Metric system dumbs us down.

[StuM]

Originally Posted by Jason Flare

I'm trying to picture this. Are you metric people carrying a ball with you to lay a piece of paper and plot on?

No we just mentally calculate haversines to work out great circle distances and angles in radians.

[Jason Flare]

Originally Posted by StuM

No we just mentally calculate haversines to work out great circle distances and angles in radians.

I'm sure you do. I suspect there's room for it.

ETA: my smiley face didn't post. Imagine, a smiley face.

[TeddyDiver]

Originally Posted by mrm

Like that?

I knew there were somebody knowing what I was talking about..

[JPA Cate]

After checking the references, at least one, it does appear that the draft horses on the Continent must have been smaller than those in Scotland. by ~10 watts.

**Buzzstar

I never thought about horses' watts before! ;-) But, consider the Shetland pony and the Scottish Highland Cattle. Both quite small for equids and bovines. The Hielanders would have had to travel quite a way to find a Shire, and then work like the devil to clear the rocky soil and plant enough grass for it, to boot!

Ann

Measuring is often idiosyncratic. Just think, in the good ol' USA, you can get a 2 X 4, generally in 8 ft. lengths; here, it's a "4 be two", don't know how long is common, but here, they cut their logs about half the length you see on logging trucks in the US and Canada. Of course, a 2 by 4 isn't really quite that large, but that's what we call it, anyway.

For the gentleman from Switzerland, we have some charts in fathoms, and two of our cruising guides mention cables. Maybe this all goes back to when the British ruled the waves, or waives the rules, but there you go. You have to convert those to metric, if you want to have the clearer understanding of those "sizes", and I'd have to do arithmetic to try and explain to you what size the regular 2 by 4 is that all Yanks know.

There's a lot of craziness in the world.....and I bet most of us on this thread have noticed that, one way and another.

Ann

[El Pinguino]

Originally Posted by StuM

No we just mentally calculate haversines to work out great circle distances and angles in radians.

Ah, the haversine, where would we be without it.... subtracting... that's where we would be.....

[Wotname]

Originally Posted by Ann T. Cate

.............
Measuring is often idiosyncratic. Just think, in the good ol' USA, you can get a 2 X 4, generally in 8 ft. lengths; here, it's a "4 be two", don't know how long is common, but here, they cut their logs about half the length you see on logging trucks in the US and Canada. ........

Six metres is a common Aussie length Ann. Other lengths are available but six metres is a routine length.

[El Pinguino]

Originally Posted by StuM

No we just mentally calculate haversines to work out great circle distances and angles in radians.

That is rollocks... I'm ok with reducing sights in my head... John Wayne and Errol Flynn could do it and they weren't even real sailors.

However the haversine formula involves degrees of arc.... not radians ... and is used to avoid having to subtract big numbers from other big numbers...

[Benz]

Originally Posted by StuM

I'll have some of what you're on! It obviously leads to very happy delusions.

I'm on a couple Imperial pints of irrefutable logic. Join me here, it's a lovely place!

[StuM]

Originally Posted by El Pinguino

That is rollocks... I'm ok with reducing sights in my head... John Wayne and Errol Flynn could do it and they weren't even real sailors.

However the haversine formula involves degrees of arc.... not radians ... and is used to avoid having to subtract big numbers from other big numbers...

No haversines just involve arcs regardless of units. And nothing to do with subtracting big numbers. The Haversine function is just: haversin(θ) = sin²(θ/2) where θ is an angle in radians. Nothing to do with adding and subtracting large numbers,

The calculations are MUCH simpler if you use radians rather than degrees.
Note that all of the working is given in radians here: https://en.wikipedia.org/wiki/Haversine_formula


But of course - it's rollocks. I bet that even The Rain Man couldn't do that in his head

I have however written computer functions to calculate great circle distances and bearings which do exactly that ( in radians), so in a way, I have done those calculations in my head.

