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Apollo
September 23, 2007, 10:36pm Report to Moderator Report to Moderator

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I've been sitting on pics of the markers for the Skelmorlie Measured Mile, and the story behind it, for months now, and it was nice to see that someone else came up with the subject too. If nothing else, it made me get my finger out and get the pics and history started.

More interesting still was the additional info that came with it for the Arran Mile, or miles to be technically accurate.

A bit of post-prompt digging suggests the Skelmorlie mile is not the favoured reference, but that the Arran course is still being maintained.

I'm not a sailor, so don't have much hope of finding them, but it would be interesting if anyone knows how/if these are depicted on modern maritime charts.

I've been trying to work out where I've seen these areas detailed, and I'm pretty sure they are shown in detailed charts on display on the walls of the Denny Ship Model Experiment Tank museum in Dumbarton. This is an excellent little museum, full of detail for anyone prepared to put in a little effort an look closely. It looks small and sparse, but is deceiving. And there's an interesting an unexpected display to be found including a cat (no, not a live one)- I leave you to find that for yourself, and only say 'Look up', or ask the staff

http://www.scottishmaritimemuseum.org/dumbart.htm

As I recall, the old charts are extremely detailed, and set out the Trial Areas in detail. Wish it wasn't so long since I'd seen them now, all I can remember is the marking out of the relevant areas.

Interestingly, the current documentary triggered by the last visit of the QE2 to her place of birth on the Clyde featured a reference to her trials, where those that were present told of the full power run, and the vibration causing the tiles to fall off one of the swimming pools, as the pool windows came loose and fell in too.

I was lucky enough to be on ship being tested off Greenock. A 400 car ferry from up north, so not a little tiddler. After enjoying the sail along the Clyde from Glasgow on a lovely sunny day, I was installed in he engine room to monitor the control systems, so didn't get to see what was happening up top. It was hard to tell what was happening, even though understood the test we were running involved steaming in a circle at full power with the rudder hard over. The ship was fitted with stabilisers, and the lean was negligible, as was the vibration. In the soundproofed engine control room, it was rather uncanny, as the instrumentation confirmed we were hard at work - you wouldn't have known.

All good things come to an end though, and we limped back to Greenock to disembark. Although the engine hadn't actually been the subject of the test, the engineer revealed that at least one of the cylinder heads had blown during the run. No real drama, although I had noticed the fuel venting until they isolate the feed.



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Apollo
September 24, 2007, 9:48am Report to Moderator Report to Moderator

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I'm trying to pin down the exact lat/lon of the Skelmorlie markers from the pics - are your chart any good for fixes to that degree of accuracy, better than 10 m or 8 digit grid ref is needed ie AB12341234. The Skelmorlie markers, as you noted, don't appear at all on new maps.

I have the Arran markers down to a few feet, but oddly, although the southern markers are identified at South Sannox, none of their positions are marked, just their name.

Of the northern and centre markers, these are shown as the pair of Mile Markers, and of a further fixed marker, making a total of three beacons on the two sites.

The old Admiralty charts shown in the Dumbarton museum are works of art now, the detail is superb, the old 'Sharp Pencil' being in evidence and they are packed with information - a bit like looking at a modern aviation map. Get your hands on one of those and you'll be wondering why all aircraft aren't flying into one another, as the pilots try and make sense of the information overload that these have become. Preparing a Flight Plan is no longer a good idea nowadays, it's a downright necessity if you have any thought of looking outside the cockpit



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Apollo
September 24, 2007, 1:35pm Report to Moderator Report to Moderator

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I wasn't sure of the seaward marker, I must have stood at it, and never noticed it!

Landward north is easy, just find the bus stop and the house and the little short street.

South's out of the way, but straightforward.

Arran's very odd, I can't understand why the upper six beacons should be marked to the foot, while the map only has the words Navigation Beacons for south Sannox, but nothing marked for their detail. I have a few pics tracked down, not of the markers themselves, but nearby features that they can sort of be seen in, but are so vague as to make their position little more than imagination.

Something wiil no doubt turn up.

As an aside, I suspect, from my experience with GPS, that Lloyds and others (military) do not currently accept GPS measured miles or trials as legally relevant to contracts, and that Arran is maintained as the 'Thing That Can Be Cited Legally' when such things are required. While the warring military have access to a highly accurate version of 'Real' GPS, we public just have access to the rough signals, albeit we are free to play with it and enhance the accuracy if we wish. Military is reputed to be cm accurate, while we do well to be metre accurate.



