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magpie patrick

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Everything posted by magpie patrick

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  3. Schroedinger's lock - full and empty at the same time? Any idea why passage is supervised? In Anthony Burton's "Back Door Britain", written in the 1980's, they just turned up and went through the locks
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  5. I'm blushing now! Don't be fooled by the qualifications, I make it up as I go along... 😄
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  8. That begs the question as to where did the company get the name from? The Somersetshire Coal Canal is rather grand given it serves only a tiny area of that county, although it does serve most, but by no means all, of the Somerset Coal Field (the Shire was added as they thought it less likely to attract objections in parliament) The subdivisions provide interesting material - not many refer to the Caldon Branch (of the T&M) - it's now the Caldon Canal, and yet few if any refer to "The Aylesbury Canal", it's the Aylesbury Arm. I think most people who haven't studied the history define the BCN by character, they would probably be surprised that Camp Hill and Garrison locks are not in it, nor is the Stourbridge Canal, they would be equally surprised that Fazeley to Whittington technically is (or was) part of the BCN
  9. Half the time you can't see it through the weedhatch either! I am pondering waders to get at Juno's outboard's delicate bits without having to take the outboard off - would they work for you?
  10. Similarly the Huddersfield Narrow Canal which is officially The Huddersfield Canal, so called to distinguish it from the Huddersfield Broad Canal which is officially Sir John Ramsden's Canal (I think)
  11. The Coal Canal, or to give it its full title "The Somersetshire Coal Canal" was originally the "Proposed Dunkerton and Radstock Canal" More familiar to many, The Kennet and Avon Canal was mooted as "The Western Canal"
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  13. Thank you - I had no idea there was still a conventional manual lock on the Thames below Oxford. The EA are a pain with the elfin safety - I used to do contracts for both BW and EA, the BW approach was minimal fencing so anyoen who fell in could easily be fished out, the EA was to construct Colditz style fencing then struggle when something went wrong inside the cage. I'm not against risk assessment etc, I'm just against misguided use of it. Are you sure? I seem to recall WW covering it's construction and opening - I was born in 1966 and WW started up in 1972
  14. A useful warning - many of us rely on the idea that whoever did it "knew what they were doing" [because we probably don't] and that a BSS catches everything - it doesn't.
  15. At the time the NRA (I think it was them) said that they would lengthen it if demand justified it - I had visions of a queue of GU Town Class gathered below to make a point... Or put another way - proving demand for more boats is easy, proving demand for bigger ones is difficult! C'est ferme - so it doesn't get used at all now There was some protest (and a parallel with the short lock on the fens) in that the parallel locks can only take 30m barges and thus 38m "Freycinet" can no longer reach Toulouse - the lift was part of the lock lengthening program Okay, I'll bite - what is "Sunbury Beam Lock", do boats go through sideways? beam on as it were?
  16. It may not surprise you, it is rather more complicated than that. Clay is not perfectly waterproof, a canal loses 5-10mm a day of it's water level in summer through the clay lining. The rate of seepage is affected by how wet the soil is behind the puddle, if the soil is saturated, no seepage, if it's dry, more seepage. A tree just behind the clay dries the soil out. Trees absorb a lot of water, I looked at an aqueduct on the long abandoned Bude canal some years ago - a tree had been cut down some years earlier to prevent further root damage to the structure, but instead the soil around the root ball had got wet without the tree to absorb the moisture, and the masonry was bulging as a result
  17. Yes, I think it's the only one that went the other way - two separate locks becoming a staircase. The new locks are longer as well as wider and I think they were a bit tight on room. Also, by then, some idea of "standard design" had crept in, so whereas the engineer of yore would have put two locks close together or the upper one close to the bridge above the locks, the 1930's engineer did not
  18. Yes, it is The wurzels are still very popular in Somerset, can't say I'm a great fan but they are good for a knees up
