Horse Latitudes

 

In the log of 11th April, Alex posed the question “Does anyone know why the latitudes close to the equator are called the Horse latitudes - and which/where are they?

 

Below are the responses that he received:

 

 

The horse latitudes are subtropical regions of poor wind. I believe they were so called because when horses were being transported by sailing ship to India a lot of them died at this stage of the voyage and the carcasses were thrown overboard. I always thought that only the southern latitudes were called that, but the info. I just looked at on the net says north and south, about 5 degrees around latitude 30 .

 

 

From the Columbia Encylclopedia:

"The term horse latitudes supposedly originates from the days when Spanish sailing vessels transported horses to the West Indies. Ships would often become becalmed in mid-ocean in this latitude, thus severely prolonging the voyage; the resulting water shortages would make it necessary for crews to throw their horses overboard."

Got any horses on board?

 

 

Courtesy of Bowditch:

The Horse Latitudes: Along the poleward side of each trade-wind belt, and corresponding approximately with the belt of high pressure in each hemisphere, is another region with weak pressure gradients and correspondingly light, variable winds. These are called the "horse latitudes", apparently so named because becalmed sailing ships threw horses overboard in this region when water supplies ran short. The weather is generally good although low clouds are common. Compared to the doldrums, periods of stagnation in the horse latitudes are less persistent. The difference is due primarily to the rising currents of warm air in the equatorial low, which carry amounts of moisture. This moisture condenses as the air cools at higher levels, while in the horse latitudes the air is apparently descending and becoming less humid as it is warmed at lower heights.

 

 

You may wish that you had not asked about "horse latitudes"! The Chambers encyclopedia says that they were so named in the times of the Spanish voyages. They are the latitudes where the wind runs out and sailing ships stalled and provisions, especially water, began to run low. As they were often carrying large cargoes of horses to the colonies, sailors often had to throw the horses overboard to conserve the water for the crews.

Who will get thrown overboard to conserve the supply of (corroding) Guiness?

 

 

The horse latitudes are at about 35 - 30deg. lat. and that then you should find the S E trade winds of 9.5 to 11.5 kt.

However it is also a rock song. As follows. Provide your own music:

 

Artist : Doors

Song : Horse Latitudes

When the still sea conspires an armour

And her sullen and aborted

Currents breed tiny monsters

True sailing is dead

Awkward instant

And the first animal is jettisoned

Legs furiously pumping

Their stiff green gallop

And heads bob up

Poise

Delicate

Pause

Consent

In mute nostril agony

Carefully refined

And sealed over

 

 

RN Manual of Seamanship Vol II (1951) defines the Horse Latitudes as a belt of light and variable winds between the Westerlies and the Trade Winds in the northern and southern hemispheres in which sailing vessels were often becalmed for some time.  The name had its origin in the middle of the nineteenth century, when numerous horses were transported from Europe to America and the West Indies, and the belt in the North Atlantic was often studded with dead horses.

 

 

Between about 30° to 35° north and 30° to 35° south of the equator lies the region known as the horse latitudes or the subtropical high. This region of subsiding dry air and high pressure results in weak winds. Tradition states that sailors gave the region of the subtropical high the name "horse latitudes" because ships relying on wind power stalled; fearful of running out of food and water, sailors threw their horses and cattle overboard to save on provisions. (It's a puzzle why sailors would not have eaten the animals instead of throwing them overboard.) The Oxford English Dictionary claims the origin of the term "uncertain."

Major deserts of the world, such as the Sahara and the Great Australian Desert, lie under the high pressure of the horse latitudes.

The region is also known as the Calms of Cancer in the northern hemisphere and the Calms of Capricorn in the southern hemisphere.

 

 

The term horse latitudes supposedly originates from the days when Spanish sailing vessels transported horses to the West Indies. Ships would often become becalmed in mid-ocean in this latitude, thus severely prolonging the voyage; the resulting water shortages would make it necessary for crews to throw their horses overboard.

There is also the theory that it's from the Spanish golfo de las yeguas, mares' sea.

They are about 30deg lat in both hemispheres and are noted for their long periods of calm weather.

