Speed Through GPS Versus Old Fashioned Paddle Log

[Wotname]

Originally Posted by El Pinguino

The world's met departments standardise wind measurements at 10 metres above ground. I'm sure someone here can come up with a simple system for wind speed adjustment using instrument height/angle of heel as arguments.

Yeah but....

got nuthing too do with wot the wind in ma sails is doing tha me..

And hey when or where did the met wind ever equal the wind over the course which I note ALWAYS increases by the time one retires to the bar.


err and should add

[Dockhead]

Originally Posted by El Pinguino

This debate seems to have centered mainly around sailing in the English Channel. Therefore I would suggest that the term 'tidal stream' should be used... not 'tidal current'

....for the avoidance of confusion etc.

We use the words "stream" and "current" interchangeably hereabouts Or mostly just "the tide". But that confuses the Yanks, who are taught, erroneously, that "tides move up and down; currents go left and right" -- see: What's the difference between a tide and a current? -- an official source, spouting such nonsense!! Therefore, I tend to throw in the word "current" to keep them calm.


But this thread is certainly NOT just about sailing in La Manche. All these discussions apply equally anywhere the water moves much. Gulf Stream, Pacific Northwest, Newfoundland -- many places.

[MarkSF]

The Oxford English dictionary describes a tide thus :

"The alternate rising and falling of the sea, usually twice in each lunar day at a particular place, due to the attraction of the moon and sun"

The source you quoted is right. The tide is a product of the gravational effect of the moon. Tidal currents, at least detectable ones, are a product of the tides, combined with confined spaces through which the water level change must move.

Think about it, in the deep ocean, there are still tidal changes, a change in depth, but no detectable current - because the change in depth is tiny relative to the depth. You only get strong currents when the water is forced through small spaces. If the Earth had no land masses at all, you would still get tides, but no current due to the tide.

[Dockhead]

Originally Posted by MarkSF

The Oxford English dictionary describes a tide thus :

"The alternate rising and falling of the sea, usually twice in each lunar day at a particular place, due to the attraction of the moon and sun"

The source you quoted is right. The tide is a product of the gravational effect of the moon. Tidal currents, at least detectable ones, are a product of the tides, combined with confined spaces through which the water level change must move.

Think about it, in the deep ocean, there are still tidal changes, a change in depth, but no detectable current - because the change in depth is tiny relative to the depth. You only get strong currents when the water is forced through small spaces. If the Earth had no land masses at all, you would still get tides, but no current due to the tide.

Well, we call the currents resulting from the tidal action as "the tide". For centuries. William Shakespeare:

"We bodged again; as I have seen a swan
With bootless labour swim against the tide
And spend her strength with over-matching waves."

Hence also the terms "fair tide" and "foul tide", which would make no sense if we're only talking about vertical motion.

Don't you use the term "fair tide"? This means a tidal current which is moving in the same direction you want to go, helping you along. Moving -- horizontally, not vertically. It certainly does not refer to the vertical motion of the tide.

[chala]

Originally Posted by Dockhead

Deviation? I think you are confusing this with true and magnetic compass bearings -- not the first time that this has entered this discussion.

If someone owns a steel boat, that someone will quickly understand deviation.
In this forum people have extolled the value of deviation cards.
Starting from Apparent Wind anyone trying to use reverse engineering to get (met) Wind will require all the “ingredients” necessary to do so including relevant Deviation data. Taking into consideration that deviation change as the boat move the chance of getting (met) Wind are small. It is maybe why B&G call this Ground Wind, a novelty. Interestingly like me, you do not think too much of that novelty but can not give any reasons for yours distrust.

Originally Posted by Dockhead

But I don't think it's a very good idea to use Ground Wind for sailing. It's not what you sail in. It will lead to big mistakes in areas with strong tidal streams. You can be 5 knots off, in a place where the tide regularly reaches 5 knots, like in the Channel, and the direction may be significantly different, too.

[El Pinguino]

Originally Posted by chala

If someone owns a steel boat, that someone will quickly understand deviation.
In this forum people have extolled the value of deviation cards.
Starting from Apparent Wind anyone trying to use reverse engineering to get (met) Wind will require all the “ingredients” necessary to do so including relevant Deviation data. Taking into consideration that deviation change as the boat move the chance of getting (met) Wind are small. It is maybe why B&G call this Ground Wind, a novelty. Interestingly like me, you do not think too much of that novelty but can not give any reasons for yours distrust.

Some dirt dwellers, presumably involved in the study of magnetism ashore, use the word 'deviation' where I would talk about 'dip'. I guess they have never owned a steel boat.

[Wotname]

Originally Posted by Dockhead

Well, we call the currents resulting from the tidal action as "the tide". For centuries. William Shakespeare:

"We bodged again; as I have seen a swan
With bootless labour swim against the tide
And spend her strength with over-matching waves."