  19. Following @dmr query I started thinking where staircase locks were replaced with conventional locks*, as this was a solution when the problem proved too great *Note - staircases replaced and the canal remaining open, not just closed staircase locks Ones I can think of - I'm sure there were others L&L, Greenberfield - 2 rise and a single replaced by three new single locks Calder and Hebble - Salterhebble (2 rise? or 3 rise?) Caldon (Hazlehurst 3 rise, replaced by three single locks and had itself had replaced two single locks T&M - Meaford - three rise replaced by three single locks T&M - bottom three of Church Lawton - three rise replaced by three single [I think there were at least two more on the T&M - Etruria?] Plus the rather odd ones at Bratch on the S&W and the double lock at Stourbridge - both converted from staircases to close formation separate locks. Related to these the middle seven at delph were close formation and replaced with what is now six locks I think there was one built on the K&A but removed before the canal was finished, and also I think a really odd one on the royal were a three rise with short chambers was converted into a two rise with proper length chambers - again before the canal was finished
  20. Not marginally easier - a LOT easier
  21. I knew the meister would be along soon! Thanks @Pluto On swing bridges, the only other canal I have detailed knowledge of, the Coal Canal, was built with swing bridges that were later all replaced with fixed bridges - it got the canal open and earning toll revenue
  22. Incidentally I've just measured from the top of Bingley five to the bottom of Bingley 3 - it's about 2000 feet for the canal fall 100 feet, or 1 in 20. That's rather steeper than Marple Locks (about 1 in 25) which are amongst the steepest in the country. The fall probably could have been done in 8 single locks but it would have been quite an undertaking - I guess the real question is why the top and bottom of the locks are where they are, because that's what was driving the formation
  23. I don't have all the answers - most is supposition based on the fact we can't deny what is actually there. Bingley Five Rise may not make any sense but it was built! The length matters for fitting in with the gradient and, occasionally for total length - e.g. the Staircase on the Ribble Link makes the canal shorter. I haven't done a topo survey around Bingley but from memory it is on sidelong ground and roughly level with the surrounding land at the top. For whatever reason it seems a decision was made to drop to the valley floor here - perhaps ahead of crossing the river at Dowley Gap. I don't think ideas on water supply and consumption were that well developed, and even now when I'm looking at canal restoration it is often leakage and evaporation that are the biggest concern. If a flight of locks is used three times a day it's consumption may have been inconsequential, not so much once traffic exceeded all expectations. There are other instances where water supply seems to have been given less thought - compare the variance of depth on the Staffs and Worcs locks with the uniformity of the Shropshire Union locks Tyrley locks, built much later, drop into a cutting and are a good example of why earlier engineers squashed their lock flights
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  25. @Pluto will be along soon with the full L&L story no doubt, but in summary... Most staircase locks are early in canal development* - they fall into the "seemed like a good idea at the time" category - some were later removed (on the L&L at Greenberfield for example, and several places on the Trent and Mersey, Church Lawton and Meaford to name two). They have two fundamental advantages - they are cheaper and steeper. A three rise has only four sets of gates and four wing walls, rather than six of each, for example. And a well laid out flight needs four to six times as much length as a staircase to achieve the same climb. They have two significant disadvantages - when traffic flow is reversed they use more water than a flight - the first ascending boat in a three rise needs three lock full of water from the top of the flight - and boats can't pass in them. Most canals seriously underestimated how much traffic they would have, and thus staircases became something of a nuisance as traffic grew. As regards being difficult to work - if you were an L&L boatman doing the run regularly you wouldn't notice that - a boat that snugly fits the lock, and a crew that was well used to the locks means they'd hardly notice. *Staircases are also a feature of canal restoration - for pretty much the same reasons - cheap and steep. A few oddities amongst staircases There are two- and three-rises on the Chesterfield Canal that have the rise of a single deep lock - 10-12 feet in total Bratch and the pair at Stourbridge were staircases when built, and adapted to save water - they remain a bottle neck for traffic Foxton and Watford were built as staircases to save money, but with side ponds to save water Caen Hill is an example of how to squeeze locks in to a short distance without using a staircase, but it was never that busy and I'm not sure how it would have coped with BCN type traffic levels as the passing places between the locks are very tight if two K&A barges met
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