YM Lies, Damn Lies and Statistics

Its typical of this country, sitting on the fence, we are supposed to have a metric measurement systems, but road distances are still miles and yards!
 
sarabande said:
if you were sending very expensive satellites to Mars, you might be concerned about a difference in measurements standards, as in confusing metres and feet.
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Then obviously I would take care, just as I would take care between metres and kilometres. Incidentally, I believe that the US did manage to put a satellite in orbit well under the surface of Mars as a result of feet/metres confusion.

Then again, closer at home, a rock at 3m, or 3ft... ?
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As long as you know the units, no problem. I stick to fathoms myself. Seriously.
 
sailorman said:
apart from old gits ( me inc.) there have been almost 4 generations through the skool system all taught metric since 72.
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I do some work with children. Every year I ask them their heights. Almost without exception, UK children know their heights in feet and inches but not in metres. Same with weight - stones and pounds, not kilograms.
 
galadriel said:
Oh, the speed issue, I'll need to read the article again, 8knts yes in the right conditions, 9? did I say that? Mid 7's is the speed we can maintain, again in the right conditions. Over the land we have hit 12knts.

There was another discrepancy, I was quoted as saying we regularly averaged 6 knts crossing the channel, in fact we regularly average 6.6knts, if you dont believe that, I'm happy for you to read the ships log.
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8 knots or even 7.5 close hauled?

Here are the polars for the Farr 40 http://www.blur.se/polar/farr40_polar.txt

That's what they can achieve sailed perfectly, usually by professionals at the top level. The fastest close hauled speed in the table is 7.33 knots at a TWA of 43.4 deg in 30 knots of true wind.

Do wave as you overtake, it'll make their day.
 
JCP said:
8 knots or even 7.5 close hauled?

Here are the polars for the Farr 40 http://www.blur.se/polar/farr40_polar.txt

That's what they can achieve sailed perfectly, usually by professionals at the top level. The fastest close hauled speed in the table is 7.33 knots at a TWA of 43.4 deg in 30 knots of true wind.

Do wave as you overtake, it'll make their day.
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I agree entirely, not close hauled, not possible. Close reach, or beam reach, thats when we can hit 8 knts. Close hauled, 6kts is more like it.
 
sailorman said:
apart from old gits ( me inc.) there have been almost 4 generations through the skool system all taught metric since 72.
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Sure, and I'm one of them. But I still think of boats in feet - if given a length in metres I have to convert it to feet before I have any idea how big a vessel we're talking about.

And I too find the obsessive "push the furtlewangle about six inches (152.4mm) to the right" subediting in sailing mags pointless and annoying. In an infobox containing a list of vital statistics by all means list both, but in the flow of text it's just disruptive, and has a dated, 70s feel to it. Not to mention cases like my example, where the author just wanted to give a rough idea of how far the furtlewangle needed to move, and the copyeditor then applied a ridiculous level of engineering precision to the metric equivalent.

I'd suggest that any functioning person in British society, regardless of their age, knows how far six inches is.

Pete
 
JCP said:
8 knots or even 7.5 close hauled?

Here are the polars for the Farr 40 http://www.blur.se/polar/farr40_polar.txt

That's what they can achieve sailed perfectly, usually by professionals at the top level. The fastest close hauled speed in the table is 7.33 knots at a TWA of 43.4 deg in 30 knots of true wind.

Do wave as you overtake, it'll make their day.
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Fraid you misunderstand polars. They are worked out by supercomputers to calculate what the boat is theoretically capable of doing. Granted, they are worked out to such a level that what is written is almost always correct, but the goal of any professional crew will be to exceed the speeds that the polar diagram says you can achieve. Most TP52's can exceed their theoretical performance by as much as 3-5%.
 
In fairness she did power past me under main alone whilst we were motorsailing the other week. I was impressed.