[cayennita]

Originally Posted by CaptTom

I find the imperial system easier. Think about it. It's basically base 8 - octal - like computers use.

Example: Cup, pint, half-gallon, quart, gallon. Easy.

Funny thing about Canada. All through the Maritimes last year I paid for slips and line by the foot, and when getting directions it was always in miles. One place even asked how many gallons of fuel I needed, even though the pump read liters. Only thing that messed me up was trying to buy deli meats in grams. Wonder what would have happened if I asked for a half-pound?

550 grams makes no sense. Ask for 1/2 kilo or 1/4 kilo. I was brought up with the metric system and then when I came to the US, the American system. I have no problem with either one. Do you know how much a cubic foot of ware weighs? Or how many gallons make a cubic foot? Or how much a gallon of water weighs? Most Americans don't. how many square feet in an acre? How big is an acre?
Metric makes sense. It is all in tens, hundreds, etc.
One hectare is 100 x 100 meters. One ton of water is one thousand kilos or one ton, etc.

[TrentePieds]

Quote: "you know how much a cubic foot of ware weighs?"

Depends on whether it's hardware of software.

Quote: "Metric makes sense. It is all in tens, hundreds"

We know it does and we know it is. The debate is not about whether it makes sense, let alone what its traits are. The debate is about whether it is USEFUL. My contention - as a Former Metric Person, a FMP - is that for a small boat sailor, qua SBS, it is not.

TrentePieds

[K_V_B]

Originally Posted by TrentePieds

Quote: "you know how much a cubic foot of ware weighs?"

Depends on whether it's hardware of software.

Quote: "Metric makes sense. It is all in tens, hundreds"

We know it does and we know it is. The debate is not about whether it makes sense, let alone what its traits are. The debate is about whether it is USEFUL. My contention - as a Former Metric Person, a FMP - is that for a small boat sailor, qua SBS, it is not.

But why?

I can understand the point of the nautical mile. So do btw. the powers that regulate the Metric system, as they made the nautical mile ( and the knot) part of the SI system.

But why would there still be a need for feet, fathoms, cables or wherever other idiosyncratic units still exist?
If you want to tell that something is 600 metre away, why not just tell that it is 600 metre away, in stead of forcing everyone to look up what a "cable" is...

[JPA Cate]

Or, you could commit the ones that are useful to know, to memory, and ignore the rest. Sort of like throwing out the baby with the bathwater, but for lazy thinkers like me, it seems to work.

I made something for the boat, Trente Pieds, using all metric measures. And it fit, and has been useable. It was an experiment. Having done it, have gone back to feet and inches for successive iterations. However, to me, it doesn't make much difference if i have 1/4", 1/2", 5/8" (often used in clothing) or 1/2 cm hem widths: just decide and get on with it. [1/4", ~ 6 mm, works well when you're trying to eke out a bit of fabric.] I must confess, though, that I am a great fan of bilingual tape measures, that show both mm, etc and inches, etc. Helps me deal with metrificated people. And if a novelist's hero is 165 cm tall, it means nothing to me till I do the conversion arithmetic, which I may do wrong! Usually it doesn't matter, tall is tall and heroes usually are, after all. Does it matter if he's 6'4" or 6'6"? not to me.

Ann

[etterridge]

Originally Posted by rom

No, but a bottle of Chardonnay is 75 cl everywhere in the world.

TRUE, but in Canada we don't call it that. It is universally known as 750 ml.

[Kelkara]

Originally Posted by K_V_B

I can understand the point of the nautical mile.

I can't.

It's time we did away with minutes of arc too, and used decimal degrees, then if you really must we can then have a "nautical km" equal to 1/100 of a degree of latitude or 1111m ... or we could just print paper charts with a km scale down the side and push the metric button on our plotters.

Some people say there are still dinosaurs living deep in the oceans ... so it makes sense that these Jurassic measurement units will have their last gasp out there too.