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Grand Union air draught


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47 minutes ago, Bronco99 said:

Funny how there are lots of maps available for wide beam waterways, of which GU is one, but they never factor in beam/headroom together. Something that, with all these arched bridges and increasing widebeam cruisers looking to explore those waterways, I'd have thought might be starting to be compiled. 

Even way back into the 60's the 'maximum dimensions' were quoted as not referring to the 'same boat' (see 'notes' RH column)

 

It would take 'dozens' of columns in a table to cover all permutations.

 

 

 

Screenshot (135).png

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The statutory dimensions figures (Long Buckby to Camp Hill locks) give 8' air draft over a 8' width. However, this would be the max dimensions of craft using this stretch of Canal in 1967 and the dimensions that have to be maintained by law rather than what is achievable. 

Regarding the imperial/metric differences,  here is just one of the responses from CRT when I queried why they kept changing a document (dated July 2020) that they purported to contain statutory dimensions unchanged since 2012 when BW became CRT -
 

Quote

- File2 to File3 - "To confirm the update made in October was to update a conversion from Imperial to metric measurements which needed to be tweaked slightly."

 

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10 minutes ago, Alan de Enfield said:

Even way back into the 60's the 'maximum dimensions' were quoted as not referring to the 'same boat' (see 'notes' RH column)

 

It would take 'dozens' of columns in a table to cover all permutations.

 

 

 

Screenshot (135).png

Yeah. At least this table does refer to the max superstructure dimensions as well as air draught. If CRT did that nowadays you'd have a much better idea if you had clearance rather than just max height at highest point in relation to beam. 

 

But the pub looks handy. and there's a couple of marinas close by. Anyone know of a slipway in those parts?

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6 minutes ago, Bronco99 said:

Yeah. At least this table does refer to the max superstructure dimensions as well as air draught. If CRT did that nowadays you'd have a much better idea if you had clearance rather than just max height at highest point in relation to beam. 

 

The air-draft is the superstructure height.

The static-draught is the 'boats (water) draught'

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1 hour ago, john6767 said:

The bridge at the Blue Lias at Stockton (Stockton Lane Bridge 23) is, low, on the skew, very rounded, not that wide, and the towpath sticks out quite a bit.  You have to be very careful with a narrowboat, and there are plenty of chunks out it from people who were not careful!

 

Not the best photo, from canalplan

7cpf_0.jpg

Lifted the chimney on a friends boat going through there, good old sea searcher

 

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Just now, Bronco99 said:

Yeah. At least this table does refer to the max superstructure dimensions as well as air draught. If CRT did that nowadays you'd have a much better idea if you had clearance rather than just max height at highest point in relation to beam. 

 

But the pub looks handy. and there's a couple of marinas close by. Anyone know of a slipway in those parts?

Kate Boats at the other end of the locks has a slipway. However, this tends not to be used as they crane in and out using local firm Tuckeys who also do boat transport.

With regard to superstructure dimensions, The ones given by Alan are the statutory dimensions converted to metric. BW and CRT have only ever published air draft.

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3 hours ago, Bronco99 said:

Please, please help if you have direct experience with this rather than, like me, loads of reading up, official and unofficial specs and guidelines and tips on revving with bins full of water! 

I want to get up the Grand Union main line from Bulls Bridge as close to the Warwick Cape locks as possible. I know what the CRT specs say and I know how they differ to other publications and chatter in pubs etc. 

I have a height of 7" (wheelhouse off, square cockpit screens). Lets assume a chart datum water level and take into account my 9" beam for the arched bridges.

Does anyone have any actual experience of attempting this passage with a similar air draught. 

If it really isn't possible then how far north IS it possible to get?

Really appreciate some first hand knowledge of this, recent if possible but all welcome.

Cheers all.

Screenshot_20201111-184611 (2).png

7 inch height and 9 inch beam should be no issue. IMHO. lol. “= inch ‘= feet

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6 minutes ago, Alan de Enfield said:

 

The air-draft is the superstructure height.

The static-draught is the 'boats (water) draught'

Yes I know, I said at least the chart refers to the superstructure DIMENSIONS as well as the air draught. Meaning it gives an idea of how wide as well as high the superstructure of a vessel is, thus giving a useful reference for safely passing underneath the structure, especially arched bridges.

Just been looking at Kate Boats. I'll enquire but I find private hire and even marinas are very arsey about passing trade. No idea why.

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13 minutes ago, Bronco99 said:

Yes I know, I said at least the chart refers to the superstructure DIMENSIONS as well as the air draught. Meaning it gives an idea of how wide as well as high the superstructure of a vessel is, thus giving a useful reference for safely passing underneath the structure, especially arched bridges.

Just been looking at Kate Boats. I'll enquire but I find private hire and even marinas are very arsey about passing trade. No idea why.

Kate Boats do maintence and boat building at Stockton Top marina, and use the slipway there for private boats as well as their hire boats.  There is also a slipway at Calcutt Boats a couple of miles towards Napton Junction from Stockton.

