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Old 13-11-2013, 12:09   #1
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Terminology ........ Whats your Flavour?

hi all
in another thread we have found these terms to have different meanings to some

whats your take on it?


here is mine

i stand to be corrected


from the English dictionary
True
/tru/ Show Spelled [troo] Show IPA adjective, tru·er, tru·est, noun, adverb, verb, trued, tru·ing or true·ing.
adjective 1. being in accordance with the actual state or conditions; conforming to reality or fact; not false: a true story.


1.) true wind = un affected by any other factors


Apparent applies to that which can readily be seen or perceived:

2.) Apparent wind = what is perceived to be the wind direction at the helm position

angle and velocity influenced by induced heading wind , leeway, current/ tidal stream and any thing else that affects what you feel .... including bean induced

3.) Tide =
a. when referenced to height or range it means one thing
b. when referenced to flow/current / stream it means velocity or direction

4.) Leeway = the affect on a vessel from wind induced side ways move ment
i think that's it for now
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Old 13-11-2013, 12:36   #2
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Re: terminology ........ whats your flavour ???

The big question is True Wind. Is this referenced to the ground, or the water? In common usage, True Wind is used in both cases, but some have been using "Ground Wind" to disambiguate the situation. Not all agree with this.
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Old 13-11-2013, 13:32   #3
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Quote:
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The big question is True Wind. Is this referenced to the ground, or the water? In common usage, True Wind is used in both cases, but some have been using "Ground Wind" to disambiguate the situation. Not all agree with this.
I think leeway was another questionable
I would not reference it to any water induced movement

Just to clarify, ground wind has been used as if you where standing on the shore or a moored boat ( as in my definition of true)
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Old 15-11-2013, 09:13   #4
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Re: terminology ........ whats your flavour ???

CTS course to steer

this is generally used in passage planning

but not always .

what additional workings are added to a rhumb line to obtain your CTS

If those additions a variable what do you do?

Is it only used if you can lay you destination in one Tack ?
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Old 15-11-2013, 09:57   #5
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Re: terminology ........ whats your flavour ???

If you take a professional class (USCG, merchant marine academy, etc) there is no real argument about terms and in fact they make a laughing stock out of you when you regurgitate terminology and facts that are either incorrect or simply not true. By memory, some of the ones I remember:

- slack tide. there is no slack tide, as tide is the vertical movement of water. you can't have slack and movement at the same time. slack water is somewhat more accessible and stand of the tide if you really want to nail it.

- king tides. neap or spring, no king.

- rogue waves. there's a 0.0000000000000001% chance the wave you're referring to is a "rogue wave".

- sea anchor. funny enough according to the USCG a sea anchor can be deployed from the stern as a drogue.

- "over and out". "over" means you're done with your transmission but still there, "out" means you're not there any more.

- "right of way". unless you're on a river, it doesn't apply and hasn't for a long time.

- "law of tonnage". doesn't exist and over simplifies the very legitimate and typically marked by shapes and lights (or simply specified in colregs) reasons why that big boat might need you to get out of its way.


There were tons of them. And some, like the sea anchor one, I still find kind of stupid because there's a fundamental difference between a drogue and a sea anchor but I get the value in having on set of definitions.
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Old 15-11-2013, 15:31   #6
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I love it when I hear the "over and out" line. I am waiting for a response but I'm not here. Lol
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Old 15-11-2013, 15:43   #7
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One of my peeves is when sailors say, "I've got 50' of chain backed up by 200' of rode.

The rode includes the chain. Better to say: "My rode is 50' chain backed up by 200' of three-strand."
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Old 15-11-2013, 16:34   #8
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Re: terminology ........ whats your flavour ???

And then there are those perennial favorites:

"Knots per hour" and "Amps per hour"

Gag reflex is engaged.

Jim
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Old 15-11-2013, 17:05   #9
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Re: terminology ........ whats your flavour ???

Not to mention "POB on board"
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Old 15-11-2013, 17:57   #10
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Re: terminology ........ whats your flavour ???

Quote:
Originally Posted by Jim Cate View Post
And then there are those perennial favorites:

"Knots per hour" and "Amps per hour"

Gag reflex is engaged.

Jim
That's a great one.
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Old 15-11-2013, 19:20   #11
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Re: terminology ........ whats your flavour ???

Quote:
Originally Posted by Jim Cate View Post
And then there are those perennial favorites:

"Knots per hour" and "Amps per hour"

Gag reflex is engaged.

Jim

Knots per hour was a pet peeve of mine for a long time too, until I learned it is traditionally the correct usage. I could not be convinced of this until I read it in Maryatt. If that's how he said it, it's the gospel. Cook too.
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Old 15-11-2013, 19:41   #12
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Re: terminology ........ whats your flavour ???

> until I learned it is traditionally the correct usage

The "traditional usage" is "knots per 30 seconds" - using a "log" paid out over the stern with a knot every x number of feet.

That said, the current usage is as a unit of speed - specifically one nautical mile per hour (as recognised by ISO).

Knots per hour is not a speed, it is a rate of acceleration.

1 knot per hour is about 0,000014g
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Old 15-11-2013, 20:02   #13
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Re: terminology ........ whats your flavour ???

Quote:
Originally Posted by StuM View Post
> until I learned it is traditionally the correct usage

The "traditional usage" is "knots per 30 seconds" - using a "log" paid out over the stern with a knot every x number of feet.

That said, the current usage is as a unit of speed - specifically one nautical mile per hour (as recognised by ISO).

Knots per hour is not a speed, it is a rate of acceleration.

1 knot per hour is about 0,000014g


We all know what a knot log is and where the term comes from. All I'm saying is that all the famous nineteenth century navigators recorded their speed in their logs as "knots per hour". It was the common usage. If it was good enough for men like Nelson, Marryat, and Cook, it's good enough for me (whether it makes sense or not).
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Old 15-11-2013, 20:13   #14
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Re: terminology ........ whats your flavour ???

Quote:
Originally Posted by StuM View Post
1 knot per hour is about 0,000014g
And one knot is about 3,093.2 furlongs per fortnight.

Here are some terms that I thought were standard, but some were unfamiliar with them:

AWA = Apparent Wind Angle
AWS = Apparent Wind Speed
AWA and AWS are measured from your boat.

TWS = True Wind Speed
TWA = True Wind Angle
but referenced to what? Some say it's to the ground, and others say it's to the water. What would be your alternate terms and definitions?

TWD = True Wind Direction (I say this is referenced to the ground)
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Old 15-11-2013, 20:29   #15
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Re: terminology ........ whats your flavour ???

To my way of thinking, True is with reference to a fixed point on the Earth's surface. If it were referenced to the water, a "constant" wind would be changing its speed and direction all the time depending on current/tide. Also, it would rarely be the same as the wind measured ashore.

TWS and TWD no problem - speed/direction over a fixed point.

TWA is another matter. I'd tend to go with difference between TWD and the direction my bow is pointing (although there could be an argument for difference betwee TWD and COG)
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