Scholar Gypsy
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Posts posted by Scholar Gypsy
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This is the one I had in mind at Alwalton - a new stretch of river was built to take out the kink!
https://maps.nls.uk/geo/explore/side-by-side-old/#zoom=15.8&lat=52.55889&lon=-0.32293&layers=168&right=193
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I think that's a flash lock, ie just one guillotine gate. When a boat wants to transit it is lifted and the boat either zooms downstream or is winched upstream as the levels equalise. I have seen photos of a very similar structure on the Brandon Ouse, near Hockwold. The remains of that are just about visible. I think one can also see the old lock structure downstream of Awalton, though I may be imagining that. One certainly can just below Lower Wellingborough lock (which looks like a 1970 structure rather than a 1930s one).
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1 hour ago, matty40s said:
It seems one of your fellow Conservators doesn't think that the title of this thread is misleading...
Helen Cleary, of Conservators of the River Cam, said that the proposal to remove navigation rights on part of the river around the sewage outfall was “of significant concern to us”.
She said: “Our biggest concern is navigational rights, and protecting the navigation users and our enforcement rights. So in terms of this, being accurate with wording around permanent extinguishment of our powers, and rights to navigate in this area, it would be extremely important for us to understand it and be able to engage legally on it, because it’s our statutory responsibility to maintain that navigation as well as the impact on its environment.”
Helen is of course, as Chief Executive, representing the views of the Conservators (who employ her). I do think this subject has got somewhat garbled in the press coverage. There is no intention on the part of AW to "stop navigation on the Cam". But (as I said earlier) there is more to do to understand the precise impact (if any) on navigation of the proposed works, during construction and then permanently, and to ensure that the legal powers granted to AW are no more than are necessary.
The other point I should add is that there are of course lots of other impacts of the project, for example on water quality and other environmental aspects, but these are primarily a matter for other agencies rather than the Conservancy. -
I hope I can offer some reassurance here, as I am a Cam Conservator. We have been discussing this a lot for quite some time (and certainly since I joined in January 2023), to understand the nature of the structure, and the impact on navigation a) during construction and b) when built; and what that means for the powers AW are seeking.
We have submitted lots of questions to Anglian Water, and as you can see from this article the Planning Inspector has just held the initial scoping meeting at the start of the process of approving the works. The Environment Agency will of course have a major interest - we are just the navigation authority.
Here's a drawing of the proposed outfall - on the opposite side of the river to the existing one which will be removed. It does involve works to protect the bed from scouring, but the bulk of the concrete structure is actually behind the river edge.
We are also interested in the rest of the project, which collects sewage from as far down as Waterbeach and pipes it south (upstream) to the new STW. This means that a number of smaller existing works (Waterbeach, Horningsea) can be closed, and a new tunnel built under the river between Bottisham lock and Clayhythe.PS The subject of this thread is somewhat misleading, IMHO.
PPS here are some photos of Jesus Lock, currently with no gates ... https://scholargypsy.org.uk/2023/10/26/jesus-lock-cambridge/
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Just now, Mike Todd said:
Strangely that only demands a compliance with the Scheme but not a current certificate!
That's a tougher test. For example if you make a modification to your boat there is no requirement to get a new certificate, but the work still has to be done in a way that maintains scheme compliance.
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Thanks for the comments. There is (of course) a cover that fits on top of the lot, to avoid shorting. The thin wires connect to a battery charger (not in use now I have solar), and a sulphator. There are a number of fuses just out of shot (eg for the Smartgauge, solar, and bilge pump).
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CRT licence terms and conditions "The Boat must always comply with Boat Safety Scheme requirements"
Section 6: https://canalrivertrust.org.uk/refresh/media/original/43943-general-terms-and-conditions-for-boat-licenses-june-2021-searchable-file.pdf
Prompted by my recent full survey, I finally got round to strapping the batteries down. They have never moved an inch in 30 years, despite some quite rough water conditions....
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I was going to quote my Craftinsure policy but @nicknorman beat me to it. I guess the problem the insurers have is that they have literally no idea how competent a particular skipper is - as we don't need any licence etc. The craftinsure underwriters were sensible when I did a Wash crossing a few years ago, ie a list of extra conditions which suggested to me someone who understood what the risks were on this trip, and what mitigations were sensible and possible.