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Tam Nugent
October 30, 2016, 12:40am Report to Moderator Report to Moderator
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I just read on the Clyde River Steamers Club site http://crsc.org.uk/clydes-measured-miles/ that there was a measured mile at Parklea, Port Glasgow which is "no longer in existence".

This got me wondering if the mystery pairs of posts at Parklea are actually the remains of this mile? I remember them being bright yellow in the mid 60s and swinging on the broken guy ropes (steel wire). I have heard that these are Port Glasgow boundary markers, or Clyde Navigation Trust boundary markers, but I think the measured mile theory is more plausible.

See my geograph photo http://www.geograph.org.uk/photo/842106
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Admin
October 30, 2016, 9:05am Report to Moderator Report to Moderator

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Nice find on the article, and interesting stuff indeed.

It's some years since the original material was dug up online, and this did not come up in the searches back then, so thanks for mentioning.

Looking at the article, I tend to stay with the indication that the markers are for the Port Glasgow boundary or more likely Clyde Navigation Trust, so they could clearly define their legal area of responsibility to mariners.

The article also goes further regarding Parklea with:
Quoted Text
The Parklea Measured Mile, east of Port Glasgow, was erected by the Denny Hovercraft Company in 1963 for testing their D1 hovercraft. This mile is no longer in existence.

This probably makes more sense too, as the hardware would not have been so robust, or maintained to survive as long as 'official' markers.

The remaining mile markers are also much larger and easier to see and align for the vessels using them.

But again, nice to see this, as there was no hint of anything more a few years back so this is welcome
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Tam Nugent
October 30, 2016, 10:29am Report to Moderator Report to Moderator
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Looking at the article, I tend to stay with the indication that the markers are for the Port Glasgow boundary or more likely Clyde Navigation Trust, so they could clearly define their legal area of responsibility to mariners.


In that case, why are there three pairs (confirmed on Bing Maps)? I think this rules out the Port Glasgow boundary theory, but not yet the CNT.

Adding links to all geograph photos below...
http://www.geograph.org.uk/photo/842209
http://www.geograph.org.uk/photo/842193
http://www.geograph.org.uk/photo/842284
http://www.geograph.org.uk/photo/842267
http://www.geograph.org.uk/photo/842106
http://www.geograph.org.uk/photo/842098

Distant views...
http://www.geograph.org.uk/photo/842235
http://www.geograph.org.uk/photo/842157

From the train...
http://www.geograph.org.uk/photo/3034174
http://www.geograph.org.uk/photo/2661398

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Admin
October 31, 2016, 9:51am Report to Moderator Report to Moderator

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On Bing maps!?

Do you actually mean when Bing maps is used to view Ordnance Survey maps as Bing map does not show such detail.

I'm having a problem actually seeing any of the markers on mapping, not even an unidentified dot (from any source), but only picked one sample - so will have to take more care and look for the others.

I'm not sure why Port Glasgow boundary would have a maritime marker, since it would also be a marker for the adjacent area.

There would also be the potential problem of this being a political boundary marker, and likely to change with political whims - see for example the current stooshie which is blowing up, or was about to blow up (I think I read that the revisions had been scrapped recently), over proposals by Argyll and Bute Council to revise wards and boundaries.

This means when checking such things it's sometimes necessary to dig up old maps in order to see the picture when things like boundaries and markers for same are concerned.

I still tend to think it more like that markers seen by mariners are to do with port authorities, or of course, the original subject... mile (or other distance) test markers, especially if they can be aligned.

Actually, that sparks off a thought...

There are also navigation markers on the Clyde, much smaller and less noticeable than the 'mile markers', so only notable for sailors using them for navigation.

These are used to align vessels navigating the channel (remember the Clyde only became, or even stays navigable, for larger vessel due to the presence of a navigation channel, and it has to be dredged. Something we learn from Taggart, since they like to dredge up body parts on occasion

I know these are still in use, and used for the subs using the base at Faslane - even with GPS! Recall a documentary from a few years back, when a departure was filmed inside one of the subs as it departed. The Captain mentioned that his vessel was only a matter of feet from the bottom as it transited the channel.

Worth more study - would be nice to be definitive about these one day
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Tam Nugent
October 31, 2016, 10:22am Report to Moderator Report to Moderator
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On Bing maps!?

Do you actually mean when Bing maps is used to view Ordnance Survey maps as Bing map does not show such detail.


No, I meant bing aerial photos. Angled, zoomed and rotated just right, you can see the poles and their shadows at low tide. With a bit of luck, this link will work and you will see one post in the lower left corner (at the shoreline) and another to the left of the row of timber pond posts, further out to sea (beneath the word "Clyde"). They are pretty faint. https://binged.it/2fmiH1G .

