What??? How???

[NigelMoore]

27 minutes ago, Captain Pegg said:

So in February 2010 the beam from Reading to Bath was published as 4.2m. In August 2014 it was 4.12m. Now it is 4.00m.

 

 

The BW publication of lock dimensions dated 2004 gives maximum craft dimensions for the K&A from Bath to Reading as 4.12mtrs in breadth, purporting to some accuracy -

 

 

 

The CaRT publication being quoted in #141, which gives a maximum breadth of 4 mtrs, specifically states to begin with that “The dimensions in this document are a rough guide only.”

 

So it is not that the published width of the canal section has decreased in reality, simply that CaRT have become more vague with the figures and rounding them down – and covering themselves with the disclaimer as to their being a rough guide only.

 

 

Edited May 4, 2019 by NigelMoore

[alias]

30 minutes ago, Captain Pegg said:

So in February 2010 the beam from Reading to Bath was published as 4.2m. In August 2014 it was 4.12m. Now it is 4.00m.

 

JP

 

 

4.12 metres beam in 2004

waterway_dimensions_2004.pdf

[NigelMoore]

11 minutes ago, Captain Pegg said:

Presumably it is genuine movement of a feature (or features) that has led to the changes and from a safety point of view it’s necessary to do that, although CRT state the published dimensions are a “rough guide”. However such instances should not be allowed to restrict the long term navigation capability of a whole waterway by stealth.

 

JP

You are absolutely right.

 

The most accurate set of comparative measurements using the old BW data from 1967 to the present day is contained in spreadsheets published by the department responsible for maintenance and dredging. If I can, I will hunt up the link, but others could find it as easily.

 

Sadly the conscientious endeavours of that department to maintain the statutory standards are hamstrung by the financial restraints and policy decisions handed down from top management.

[Alan de Enfield]

10 minutes ago, NigelMoore said:

 

 

 

 

I may be being extremely dense but -

 

Maximum beam = 13ft 6 inches

Absolute maximum beam = 7ft.

 

I though maybe the 'absolute' is based on 2 of NB's, but obviously not as 2x 7ft = 14ft (not 13ft 6 inches)

2 minutes ago, NigelMoore said:

You are absolutely right.

 

The most accurate set of comparative measurements using the old BW data from 1967 to the present day is contained in spreadsheets published by the department responsible for maintenance and dredging. If I can, I will hunt up the link, but others could find it as easily.

 

Sadly the conscientious endeavours of that department to maintain the statutory standards are hamstrung by the financial restraints and policy decisions handed down from top management.

Is this the one ?

 

 

Dredging Depths and widths.xls

[magnetman]

You can get two narrow boats in a lock chamber but you may not be able to bring a breasted pair into a lock due to gate opening restrictions. 

 

I know this as I wedged a pair of of narrow boats in a lock near Theale in 2001. Going slowly into the lock uphill and stuck on the gates which did not open fully.  Needed to use the tirfor to move them back then come in singled.

Edited May 4, 2019 by magnetman

[Captain Pegg]

14 minutes ago, NigelMoore said:

The BW publication of lock dimensions dated 2004 gives maximum craft dimensions for the K&A from Bath to Reading as 4.12mtrs in breadth, purporting to some accuracy -

 

 

 

The CaRT publication being quoted in #141, which gives a maximum breadth of 4 mtrs, specifically states to begin with that “The dimensions in this document are a rough guide only.”

 

So it is not that the published width of the canal section has decreased in reality, simply that CaRT have become more vague with the figures and rounding them down – and covering themselves with the disclaimer as to their being a rough guide only.

 

 

Interesting then that the February 2010 document shows 4.2m. It may be an error but is also repeated in the imperial equivalent of 13.78ft (BWB’s ridiculous use of decimalised imperial measurements not mine). As stated above that’s 13’ 9” expressed properly.

 

I don’t concur with the latter point, I think it’s just coincidence that the specific dimension concerned can be expressed as an integer. The same lack of accuracy isn’t present in the imperial equivalents or metric dimensions for other waterways. For clarity the metric dimensions would be better if they were all expressed to same number of decimal points and imperial measurements to the nearest inch including when it’s 0”.

 

JP

[NigelMoore]

8 minutes ago, Alan de Enfield said:

 

 

Is this the one ?

