magpie patrick
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Posts posted by magpie patrick
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49 minutes ago, Iain_S said:
Dalmuir Drop Lock on the Forth and Clyde. It's a bit of a monster, really. The water has to be pumped out of the lock once the boats are in it. Takes about 40 minutes, assuming the inflows to the pumps are reasonably clear and not blocked by weed. Used to be a bit quicker, when the operator was able to drop the lock just enough to get the boats under the bridge, but it now has to go all the way down for H&S reasons.
If building another one, a big improvement would be the provision of a reservoir below lock level, so that the lock could be emptied using paddles rather than a pump. You'd still need pumps to empty the reservoir back into the canal, but you'd get away with lower pumping capacity and the lock operation would be a lot quicker.
The original plan was simply to drain the water away, but presumably this used too much water.
Having done a certain amount of work on the safety of these monstrosities I'm curious as to why a partial drain too reveal "enough" headroom is unsafe.
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Moral codes of the time would not have encouraged a woman to be anywhere near the Bridgewater Canal - it wasn't so much being with their husbands, it was all the other men, some of who would have felt distinctly uncomfortable in the presence of a woman who was not their wife. Just not the done thing. Women and men didn't mix in pubs either (if the women went in a pub at all)
There would be many other social and moral conventions too, this was an era when women and men only mixed in a family setting.
I'm not sure when families started living on narrow boats but that was a change of context, the woman was now with her family
It's hard to think of a modern parallel for "not the done thing"
15 hours ago, booke23 said:One things for sure, James Loch would be turning in his grave if he could see the change in morals today compared to 1837!
Indeed - although I'm rather glad I can go to the boat with Ness (or any other woman for that matter) without Mr Loch feeling moved to write a letter about it! Can you imagine the pages of this forum... 😳
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31 minutes ago, ditchcrawler said:
I did point that out
I did point that out
So you did
So you did
🤭
I have to be honest and say I'd missed the reference you were making
1 hour ago, Pluto said:I would recommend trying to keel any design as simple as possible.
Wise words! The ability of folks to embellish designs with needless add ons that then go wrong is astounding.
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9 hours ago, ditchcrawler said:
But on a much smaller scale
I note the video claims 1890s for the rolling bridge idea, but the Oxford Canal bridges roll, and the concept there is presumably a century older. This is just a huge Oxford Canal Bridge!
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18 minutes ago, David Mack said:
Is this for a farm track or a public road?
Right of access to third party land (and even that's disputed but we need a bridge for other reasons e.g. maintenance and towpath access) - public road loading first choice is for a swing bridge with jacks (edited to add - powered swing bridge) - it's not the absolute axle load but the frequency that does the damage.
Last scheme I looked at on a public road though the gradient wouldn't work with a swing bridge! I am also looking at one in south Wales where it will have to swing as its half under a railway bridge - no room to lift
I can see it might be worth locking a lift bridge down though
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15 minutes ago, David Mack said:
Why a lifting bridge anyway? Surely a swing bridge is less intrusive, more reliable, well established technology and probably no more expensive.
At larger sizes I'd agree, indeed at very large sizes swing is undoubtedly better. But at narrow canal size, where a bridge can easily be hand operated, it's no contest. The main issue is that without jacks a swing bridge takes all the weight through the bearings and will tend to hog, a lift bridge doesn't do this. A manual swing bridge can have jacks, but it complicates operation, a lift bridge doesn't need them.
Reading through stoppages and complaints about difficult bridges on the canal system, I'd say swing bridges give far more trouble.
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I've become involved in a discussion about whether to build a moveable bridge on a canal restoration project rather than a fixed bridge - in this case the advantage of a moveable bridge is less ground load and less land take (utility services being a major influence in this) - in reviewing options we looked at others elsewhere for inspiration and among them is the vertical lift bridge, as opposed to the bascule bridge - an example below
This is Locomotive Bridge, Huddersfield, with acknowledgements to Martin Clark and Pennine Waterways. Cables pull the bridge vertically. When asked to consider the pros and cons of such a bridge I'm stumped - there is, as far as I know, no documented design considerations, and there are so few that I can't really work out the reasoning, a sample of one (that I used once, many years ago) doesn't really tell me what the advantages of this design are.
