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Tunnel Lights


Col_T

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1 minute ago, Alan de Enfield said:

 

Which parts are you struggling with - I'm sure its pretty clear to the majority of boaters who are affected by it.

 

Given :


 

Quote

 

FULL Navigation lights are required by all powered craft (Including NBs) as follows :

 

(5) On the Trent Navigation, the Weaver Navigation, the Aire and Calder Navigation, the New Junction Canal and the Sheffield and South Yorkshire Navigation (below Doncaster) a power-driven vessel shall in addition to the lights prescribed in paragraphs (1), (2), (3) and (4) as the case may be of this Bye-law display:-

 

 

that means anyone taking a narrowboat on to any of those navigations has to understand it.

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9 minutes ago, StephenA said:

 

Given :


 

 

that means anyone taking a narrowboat on to any of those navigations has to understand it.

 

So, are you suggesting that anyone helming a NB is unable to comprehend instructions written clearly and unambiguously in English?

 

In reality it just means that the person fitting out the boat needs to understand the laws - all the helm has to do switch them on.

 

Maybe using pictures will make it easier :

 

9 Boat navigation lights ideas | boat navigation, boat navigation lights,  navigation lights

Edited by Alan de Enfield
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1 minute ago, Alan de Enfield said:

 

So, are you suggesting that anyone helming a NB is unable to comprehend instructions written clearly and unambiguously in English?

 

Maybe using pictures will make it easier :

 

9 Boat navigation lights ideas | boat navigation, boat navigation lights,  navigation lights

 

I'd argue that to many people " w an unbroken light over an arc of the horizon of ten points of the compass (112½°)" is pretty meaningless.

 

And did you really need to resort to sarcasm?

 

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On 23/09/2021 at 14:08, Captain Pegg said:


Obviously going north there’s Braunston - or Crick - but that got me thinking about south of Blisworth.

 

Am I right in thinking that on the Grand Circle, Braunston is the next tunnel in both directions?

 

You have forgotten about Fenny Compton tunnel, about 1100 yards long I think ...

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1 hour ago, StephenA said:

 

I'd argue that to many people " w an unbroken light over an arc of the horizon of ten points of the compass (112½°)" is pretty meaningless.

I'll grant that "ten points of the compass" might not be widely understood, but since the text also refers to that as 112½°, I don't see why a person of average intelligence shouldn't be able to work out the meaning.

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38 minutes ago, David Mack said:

I'll grant that "ten points of the compass" might not be widely understood, but since the text also refers to that as 112½°, I don't see why a person of average intelligence shouldn't be able to work out the meaning.

 

Maybe Stephen is confusing it with a 'metric compass'.

 

Many years ago I was teaching Orienteering at an International Scout Jamboree and no matter how I explained it, a group of Swedish scouts headed off on the wrong heading, after recalling them and trying again I eventually looked at their compass, and sure enough they were on the 'correct heading', but as it was a 'metric' compass it had 400 degrees (100 degrees between each cardinal point- which is based on the metric system of 'Rads')

 

Therefore the required heading of (say) 180 required a heading of 200 on their compass.

 

Then of course you have the military compass with 640 degrees (Mils) but that may just confuse things.

 

Using mils, the actual size of an object observed in the field can be estimated. An object that appears to be n mils wide when it is 1000 units away from you, is actually n units wide - the units used does not matter, feet, yards, meters, miles
A vehicle that appears to be 15 mils long and is 1000 feet distant is actually 15 feet long. Or, two vehicles that appear to be 100 mils apart and are 1000 meters away, are actually 100 meters apart.

Sighting on a man (approximately 6 feet tall) who appears to be 12 mils tall must be about 500 feet away. If he seemed 3 mils tall, he'd be 2000 feet away.

 

 

IMG_20140106_104001.jpg

Edited by Alan de Enfield
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2 minutes ago, dixi188 said:

I think it may be 1868 or 1870, as that is when the tunnels were opened out.

I think that photography was only just starting in 1838.

Yes.

"The Oxford Company bought the land over the tunnel in 1838 with the idea of opening it up. The first stage of this work started in 1838 and by 1840, they had removed several parts of the tunnel roof — a section at each end and a short section in the centre, creating two separate tunnels, one 307m long and the other 413m long.
In 1865, the decision was made to opened out the rest of the tunnel. The southern end was open by 1868 and the northern by 1870. During the opening out works several bridges were constructed, including the cast iron roving bridge (shown in the photo) that carries the towpath across the canal, a bridge carrying the A423 Southam to Banbury road (recently rebuilt in reinforced concrete) and a rectangular wrought iron trough (now demolished) carrying a stream that fed Wormleighton Reservoir.
The canal now runs through a deep cutting and there is little evidence of the tunnel to be seen."
Edited by Ray T
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On 24/09/2021 at 14:35, Neil2 said:

I've always been sceptical about this "tunnel bands" theory.  If you are following another narrowboat in a tunnel you don't pick out the white bands on the stern of a boat in front as your headlight is pointing slightly above horizontal and the bands are too low.  In any case the old working boats wouldn't have had a powerful tunnel light would they?