 

 

Dredging Depths and widths.xls 112 kB · 2 downloads

Yes – thanks Alan. The 2011 discussion paper that refers to the spreadsheet describes the content & work that went into it -

 

"The spreadsheet has individual lines for data on each canal and river navigation, and where it has been possible to do so, for individual sections of each navigation.

 

Cols 4 to 7 represent previously used MOC dimensions back to 1998 showing how they have changed (if at all) over the years.  In some cases it has been possible to determine the logic that was used at the time to determine the most appropriate MOC dimension. There are no records of this process. However in other cases the logic that led to the chosen dimension cannot be determined.

Cols 8 to 12 represent the 1975 Fraenkel  Report dimensions of boats using the canals during a period of 9 months prior to the 1968 Transport Act. Cols 10, 11 and 12 show the calculated maintenance standard of width and depth, and the resultant dredge depth using the methodology outlined in that report.  and what they would mean for MOC

Cols 13 to 20 give published maximum craft dimensions from BW, Nicholsons, and Bradshaws.

Cols 21 to 27 show the summary results for minimum width and depth contained in BW’s 20099 pinch point data on which the current BW website is based.

Cols 28 to 31 represent the BW Head of Asset Management’s  interpretation and suggested MOC dimensions to be discussed, agreed and used by BW to compare with all future hydrographic survey data. The MOC dimension for each navigation will act as a trigger point to BW to indicate siltation problems in the navigation, and to commence the process of ancillary data gathering in preparation of developing and agreeing a dredging project."

 

( http://www.britishwaterways.co.uk/media/documents/meetings/wusig/WUSIG-MOC-dimensions-paper-April-2011.doc )

 

[NigelMoore]

10 minutes ago, Alan de Enfield said:

 

I may be being extremely dense but -

 

Maximum beam = 13ft 6 inches

Absolute maximum beam = 7ft.

 

I though maybe the 'absolute' is based on 2 of NB's, but obviously not as 2x 7ft = 14ft (not 13ft 6 inches)

 

I did a double-take on that seeming nonsense at first, myself. Then I realised that they must be referring to the maximum size (as in length) that could fit through a lock diagonally. Only the narrowbeams could do that. I think that is the explanation anyway.

[Captain Pegg]

16 minutes ago, Alan de Enfield said:

 

I may be being extremely dense but -

 

Maximum beam = 13ft 6 inches

Absolute maximum beam = 7ft.

 

I though maybe the 'absolute' is based on 2 of NB's, but obviously not as 2x 7ft = 14ft (not 13ft 6 inches)

Is this the one ?

 

 

Dredging Depths and widths.xls 112 kB · 3 downloads

For the umpteenth time this week I’ll bang on about the need to read dimensions in combination. Read the line above those dimensions in the document. The 13’ 6” dimension applies to a 70’ craft. There is an additional limit that permits a 72’ craft providing it has a beam of no more than 7’.

 

JP

 

ETA - presumably for the reasons Nigel mentioned while I was typing.

Edited May 4, 2019 by Captain Pegg

[TheBiscuits]

8 minutes ago, Captain Pegg said:

I don’t concur with the latter point, I think it’s just coincidence that the specific dimension concerned can be expressed as an integer. The same lack of accuracy isn’t present in the imperial equivalents or metric dimensions for other waterways. For clarity the metric dimensions would be better if they were all expressed to same number of decimal points and imperial measurements to the nearest inch including when it’s 0”.

I will bet it's compiled in an Excel spreadsheet and whoever did it was sloppy with the number formatting.

 

If you do not specify the number format you require, Excel displays 4.00 as 4 in a numeric cell.

[Captain Pegg]

1 minute ago, TheBiscuits said:

I will bet it's compiled in an Excel spreadsheet and whoever did it was sloppy with the number formatting.

 

If you do not specify the number format you require, Excel displays 4.00 as 4 in a numeric cell.

I suspect so.

 

 

[MtB]

And examining carefully the photo in Post 64, it looks as if the boat is jammed on the gates not the exit brickwork. There is even a sliver of daylight visible right at the bow. 

 

This would be consistent with the "Additional cruising notes" posted by Nigel, pointing out that most of the chambers may be 14ft wide, but not all the exit gates are. 

