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30-11-2011, 08:25
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#76
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Registered User
Join Date: Dec 2010
Location: B.C.,Canada
Boat: 29'
Posts: 2,423
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Re: Reading a Chart in Metres
Actually,I was thinking "length as spectrum" -not as a unit of an arbitrarily- chosen wavelength which is an angstrom I think.Merely a flight of fancy..doing mathematics with spectrum interference.
PS: Waves are more than length.Waveforms.
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30-11-2011, 08:34
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#77
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Registered User
Join Date: Dec 2010
Location: B.C.,Canada
Boat: 29'
Posts: 2,423
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Re: Reading a Chart in Metres
For the OP,a very simple slide rule would be the easiest way of fast conversion.or just a slider on a ruler having both scales.
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30-11-2011, 08:53
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#78
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cat herder, extreme blacksheep
Join Date: Jul 2008
Location: furycame alley , tropics, mexico for now
Boat: 1976 FORMOSA yankee clipper 41
Posts: 18,967
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Re: Reading a Chart in Metres
medicine in usa uses metric now--isn to difficult to convert...
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30-11-2011, 09:42
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#79
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Registered User
Join Date: Dec 2008
Location: St. Georges, Bda
Boat: Rhodes Reliant 41ft
Posts: 4,131
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Re: Reading a Chart in Metres
How do you tell someone that their system doesn't work, when they has used it successfully for 100 yrs.
__________________
so many projects--so little time !!
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30-11-2011, 10:00
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#80
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Registered User
Join Date: Mar 2003
Location: Philippines in the winters
Boat: It’s in French Polynesia now
Posts: 11,368
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Re: Reading a Chart in Metres
Quote:
Originally Posted by HappySeagull
For the OP,a very simple slide rule would be the easiest way of fast conversion.or just a slider on a ruler having both scales.
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This what I've been using for the past 30 years. As long as they don't change the standards, it's as EZ as the push of a button.
.
__________________
Faithful are the Wounds of a Friend, but the Kisses of the Enemy are Deceitful! ........
The measure of a man is how he navigates to a proper shore in the midst of a storm!
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30-11-2011, 10:17
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#81
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cat herder, extreme blacksheep
Join Date: Jul 2008
Location: furycame alley , tropics, mexico for now
Boat: 1976 FORMOSA yankee clipper 41
Posts: 18,967
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Re: Reading a Chart in Metres
metric is actually much easier than our usa system.... makes more sense.
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30-11-2011, 10:27
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#82
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Registered User
Join Date: Mar 2008
Location: Calgary, AB, Canada
Posts: 6,252
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Re: Reading a Chart in Metres
In Canada our charts are mostly metric except for a few that still use fathoms and feet. Our official tide tables use both feet and metres, but corrections are done in feet only.
There was huge uproar a few years when there was an announcement that the corrections would be done metres. We are still making the corrections in feet.
That uproar will be miniscule compared to the day when we all agree that chart datum will lowest astronomical tide.
__________________
CRYA Yachtmaster Ocean Instructor Evaluator, Sail
IYT Yachtmaster Coastal Instructor
As I sail, I praise God, and care not. (Luke Foxe)
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30-11-2011, 11:24
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#83
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Registered User
Join Date: Dec 2005
Location: Helsingborg
Boat: Dufour 35
Posts: 3,891
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Re: Reading a Chart in Metres
Quote:
Originally Posted by zeehag
metric is actually much easier than our usa system.... makes more sense.
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OK, then you are ready for the next step, total metric navigation
I haven't heard much about this subject for, say 20 years, but at that time, it was said to be scheduled for about 2015. I wonder if there is an obscure international committee plotting this change, behind closed doors?
One possible scenario could run like this.
