Aeolus - the god of all winds

May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
there are only two kinds of winds, do you know them?
 
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May 1, 2011
4,189
Pearson 37 Lusby MD
1. Planetary Winds:
The winds blowing through out the year from one latitude to another in response to latitudinal differences in air pressure are called “planetary or prevailing winds”. They involve large areas of the globe.

2. Trade Winds:
These are extremely steady winds blowing from sub-tropical high pressure areas (30°N and S) towards the equatorial low pressure belt. These winds should have blown from the north to south in Northern Hemisphere and south to north in Southern Hemisphere, but, they get deflected to the right in Northern Hemisphere and to the left in Southern Hemisphere due to Coriolis effect and Ferrel’s law. Thus, they blow as north eastern trades in Northern Hemisphere and south eastern trades in Southern Hemisphere.

They are also known as tropical easterlies, and they blow steadily in the same direction. They are noted for consistency in both force and direction.

3. The Westerlies:
These winds blow from sub tropical high pressure belts towards sub-polar low pressure belts. The westerlies of Southern Hemisphere are more stronger and constant in direction than Northern Hemisphere. These winds develop between 40° and 65°S latitudes and these latitudes are known as Roaring Forties, Furious Fifties and Shrieking Sixties.

4. Periodic Winds:
Periodic winds change their direction periodically with the change in season, e.g., Monsoons, Land and Sea Breezes, Mountain and Valley Breezes.

5. Local Winds:
The local difference in temperature and pressure causes local winds. It is of four types: hot, cold, convectional and slope.
 
May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
hint: all those are sub chapters to the answer. 12&3 are the same, 4&5 are the same

it's not a trick question. it's rule number 1 understanding what powers our toys.
 
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Aug 2, 2005
1,155
Pearson 33-2 & Typhoon 18 Seneca Lake
Winds......On shore and Off shore?? Probably not. Where is our local meteorologist when we need one?
 
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May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
thermal & gradient are the two winds
the winds between the highs and lows then the heating from the daily sun.

kappy has part of the picture for sure.
having a common language to discuss these things is important.

next: at what wind speed do we start to see ripples on the water's surface?
at what wind speed do we start to see just a few white caps starting to form?

thermal excitation is part of the language :)
 
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Jan 5, 2017
2,263
Beneteau First 38 Lyall Harbour Saturna Island
next: at what wind speed do we start to see ripples on the water's surface?
at what wind speed do we start to see just a few white caps starting to form?
Ripples at 1 to 3 knots occasional white caps 7-10 knots depending on fetch.
 
May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
ripples first start at 6, then those first white caps at ten, at fifteen white caps all around, at twenty it goes to all white caps. below 6 the ground effects keeps the the winds off the deck.


all this info in this thread have been taught to me by the the top players in this sport, but i will also say that i agree with it all with my own observations. :)
 
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May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
why do we want twist in our sails in order to get the best performance? and at what point do we no longer want twist but then want the sails set straight?


i'm just doing this for fun and to start a conversation about sailing these toys we so enjoy. create food for thought.
my boats aren't broke, so i have no "how to fix it questions"
 
May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
understanding the wind and the weather is such a huge part of sailing and yet most do not understand it and never talk about it. prepping the vessel is needed but playing the wind and the waves is the great chess match with mother nature. where is the wind, where will it go next are skills that take a life time to learn. it continues for me. how to play it all while having the advantage. fun stuff :)
 
Jun 25, 2004
1,108
Corsair F24 Mk1 003 San Francisco Bay, CA
Jon, I'd guess that you've read Frank Bethwaite's book, High Performance sailing, first edition 1994?, second edition 2010. Chapter 1 covers the topics raised so far in this thread.

He passed away in 2012, IIRC, a great loss
 
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