 

So I'm not sure (is anyone) where the practice of painting red and white bands on the stern of narrowboats comes from.  

 

IIRC the old British Waterways boats had yellow and blue bands, so I think it's origins are in fleet identification.

Didn't most motors have a thing called a butty obscuring the tunnel bands from astern?

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11 hours ago, David Mack said:

I'll grant that "ten points of the compass" might not be widely understood, but since the text also refers to that as 112½°, I don't see why a person of average intelligence shouldn't be able to work out the meaning.

 

Bear in mind 50% of the population is of below average intelligence.

 

 

 

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5 hours ago, MtB said:

 

Bear in mind 50% of the population is of below average intelligence.

 

 

 

 

With apologies for splitting hairs, that doesn't seem right.

 

There will be a band of people with greater than average intelligence, another band of people who are of average intelligence and a third band of people who will be below average intelligence. It would seem, then, that less than 50% will be below average intelligence.

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19 hours ago, Captain Pegg said:

 

 

I suspect the notion of 'tunnel' bands is likely modern terminology but the practice of using both light colours for visibility and contrasting lighter and darker colours to distinguish form in poor lighting conditions is well established in the decoration of both canal boats and infrastructure. Therefore I would have little doubt that the painting of the rear of the counter with different coloured bands is about visibility.

 

Horse boats and later butty boats had large amounts of painted woodwork at their helms which demonstrated the above principles. The application of counter bands to motors is possibly compensation for losing this paintwork. Irrespective of the intricacy often displayed the root of boat decoration lies in practical requirements. Latterly BWB painted the bands to match fleet livery but it still adhered to the principles of a lighter and darker colour. I doubt anyone who really needed to identify a boat's ownership would use the counter bands for the purpose. There is so much else that is more definitive.

 

I think it's often difficult for modern boaters to fully appreciate the conditions in which carrying craft operated in past times.

 

 

I notice that the GUCC also employed their livery colours of white, light blue and dark blue in the counter bands.

 

I don't doubt there was a visibility aspect to it but that doesn't explain why/how  white over red became so ubiquitous.  There's evidence from pictures of working boats from the past that the counter bands were painted in sympathy with the company's livery, and I wonder if it's simply that a number of fleets eg FMC used white lettering on a red background so white and red counter bands predominated. 

 

In the modern age I've noticed that Black Prince hire boats use a particular shade of cream/yellow which matches the coachline colour - but it's still combined with red!   

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17 hours ago, Alan de Enfield said:

 

Maybe Stephen is confusing it with a 'metric compass'.

 

Many years ago I was teaching Orienteering at an International Scout Jamboree and no matter how I explained it, a group of Swedish scouts headed off on the wrong heading, after recalling them and trying again I eventually looked at their compass, and sure enough they were on the 'correct heading', but as it was a 'metric' compass it had 400 degrees (100 degrees between each cardinal point- which is based on the metric system of 'Rads')

 

Therefore the required heading of (say) 180 required a heading of 200 on their compass.

 

Then of course you have the military compass with 640 degrees (Mils) but that may just confuse things.

 

Using mils, the actual size of an object observed in the field can be estimated. An object that appears to be n mils wide when it is 1000 units away from you, is actually n units wide - the units used does not matter, feet, yards, meters, miles
A vehicle that appears to be 15 mils long and is 1000 feet distant is actually 15 feet long. Or, two vehicles that appear to be 100 mils apart and are 1000 meters away, are actually 100 meters apart.

Sighting on a man (approximately 6 feet tall) who appears to be 12 mils tall must be about 500 feet away. If he seemed 3 mils tall, he'd be 2000 feet away.

 

 

IMG_20140106_104001.jpg

 

Thank you, I feel that my education is now complete.

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47 minutes ago, Col_T said:

 

With apologies for splitting hairs, that doesn't seem right.

 

There will be a band of people with greater than average intelligence, another band of people who are of average intelligence and a third band of people who will be below average intelligence. It would seem, then, that less than 50% will be below average intelligence.

 

 

Well it all leads back to semantics as is often the case when quibbling about stuff like this. No need to apologise though!

 

Firstly it depends on which of the three types of average one means, the mean, the median or the mode. I meant the mean. 

 

Secondly it depends how you measure intelligence. I was imagining the IQ test. Everyone taking it gets a score, with 100 being someone of average intelligence, with 100 being the marker where half the subjects score higher and half score lower. 

 

Your way - placing each subject in your cohort into one of three bands - then I agree, approx one third will be of average intelligence. It is all down to the resolution of the measuring.

 

 

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15 minutes ago, MtB said:

Firstly it depends on which of the three types of average one means, the mean, the median or the mode. I meant the mean. 

Indeed. But I recall from my A level maths statistics lessons that in large populations with a normal distribution, the mean, median and mode converge on a single value. So when talking in terms of say the entire UK population the difference between the different averages is not material.

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1 minute ago, David Mack said:

Indeed. But I recall from my A level maths statistics lessons that in large populations with a normal distribution, the mean, median and mode converge on a single value. So when talking in terms of say the entire UK population the difference between the different averages is not material.

 

This is true, and I'd forgotten that...

 

When it comes to hair splitting, this board is peerless! 

