CRT lockage report - reality check

[magpie patrick]

Hi folks,

 

I'm looking up various figures from the latest CRT lockage report (although the question could apply to any year) - briefly, reading the introduction and from my past understanding a "lockage" one filling (or possibly one emptying) so if a boat arrives and fills the lock (whether or not the boat is in it) that is "one lockage". The introduction states that the ratio of lockages to boats can vary and cites that at a wide lock "one lockage" could see anything between one and four boats transit - I assume this means the lock might be filled once for one boat or it might be filled with a pair of boats in it and then emptied with another pair of boats in it - the latter would still count as "one"

 

If this is the case, then the busiest single lock at New Marton (Hillmorton are top of the charts but are paired) which has 7457 lockages in 2021, this means it was filled over 20 times a day on average, over the course of 365 days - of course it would have to be emptied just over 20 times too. Assuming a turnaround of 15 minutes that means on average the lock is in use just over five hours every day of the year. On the basis that these are average figures there are clearly days when it is a lot busier than that, I don't have a model to calculate the spread but there must be many days in peak season when the lock is going flat out for more than ten hours if these figures are correct. 

 

Often with tourism figures one assumes that the busiest day is at least 1% of the annual total, in this case that would be 75 lockages in one day and the lock would be in action for 18 hours that day - clearly this doesn't happen and actually the availability of hire boats spreads the peak, but peak spreading simply results in more  days when the lock is in continuous use for ten hours or so. 

 

I know the Llangollen is busy, but it is probably 25 years since I last saw New Marton Locks - are they as busy as my calcs suggest? There are two possible flaws in my assumtions - one is that the locks can be turned round in less than fifteen minutes which means the capacity is greater than I think (turn round being the time between a boat entering to ascend and the next boat entering to ascend, or indeed between any two points on the cycle) - the other is that filling and emptying a lock counts as two lockages rather than one.

I'm not that worried about New Marton lock itself, it's just a way of understanding the figures in the report. 

Any thoughts or comments? Thanks

[Idle Days]

I suggest that many locks are turned around in less than 15 minutes, perhaps closer to ten.

[Rob-M]

4 minutes ago, magpie patrick said:

Hi folks,

 

I'm looking up various figures from the latest CRT lockage report (although the question could apply to any year) - briefly, reading the introduction and from my past understanding a "lockage" one filling (or possibly one emptying) so if a boat arrives and fills the lock (whether or not the boat is in it) that is "one lockage". The introduction states that the ratio of lockages to boats can vary and cites that at a wide lock "one lockage" could see anything between one and four boats transit - I assume this means the lock might be filled once for one boat or it might be filled with a pair of boats in it and then emptied with another pair of boats in it - the latter would still count as "one"

 

If this is the case, then the busiest single lock at New Marton (Hillmorton are top of the charts but are paired) which has 7457 lockages in 2021, this means it was filled over 20 times a day on average, over the course of 365 days - of course it would have to be emptied just over 20 times too. Assuming a turnaround of 15 minutes that means on average the lock is in use just over five hours every day of the year. On the basis that these are average figures there are clearly days when it is a lot busier than that, I don't have a model to calculate the spread but there must be many days in peak season when the lock is going flat out for more than ten hours if these figures are correct. 

 

Often with tourism figures one assumes that the busiest day is at least 1% of the annual total, in this case that would be 75 lockages in one day and the lock would be in action for 18 hours that day - clearly this doesn't happen and actually the availability of hire boats spreads the peak, but peak spreading simply results in more  days when the lock is in continuous use for ten hours or so. 

 

I know the Llangollen is busy, but it is probably 25 years since I last saw New Marton Locks - are they as busy as my calcs suggest? There are two possible flaws in my assumtions - one is that the locks can be turned round in less than fifteen minutes which means the capacity is greater than I think (turn round being the time between a boat entering to ascend and the next boat entering to ascend, or indeed between any two points on the cycle) - the other is that filling and emptying a lock counts as two lockages rather than one.

I'm not that worried about New Marton lock itself, it's just a way of understanding the figures in the report. 

Any thoughts or comments? Thanks

It can take as little as 5 minutes to transit a narrow lock, at somewhere where boats are queuing both sides then you could be seeing 10 boats an hour passing through the lock.  Discussing with the volunteers are Fradley they often have days with 50+ boats passing through the locks.

[David Mack]

Something fishy about this map. How can lockage be different on the two halves of the Ashby when there are no locks on either section?  Or 3 different levels of lockage along the (lockless) Staffs and Worcs summit pound? And is lockage really in the second highest category for the one usable lock on the Hatherton branch which is effectively part of the marina and not available for general use?

