Rochdale Canal reduced dimensions

[cuthound]

8 hours ago, Midnight said:

Just a thought. Considering the trouble C&RT were having with the M62 floating walkway I wonder have they decided they won't be moving it again? In which case the new dimensions are correct.

 

Perhaps they can consider installing something similar for the A45 Bridge just north of Braunston?

[Francis Herne]

A much clearer, and sensible, message from CRT this morning, having quoted the one above and asked the obvious questions:

 

"Further to your email regarding the maximum beam on Rochdale Canal,
the narrower width relates to the M62 tunnel with the floating towpath
in situ.

With sufficient notice this can be removed and then the pinch points
become the narrow locks such as Punchbowl (13ft 6 inches). The 9ft
5inches is the maximum beam for boats to pass without a booking for
the M62 tunnel. Larger craft can navigate under the M62 tunnel, but
this requires the floating towpath to be moved. Hence the unrestricted
dimension is 9ft 5inches.

This is detailed on the Notices and Stoppages page of our website
which can be found via the following link:
https://canalrivertrust.org.uk/notices/2499-floating-towpath-rochdale-canal-under-the-m62

I hope this helps to clarify the matter.

Regards, [name]"

 

It looks like there's no change in policy, just the usual fuzzy knowledge of their own infrastructure.

[David Mack]

2 hours ago, Francis Herne said:

Hence the unrestricted
dimension is 9ft 5inches.

Still not the whole story. The unrestricted dimension is 9ft 5ins at the M62 tunnel, but for the rest of the canal it is still 13ft or more.

[Francis Herne]

1 minute ago, David Mack said:

Still not the whole story. The unrestricted dimension is 9ft 5ins at the M62 tunnel, but for the rest of the canal it is still 13ft or more.

Right. I did reply along those lines. The dimension of canals with swing bridges isn't set at 2ft air draft!

[David Mack]

34 minutes ago, Francis Herne said:

Right. I did reply along those lines. The dimension of canals with swing bridges isn't set at 2ft air draft!

And do CRT quote an unrestricted width of 7ft on the whole of the GU from Brentford to Camp Hill on the basis that wider craft have to book passage through Blisworth and Braunston tunnels?

[IanD]

2 minutes ago, David Mack said:

And do CRT quote an unrestricted width of 7ft on the whole of the GU from Brentford to Camp Hill on the basis that wider craft have to book passage through Blisworth and Braunston tunnels?

Presumably not because there's no physical restriction or need for CART staff to turn out and spend most of a day moving a walkway, a wideboat could go through in the middle of the might and nobody would be any the wiser, booking or no booking...

 

If CART's database only allows one width figure to be given for a canal rather than splitting it down into lots of separate sections, what they're doing now is the right thing. A footnote or explanation would be better still, but people don't often read these...

[Jim Riley]

Latest email back regarding the misinformation, looks like it's being thought about

 

Good morning, 

 

Having reviewed your original email and with the correct information to hand I can fully understand your concerns regarding the published information.

 

I have sent over a request to our Web Content team asking for the restricted and unrestricted widths to be published with more clarity and this will be completed in due course. 

 

Thank you for raising this with us, i'm sure it will prove very helpful to boaters going forward. 

[Captain Pegg]

18 minutes ago, Jim Riley said:

Latest email back regarding the misinformation, looks like it's being thought about

 

Good morning, 

 

Having reviewed your original email and with the correct information to hand I can fully understand your concerns regarding the published information.

 

I have sent over a request to our Web Content team asking for the restricted and unrestricted widths to be published with more clarity and this will be completed in due course. 

 

Thank you for raising this with us, i'm sure it will prove very helpful to boaters going forward. 

Good work. It needs the correct information publishing to a useful level of detail.

[Jim Riley]

My initial email told them their info was the subject of much ridicule on a discussion forum. 

[Midnight]

28 minutes ago, Jim Riley said:

My initial email told them their info was the subject of much ridicule on a discussion forum. 

The whole C&RT management team is the subject of ridicule on a discussion forum 🤣

[dmr]

4 hours ago, Jim Riley said:

Latest email back regarding the misinformation, looks like it's being thought about

 

Good morning, 

 

Having reviewed your original email and with the correct information to hand I can fully understand your concerns regarding the published information.

 

I have sent over a request to our Web Content team asking for the restricted and unrestricted widths to be published with more clarity and this will be completed in due course. 

 

Thank you for raising this with us, i'm sure it will prove very helpful to boaters going forward. 

 

Well done, thats a good result, and well done to CRT for a sensible response.

[Richard Fairhurst]

CRT/BW have always struggled with dimension information. In the early 00s (or late 90s?) Paul Wagstaffe at BW worked with HNBOC on a document which is still the definitive ground-truthed list of what can fit where. Unfortunately it’s been reworked and replaced numerous times since.
 

I think there’s traditionally a confusion between “what fits though the structures”, “what are we prepared to support operationally this week”, and (most exasperatingly) “what is some half-remembered figure we saw somewhere once or copied down from an old Nicholsons”. The early 00s document was unusual in that it was very rigorously “what fits” and explained each individual pinch point. 

[Alan de Enfield]

2 minutes ago, Richard Fairhurst said:

I think there’s traditionally a confusion between “what fits though the structures”, “what are we prepared to support operationally this week”, and (most exasperatingly) “what is some half-remembered figure we saw somewhere once or copied down from an old Nicholsons”. The early 00s document was unusual in that it was very rigorously “what fits” and explained each individual pinch point. 

 

I believe one of the problems is how to quote 'what will fit' because of the 3-dimensional aspect of both boats and bridges.

 

So, whilst a 7 foot beam 7 foot air-draft NB might fit under a certain bridge, the same air-draft 10 foot widebeam may just scrape thru, whilst a 12 foot widebeam definitely will not.

 

 

 

As the Fraenkel Report ( 1968 I think) states :

 

 

 

 

 

[Tacet]

It's never going to be as simple as three dimensions unless understated to be on the safe side. 

 

As someone recently proved, some boats in some locks can pass forward in one direction but not the other.  And a boat shorter than the maximum dimensions can be a bit wider than otherwise and so on.

[dmr]

Dimensions can only ever be a rough guide, and canal depth changes from day to day, heavy rain can create little shoals, and shopping trollies are a big variable. Another factor is how much effort a boater is prepared to live with, for some just touching the bottom is a big issue. Our last trip up the Rochdale required a little bit of bow hauling by myself and the volunteer to get us over a significan shoal, but the Oxford summit also often gives us a little bit of trouble though the bottom is nice and soft.  Should the stated dimensions be for "trouble free" boating, or boating with a bit of effort and a few scrapes?