 

Anglo Welsh was mentioned in relation to Stockton Top, I think it the case that there are a few Anglo Welsh boats based there that are turned round by Kate Boats, there is not an Anglo Welch facility as such there.

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45 minutes ago, john6767 said:

Kate Boats do maintence and boat building at Stockton Top marina, and use the slipway there for private boats as well as their hire boats.  There is also a slipway at Calcutt Boats a couple of miles towards Napton Junction from Stockton.

 

Anglo Welsh was mentioned in relation to Stockton Top, I think it the case that there are a few Anglo Welsh boats based there that are turned round by Kate Boats, there is not an Anglo Welch facility as such there.

Not sure if Calcutt slip and marina entrance are suitable for widebeams. 

 

With regard to Anglo Welsh,  Kate Boats started to turn round boats for the 'big boys' after the collapse of OwnerShips (the shared ownership company). 

 

Stockton Top marina can take widebeams (and has!) but is rather shallow with a lip on the entrance. I'm not sure that Tuckey's crane or transport can cope.

 

 

 

 

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13 minutes ago, Allan(nb Albert) said:

 

Stockton Top marina can take widebeams (and has!) but is rather shallow with a lip on the entrance. I'm not sure that Tuckey's crane or transport can cope.

 

 

Of course not, it's not them that lift all the widebeams out of and back into Crick at every festival, and deliver virtually everything wide Collingwood send out. They have 2 cranes, biggest one is 100T.

 

Edited by matty40s
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27 minutes ago, matty40s said:

Of course not, it's not them that lift all the widebeams out of and back into Crick at every festival, and deliver virtually everything wide Collingwood send out. They have 2 cranes, biggest one is 100T.

 

I was refering to the only wide beam lift of which I am aware at Stockton Top which Tuckeys could not do. 

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13 minutes ago, Allan(nb Albert) said:

I was refering to the only wide beam lift of which I am aware at Stockton Top which Tuckeys could not do. 

If you are talking Balhalla, there is a story behind that.

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2 minutes ago, matty40s said:

If you are talking Balhalla, there is a story behind that.

If you mean Valhalla the narrowboat or Valhalla the widebeam (both built by Kate Boats) that is not what I was refering to.

 

.... although there is certainly a story there ...

 

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11 hours ago, Allan(nb Albert) said:

Not sure if Calcutt slip and marina entrance are suitable for widebeams. 

 

With regard to Anglo Welsh,  Kate Boats started to turn round boats for the 'big boys' after the collapse of OwnerShips (the shared ownership company). 

 

Stockton Top marina can take widebeams (and has!) but is rather shallow with a lip on the entrance. I'm not sure that Tuckey's crane or transport can cope.

 

 

 

 

Calcutt marina entrance can not take14 foot ones hence the one moored in the lock pound.  But as this boat is 9 foot that should be no problem at all and will easily fit.

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11 hours ago, Allan(nb Albert) said:

If you mean Valhalla the narrowboat or Valhalla the widebeam (both built by Kate Boats) that is not what I was refering to.

 

.... although there is certainly a story there ...

 

Actually, both of us were talking about Walhalla

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14 hours ago, Alan de Enfield said:

Even way back into the 60's the 'maximum dimensions' were quoted as not referring to the 'same boat' (see 'notes' RH column)

 

It would take 'dozens' of columns in a table to cover all permutations.

 

 

 

Screenshot (135).png

It requires some kind soul to undertake a measured survey of each bridge; realistically 2D would be a very good start.  By overlaying the the profile of your craft, you could see if it passes.

 

If the underwater profile was measured too (more tricky) you could tinker with the hypothetical water levels too - to ascertain whether you needed to drain or flood the pound or, perhaps your boat, depending on who is watching.

 

A mammoth task to measure all the bridges - but much less so if you commenced with the most restricted ones.

 

 

 

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Just spoke to Calcutt. Happy to accommodate my 9' (that's feet, right?) for a 50 quid fee. Seems like a lovely place. I was watching Tim & Pru last night who kept their nb there and were visiting the festival at Braunston. Little chance we'll all be happily jabbed and that will be on in 2021 but I'd love to experience it.

 

Hopefully I'll get as far as there without incident and my tow can then get me down to Stratford for the onward leg.

 

Invaluable advice, thanks. Sorry if I struggle occasionally with a perception of patronising piss-takes. It's all good banter and we're all up against it atm.

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20 hours ago, Bronco99 said:

 

Screenshot_20201111-184611 (2).png

 

It's not just the tight bridges that have already been mentioned though. With a boat that size and shape you will be worrying about every arched bridge you come to. Too close one side and you scrape your grp hull against the towpath wall, too close the other side and you scrape the grp fly bridge against the bridge arch. Steel boat owners may be prepared to risk scratching their paintwork; grp owners are much less likely to accept the corresponding damage.

Blisworth and Braunston tunnels could be a nightmare , even though the need to book a wide beam passage does at least mean you shouldn't meet someone coming the other way.

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