[magpie patrick]

1 minute ago, David Mack said:

 

Something fishy about this map. How can lockage be different on the two halves of the Ashby when there are no locks on either section?  Or 3 different levels of lockage along the (lockless) Staffs and Worcs summit pound? And is lockage really in the second highest category for the one usable lock on the Hatherton branch which is effectively part of the marina and not available for general use?

 That's why I like figures from source rather than graphics generated from a spreadsheet! I assume the figures in the tables are correct. 

 

But yes, a lock counter on the CRT section of the Ashby would be pretty pointless 

[Sea Dog]

51 minutes ago, magpie patrick said:

But yes, a lock counter on the CRT section of the Ashby would be pretty pointless 

Still, I reckon a fair few folk could be persuaded to sit by the Ashby in a deck chair for the day, write 'zero' on a form and push off home... if the remuneration suited. 

[john6767]

My observations with New Marton is that they are quite strange in their usage pattern.  In the summer for much of the daylight hours there is a queue both above and below the locks.  There are a lot of hire boats that these two locks are the only ones that they do, so you see a

 lot of boats mooring up, lock the boat up, walk up to the bottom locks and try and work out what they have to do, so it can take an age for a boat to go through, which is why there are queues, not because the lock is being cycled every 5 mins.  If you know what you are doing you can certainly cycle these locks quickly though.  But I would have thought even with this going on the throughput would be cycling the locks at least  4 times an hour for at least 10 hours a day in the peak summer 

[Rob-M]

1 hour ago, David Mack said:

Something fishy about this map. How can lockage be different on the two halves of the Ashby when there are no locks on either section?  Or 3 different levels of lockage along the (lockless) Staffs and Worcs summit pound? And is lockage really in the second highest category for the one usable lock on the Hatherton branch which is effectively part of the marina and not available for general use?

How many boats pass through Moira Lock on the disconnected restored section of the Ashby...?

[Mad Harold]

2 hours ago, Idle Days said:

I suggest that many locks are turned around in less than 15 minutes, perhaps closer to ten.

Only if they are working properly.

Last time I went through the Cromwell Lock, (Calder and Hebble) only one paddle working, it took a good thirty minutes to fill.

[davem399]

1 hour ago, john6767 said:

My observations with New Marton is that they are quite strange in their usage pattern.  In the summer for much of the daylight hours there is a queue both above and below the locks.  There are a lot of hire boats that these two locks are the only ones that they do, so you see a

 lot of boats mooring up, lock the boat up, walk up to the bottom locks and try and work out what they have to do, so it can take an age for a boat to go through, which is why there are queues, not because the lock is being cycled every 5 mins.  If you know what you are doing you can certainly cycle these locks quickly though.  But I would have thought even with this going on the throughput would be cycling the locks at least  4 times an hour for at least 10 hours a day in the peak summer 

We’ve just got home from doing the Llangollen over the past two weeks and was surprised at how quiet the New Martin locks were.  I think it might be something to do with the timing, when many of the hire boats were back at their bases for turnaround?  Likewise, we got through Grindley Brook both ways with virtually no wait either.

[Athy]

5 hours ago, David Mack said:

 

Something fishy about this map. How can lockage be different on the two halves of the Ashby 

Perhaps because one half has a lock and the other half doesn't.

[billS]

9 minutes ago, Athy said:

Perhaps because one half has a lock and the other half doesn't.

Does the de-gated stop lock at Marston Junction count? That would explain the figure.

[magpie patrick]

Just now, billS said:

Does the de-gated stop lock at Marston Junction count? That would explain the figure.

Most of the counts are done with a pressure tube that measures changes in water level (or my precisely, measures changes in air pressure in the tube caused by a change of water level) - these don't work very well in locks that don't have a change in level! 

[Mike Todd]

5 hours ago, magpie patrick said:

 That's why I like figures from source rather than graphics generated from a spreadsheet! I assume the figures in the tables are correct. 

 

But yes, a lock counter on the CRT section of the Ashby would be pretty pointless 

Is there not a restored lock on the detached section that is used by a trip boat?

[magpie patrick]

6 minutes ago, Mike Todd said:

Is there not a restored lock on the detached section that is used by a trip boat?

There is but it's not CRT

[Alan de Enfield]

1 minute ago, magpie patrick said:

There is but it's not CRT

 

 

It is a shame that Lock usage / cycles is not one of the DEFRA Grant KPI's - C&RT could prove that the locks were in use 27 hours per day 8 days per week and an extra 'week' in Leap Years.