So does anyone have any thoughts on the pros and cons of vertical lifting ? And are there any others on the canal system? I'm aware of them on much bigger waterways where presumably the size of the span is a factor, but not really on waterways the size of our typical canals, where lift bridges are nearly all the bascule type.
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3 hours ago, magnetman said:
Water pistols are good for swans.
I think the swan would argue with that assessment, unless you're suggesting it's the swan who's using it
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1 hour ago, David Mack said:
There are several on the National Rail network too. A forum discussion on the subject:
https://www.rmweb.co.uk/forums/topic/119160-stations-with-the-same-name/
I spend quite enough time on this forum with people pointing out others I could get absorbed in!
I could add that it was the railways that added the "Welsh" to Welshpool....
Going back to the tunnels. Bradshaw refers to the one on the Worcester and Birmingham as "West Hill, commonly called King's Norton" and the one on the Stratford as "King's Norton"
I'm not sure when West Hill became Wast Hill.
I note in the railway forum reference to BR changing station names when they ended up with two in the same town that had previously been in separate ownership. Maybe BW did the same with these tunnels, and then briefly thought better of it
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There was a period when BWB renamed both Wast Hill and Brandwood Tunnel (nearby and on the Stratford Canal) as King's Norton Tunnel - early 70s I think, as that's their name in the early Nicholson guides
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My first boat, Ripple, was a 62 foot semi-trad built by SW Durham Steel for Clifton Cruisers in 1999. It was good, solid, practical and swam well. As far as I'm aware SWDS didn't fit boats out. Mine was fitted by Clifton Cruisers.
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24 minutes ago, Pluto said:
The layout of Ystalyfera aqueduct is fairly standard
But others don't have such a poetic name, with Ystalyfera one can almost hear the close harmony singing....
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Sorry, late to the party! Following @1st ade invitation, I tend only to get involved when restoration and the local authority heritage conservation officer collide. As a general rule we don't know the composition of the mortar on particular structures without a sample analysis. Two observations, the original would be very local in origin, and subsequent repairs may not have been faithful to the original. Loathe as I am to criticise the local authority officer, we do get some bizarre ideas. One asked for mortar to match the original on a boundary wall in Frome (Dissenters Cemetery) - analysis showed it contained ash from Frome Power Station. The officer struggled with why we couldn't get this any more...
Ystalyfera aqueduct on the Swansea Canal was thought to be one of the earliest canal structures to use hydraulic lime - link below, however I think earlier ones may have now been noted. Even when the claim was made it was acknowledged the Romans had used it, but we then forgot the technology
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1 hour ago, Hudds Lad said:
I was confused by it in Nov 2021, never come across gear like it. I was told by one of the denizens to leave the gates open when leaving, as someone had gone out and would be back at some point in the day (basically how we found it).
The ground paddle dates from when the lock could work either way, falling to the Thames as well as away from it. Most ground paddles will struggle to seal if the head is reversed so clearly there's something different about this one. The mechanism may not be quite that old but it predates nationalisation..
There was a ground paddle at the other end too, when the lock is drained for maintenance the culvert can still be seen.
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Not my pictures - but around two years ago I met the Louth Navigation Trust and as we walked and talked we had a conversation along the lines that getting access to the water on the seven mile level from Tetney would be a good plan. A slipway perhaps...
About that time the warehouse at Austen Fen was being sold, and the new owners also thought this was a splendid idea - so splendid they went and did it. If I have the details right the owners got all the permissions and the Louth Navigation Trust found grant funding (it is mostly on EA land) - it's now in use and the water accessible. Okay just for paddles at the moment but from small seeds...
The Louth Canal is unlikely to ever be a major holiday waterway, unconnected, only 11 miles and with seven of its eight locks in the top four miles. But personally I think this is wonderful - but then I do have a soft spot for Louth and its Canal.
Photos by Chau Lee, one of the new owners of the warehouse, taken from the Louth Navigation Trust Facebook page - link here for those who "do" Facebook
https://www.facebook.com/groups/478410456289005/permalink/1861313831331987/
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7 hours ago, Ronaldo47 said:
I seem to remember reading that after they filled in the Derby canal, a nearby railway line started to suffer flooding in bad weather due to the loss of drainage.
