Northampton Arm - Actual width

[Ouse on Board?]

This may sound a strange request, but has anyone got the specific widths of the locks on the Northampton Arm? I know all the official guides and maps show the maximum boat beam to be 7ft however I was wondering (hoping) the locks might be a little wider at their narrowest point. 

[Alan de Enfield]

Northampton Arm Lock dimensions = 22.86m (Long) x 2.18m (Wide) x 1.15m(Cill depth)

[Ouse on Board?]

Thats very specific, thankyou

[Alan de Enfield]

Just now, Ouse on Board? said:

Thats very specific, thankyou

What size boat are you trying to get up there ?

[Ouse on Board?]

We're on the Great Ouse.  Long Story but Its a narrowboat, based on an old 1930s coal boat but overplated and with the rubbing strips etc shes a little wider than standard at 7ft2

[GUMPY]

I suspect the metric measurement is a conversion from 7'2" as its very close  to it.

[Keeping Up]

11 minutes ago, Alan de Enfield said:

Northampton Arm Lock dimensions = 22.86m (Long) x 2.18m (Wide) x 1.15m(Cill depth)

I'd agree that there's not much leeway over 7ft, but I'd be very surprised if there weren't at least a couple of inches to spare. The fact that CRT quote 2.18m doesn't necessarily mean they know the width to within +/- 1cm, it just means that somebody in the organisation knows how to calculate the metric equivalent of a nominal 7ft 2in.

[Ouse on Board?]

There is a little bit of me that says sod it lets just try it and see what happens, but its an embarrassing mistake when you end up blocking the lock or have to do a lot or reversing. 

[GUMPY]

I haven't heard about any historic boat getting stuck on the arm unlike other places on the system.

[robtheplod]

2 minutes ago, Ouse on Board? said:

There is a little bit of me that says sod it lets just try it and see what happens, but its an embarrassing mistake when you end up blocking the lock or have to do a lot or reversing. 

Are you the gambling type? 

[Phoenix_V]

We used to go up there in Bargus a Small Woolwich 7'1 and quite a bit

[Ouse on Board?]

Just now, Phoenix_V said:

We used to go up there in Bargus a Small Woolwich 7'1 and quite a bit

how much room did you have?

 

1 minute ago, robtheplod said:

Are you the gambling type? 

yeah why not

[Phoenix_V]

sorry don't know as  i wasn't on it at the time but would certainly have heard if there was a problem. Does your boat stick anywhere else?

[Ouse on Board?]

Just now, Phoenix_V said:

sorry don't know as  i wasn't on it at the time but would certainly have heard if there was a problem. Does your boat stick anywhere else?

never taken it in any narrow locks

[Phoenix_V]

a whole new world of excitement awaits,

 

I remember problems at Napton bottom, Worcester and Birmingham and on the Ashton and there was one of the paired locks on the Trent and Mersey where only one side was wide enough but lock walls tend to move over the seasons and pinch points come and go.

 

There are tricks like opening the top paddles to lift  you up as you go in but it is always a judgement as to how far to push it before becoming stuck fast and calling out CRT.

 

presumably it wasn't built on the Ouse and got there through the Nene at some point though.

 

a suggestion, join/ask the Historic Narrowboat Owners Club

[Scholar Gypsy]

@FadeToScarlet would know.

 

[Alan de Enfield]

39 minutes ago, Keeping Up said:

I'd agree that there's not much leeway over 7ft, but I'd be very surprised if there weren't at least a couple of inches to spare. The fact that CRT quote 2.18m doesn't necessarily mean they know the width to within +/- 1cm, it just means that somebody in the organisation knows how to calculate the metric equivalent of a nominal 7ft 2in.

The dimension I gave pre-dates C&RT by some considerable time.

[Captain Pegg]

3 hours ago, Ouse on Board? said:

There is a little bit of me that says sod it lets just try it and see what happens, but its an embarrassing mistake when you end up blocking the lock or have to do a lot or reversing. 

That is the only way you can answer your own question to the degree of accuracy you need if it’s going to be at all borderline.
 

The passage of a boat through a lock is a four dimensional puzzle and you can never solve it by studying just one of those dimensions. It’s incredibly difficult to solve it all with high levels of accuracy.

 

CRT quote maximum craft dimensions and these describe a theoretical 3D brick shape for which any craft that sits entirely within that shape should in theory be able to pass through the section of waterway concerned because CRT are legally obliged to maintain the waterway to enable such. It tells you nothing in absolute terms of the individual maximum lengths, widths and drafts that will fit in isolation.

 

My only caveat to that is that I suspect CRT don’t really understand the nature or accuracy of those dimensions apart from perhaps a small number of engineering staff sat in an office somewhere well removed from the day to day requirements of maintaining and operating the infrastructure outwith of those dimensions.

 

JP

Edited June 26, 2020 by Captain Pegg

[Phoenix_V]

to further add to the problem some locks and some boats are not straight but bannana shaped

[matty40s]

There are quite a few historics been up and down and none as far as I know have had any problems with the lock widths, just the normal empty pounds and weed further down.

[Mac of Cygnet]

Where are you going once (if) you get up?   Just don't try the Huddersfield Narrow or the Llangollen!  (Or has Hurleston been fixed now?)

[Phoenix_V]

8 minutes ago, Mac of Cygnet said:

Where are you going once (if) you get up?   Just don't try the Huddersfield Narrow or the Llangollen!  (Or has Hurleston been fixed now?)

he'll be fine on the Grand Union, North oxford BCN to name but a few

 

[Alway Swilby]

16 minutes ago, Mac of Cygnet said:

Where are you going once (if) you get up?   Just don't try the Huddersfield Narrow or the Llangollen!  (Or has Hurleston been fixed now?)

Hurleston bottom lock has been rebuilt and the coal boat Mountbatten can get through. But Richard on Mountbatten says that the next lock up is a bit tight.

[Ouse on Board?]

1 hour ago, Mac of Cygnet said:

Where are you going once (if) you get up?   Just don't try the Huddersfield Narrow or the Llangollen!  (Or has Hurleston been fixed now?)

Just thought it would be nice to open up a bit more of the network on the GU, i think going south would be ok though

[roland elsdon]

If it’s a grand union boat you should be fine. We can go everywhere pretty much, but on the southern Stratford we have to ask the volunteer lock keepers to step aside, and not get involved, as we descend very carefully and, have to perform various shenanigans, dropping and raising levels.

The other question is how did it get to the Nene in the first place?