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 Wind Direction expressions 
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Post Wind Direction expressions
Wind Direction expressions

When I read that a wind is "from the South" (for example), the meaning is pretty clear. However some other expressions of wind direction are a bit confusing to me.

Easterly Wind - does this mean the wind is "from" the East or going "toward" the East?

Wind is in the North - does this mean that the wind is "from" the North or going "toward" the North?

Any other wind direction expressions that might be confusing to new readers of AoS fiction and non-fiction?

Is there an authoritative source that covers my question?

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Don Campbell
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Fri Aug 08, 2008 7:45 am
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Don,

Wind is from, tide is to - or so I learnt.

Probably most basic navigational books would cover this question.

Hope this helps.

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Kester


Fri Aug 08, 2008 11:28 am
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Devenish wrote:
Wind is from, tide is to - or so I learnt.
Thanks for the response Devenish and the "wind is from" seems to answer my question. So, if I understand your expression, an "Easterly" wind is "from" the East. For example, Napoleon was waiting for an Easterly wind in order to sail West to invade England. Very helpful.

"Wind is in the North" doesn't seem to be covered specifially unless your expression means that any mention of a direction is always "from." In this case, does this mean the wind is "from" the North? Certainly it would be consistant.

The tide reference is a bit confusing as I thought that a tide was either "coming in" or "going out" rather than being connected to a direction. Another comment about tides might be helpful.

Is your expression ("Wind is from, tide is to") something that modern or AoS sailors would learn as part of navigation training? A Google search failed to find anything at all.


Devenish wrote:
Probably most basic navigational books would cover this question.
Could you or someone recommend something simple and available?

Thanks,

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Don Campbell
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Sat Aug 09, 2008 10:37 am
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Winds are always "from" the direction named - this practice goes back to Homer. In antiquity mariners often named winds after the lands from which they appeared to originate. The expression “wind is in the north” is simply another way of describing a north wind.

Currents and tidal streams are "to" and are often referred to as resulting in an "easterly set" or “southerly set" and as "east-going" or "south-going"etc.

Oddly enough, I cannot recall seeing these facts concisely stated in a navigation manual!

Tidal streams are horizontal movements of water in response to the tide-raising forces. The tidal stream can become very noticeable in narrow waters where sailing vessels must sometimes anchor to await a favourable tidal flow to enable them to work up or down channel. Tidal streams can be quite strong – I have experienced streams of 8 knots and there are stronger streams than that. They change their direction with the tide but not necessarily at the times of local high and low water. As an example, the Straits of Messina connect the Tyrrhenian Sea to the north with the Ionian Sea to the south. Both of these seas have two high waters and two low waters each lunar day (basically semi-diurnal). But the tides in these two seas differ in their timing by about six hours so that twice each lunar day the water in the strait has a slope northwards and twice it has a slope southwards. Even though the difference in levels is only about one foot at springs, this difference can result in a stream of up to four knots. So, to pass a fleet of ships of the line through the Straits of Messina required some mulling over beforehand.

The various Hydrographic Offices publish Tidal Stream Tables covering the time, speed and direction of tidal streams e.g. Singapore Strait, Torres Strait, English Channel.


Sat Aug 09, 2008 10:38 pm
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I found this bit earlier today.

<a href="http://books.google.co.uk/books?id=gCk6YV5AslIC&pg=PR33&ci=46,246,876,695&source=bookclip"><img src="http://bks8.books.google.co.uk/books?id=gCk6YV5AslIC&pg=PR33&img=1&zoom=3&hl=en&sig=ACfU3U1HlKZ5Z2hJU3hu7CfBIbQBBWaIPQ&ci=46%2C246%2C876%2C695&edge=1" border="0" alt="Text not available"/></a><br/><a href="http://books.google.co.uk/books?id=gCk6YV5AslIC&pg=PR33&ci=46,246,876,695&source=bookclip">The India Directory, Or Directions for Sailing to and from the East Indies, China, Australia, and the Interjacent Ports of Africa and South America Originally Compiled from Journals of the Honourable Company's Ships, and from Observations and Remarks, Resulting from the Experience of Twenty-one Years in the Navigating of Those Seas By James Horsburgh</a>

Comment: Mil pointed out this Google Books feature to me a while back. It's useful for long bits of text. However, I do worry about links changing over time, so I'm not sure how extensively it should be used here in the forum.

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susan


Sun Aug 10, 2008 12:18 am
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Devenish wrote:
Wind is from, tide is to...

Thanks to Susan and IONIA, it looks like Devenish's expression might be revised to "Wind is from, current/tidal stream is to" which makes more sense than "tide."

As IONIA notes, the wind convention [from] certainly predates the Forum period.

However, from the source that Susan found, this convention was followed by most but not every single navagator, at least in the source she quotes, circa 1836.

Interesting info, thanks everyone. I'm much less confused.

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Sun Aug 10, 2008 7:29 am
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Don,

Yes, as Ionia says, the expression the 'wind is in the north' would mean the same as the wind is from the north, it's just another way of expressing it.

The tidal reference, would also include currents, so yes, you could revise my earlier reference! It is a way of differenciating between the two forces and is probably taught that way in navigational classes. The terms 'coming in' or 'going out' are not really those that a seafarer would use, since it is actually a vertical movement, caused as we know by the gravitational pull of the sun and the moon. Of course it does not look like that if one were to stand on the seashore to watch - hence presumably the ordinary persons use of those terms. A mariner would more usually talk of the height of the tide, its extremes being called 'high water' and 'low water'; thus also a 'rising tide' when a tide is 'making' or 'coming in', and a 'falling tide' or 'ebbing tide' when 'going out'.

The direction of a particular tidal stream is as important to a mariner to know as is the wind direction, so that he can allow for it when making calculations for the navigation of his ship.

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Sun Aug 10, 2008 8:24 am
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