise around a low pressure area.

Predecessors Coffin and Ferrel

A year before the discovery by Buys Ballot, American meteorologists J.H. Coffin and William Ferrel already make this connection. Buys Ballot, however, was the first to provide an empirical basis for their theory. Thirty years later, Buys Ballot asked Ferrel whether the law should be renamed, but the name remained unchanged.

This was Buy Ballot’s first pass at it, based on his observations.

Buy's_Ballot_0

Here’s his first statement of the law. (From here.)

Buy's_Ballot

This is the reference used to describe directions in explanations of the Coriolis effect. It would be cumbersome to use an observer as a point of reference. . This is also the reference Buys Ballot used.

Put “The Mariner’s Dictionary” by Bradford in the “salty” category, facing the wind.

Also learned that the term “fair wind” has two meanings and a “draft” is a single sling load of cargo. Working break bulk we called that a “lift”.

Ditto de Kerchove’s International Maritime Dictionary (1949). He also has ‘draft’ and ‘sling’ for a single sling load, but only one meaning for fair wind (generally favorable to the ship’s progress – more comprehensive than ‘large’ since it includes about 16 points).

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Another dimension to the choice of face-to or back-to is the phenomena of “thinking with movement”

If Buy Ballot’s law is applied by actually physically orienting (either way) to the wind and extending the appropriate arm, that movement is going be stored using the deeper, more robust procedural memory.

Is procedural knowledge then fundamentally more stable than explicit knowledge? As it turns out, the former is more resistant to both loss and trauma.

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Why Don’t We Forget How to Ride a Bike?

This is akin to the repetitious form of training used in law enforcement and military training to prepare for life threatening encounters. The natural tendency of humans in those scenarios is go into a dangerous condition of brain freeze and quickly develop tunnel vision. Repetition and constant practice allows an individual to react using muscle memory acquired during training and continue to function without intellectual thought. Whether it’s used to learn a musical instrument or train for the olympics, it’s the same phenomenon.

Yes, it’s closely related. Wikipedia says “muscle memory is a form of procedural memory”

In this case it’s a bit different because the goal is not to learn the movement but to use the movement to learn the concept; “thinking with movement”.

“Knowledge is not understanding” I was referring to muscle memory and bike riding, not Buys Ballot’s law. I think I’ve posted this video before.

A post was merged into an existing topic: “The Extended Mind” - Hutchins again

The term “muscle memory” is frequently used but strictly speaking is not technically correct. “Motor memory” is the correct term for how people remember how to ride a bicycle.

“Procedural memory” refers to the performance of both certain motor and cognitive tasks. Examples of the use of procedural memory for cognitive tasks include things such as pointing when giving helm orders and recalling Buy Ballot’s Law.

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We were taught back to the wind purely because the alliteration of the Low Lying (to your)Left was easy to remember.
I remember saying back to the wind to an Indian colleague and he looked at me as if I was speaking Klingon.

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I don’t blame him. Ya’ll drive on the wrong side of the road. That should tell you something.

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