I have been looking at the NLS online maps, including very detailed admiralty charts, and can see no sign of them on any map during any period.

It looks like there are three pairs, and that there is 1Km between the two furthest pairs, which is much less than a nautical mile. It's possible that there were others - I seem to recall one near the bowling club, but I could be wrong there as it was a long time ago and I was just a wee boy

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Admin
October 31, 2016, 5:11pm Report to Moderator Report to Moderator

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Ah!

I misunderstood

I thought you were referring to a map that recorded the markers as features - oh well... assume and a** are so close

Funny if they are not on Admiralty charts, being (I think) so obviously some sort of nautical item, or at least of interest to those in boats.

Still, at least I know it may not be worth staring at those particular sheets, and can try alternatives.
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Tam Nugent
October 31, 2016, 5:56pm Report to Moderator Report to Moderator
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Ah!

I misunderstood


Nah, I just never explained properly

The admiralty charts that I checked are all pre-1960, so that supports the Denny mile theory, since it was not created until the early 60s.


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Tam Nugent
February 16, 2017, 11:41pm Report to Moderator Report to Moderator
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I just came across this PDF extract from a 1961 edition of "Flight" which confirms that Denny used a "specially prepared measured mile course in shallow water outside the navigation channel in the Clyde near Langbank" for testing the D1 hovercraft. This testing took place after the more publicised Gareloch measured mile testing.

I'm now fairly certain that the posts at Parklea are the remains of this mile.

https://www.flightglobal.com/FlightPDFArchive/1961/1961%20-%200872.PDF
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February 17, 2017, 12:25am Report to Moderator Report to Moderator

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Your note was handy

I update our Measured Mile with the new info found on the CRSC page, and extend our list with the 'miles' that had not come up elsewhere.

The Flight item is nice, with decent pic of the D1 hovercraft - I think anything I found ages ago was tiny, and did not do it justice.

There's not really much else the post could be, I suppose, unless forming some long-forgotten navaid. But then again, that should then appear on charts, and be easy to find, if that was the case.

I forgot I got a little diverted, and should go back and add the gegraphs to the page, and their locations on the map.
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FordPerfect
February 17, 2017, 11:08am Report to Moderator Report to Moderator

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Quoted from Tam Nugent
I just came across this PDF extract from a 1961 edition of "Flight" which confirms that Denny used a "specially prepared measured mile course in shallow water outside the navigation channel in the Clyde near Langbank" for testing the D1 hovercraft. This testing took place after the more publicised Gareloch measured mile testing.

I'm now fairly certain that the posts at Parklea are the remains of this mile.

https://www.flightglobal.com/FlightPDFArchive/1961/1961%20-%200872.PDF


Well done  !   10/10  results ,  perseverance    

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Admin
February 19, 2017, 11:36am Report to Moderator Report to Moderator

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Well, I really put my foot in this one

We don't have my usual 'fix' of exact lat/lon for a subject for these posts (geograph gets you in the area, but is only with a 100 m or 10 m square), and unlike many similar navaids, they have never been caught by an OS survey and added to any OS maps (I've looked at them from 1960 onward).

This is NOT a complaint, just means I was careless when I started and began to play with this...

After a load of fiddling with pics etc, I finally woke up!

And checked to find that while their may be 6 (or more)  of these poles, I had not realised that more than 50 pics related to the spot had been uploaded to geograph!

Muggins had started selecting them before checking - boy, did I waste a wedge of time.

Off to clear my head and start over - it's simpler.



More seriously, it's lucky the record has been made, as I see the evil rust is having its way the poor innocent posts, and they are collapsing, but at least not 'lost'.

Again, good catch on this, both a few years ago, and more recently.
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Admin
February 23, 2017, 4:17pm Report to Moderator Report to Moderator

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I think I managed to shake all the boiled snow out of my head (even if more did actually fall this morning, thanks to Storm Doris) and get the right pics to show the three pairs of markers for Parklea, plus relevant notes.

I need to work out a 'best guess' for location markers for the six though, since I can't go there and sit a GPSr on them, and geograph grid refs only manage a 100 m or 10 m square at best, which is just not acceptable. But... that's my problem

I did notice one point that doesn't seem to match the map though.

Quoting is easiest:
Quoted Text
This suggests that the posts were used as a "measured mile" or, more accurately, a measured kilometre since the two furthest pairs of posts are around 1Km apart.