It's worth noting that on some rivers - the Nene is a good example - the whole river goes on red even when the problem is fairly localised (or as with the recent storms, as a precautionary measure before the significant rainfall has actually happened). If you know the river then moving in those conditions is not reckless (I would argue). The EA are working on this, but it's not a straightforward issue. -
This website provides some practical advice on how to get there from the canal system at Northampton. It includes links to various guides and websites.
There's a great list of moorings above, I am moored at Cathedral in Ely.
https://goba.org.uk/a-guide-for-visitors-to-the-east/PS you can also get to the rest of the system by crossing the Wash to Boston and Lincoln.
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On 28/09/2009 at 20:27, nb Innisfree said:
Ours was a fail safe i.e. solenoid energises to switch fuel on. I assume they are all the same
I would say that is fail unsafe, as if there is a problem with that electrical circuit the engine might decide to stop at a most inconvenient moment!
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7 minutes ago, dmr said:
Thats sort of what I was saying to say, with Foxton the water comes from the sideponds, not the top pound, but this leaves the sideponds a bit lower and the water to replenish them must ultimately come from the top pound, but maybe not till uch later.
The Soar has wide locks, as does the GU, so when the inclined plane was replaced with narrow locks I reckon the engineer knew it would be a bottleneck so the sideponds were included to speed things up.
Foxton and Watford locks were built as narrow locks. The left hand map here shows there were sideponds in the mid 1800s (and probably earlier). Some of them got a bit squished when the inclined plane was built ca 1900 (see right hand map). The one by the crossing pound in the middle was completely obliterated, I think.
https://maps.nls.uk/geo/explore/side-by-side/#zoom=16.3&lat=52.49936&lon=-0.98177&layers=257&right=168 -
10 minutes ago, dmr said:
Going through a lock moves a lockfull of water, and going through a flight of locks moves a lockfull for each lock regardless of whether its a flight of locks, a staircase, or a Foxton staircase.
Going down a full flight of locks is a bit variable depending upon if you "take a lockfull with you" or let lockfulls go over the bywash, but ideally one lockful from the top pound will get you down.
When going up water must come from the next pound or next chamber up and all the water used must ultimately come from the very top pound.
With a conventional staircase all the lockfulls come from the top pound but with Foxton or a conventional flight most of the water comes from the intermediate pounds (which is quicker) but ultimately the water used must be replenished from the top pound via the bywashes and this can happen slowly or overnight.
So I think the Foxton sideponds are a store of water to keep the flight working quickly if boat traffic is taking water out quicker than the bywash flow is putting it back in ???????
With Bingley, if you are going uphill and all the lock chambers are empty, then you will need to take four lockfulls of water from the top pound, to fill up each of the top four locks. Conversely if you are going downhill and the locks are full then you will empty four locks of water into the lower pound. Not as efficient as a Foxton type arrangement. (To make Bingley more efficient, you need something like boats only going uphill in the morning, and only doing downhill in the afternoon. This is a bit counter-intuitive, I know, and ignores the possibility of shuffling.) -
10 hours ago, adam1uk said:
Going up a normal staircase you need the bottom one empty and the ones above full -- but at Foxton and Watford you don't; as you say you're just taking the water from the side pond. So doesn't that give a water saving? Or is it just a time saving?
Comparing Foxton and Bingley - both five lock staircases - the latter will use more water, unless all the boats are travelling in the same direction. (Ignore the fact that the latter are wide locks, which also permits the shuffle maneuver...)
I quite like the French approach which is to open all the gates and then fill the chambers up from the top, moving the boats forward as you go!
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9 hours ago, MtB said:
I notice the headline says "Four more Oxford bridges..."
Which other Oxford bridges already have windlass-operated hydraulic gear to open them? I can think of the one in Banbury town centre and that's about it. There are two electrically operated but no others done with manual power. Or are there others I'm missing?
One just above Duke's lock.
Banbury, above the lock.
Heyford mill is electric, ditto Thrupp.