[Athy]

7 minutes ago, Alan de Enfield said:

 

 

 the DEFRA Grant KPI's 

Are these a brand of peanuts? Perhaps a reference to the size of the grant?

[Alan de Enfield]

9 minutes ago, Athy said:

Are these a brand of peanuts? Perhaps a reference to the size of the grant?

 

No, but very droll !!

 

They are measures that C&RT have to report on (and improve on) for every report to C&RT if they wish to maintain the Grant, 

 

Here are the KPI's (note there are non that must be achieved for boaters or navigation, the grant is only based on Environmental & Safety issues and Towpath users)

 

 

 

 

It is surprising to me, and I guess many here, that there are no targets for C&RT re the 'waterways', maybe if they had to report on :

 

"Number of unplanned waterway closures", and 

"Percentage of waterways in condition A to C"

 

More attention would be given to the actual 'navigations' instead of just the condition of the towpaths.

 

Edited June 20, 2022 by Alan de Enfield

[Athy]

Thanks - but I'm none the wiser regarding what "KPI" (assuming that it is an abbreviation) stands for.

[Alan de Enfield]

11 minutes ago, Athy said:

Thanks - but I'm none the wiser regarding what "KPI" (assuming that it is an abbreviation) stands for.

 

 

Key Perfomance Indicators.

 

Targets set and you are paid by achieving the KPIs, In C&RTs case the grant is paid if they achieve the KPIs

 

Unfortunately they are failing miserably in half of their KPIs

 

 

The stewardship score has dropped from 142 to 136 (not improved)

 

Number of injuries to customers has increased from 17 to 53 (not a good direction)

 

Duration of towpath closures increased from 347 days to 429 days (bad)

 

Average number of individual visitors (not number of visits) dropped from 9.2 million per two week period  to 8.3 million per 2 week period.

Edited June 20, 2022 by Alan de Enfield

[Athy]

Just now, Alan de Enfield said:

 

 

Key Performance Indicators.

 

 

 

 

 

 

 

Ta.

I realise that people could always "Google it" but that would rather erode the purpose of a discussion and information site such as this one.

[Cheshire cat]

Using a pressure tube to monitor usage is unreliable and has the potential to create a huge margin of error. The vast majority of locks will self empty if no boats come there way.

[magpie patrick]

2 hours ago, Athy said:

Ta.

I realise that people could always "Google it" but that would rather erode the purpose of a discussion and information site such as this one.

 And can come up with interesting answers

 

In my role as Chair of the Railway and Canal Historical Society I had an email from the treasurer of the Royal Caledonian Horticultural Society, passing on some queries they'd had which weren't in their field of interest

[Paul C]

7 hours ago, john6767 said:

My observations with New Marton is that they are quite strange in their usage pattern.  In the summer for much of the daylight hours there is a queue both above and below the locks.  There are a lot of hire boats that these two locks are the only ones that they do, so you see a

 lot of boats mooring up, lock the boat up, walk up to the bottom locks and try and work out what they have to do, so it can take an age for a boat to go through, which is why there are queues, not because the lock is being cycled every 5 mins.  If you know what you are doing you can certainly cycle these locks quickly though.  But I would have thought even with this going on the throughput would be cycling the locks at least  4 times an hour for at least 10 hours a day in the peak summer 

 

New Marton is 1) on a busy canal, 2) with long pounds before and after (with plenty of marinas and moorings on these). But also remember, its a pair of locks about 1/2 mile apart. So what happens is the queues of boats on the 'middle' pound (ie they're doing the second lock of the pair, in their journey) don't really occur, because they are spaced out (let's say 6-10 mins) by having done their previous lock.

 

Also there's a number (eg Whixhall, Blackwater Meadow, Chirk, Trefor) of marinas and hire bases where their holiday is a short break or mainly flat trip, and these are the ONLY locks the newbie hirers do, so there are often confused or slow transits (experienced boaters in the queue can only help so much, after all.....)

5 hours ago, davem399 said:

We’ve just got home from doing the Llangollen over the past two weeks and was surprised at how quiet the New Martin locks were.  I think it might be something to do with the timing, when many of the hire boats were back at their bases for turnaround?  Likewise, we got through Grindley Brook both ways with virtually no wait either.

 

Where did you start from? Most holidaymakers do it in one week, so there's "busy" days and "quiet" days which are quite contrasting.

[Paul C]

1 hour ago, Cheshire cat said:

Using a pressure tube to monitor usage is unreliable and has the potential to create a huge margin of error. The vast majority of locks will self empty if no boats come there way.

It would depend how the information is filtered - it might sense between a "paddles open" emptying/filling, based on rate of change.