The other thing is "what is close hauled"? My grandfather's lugger could do it close hauled but in her that meant 89.9' from the wind.
 
galadriel said:
Oh, the speed issue, I'll need to read the article again, 8knts yes in the right conditions, 9? did I say that? Mid 7's is the speed we can maintain, again in the right conditions. Over the land we have hit 12knts.
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12 kts over the land !! Impressive. I didn't know there was an option to fit wheels. How effective is the rudder when the boat is out of the water? :D
 
DJE said:
It has failed to be adopted because it ignores a basic principle that people like to deal in whole numbers between 1 and 100. It's much easier to remember and visualise the difference between a 32ft boat and a 35ft boat than it is when the measurements are expressed as 9.8m and 10.7m.
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I am afraid I agree with this concept, although I am European I use sometimes inches when doing DIY to get an easier to remember approx size. No doubt the metric system is the easiest to work with when passing from lengths to volumes to weights: 1m=1/44millionth of an earth meridian, a cube with 10cm. side (or 1dm.). contains 1l. volume. 1l. of pure water weighs 1kg, etc.

I have been wondering however why European yacht builders use feet to define a yacht model. Perhaps a cunning plan to extend the model range and price. The same applies to marina berths charges. It would be better for the consumer if we had 10, 11, 12, 13 metres boats rather than 30, 32, 34, 36, 38, 40, 42, 45, ... less space for producers and marinas to fiddle with prices.
 
DJE said:
For some reason in the UK we have chosen to use metres and millimetres which lumbers people with either decimals or uncomfortably large numbers.
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Your first (unquoted part) is unverified by any experimentation - so I don't see why it shouldn't be correct, or not.

On the quoted part, having been around in 1972, in the engineering industry, I can tell you that the mm were very much driven by that industry.
I still tend to work in mm which has drawn some very strange looks all round Europe.
 
charles_reed said:
On the quoted part, having been around in 1972, in the engineering industry, I can tell you that the mm were very much driven by that industry.
I still tend to work in mm which has drawn some very strange looks all round Europe.
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It makes sense, I noticed in the UK the extensive use of mm and g (grams). Whilst in Europe we are more used to km (kilometres) for distances, metres to measure short distances and areas and cm (centimetres) for DIY lengths and medium to small obejects dimensions (a TV, a cooker), whilst mm are used only when measuring small items, nuts and bolts diametres are normally in mm for example.

The one I cannot get used to is grams when buying food: "please may I have threehundred grams of beacon?". Hectogram (100g) is what we use, shorted to hects. 2 hects of parma ham is a good portion for an hungry sailor. 1 hect is good to fill half a baguette accompanied by some brie and lectuce. Did I slip on to food? Sorry nearly dinner time!
 
haydude said:
I am afraid I agree with this concept, although I am European I use sometimes inches when doing DIY to get an easier to remember approx size. No doubt the metric system is the easiest to work with when passing from lengths to volumes to weights: 1m=1/44millionth of an earth meridian, a cube with 10cm. side (or 1dm.). contains 1l. volume. 1l. of pure water weighs 1kg, etc.

I have been wondering however why European yacht builders use feet to define a yacht model. Perhaps a cunning plan to extend the model range and price. The same applies to marina berths charges. It would be better for the consumer if we had 10, 11, 12, 13 metres boats rather than 30, 32, 34, 36, 38, 40, 42, 45, ... less space for producers and marinas to fiddle with prices.
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European boat builders have an eye firmly on their export markets and the biggest of the bunch is the USA.

For myself I have worked in millimetres since the '70s but in sizes from 0-100 of the little critters, much easier than inches and thousands of an inch (or 'thou') but it is a mental challenge for me to instantly 'see' the difference between say 1.68m and 1.8m. I'm sort of OK at larger ranges like when playing golf if the distance is a 150m shot I can visualise it as being roughly 165yds but for depths I still prefer to work in old money. My echosounder is always set to read in feet and the chart plotter to display depths in feet. The paper charts are in metres of course but if I mistakenly read on as feet it at least is erring on the safe side!
 
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