 

 

Edited May 4, 2019 by Mike the Boilerman

[Captain Pegg]

39 minutes ago, Alan de Enfield said:

I'm not sure that C&RT are capable of getting any dimension correct - they seem to have some strange idea's.

Maybe the 'tape measure holder' was on work experience and did not understand English measurements.

 

3 examples - Moorings :

 

Up to 64' 12" / 19.80m mooring at Knowle Bottom Lock L1

Drinking Water Elsan Disposal Refuse Disposal

Availability Occupied

Waterway Grand Union Canal

Maximum Length 64' 12" / 19.8m

Mooring Use Leisure

Distance 218.28 miles

 

Up to 21' 12" / 6.70m mooring at Knowle Bottom Lock L1

Drinking Water Elsan Disposal Refuse Disposal

Availability Occupied

Waterway Grand Union Canal

Maximum Length 21' 12" / 6.7m

Mooring Use Leisure

Distance 218.32 miles

 

Up to 63' 12" / 19.50m mooring at Foxton Bottom Basin L1

Car Parking Drinking Water Electricity Elsan Disposal Refuse Disposal

Availability Occupied

Waterway Grand Union Canal

Maximum Length 63' 12" / 19.5m

Maximum Draught 3' 3" / 1m

Maximum Width 6' 11" / 2.1m

Mooring Use Leisure

Distance 222.22 miles

Similarly I wonder if this arises because there is a piece of custom software used for compiling the adverts that demands a data entry for “inches” but can’t accept 0 as an input value.

 

JP

[NigelMoore]

8 minutes ago, Captain Pegg said:

For the umpteenth time this week I’ll bang on about the need to read dimensions in combination. Read the line above those dimensions in the document. The 13’ 6” dimension applies to a 70’ craft. There is an additional limit that permits a 72’ craft providing it has a beam of no more than 7’.

 

There is also a clue in the 'Additional Cruising notes' under the Reading to Newbury section, which explains that narrowboats over 70' can fit through shorter locks diagonally.

[TheBiscuits]

Of course these are the same documents that suggest there is a 4ft draught on the L&L from Leigh to Liverpool ...

 

I'd like to know where they found that depth, because I haven't!

[Captain Pegg]

4 minutes ago, Mike the Boilerman said:

And examining carefully the photo in Post 64, it looks as if the boat is jammed on the gates not the exit brickwork. There is even a sliver of daylight visible right at the bow. 

 

This would be consistent with the "Additional cruising notes" posted by Nigel, pointing out that most of the chambers may be 14ft wide, but not all the exit gates are. 

 

 

You’re still determined to find an alternative cause aren’t you? ?

 

I have no idea how you can see that from the photo. As others have pointed out the important feature is probably below the waterline.

 

JP

[MtB]

4 minutes ago, Captain Pegg said:

You’re still determined to find an alternative cause aren’t you? ?

 

I have no idea how you can see that from the photo. As others have pointed out the important feature is probably below the waterline.

 

JP

 

And you seem equally determined to blame CRT with no evidence. 

 

Stupid way to build a boat, wider below the waterline than above. IF they did....

 

 

[magnetman]

17 minutes ago, Captain Pegg said:

the important feature is probably below the waterline.

 

JP

Well yes lock gates do generally flex a little above the water even if they have something below the water preventing them from opening fully. Its the nature of the lock gate structure to be moderately flexible. 

 

Is it also in the nature of boats with big engines (120hp?) to suddenly run out of fuel when being operated at idle as you would obviously do when attempting to exit a lock in a boat which is within a gnats whisker of the published dimensions. 

 

Or is the real story perhaps that person driving boat revved the <word removed> out of it hoping to force it through the fouled gates only to get stuck when it got to the bit where the boat fabricator added an extra rubbing strake before turning the plating in to the stern? 

 

Fouled gates.

Edited May 4, 2019 by magnetman

[Captain Pegg]

14 minutes ago, Mike the Boilerman said:

 

And you seem equally determined to blame CRT with no evidence. 

 

Stupid way to build a boat, wider below the waterline than above. IF they did....

 

 

I haven’t blamed CRT but I didn’t expect to find the published dimensions varying in the manner they have and in that context I don’t think there should be references to the boat being wider than the published dimensions when in comparison to those published between 2010 to 2014 it wasn’t and given CRT themselves are very circumspect about the accuracy of what they publish in any case. Tolerance works both ways so they have to be prepared for the odd cock-up by the nature of their approach.