Thats all I can remember from my recent trip...
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I agree this is a pity. But gives me an opportunity to show my Banbury stick in operation this summer (just north of Wolvercote lock). The bridge is naturally fairly finely balanced, and it was windy, so that's why there is a rope to hold the bridge down on the pole. This bridge also had a locking mechanism (you can see it at ground level) that uses a standard CRT key.
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1 hour ago, davidg said:
Boing!
As I said earlier, the "side ponds" at Watford & Foxton do not save water at all. You empty the complete contents of the upper lock into the "side pond" and completey fill the lower lock from the "side pond" in exactly the same way as you would if it were a normal pound between the locks.
edit: I should qualify that by saying no water saving compared to having five separate locks
Yes, agreed.PS Looking on Google earth, the sideponds at Watford are about 350' x 50', which is over 30 times the area of the lock.
The ones at Foxton are more variable, as to shape, size and orientation. This map makes it clear they were squashed up a bit when the inclined plane was built... I think it also shows that the pound between the two flights used to be much bigger than it is today..
https://maps.nls.uk/geo/explore/side-by-side/#zoom=16.3&lat=52.49939&lon=-0.98171&layers=257&right=BingHyb -
5 hours ago, 1st ade said:
Considered as a problem within the laws of physics, there are two requirements to solve: -
- You need to fill each chamber to a certain level (to meet the requirement of getting the craft in to (or out of) the next chamber)
- Water only goes downhill (unless back pumping is in operation)
So the trick is to fill (or empty) the next stage in the sequence with the minimum amount of water going downhill (not just volume but "head")
E.G. (all going uphill with full locks in front of you, but the scenario is reversible): -
- Single lock - empty into navigation below, drive in, fill from navigation above, drive out. Job done
- Single lock with side pond - empty half the lock into the side pond (as it is higher than the lower navigation), empty the rest into navigation below. Drive in. Fill from side pond (as it's lower than navigation above), fill from upper navigation, drive out.
- Single lock with two Side Ponds - empty chamber into A and close paddles. Empty rest of chamber to B and close paddles. Empty the rest into the lower navigation. Drive in. Fill from B (as it will be lower), then from A (higher) then from upper navigation - in each case closing paddles before you start the next one. Drive out
I don't think this calculation is quite right (though the operating process is correct).
With side ponds that have the same area as the lock, then
1) With a single side pond the water level will vary between 1/3 and 2/3 full. When going downhill you put 1/3 of a lockful into the side pond (which then goes from 1/3 to 2/3 full), and then you empty the rest into the lower pound. When going uphill you take 1/3 of a lockful out of the sidepond (which then goes from 2/3 to 1/3 full), and then fill the remaining 2/3 from the upper pound. 33% of water saved.
2) With two side ponds, the upper one will vary between 1/2 and 3/4 full, and the lower one between 1/4 and 1/2 full. Going downhill you put 1/4 lockful into the upper pound (which goes from 1/2 to 3/4 full, with the lock going down from full to 3/4 full). Then you put another 1/4 lockful into the lower pond (which goes from 1/4 to 1/2 full). Then you empty the remaining 1/2 lockful to the lower pound. Going uphill you take 1/4 lockful from the lower pond (which goes from 1/2 to 1/4 full) and then another 1/4 from the top one (which goes from 3/4 to 1/2 full), and then fill the remaining 1/2 lock from the upper pound. 50% of water saved.
With large side ponds (say 20 times the area of the lock, which I would guess is the case at Foxton and Watford), they are much more efficient as the level in the side ponds can be assumed constant. So a single side pond will be at the 1/2 full level, and can take and then discharge 1/2 a lockful of water with only a small change in level. This is logically equivalent to replacing one deep lock with two shallow ones, and so will use half the amount of water.
I really should get out more. -
1 hour ago, Lady M said:
Can anyone please explain how donations to Fund Britain's Waterways are eligible for Gift Aid?
It's hard to see how this would be possible, as a) FBW is a coalition of many different organisations, many of which are not charities (eg boat clubs); and b) I don't believe FBW has yet been set up as a separate legal entity, let along a charity.