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1 hour ago, Col_T said:

 

With apologies for splitting hairs, that doesn't seem right.

 

There will be a band of people with greater than average intelligence, another band of people who are of average intelligence and a third band of people who will be below average intelligence. It would seem, then, that less than 50% will be below average intelligence.

Roughly anybody with an IQ between 85 and 115 is classes as average IQ so about 68% the other 32% will be split more or less equally between below average and above average.

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Thanks very much for the explanation of the ratiionale for the military compass using an unit that is normally confined to scientific and electrical engineering  calculations.

 

When reconstructing liveries from old photographs, you have to bear in mind that the early photographic emulsions were not sensitive to all colours. Thus the early "ordinary" plates were only sensitive to blue, and would render both red and green as black, the later "ortho" plates were sensitive to blue and green and so would render red as black, and the modern "panchromatic" films are sensitive to all colours, although still over-sensitive to blue unless a yellow-green filter is used.  Ortho and Pan emulsions only started to be used around the turn of the 20th century, so virtually all Victorian photos would have been taken on "ordindary" film. Pan cost more than the other earlier types, which continued to be available to general-pupose photographers into the mid-  1950's.

Edited by Ronaldo47
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2 hours ago, Neil2 said:

 

I notice that the GUCC also employed their livery colours of white, light blue and dark blue in the counter bands.

 

I don't doubt there was a visibility aspect to it but that doesn't explain why/how  white over red became so ubiquitous.  There's evidence from pictures of working boats from the past that the counter bands were painted in sympathy with the company's livery, and I wonder if it's simply that a number of fleets eg FMC used white lettering on a red background so white and red counter bands predominated. 

 

In the modern age I've noticed that Black Prince hire boats use a particular shade of cream/yellow which matches the coachline colour - but it's still combined with red!   

 

The obvious reason for counter bands using the same colours as the boat livery would be the economics of using the paints the company would have held in large stock rather than buying a small volume of another colour for the purpose. The colour wasn't the important issue, simply the contrast between the colours and also with the hull. They would mostly appear as different shades of grey in poor light which was the intent.

 

Red and white were common colours used on the top bends of horse boats and may have transferred from there to counter bands, but it's ubiquity on modern boats is possibly a modern version of what is thought of as 'traditional' for counter bands, whether that's accurate or not.

 

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22 hours ago, Alan de Enfield said:

 

Maybe Stephen is confusing it with a 'metric compass'.

 

Many years ago I was teaching Orienteering at an International Scout Jamboree and no matter how I explained it, a group of Swedish scouts headed off on the wrong heading, after recalling them and trying again I eventually looked at their compass, and sure enough they were on the 'correct heading', but as it was a 'metric' compass it had 400 degrees (100 degrees between each cardinal point- which is based on the metric system of 'Rads')

 

Therefore the required heading of (say) 180 required a heading of 200 on their compass.

 

Then of course you have the military compass with 640 degrees (Mils) but that may just confuse things.

 

Using mils, the actual size of an object observed in the field can be estimated. An object that appears to be n mils wide when it is 1000 units away from you, is actually n units wide - the units used does not matter, feet, yards, meters, miles
A vehicle that appears to be 15 mils long and is 1000 feet distant is actually 15 feet long. Or, two vehicles that appear to be 100 mils apart and are 1000 meters away, are actually 100 meters apart.

Sighting on a man (approximately 6 feet tall) who appears to be 12 mils tall must be about 500 feet away. If he seemed 3 mils tall, he'd be 2000 feet away.

 

 

If those military compasses have 640 "Mils" in a full circle to get the 1/1000 height factor, they're wrong anyway -- for that a "Mil" would need to be a thousandth of a radian (57.3 degrees), so there would be 6283 of them in a circle. It's even wrong if the "height factor" was 100, meaning 628 of them in a circle. And to make things worse, in the USA a "mil" is a thousandth of an inch, a major pain when they use this for things like track widths on PCBs when the suppliers use mm or microns -- or vice versa... 😞

Edited by IanD
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1 hour ago, IanD said:

If those military compasses have 640 "Mils" in a full circle to get the 1/1000 height factor, they're wrong anyway -- for that a "Mil" would need to be a thousandth of a radian (57.3 degrees), so there would be 6283 of them in a circle.

 

Correct.

The UK has 'rounded up' to 6400, other Militaries have rounded down to 6000

 

My mistake - I missed a 0 off when I quoted 640. The compass is marked 0 to 64 which equates to 0 to 6400.

 

Google explains it better than I :

 

Another unit of measure, the radian, is used mainly by militaries in artillery, tank, and mortar gunnery.
There are 2 PI radians in a circle. PI is a constant of approximately 3.1416. That is 2 * 3.1416, or 6.283 radians. Divide each radian into 1000 mil-radians and you see there are 6283 mil-radians in a circle. Mil-radians are called mils for short.
17.78 mils equal 1 degree.

Compass use of mils typically rounds 6283 to 6400 for simplification. Some foreign militaries have simplified the other direction and divided the compass face into 6000 units, exactly like the face of a watch, with 100 units the same angle as a minute on the watch face.

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