Draycott - Network Rail (or Railtrack I think) paid for it to be dug out again. This was in about 1995
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As you can see above, the specified trailer isn't a flatbed, and has four runners for the boat to slide on during launch and retrieval - it won't slide much but it is likely to slide a bit during this. These runners also bear the load and match the hull moulding.
If you use a flatbed ask yourself how you'll get the boat on and off and make sure it isn't going to place a load on the hull where it shouldn't
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1 hour ago, Rev said:
Hi,
A friend and I are hiring a boat for 4 days on the Grand Union in the first week in June. I haven't taken out any holiday insurance yet but I'm getting jittery about water levels etc.
Do other people who hire take out their own insurance to cover things like having to cancel at short notice or having a holiday cancelled due to water levels please?
Can you recommend any decent insurance companies who specialise in boats or will any company do?
Am I being over cautious?
Sorry for all of the questions. Thanks in advance for any help.
As a general rule you can only insure against the party being unable to go on the holiday e.g. for health reasons. If the boat yard can't give you the holiday because of navigation issues that's a completely different matter, most will cover this in their terms and conditions.
Often hire companies will move boats away if the navigation is closed, so you'll still get a holiday, just not where you thought you were going to get one!
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18 minutes ago, Derek R. said:
I think the roof over American bridges is more intended to increase longevity of the bridge deck. An umbrella reduces the chance of a soaking. Snow, not so much. Snow on a bridge roof will bring the same amount of weight applied to the roof, thereby the bridge as a whole.
Thanks Derek, the book clearly states the idea developed to increase bridge longevity by protecting the main elements from the weather. The book refers to the number of joints involved in a wooden bridge of any significant span, and I believe joints are where rot sets in first.
Although it's a slim volume I haven't finished the book yet as I bought four more the same day and I keep reading those too! As well as doing Internet searches to add to what I'm learning. I now understand the difference beyond King trusses and Queen trusses for example.
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11 hours ago, Pluto said:
Although the low temperatures would have been a problem, the spring floods probably damaged American canals to a greater degree.
This is very true, the Whitewater Canal being a case in point I find. Apparently it opened in full in 1847 but the same year parts were washed away in floods, some of the damage was never repaired. The canal as a whole lasted only a few months, although some bits traded for many years before the canal was completed and after the floods closed part of it.
I'm only one page ahead at the moment, so the above is almost all I know...
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According to the book they were used because open bridges didn't last more than about twenty years, the rainfall is cited but I guess it would be a combination of rain, wind and sun that would do the damage. I'm not entirely clear whether the open bridges that preceded them were truss bridges and thus the covered bridge was just a truss bridge with cladding.
As for the aqueduct, my thoughts were the same as @Pluto - what's the point in stopping it getting wet! More research needed...
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Took the Stepdaughter to the American Museum in Claverton today. Whilst there I attempted to rectify the shortage of books in my collection 🤭 with several purchases including this one. "Covered Bridges" - I've known of their existence and even driven over a few, but knew nothing about them.
Imagine my delight on finding within a picture of a covered aqueduct!
Apparently its on the Whitewater Canal in Indiana - so I'm off to research that now!
It seems there is always something out there to discover.
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On 24/02/2025 at 22:35, Gybe Ho said:
It makes sense for the CRT to implement a local interpretation of the CC regs. If all the CCers west of the Caen flight met their 26 mile target with a mid summer cruise East of Devizes they would drain too much water.
Caen Hill has back pumps - water supply is not the issue.
All the CCERS I know do go up Caen Hill and stay above for several weeks. Their view is that this keeps them off the radar. Obviously there are many I don't know and they may well not do this. Some do go on the river in Summer as well.
Going to Pewsey OR Hanham as well as Bath to Foxhangers would get over the line on CRT range each year, you don't need to do both.
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4 hours ago, LadyG said:
cat was in basket on towpath.
This would seem to suggest Fernando didn't simply wander off
Vertical lifting bridges - why or why not?
in History & Heritage
Posted
In principle I'd agree, but that's why the thing has more than the usual number of gates at both ends - a mitre pair and single leaf gate that (I think) folds to the floor. They're both closed when the lock operates.
We did look at this at the time, because occasionally gates "blow", something that would fill the lock in seconds, hence doubling up on the gates - something also done on the Panama Canal BTW.