 

I do think CRT could have a better - or perhaps more transparent - strategic approach to maintaining dimensions. I also note that 7’ dead seems to be a default for all narrow canals. I’d like to see some improvement in the way things are done. I work on the basis CRT wish to improve rather than they are engaged in a conspiracy against boaters. I’m an active supporter but that doesn’t mean I think they are infallible. Public bodies must be accountable. I have some very significant professional experience of exactly the sort of issues raised here only with millions of pounds attached to the outcome.

 

JP

Edited May 4, 2019 by Captain Pegg

[Captain Pegg]

1 hour ago, Mike the Boilerman said:

 

 

 

Stupid way to build a boat, wider below the waterline than above. IF they did....

 

 

 

55 minutes ago, magnetman said:

Well yes lock gates do generally flex a little above the water even if they have something below the water preventing them from opening fully. Its the nature of the lock gate structure to be moderately flexible. 

 

Is it also in the nature of boats with big engines (120hp?) to suddenly run out of fuel when being operated at idle as you would obviously do when attempting to exit a lock in a boat which is within a gnats whisker of the published dimensions. 

 

Or is the real story perhaps that person driving boat revved the <word removed> out of it hoping to force it through the fouled gates only to get stuck when it got to the bit where the boat fabricator added an extra rubbing strake before turning the plating in to the stern? 

 

Fouled gates.

That’s new information to me; have I missed it on the thread?

 

Assuming that this isn’t the only K&A lock that the boat has ever been through in its current condition then the lock it is still a pinch point and potentially one that has led to a (hopefully temporary) reduction in the capability of the K&A.

 

I note that when a heritage boat has a go at pushing through but gets stuck in one of the known pinch points on one of the canals that are technically narrower than the boats concerned and needs extricating it becomes the stuff a good story on the forum or on a blog. There’s seemingly a different reaction to an incident on the K&A but I don’t see a whole lot different about the circumstances in which this boat got stuck. Boat’s a bit wide, lock’s a bit narrow. It happens.

 

JP

Edited May 4, 2019 by Captain Pegg

[Murflynn]

9 hours ago, Captain Pegg said:

Interesting then that the February 2010 document shows 4.2m. It may be an error but is also repeated in the imperial equivalent of 13.78ft (BWB’s ridiculous use of decimalised imperial measurements not mine). As stated above that’s 13’ 9” expressed properly.

 

 

nothing ridiculous about that.

 

in the surveying and large scale construction industries, all measurement was in feet using the decimal system until full scale metrication took over.

there was no other way to do it.

you try to use 7 figure log tables to do surveying calculations when some twit has measured the distance as 1,056ft - 8and13/32inches.

that is exactly what I had to do when I joined the industry in the 60's.

all serious accurate measuring tapes and levelling staffs were graduated in decimal parts of a foot.

[Captain Pegg]

6 minutes ago, Murflynn said:

nothing ridiculous about that.

 

in the surveying and large scale construction industries, all measurement was in feet using the decimal system until full scale metrication took over.

there was no other way to do it.

you try to use 7 figure log tables to do surveying calculations when some twit has measured the distance as 1,056ft - 8and13/32inches.

that is exactly what I had to do when I joined the industry in the 60's.

all serious accurate measuring tapes and levelling staffs were graduated in decimal parts of a foot.

Yikes, glad I’m young enough never to have surveyed in imperial; other than I have done chain surveying.

 

It seems counter intuitive but I guess you get used to it and it becomes instinctive, which is part of the reason why debates about whether imperial or metric is ‘best’ are a bit nonsensical.

 

For general public consumption using feet and inches would be better communication.

 

JP

[StephenA]

So we've got into an indepth argument/discussion over lock dimensions but do we actually know what happened at the lock?

[Alan de Enfield]

16 minutes ago, StephenA said:

So we've got into an indepth argument/discussion over lock dimensions but do we actually know what happened at the lock?

An ugly fat boat got stuck.

[MtB]

6 minutes ago, Alan de Enfield said:

An ugly fat boat got stuck.

 

An ugly fat boat with masses of living space (according to the sales brochure) got stuck.