Hence also the terms "fair tide" and "foul tide", which would make no sense if we're only talking about vertical motion.

Don't you use the term "fair tide"? This means a tidal current which is moving in the same direction you want to go, helping you along. Moving -- horizontally, not vertically. It certainly does not refer to the vertical motion of the tide.

It seems to me that some folk (not you) like to stem the tide over trivial matters and others like to stem the tide over matters that truly count and affect our sailing experiences.

On reflection, I seem to have a foot in each camp but I do try to spend more time with the latter.

And let me add "Time and tide wait for no man"
And oh... precious few woman

[Wotname]

Originally Posted by El Pinguino

Some dirt dwellers, presumably involved in the study of magnetism ashore, use the word 'deviation' where I would talk about 'dip'. I guess they have never owned a steel boat.

Haha lol

Here's one steel boat ex-owner who does not mistake the two and their quite different effects but YMMV.

EDIT: maybe one of use has taken naughty pills today - I will leave for the reader to decide "if and who".

[El Pinguino]

Originally Posted by Wotname

Haha lol

Here's one steel boat ex-owner who does not mistake the two and their quite different effects but YMMV.

My bad... they call 'dip' 'declination' .... I still found it odd usage as I am used to declination being used soley with stars and stuff...

Magnetic Declination | Magnetic Inclination - Magnetic Dip

[Wotname]

And there was I thinking you might have been just taking the weewee

[Robin3]

Originally Posted by Dockhead

Well, we call the currents resulting from the tidal action as "the tide". For centuries. William Shakespeare:

"We bodged again; as I have seen a swan
With bootless labour swim against the tide
And spend her strength with over-matching waves."

Hence also the terms "fair tide" and "foul tide", which would make no sense if we're only talking about vertical motion.

Don't you use the term "fair tide"? This means a tidal current which is moving in the same direction you want to go, helping you along. Moving -- horizontally, not vertically. It certainly does not refer to the vertical motion of the tide.

Usually with me it is two nations separated by a common language but in reality there are more than two nations speaking some kinda English with differing translations but then every bugger misunderstands me anyway!

Flogging against or bucking a foul tide never a good idea in my book.

[RaymondR]

Imagine Captain Cook getting his head around satellite and GPS/PLOTTER navigation and plotting his boats position on the earth accurately every second..........but that is another topic

As a master navigator and one of the first explorers to use a chronometer I imagine Captain Jimmy would have found it a breeze.

[RaymondR]

We bodged again; as I have seen a swan
With bootless labour swim against the tide
And spend her strength with over-matching waves

Carrol in the Hunting of the Snark uses tide to describe the rise and fall of the boat from waves, surge or swell.

"assisting each man at the top of the tide with a finger entwined in his hair"

[Dockhead]

Originally Posted by RaymondR

Carrol in the Hunting of the Snark uses tide to describe the rise and fall of the boat from waves, surge or swell.

"assisting each man at the top of the tide with a finger entwined in his hair"

I don't think that Lewis Carroll meant that every time a boat bobs up from "waves, surge, or swell" that this is a high tide. Certainly no one here has used the term that way.

In any case, the tide is not a specifically vertical movement. The tide is a kind of very low frequency wave induced by the gravitational forces of sun and moon. It has both vertical and horizontal effects.

It is just perceived as a vertical phenomenon from the point of view of the land; hence all the wrong definitions. From the sea, you are much more likely to perceive the horizontal effects of the tide, which will either help you along your way, hinder you, or throw you off course. Well, until you run aground at low tide, of course

[Dockhead]

Originally Posted by Robin3

Usually with me it is two nations separated by a common language but in reality there are more than two nations speaking some kinda English with differing translations but then every bugger misunderstands me anyway!

Flogging against or bucking a foul tide never a good idea in my book.

Yes, well. English English (note to my compatriots -- there is no such thing as "British English") and American English have converged a lot even in my lifetime. The differences are actually pretty small.

I like American English and I don't generally find it to be inferior to the home version. In fact, I think that the integrity of the language is even holding up better in the Colonies; my best friend and business partner here is an honors graduate of Eton and Cambridge -- so the best education you can have hereabouts -- and he drives me up the wall saying things like "with my wife and I" and using apostrophes to make plurals . . . yes, I am not too shy to correct him Very few Yanks would make such mistakes. But where nautical terminology is concerned, it's the other way around. Here the English really use it well and precisely, and a lot of American usage is just wrong. For example, the idea that "there is no such thing as rope on board"; and calling a toilet fixture itself a "head". Now we can add "tide" to the list; although I don't think this usage, excluding horizontal elements of tides, is common, but no single English person would ever say such a thing. My perception is that Yanks tend to speak about the sea like land people even when they're seasoned seamen; the English tend to speak about the sea like seamen -- even when they are land people. One of the many things I like about being over here. Even if the English language is generally going to hell.