This doesn't match my check of the separation between the western and eastern post pairs.

While I obviously can't spot these on any pics or maps, going by the grid ref locations and post pics, these measure as near as dammit 1 mile apart, and nowhere near 1 km.

Am I wrong in some way, or missing or misinterpreting something?
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Tam Nugent
March 4, 2017, 10:09pm Report to Moderator Report to Moderator
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Quoted Text

This suggests that the posts were used as a "measured mile" or, more accurately, a measured kilometre since the two furthest pairs of posts are around 1Km apart.

This doesn't match my check of the separation between the western and eastern post pairs.


If this link to Bing Maps works, you should see where I have dropped pins to show the location of each post (based on seeing their shadows on the aerial photo).

https://binged.it/2lqWmD1

If it works, click on each entry in the left sidebar to get the precise locations of the pins. With a bit of luck, my measured distance line might also show. This comes in at around 950m.
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Tam Nugent
March 4, 2017, 10:17pm Report to Moderator Report to Moderator
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In case the link doesn't work, try the attached photo, which is a screen capture from Bing.



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March 4, 2017, 11:20pm Report to Moderator Report to Moderator

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Well, THAT cunning plan worked (to get accurate post positions)

Just kidding, but it is a handy side-effect of my query

For a moment, I thought we might have had a disagreement between Google and Bing about the distance, but it's clearly down to me.

I (obviously?) had to take a best guess or stab at the positions of the post since I haven't been to them, or am likely to get the chance.

Looks like my guesses based on the NGRs were lucky (or unlucky) enough to extent the distance and coincidentally make it just about a mile - I think I was well off with the western posts

Bing link work fine, but as you noted, no line apparent, but no matter.

How accurately placed are the markers placed for the posts?

I only as because I imagined the pairs would have been parallel - this would accurately transfer and accurately measured land distance out into the water.

If they are angled or even radial (which they look like) then the distance on water will vary if the vessel does not pass at the same distance from the shore every time.

So I'm curious if the markers are 'kind of close to reality' or just indicative - bit still a lot better than a 100 m grid square
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Tam Nugent
March 4, 2017, 11:59pm Report to Moderator Report to Moderator
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How accurately placed are the markers placed for the posts?

I only as because I imagined the pairs would have been parallel - this would accurately transfer and accurately measured land distance out into the water.

If they are angled or even radial (which they look like) then the distance on water will vary if the vessel does not pass at the same distance from the shore every time.

So I'm curious if the markers are 'kind of close to reality' or just indicative - bit still a lot better than a 100 m grid square


They are probably parallel in reality. I just took a stab at the location based on what appears to be the shadows of the posts, but a few pixels out each way could lead to a few degrees overall. I'm also not sure how accurate Bing is, as the pins move considerably when you rotate the view in birdseye mode.

If you switch Bing to the birds-eye view you can see the posts more clearly (see attached photo) and you can rotate the view too.

When I go back there (hmmm, should I do Largs or Parklea first?   ) I will take photos with my phone to get the GPS locations, but I have no idea when I will go back (I still work abroad full time).

Edit: Looking at this photo, I probably have the wrong location for the landward post (west set) on the original map a few posts (posts - gettit?) above. It should be ever so slightly further west, enough to make this pair parallel with the others.



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March 5, 2017, 12:54am Report to Moderator Report to Moderator

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Oh the advantages of having been there and seen things in real life.

Without that, I could probably stare at those views and maybe never manage to pick out the posts or shadows.

Fine on the positions, I just didn't want to assume dead accurate, or just indicated positions. As I said, still way better than 100 m grid.

As regard the apparent movement of the markers when the view is rotates, this may be down to the same effect I have seen in recent Google oblique aerial views.

All items seen on these mapping systems (and I refer to anything placed on them) exist on layers, Layers may exist at a slight altitude above or below one another, and also about the Earth, or base layer. This gets further complicated by the fact the the Earth is not 'flat', by which I mean ground is not level due to hills and valleys. And there is, of course, one further aspect, the Earth is not spherical but ellipsoidal.

All these things have to mathematically modelled, and while it may be accurate, it's not perfect.

What I noted recently was that while markers placed looked perfect when viewed from directly overhead, normal to the ground, when I switch to recent (high res) obliques, the markers move, as you seem to have noted.

When I looked closer at what appeared to be a positional error, I realised what was actually happening was the marker was moving consistently as I changed he view, as if it was bound not to the ground, but more like the top of a pole a few metres high, same as a flag at the top of a flagpole would have appeared to move if not being viewed from directly overhead.
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