 

 

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2005, Columbia University Press

Two belts of latitude where winds are light and the weather is hot and dry. They are located mostly over the oceans, at about 30° lat. in each hemisphere, and have a north-south range of about 5° as they follow the seasonal migration of the sun. The horse latitudes are associated with the subtropical anticyclone and the large-scale descent of air from high-altitude currents moving toward the poles. After reaching the earth's surface, this air spreads toward the equator as part of the prevailing trade winds or toward the poles as part of the westerlies. The belt in the Northern Hemisphere is sometimes called the "calms of Cancer" and that in the Southern Hemisphere the "calms of Capricorn." The term horse latitudes supposedly originates from the days when Spanish sailing vessels transported horses to the West Indies. Ships would often become becalmed in mid-ocean in this latitude, thus severely prolonging the voyage; the resulting water shortages would make it necessary for crews to throw their horses overboard.

 

 

Solar radiation warms the air over the equator, causing it to rise. The rising air then proceeds south and north toward the poles. From approximately 20° to 30° North and South latitude, the air sinks. Then, the air flows along the surface of the earth back toward the equator.

 

Doldrums

Sailors noticed the stillness of the rising (and not blowing) air near the equator and gave the region the depressing name "doldrums." The doldrums, usually located between 5° north and 5° south of the equator, are also known as the Intertropical Convergence Zone or ITCZ for short. The trade winds converge in the region of the ITCZ, producing convectional storms that produce some of the world's heaviest precipitation regions.

The ITCZ moves north and south of the equator depending on the season and solar energy received. The location of the ITCZ can vary as much as 40° to 45° of latitude north or south of the equator based on the pattern of land and ocean. The Intertropical Convergence Zone is also known as the Equatorial Convergence Zone or Intertropical Front.

 

Horse Latitudes

Between about 30° to 35° north and 30° to 35° south of the equator lies the region known as the horse latitudes or the subtropical high. This region of subsiding dry air and high pressure results in weak winds. Tradition states that sailors gave the region of the subtropical high the name "horse latitudes" because ships relying on wind power stalled; fearful of running out of food and water, sailors threw their horses and cattle overboard to save on provisions. (It's a puzzle why sailors would not have eaten the animals instead of throwing them overboard.) The Oxford English Dictionary claims the origin of the term "uncertain."

Major deserts of the world, such as the Sahara and the Great Australian Desert, lie under the high pressure of the horse latitudes.

The region is also known as the Calms of Cancer in the northern hemisphere and the Calms of Capricorn in the southern hemisphere.

 

Trade Winds

Blowing from the subtropical highs or horse latitudes toward the low pressure of the ITCZ are the trade winds. Named from their ability to quickly propel trading ships across the ocean, the trade winds between about 30° latitude and the equator are steady and blow about 11 to 13 miles per hour. In the Northern Hemisphere, the trade winds blow from the northeast and are known as the Northeast Trade Winds; in the Southern Hemisphere, the winds blow from the southeast and are called the Southeast Trade Winds.

 

 

From "Ships" by Frank C. Bowen (Ex Captain, Royal Marines) and published by Ward, Lock & Co. 370 pages of fascinating tidbits.

 

"THE TRADE WINDS"

At round about thirty degrees north of the Equator the ship will begin to run into the Trade winds, which blow from the north-east year in and year out, and in the old days of sailing ships might well have been described as the mainstay of commerce. Under steam the region of the Trades is blessed as a broad area in which you may well know what to expect, and nothing more. The first month out will probably end somewhere in the Trades, and everything will be favourable for " burying the dead horse."

 

"BURYING THE DEAD HORSE"

When a man signs on, he receives his first month's pay in advance, the ostensible reason being that he may leave port without being in debt. Quite probably the greater part of his pay will go to the lodging-house keeper who has been letting him run up a bill, for motives that are anything but disinterested. If there was any money over it almost certainly went in a big spree before going to sea again, or, in the case of the more thoughtful men, in making a little stand-by for the missus and kiddies. Anyhow, if there were two men in her forecastle with hard cash in their pockets when she left the London River, our ship was a very extraordinary one indeed. The money for this first month of their voyage having been spent, the men, sailorlike, consider that they are working for nothing, and at the end of it, when the period of earning " real money " begins, there were formerly general rejoicings which are now, like so many of the old sea customs, sadly shorn of their glory. Some few ships still go through the whole ceremony, but they are few and far between. A horse was made out of sacking and straw, and after various junketings on deck, was hanged by the neck at the yardarm and then cut adrift to drop into the sea. Perhaps he was well soaked with paraffin and went down blazing, but there was too much risk of setting fire to the ship in this part of the proceedings and the average shipmaster did not encourage it. When the horse and the memory of the month were safely overboard, discipline was tightened again, and the life of the ship went on as before.