However I think you could make a donation to IWA and ask for this to be used to support the FBW campaign. -
2 hours ago, magpie patrick said:
The Hanwell ones need using in sequence - going up draw on the lowest one first, going down fill the highest one first.
Sideponds at Bascote two-rise seem a recipe for confusion. I guess one would start by emptying the upper lock into its side pond whilst simultaneously filling the lower on from its sidepond, once that process is complete start emptying the lower lock back into its sidepond before finally emptying the lock into the canal below and going on your way, slow and lots of scope for errors, I can imagine the working boatman not bothering....
The maths of side ponds is quite interesting (well I think so!). The key variable is the ratio of the area of the pond to the area of the lock. If this is 1:1 then you get one solution (for the full and empty levels of each side pond, and for the amount of water that is saved - for example with two side ponds you can save 50% of the water, with one only 33%). If the ratio is much bigger then one can assume the level stays fixed in the side pond (like Foxton), and two ponds can save 2/3 of the water.
One could re-imagine each five lock flight at Foxton as one huge lock, 70' long and with a single drop of 37'6", with four large side ponds at intermediate levels. In this case 4/5 of the water is saved (the consumption is to fill or empty the last part) compared with operating it as a single 37'6" lock. Of course the reason the lock is not built that way is that it would require rather large bottom gates (*), though it would save on brickwork.(* Footnote, unless one made the bottom end of the lock a solid wall, with a hole for the boat to go through ...)
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9 hours ago, Big Bob W said:
Isn't it the other way round?
Red Paddle empties the upper pound directly to the lower pound.
White paddle is to the side pond.
No. The Red paddle connects the side pond to the lower lock, the white paddle to the upper lock. When both paddles are up then the water level equalises between both locks and the side pond, you open the gate and move from one lock to the next.-
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Thank you - some nice photos. That almost looks like the Waverley at Southend pier.... but the wrong number of chimneys
https://scholargypsy.org.uk/2022/09/29/ps-waverley-gravesend-to-clacton/ -
14 minutes ago, SnippetySnip said:
Adding my tuppence worth to this thread and to encourage other boaters. I've been up and down the Northampton Arm a couple of times over the last month. I have a heavy deep drafted boat, so I was worried about the trip the first time I did it, but there is really no issue.
The flight was in good condition and apart from having to let some water down to raise the level in a one of the pounds to get across it (which really wasn't a big drama) it was very pleasant.
The lower section was very weedy and reedy. But I didn't need to get the weed hatch up, I managed to chug on through at a slow pace. A couple of the long pounds have got crystal clear water, teeming with fish, it's very picturesque! I understand that the clear water encourages the weed growth, but it seems a shame to complain about the water being so clean.
The water level in the lower sections seemed pretty good in terms of depth, I was not stirring up mud at any stage, so I guess the draft in the centre of the channel is pretty good. However, the usable channel is really quite narrow, so for long stretches it's a bit like being in a bridge hole, pushing water backwards around the boat in the limited channel. Not a drama, just rather leisurely.
In summary, slow going, but no drama and very picturesque.
A very fair description! I do a lot of cruising on the Fens and Middle Level as well, and it has been three years since I have had to go down the weed hatch. (though my son had to go down recently to untangle the stern line ....)-
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Ah, I was wondering if I couldn't see this data as I have a gold licence and my home mooring is on an EA waterway. But I see that's not the case as the option has been withdrawn.
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12 hours ago, magnetman said:
If you are the only boat in the lock the engine can stay on. Lock keepers know this and I have seen them hold back narrow boats with Bolinders type engines and put them through alone.
That is the byelaw however there is also the noise byelaw to contend with and following instructions given.
I actually got into this with an experienced lock keeper not relating to my own boat at one stage and he suggested that in reality the boater probably can leave the engine running because it is unlikely to be so loud that instructions will not be heard.
However... It could be a reasonable cause for annoyance.
I suspect another reason for this byelaw is to stop boats using their engine to control their position in the lock. That's what the bow and stern line are for.
Stern Gland repacking
in New to Boating?
Posted
My stern tube now drips much less after a week out of the water in September (for blacking). Very strange!