Four more Oxford bridges to receive hydraulic mechanisms- £650,000. Thoughts?

[Stroudwater1]

https://canalrivertrust.org.uk/news-and-views/news/lb650000-lift-for-iconic-oxford-canal-bridges
 

Currently many of these are usually open with a chain to pull at both ends of the bridge so can be closed from either side of the canal. Will these 4 be in the default of being permanently closed apart from boater’s opening them?  Three are funded from CRT funds.
 

CRT could have missed a trick I fear (possibly the IWA too) as they could have saught funding from developers for one when the new sprawl of housing out of Banbury took place recently. Perhaps they did but didn’t get the hydraulic bit funded as the bridges look fairly recent. 

We will miss the dangling on a chain, or rope thrown over to occasionally open them. Appreciate some can’t do that but easily for physical reasons 

Interesting that this is to partly “improve longevity” as the new ones looked rather short of maintenance.
 

Are they more safe with hydraulic mechanism? We find that they shut very rapidly compared to opening so some folk in eagerness could start shutting the bridge before they ought to? 

Edited October 8, 2023 by Stroudwater1

[magnetman]

£150k to convert a lift bridge to manually operated hydraulic operation?

[frangar]

I wonder if the “control” will be on the towpath side to help those boating single handed? 

[magnetman]

A bit awkward to do that as it would need some sort of inverted goalpost thing buried in the canal. May not be allowed if they are listed structures.

 

 

 

I reckon all the control parts will be on the same side as the rams.

 

 

 

 

Does this mean the end of the Banbury stick?

[Chewbacka]

1 hour ago, magnetman said:

A bit awkward to do that as it would need some sort of inverted goalpost thing buried in the canal. May not be allowed if they are listed structures.

 

 

 

I reckon all the control parts will be on the same side as the rams.

 

 

 

 

Does this mean the end of the Banbury stick?

As it is a "manual hydraulic winding mechanism" I don't suppose there will be any control gear as such, just fit the windlass and wind one way for up and the other way for down.

[magnetman]

10 minutes ago, Chewbacka said:

As it is a "manual hydraulic winding mechanism" I don't suppose there will be any control gear as such, just fit the windlass and wind one way for up and the other way for down.

I meant the pipework. 

Between the hydraulic pump and the rams. 

If the winder was on the towpath side these pipes would have to be routed under the water or an arch made. 

 

Or you could put the rams on the towpath side but I don't think this would be allowed on a Listed structure. 

[MtB]

2 hours ago, magnetman said:

£150k to convert a lift bridge to manually operated hydraulic operation?

 

Seems a lot, but if boaters are to be formally required to get off the boat to open every bridge, that £150k per bridge will presumably include building proper landing stages with bollards to tie the boat...

 

 

[billS]

The first bridge north of Duke's lock has already been converted to this mechanism, with the winding mechanism on the towpath side. When we used it last month, it only lifted by a foot however quickly or slowly we turned the handle. We only got it to rise by helping it by a second person pushing it up manually at the same time.

 

At least 3 of the bridges are normally open to boats. I suspect this change means they will normally be closed. Bummer.

[Tony Brooks]

21 minutes ago, billS said:

The first bridge north of Duke's lock has already been converted to this mechanism, with the winding mechanism on the towpath side. When we used it last month, it only lifted by a foot however quickly or slowly we turned the handle. We only got it to rise by helping it by a second person pushing it up manually at the same time.

 

At least 3 of the bridges are normally open to boats. I suspect this change means they will normally be closed. Bummer.

 

That is bad design, there is one on the North Stratford like that. Basically, the ram does not have enough diameter to lift the bridge before the pressure is such the PRV in the winding "drum" opens. BW/CaRT seem a bit poor on the design of such things. It is not helped when the pivots get stiff or the structure twists.

[PaulJ]

45 minutes ago, billS said:

The first bridge north of Duke's lock has already been converted to this mechanism, with the winding mechanism on the towpath side. When we used it last month, it only lifted by a foot however quickly or slowly we turned the handle. We only got it to rise by helping it by a second person pushing it up manually at the same time.