Replace 360 degrees with 400 "gons". The latitude of the poles would then be 100 gon ( N or S). A "centigon", 1/100 th of a gon, also equal to 1/10.000 of the arc from the equator to the poles. And.... as the original definition of a meter was supposed to be 1/10.000.000 of the distance from the equator to the pole....a "centigon" would also equal 1 km (kilometer) similar to todays minute of arc being equal to a mile (M) or 1852 m, and with similar accuracy. With this "minor" change all speeds would naturally be measured in km/h, boat speed and wind speed alike.
Thinking about it, this must be an easy feature to implement in OpenCPN, just a few magic numbers here and there in the code.
Any early adopters for an alpha test??
Thomas
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30-11-2011, 12:04
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#84
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Registered User
Join Date: Mar 2008
Location: Calgary, AB, Canada
Posts: 6,252
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Re: Reading a Chart in Metres
Quote:
Originally Posted by cagney
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Winds are measured by meteorologists in m/s (metres per second) and then converted.
__________________
CRYA Yachtmaster Ocean Instructor Evaluator, Sail
IYT Yachtmaster Coastal Instructor
As I sail, I praise God, and care not. (Luke Foxe)
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04-12-2011, 16:54
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#85
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Registered User
Join Date: Aug 2011
Location: Brisbane River, Queensland
Boat: Hunter 430. 43'
Posts: 4
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Re: Reading a Chart in Metres
Just a note on drying heights.
If the large number is underlined it means that the area will be above the waterline at LAT.
Trap for young players that think they have more room below than they actually have
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04-12-2011, 19:11
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#86
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Registered User
Join Date: Nov 2011
Location: Montegut LA.
Boat: Now we need to get her to Louisiana !! she's ours
Posts: 3,421
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Re: Reading a Chart in Metres
Dog Gone it How am I going to re-work my Lead Line ??? I find it still tells me depth in fathoms no matter what the chart says ?? I guess Im gonna have to learn Metric after all LOL and at 73 this will be hard !! Bob and Connie and PS got our new boat ! be aboard by new years we hope.
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04-12-2011, 20:59
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#87
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Registered User
Join Date: Mar 2008
Location: Calgary, AB, Canada
Posts: 6,252
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Re: Reading a Chart in Metres
Quote:
Originally Posted by bobconnie
Dog Gone it How am I going to re-work my Lead Line ??? I find it still tells me depth in fathoms no matter what the chart says ?? I guess Im gonna have to learn Metric after all LOL and at 73 this will be hard !! Bob and Connie and PS got our new boat ! be aboard by new years we hope.
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Keep your lead line in fathoms. If you are worried about a meter being 3" longer that a yard (.5 fathoms) in your going places you ought not to go.
__________________
CRYA Yachtmaster Ocean Instructor Evaluator, Sail
IYT Yachtmaster Coastal Instructor
As I sail, I praise God, and care not. (Luke Foxe)
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04-12-2011, 21:47
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#88
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Registered User
Join Date: Nov 2011
Location: Montegut LA.
Boat: Now we need to get her to Louisiana !! she's ours
Posts: 3,421
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Re: Reading a Chart in Metres
Jackdale, it was a Humerous statement, Ive been at this for over 50yrs and have never not gotten home yet ! LOL, bob nad connie
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04-12-2011, 23:35
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#89
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Registered User
Join Date: Jul 2008
Location: Plimmerton, New Zealand
Boat: Samsara, a Ross 930
Posts: 380
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Re: Reading a Chart in Metres
Quote:
Originally Posted by AussieGeoff
Eh? ...
As someone else mentioned, the main issue is when you are converting between units. Having used both systems for many years, I can now say that I prefer metric for virtually everything.
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x2 on that. The Imperial system was the worst invention of mankind. Until the USA trumped Imperial stupidity by inventing a smaller gallon ...
Gallons, cables, chains, furlongs, fathoms, feet, pints, gills, pounds, ounces, shillings ... OMG!
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05-12-2011, 01:56
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#90
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Moderator and Certifiable Refitter
Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 20,304
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Re: Reading a Chart in Metres
OK, it will be hard to drift this thread further but I will give it a go.
Which is heavier, a pound of gold or a pound of feathers?
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
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