 

At least 3 of the bridges are normally open to boats. I suspect this change means they will normally be closed. Bummer.

 

20 minutes ago, Tony Brooks said:

 

That is bad design, there is one on the North Stratford like that. Basically, the ram does not have enough diameter to lift the bridge before the pressure is such the PRV in the winding "drum" opens. BW/CaRT seem a bit poor on the design of such things. It is not helped when the pivots get stiff or the structure twists.

Think you was unlucky.Perhaps just a bit low on oil or something at that time-maybe it had a small leak?

Came through (single handed as always) a couple of days ago with no problems and everytime before has been the same too.

[Tony Brooks]

5 minutes ago, PaulJ said:

 

Think you was unlucky.Perhaps just a bit low on oil or something at that time-maybe it had a small leak?

Came through (single handed as always) a couple of days ago with no problems and everytime before has been the same too.

 

No, I know what a blowing PRV sounds and feels like.

[PaulJ]

3 minutes ago, Tony Brooks said:

 

No, I know what a blowing PRV sounds and feels like.

Oops..You were talking abut a different lift bridge to me 😀

[magnetman]

So there is some sort of inverted goalpost then for the hydraulic pipes. 

 

I wonder how deep they are. 

 

 

[Chris Lowe]

Takes the fun out of running up the bridge deck to close it.

[magnetman]

Hydraulic creep could be a nasty situation over time. Presumably there is a locking mechanism rather than just holding the weight up on the ram(s). 

 

Probably fine as the CRT are known to be Very Good with maintenance.

 

 

 

 

[MtB]

1 minute ago, magnetman said:

Hydraulic creep could be a nasty situation over time. Presumably there is a locking mechanism rather than just holding the weight up on the ram(s). 

 

Probably fine as the CRT are known to be Very Good with maintenance.

 

 

I can imagine them all being taken off again after strings of weekend emergency callouts from queues of hire boats being held up by busted hydraulics. 

 

 

[Tony Brooks]

55 minutes ago, PaulJ said:

Oops..You were talking abut a different lift bridge to me 😀

 

The one in the middle of Banbury does/did it of you wind too fast. You can hear the PRV venting inside the case.

[magnetman]

It might have a low quality spring in it and no routine adjustment happening..

 

A bad spring in a joystick caused a nasty accident on a Thames clipper high speed catamaran a number of yars ago. 

 

Very Important to have quality springs. 

[Tractor]

The bridge close to Dukes Cut is a road crossing which is best to remain closed. For the remainder which are not used for access ‘what is the point’ of installing a mechanism which is costly to install, will require maintenance, and is not necessary.

 

[magnetman]

It is a good question.

Given the quoted figure of £650k for four lift bridges maybe someone just spotted a money making scheme..

 

 

 

 

[ditchcrawler]

1 hour ago, Tractor said:

The bridge close to Dukes Cut is a road crossing which is best to remain closed. For the remainder which are not used for access ‘what is the point’ of installing a mechanism which is costly to install, will require maintenance, and is not necessary.

 

Like the one up the Caldon that doesn't go anywhere 

[Tractor]

It seems odd that, a mere sum (£650K), can be floating around in some CRT account which has not got a proper justification.

With licence and mooring fees increasing, the prospect of maintaining this lifestyle is fast loosing its justification. I have now doubt many will carry on, and maintain this heritage; sadly this may not be for me.

Apologies for this, depression will lift tomorrow..

 

[ditchcrawler]

27 minutes ago, Tractor said:

 I have now doubt many will carry on, and maintain this heritage; sadly this may not be for me.

 

 

A good turn of phrase when the money is being spent to convert a bridge that has been opened with a chain for 200 years to work with a hydraulic ram and pump 

[Scholar Gypsy]

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.

[ditchcrawler]

37 minutes ago, Scholar Gypsy said:

   This bridge also had a locking mechanism (you can see it at ground level) that uses a standard CRT key.

 

Another fine device to stop you leaving it open for the boat following